Metabolities from Marine Sponges of the Genus Callyspongia: Occurrence, Biological Activity, and NMR Data.

The genus Callyspongia (Callyspongiidae) encompasses a group of demosponges including 261 described species, of which approximately 180 have been accepted after taxonomic reviews. The marine organisms of Callyspongia are distributed in tropical ecosystems, especially in the central and western Pacific, but also in the regions of the Indian, the West Atlantic, and the East Pacific Oceans. The reason for the interest in the genus Callyspongia is related to its potential production of bioactive compounds. In this review, we group the chemical information about the metabolites isolated from the genus Callyspongia, as well as studies of the biological activity of these compounds. Through NMR data, 212 metabolites were identified from genus Callyspongia (15 species and Callyspongia sp.), belonging to classes such as polyacetylenes, terpenoids, steroids, alkaloids, polyketides, simple phenols, phenylpropanoids, nucleosides, cyclic peptides, and cyclic depsipeptides. A total of 109 molecules have been reported with bioactive activity, mainly cytotoxic and antimicrobial (antibacterial and antifungal) action. Thus, we conclude that polyacetylenes, terpenoids and steroids correspond to the largest classes of compounds of the genus, and that future research involving the anticancer action of the species' bioactive metabolites may become relevant.

1. Introduction

The genus Callyspongia Duchassaing and Michelotti, 1864, belonging to the family Callyspongiidae and the order Haplosclerida, is structured in six subgenera: Callyspongia (Callyspongia) Duchassaing and Michelotti, Callyspongia (Cavochalina) Carter, Callyspongia (Cladochalina) Schmidt, Callyspongia (Euplacella) Lendenfeld, Callyspongia (Toxochalina) Ridley, and Callyspongia (Spinosella) Vosmaer [1,2]. This group of demosponges includes 261 described species and approximately 180 accepted by taxonomic review [3,4].

The marine organisms of Callyspongia are distributed in tropical ecosystems, especially in the Central and Western Pacific [1,5,6]. They can also be seen in regions of the Indian Ocean, the West Atlantic Ocean, and the East Pacific Ocean, such as Indonesia [4], the Red Sea [7,8], Cuba [3], Barbados [9], Brazil [10,11], and Ecuador [12]. Because of this, the great variety of species allows the existence of new studies, but it also generates a large amount of data, which can cause confusion in research due to the accumulation of information.

Sponge species have their particularities, but they also have common characteristics. Regarding sponges of the genus Callyspongia, their regular ectosomal tangential reticulation (formed mainly by primary and secondary spongin fibers, but also by tertiary ones) identifies them [13]. In general, marine organisms produce compounds with enormous diversity and structural complexity resulting from the chemical strategies of their secondary metabolism to adapt to the extreme and competitive conditions of the marine environment [14,15]. NMR spectroscopy is the most important tool for structural elucidation of natural products, and it have been efficiently used to characterize the complex marine-derived molecules [16]. A compilation of the 13C NMR data for a plant or animal genus optimizes the exhaustive structural elucidation process.

As confirmed by biological studies, Callyspongia’s species are very rich sources of bioactive compounds. Several classes of primary and secondary metabolites have been associated with the genus, such as fatty acids [17], alkaloids [18], steroids [19], nucleosides [20], peptides [4], polyacetylenes [21], and terpenoids [11]. Furthermore, molecules isolated from these species are found to present relevant biological activities, including antibacterial [7], antituberculosis [22], anti-inflammatory [19], antimalarial [23], and cytotoxic [7,12,24].

A respectable number of publications focusing on isolation, structural characterization, and bioactivity of species from the Callyspongia genus are reported in the literature. However, to the best of our knowlegment, the genus Callyspongia lacks in deeper discussion on structural aspects and biological activities. Therefore, this review aims to fill a relevant gap associated with the occurrence and frequency of several metabolites isolated from species from the Callyspongia genus in the last 40 years [25,26], as well as to present a prospection and compilation of Nuclear Magnetic Resonance (NMR) spectroscopy data of these molecules, which can be employed as a library for further studies. Additionally, this work presents a survey of their biological activities, which magnifies the relevance of the Callyspongia genus in relation to development in the field of natural products, and its significance in the development of nature-based bioactive compounds.

2. Chemical Aspects of Callyspongia species

NMR spectroscopy-based studies on Callyspongia unidentified species (Callyspongia sp.) along with other 15 identified species (C. abnormis, C. aerizusa, C. bilamellata, C. californica, C. diffusa, C. fibrosa, C. fistularis, C. flammea, C. implexa, C. lindgreni, C. pseudoreticulata, C. siphonella, C. spinosissima, C. truncata and C. vaginalis) resulted in the structural characterization of 212 isolated metabolites from different classes: polyacetylenes; terpenoids and steroids; alkaloids; simple phenols and phenylpropanoids; nucleosides; cyclic peptides and cyclic depsipeptides; polyketides; and miscellaneous.

These substances were described according to the extract used in the isolation, relevant structural characteristics, and the elucidation data based on NMR data. This information is presented in Tables S1–S8 together with additional information such as chemical formula, type of metabolite, one-dimensional NMR data, geographic location, and references related to the compound obtention in Callyspongia species. Regarding the 1D NMR data, the chemical shifts, the solvent and frequency used in process, and the coupling constant of all compounds, were investigated. In addition, although NMR was the only spectroscopic information reported in this study, mainly due to the large volume of data, other techniques were used in the primary studies to support structural identification and elucidation, such as: specific rotation, X-ray crystallography, Thin-Layer Chromatography (TLC), melting point, two-dimensional NMR spectroscopy, Mass Spectrometry (EM), and spectroscopy in the infrared (IR) and ultraviolet (UV) regions.

2.1. Polyacetylenes

The polyacetylenes aikupikanynes A (1), B (2) and C (3), D (4), E (5) and F (6) and octahydrosiphonochalyne (7) were isolated from methanol (MeOH) extract of Callyspongia sp., a red sea sponge [27]. Other metabolites were also isolated: callimplexen A (8) from Callyspongia implexa (MeOH/Dichloromethane (CH2Cl2) 1:1 extract) [28]; callyberynes A (9), B (10) and C (11) from Callyspongia sp. (MeOH/CH2Cl2 3:1 extract) [21]; 9 and 11 from Callyspongia truncata (MeOH extract) [29]; and the diacetylene Callydiyne (12) from Callyspongia flammea (MeOH extract) [30]. Polyacetylenes 1–12 (Figure 1 and Table S1) were elucidated by 1H and 13C NMR and have unsaturated hydrocarbon moieties associated with olefinic and alkynyl double and triple bonds, respectively. The only symmetrical compound is 12 and structures 4, 5 and 6 have characteristics of fatty acyls.

Figure 1

Structures of polyacetylenes isolated from Callyspongia species.

Six polyacetylene diols were obtained from studies based on Callyspongia genus. 14,15-dihydrosiphonodiol (13), Callyspongidiol (14) and siphonodiol (15) were isolated from Ethyl acetate (EtOAc) extract of Callyspongia sp. [31]; 13 and 15 from ethanol (EtOH) extract of Callyspongia lindgreni [32]; from these later, only 15 from Callyspongia lindgreni (CH2Cl2 extract) [33] and Callyspongia truncata (MeOH extract) [29]. Two isomeric structures were isolated from Callyspongia sp. (EtOH extract): (3S,18S,4E,16E)-eicosa-1,19-diyne-3,18-diol-4,16-diene (16a) and (−)-(4E,16E)-icosa-4,16-diene-1,19-diyne-3,18-diol (16b). Compound 16a has also been identified in Callyspongia pseudoreticulata (MeOH extract) [34,35]. In addition, callyspongendiol (17) was isolated from Callyspongia siphonella (CH2Cl2/MeOH 1:1 extract) [8,36], and Tetrahydrosiphonodiol (18) from Callyspongia lindgreni (EtOH extract) [32]. Polyacetylene Diols 13–18 are open chain unsaturated hydrocarbons (Figure 1 and Table S1) that have their structures elucidated by 1H and 13C NMR. The regiochemistry patterns for the two hydroxyls in the structures vary considerably depending on the metabolite, having close proximity in 13, 14, 15 and 18. Isomers 16a and 16b are the only structures with symmetric atom connectivity; they differ from each other according to the configuration of stereogenic centers.

A total of 12 polyacetylene alcohols were obtained from Callyspongia species: (3R,4E,28Z)-hentriacont-4,28-diene-1,23,30-triyn-3-ol (19), Callyspongenols A (20), B (21), C (22) and D (23), Callysponynes A (24) and B (25), dehydroisophonochalynol (26), siphonellanols A (27), B (28) and C (29) and siphonchalynol (30) (Figure 1 and Table S1). Studies involving Callyspongia sp. afforded different metabolites depending on the solvent used in the extraction: acetone (19) [37], MeOH/CH2Cl2 1:1 (20–22 and 26) [38] and EtOAc (24 and 25) [39] extracts; while those related to Callyspongia siphonella were obtained from MeOH/CH2Cl2 1:1 (23 and 26) [8,36] and MeOH (26–30) [40] extracts. The polyacetylene alcohols were elucidated by 1H and 13C NMR, but only 19–29 present elucidative data.

Studies involving Callyspongia truncata resulted in obtaining the acetylenic sulfate fatty acid callysponginol sulfate A (31) from a mixture of H2O, MeOH, CHCl3, and EtOAc extracts [41]. The methanolic extract provided callyspongins A (32) and B (33) [29,42], as well as callytriols A (34), B (35), C (36), D (37), and E (38) [29]. The polyacetylene lipids callyspongynes A (39) and B (40) were also isolated from an ethanolic extract of Callyspongia sp. [43]. The metabolites 32–40 were elucidated by 1H and 13C NMR and have an oxygenated and unsaturated aliphatic structure with double and triple bonds (Figure 1 and Table S1). Compounds 32 and 33 are derived from siphonodiol and along with 31 are classified as sulfated compounds. Metabolites 34–38 have three hydroxyls, while 39 and 40 are simple monoalcohol.

Four metabolites were isolated from ethanolic extracts from different species: (6Z,9Z,12Z,15Z)-1,6,9,12,15-octadecapenten-3-one (41) (Callyspongia sp.) [17], (4Z,7Z,10Z,13Z)-4,7,10,13-hexadecatetraenoic acid (42) (Callyspongia sp.) [17], petroselenic acid (43) (Callyspongia siphonella) [7], and callyspongynic Acid (44) (Callyspongia truncata) [44]. In addition, glycerolipid 3-octadecyloxy-propane-1,2-diol (45) was obtained from 95% EtOH + MeOH/CH2Cl2 1:1 extracts [45], and batyl alcohol (46) from methanolic extract, both from Callyspongia fibrosa [23]; the polyacetylenic amide callyspongamide A (47) was isolated from Callyspongia fistularis (MeOH/CH2Cl2 1:1 extract) [46,47,48]. Among the elucidated compounds, only 41, 44, 45, and 47 have 1H and 13C NMR data reported. Compound 46 was characterized by 1H NMR only, while 41 and 44–47 present the spectroscopic data. The metabolites are structurally distinct, but some similarities are visible (Figure 1 and Table S1). Substance 41 has a conjugated ketone system, while 42–44 have carboxyl groups, among which 44 also has a hydroxyl unit. Glycerolipids 45 and 46 are the only saturated compounds having hydroxyls and ether oxygen, with the only structural difference between them being the presence of an additional methylene unit in 45. Double and triple bonds, an aromatic unit, and an amide form compound 47.

2.2. Terpenoids and Steroids

The diterpenes callyspinol (48) and isocopalanol (49) were isolated, respectively, from Callyspongia spinosissima (MeOH extract) [49] and Callyspongia sp. (acetone extract) [50]. Compounds 48 and 49 were elucidated by 1H and 13C NMR and are structurally different (Figure 2 and Table S2): 48 has only one ring and a double bond, and is monooxygenated, while 49 has a three-membered ring and is saturated and polyoxygenated. Four Callyspongia sp. triterpenes were also isolated: akaterpin (50) from an acetone extract [51] and ilhabelanol (51), ilhabrene (52), and isoakaterpin (53) from an extraction with EtOH followed by MeOH [11]. The molecules 50–53 (Figure 2 and Table S2) were characterized by 1H and 13C NMR and they are oxygenated, sulfated, and formed by cyclic and aromatic units.

Figure 2

Structures of terpenoids and steroids from Callyspongia species.

A total of 38 sipholane triterpenoids were isolated from Callyspongia sipholena (Siphonochalina Siphonela): (2S,4aS,5S,6R,8aS)-5-(2-((1S,3aS,5R,8aS,Z)-1-hydroxy-1,4,4,6-tetramethyl-1,2,3,3a,4,5,8,8a-octahydroazulen-5-yl)-ethyl)-4a,6-dimethyloctahydro-2H-chromene-2,6-diol (54) [52]; dahabinone A (55) [53]; neviotives A (56) [54,55,56,57], B (57) [53], C (58) [55], and D (59) [57]; sipholenols A (60) [7,8,25,55,56,57,58,59,60,61], B (61) [61], C (62) [61], D (63) [61], E (64) [61], F (65) [53], G (66) [53], H (67) [53], I (68) [59], J (69) [52], K (70) [52], L (71) [55], L (72) [8,52,56], M (73) [52], N (74) [57], and O (75) [57]; sipholenones A (76) [7,8,25,55,56,58,59,60,61], B (77) [61], C (78) [61], D (79) [53], and E (80) [52]; sipholenosides A (81) [53] and B (82) [53]; siphonellinol (83) [62] and siphonellinols B (84) [53], C (85) [59], C-23-hydroperoxide (86) [52], D (87) [52,57], and E (88) [52]. The extracts studied were: EtOAc (54, 60, 69, 70, 72, 73, 76, 80, and 86–88), EtOAc/MeOH 1:1 (55, 57, 65–67, 79, 81–82, and 84), petroleum ether (60–64, 76–78, and 83), chloroform (56), CH2Cl2/MeOH 1:1 (56, 58, 60, 71, 72, and 76), MeOH (60, 68, 76, and 85), EtOH (56, 59, 60, 74–76, and 87) and EtOH 70% (56, 60, 72, and 76) extracts. Molecules 63 and 67 present elucidating 1H NMR data, and the other metabolites are fully characterized by both 1H and 13C NMR. Sipholane triterpenoids have distinct structures (Figure 2 and Table S2), which are composed of monocyclic and polycyclic rings, unsaturation, epoxy oxygen, ether, alcohol, and carbonyls.

Fifteen sterols were isolated from Callyspongia species: 24S-24-methyl-cholestane-3β,5α,6β,25-tetraol-25-mono acetate (89), 24S-24-methyl chelestane-3β,5α,6β,12β,25-pentaol-25-O-acetate (90), 24S-24-methyl cholest-25-ene-3β,5α,6β,12β-tetrol (91), 24S-24-methyl cholestane-3β,6β,25-triol-25-O-acetate (92), 24S-24-methyl cholestane-3β,6β,8β,25-tetraol-25-O-acetate (93) and 24S-24-methylcholesterol (94), 5α-cholestanone (95), callysterol (96 and 97) or ergosta-5,11-dien-3β-ol (97), cholestenone (98), Stigmasta-4,22-dien-3,6-dione (99), stigmasterone (100), gelliusterol E (101), β-sitosterol (102), siphonocholin (103), and ergosta-5,24(28)-dien-3β-ol (104). The obtainment of these metabolites is associated with the following extracts: 89–94 to MeOH extract from Callyspongia fibrosa [23]; 95, 96 [7], 98–100 [7], and 103 [63,64] to EtOH extract from Callyspongia siphonella; 97 [19] and 104 [8] to MeOH/CH2Cl2 1:1 extract from Callyspongia siphonella and, 101, and 102 to MeOH/CH2Cl2 1:1 extract from Callyspongia implexa [28]. Compounds 89–94, 97, and 101 were elucidated by 1H and 13C NMR, while remaining compounds of this set do not present NMR data, but are compared with information from other studies. These compounds are four-ring sterols (Figure 2 and Table S2), with 89–103 being formed by three six-membered rings and one of five, while in 104 a four six-membered ring system is present.

2.3. Alkaloids

Several alkaloids were isolated and properly characterized from Callyspongia species. The bromopyrrole alkaloids 2-bromoaldisine (105), callyspongisines A (106), B (107), C (108), and D (109) and hymenialdisine (110) were obtained from the hydroalcoholic extract from Callyspongia sp. [65]. The bicyclic structures of compounds 105–110 were elucidated by 1H and 13C NMR and are formed by a seven-membered cyclic amide and a pyrrole attached to a bromine atom (Figure 3 and Table S3).

Figure 3

Structures of alkaloids isolated from Callyspongia species.

Some alkaloids were obtained from EtOH 95% extract of Callyspongia sp.: callyimine A (111) [18], callylactam A (112) [18], clathryimine B (113) [18], 3-(2-(1H-indol-3-yl)-2-oxoethyl)-5,6-dihydropyridin-2(1H)-one (114) [18], 3-(2-(4-hydroxyphenyl)-2-oxoethyl)-5,6-dihydropyridin-2(1H)-one (115) [18], (1R,3R)-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (116a) [66], (1R,3S)-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (116b) [66], C2-α-D-mannosylpyranosyl-tryptophan (117) [66], Ethyl 2-(1H-indol-3-yl) acetate (118) [67], and the indol derivative 1H-indole-3-carbaldehyde (119) [67] (Figure 3 and Table S3). Molecules 111 and 113 are structurally similar due to the presence of aromatic rings and nitrogen as a heteroatom, while 112 and 115 are only differentiated by the presence of a hydroxyl group in 115; and the structures 114 and 116a-119 are formed by an indol heterocycle. Metabolites 111–119 not present NMR data, but compare with information from others studies.

The isomers 5-bromo trisindoline (120) and 6-bromo trisindoline (121) were isolated from the ethanolic extract of Callyspongia siphonella [7], and they are differentiated by the position of bromine in the aromatic ring of the indole unit of the molecules. In addition, from Callyspongia sp. were isolated the untenines A (122), B (123), and C (124), from the methanolic extract [68], and niphatoxin C (125), from the mixture of CH2Cl2/MeOH 4:1 and MeOH extracts [69]. The 122–125 structures have the pyridine group in the molecule. Metabolites 120–125 (Figure 3 and Table S3) were determined by 1H and 13C NMR.

Studies of some sponges Callyspongia sp. resulted in the isolation of Callysponine (126), cyclo-(S-Pro-R-Tyr) (127), cyclo-(S-Pro-R-Val) (128), cyclo-(S-Pro-R-Ala) (129), cyclo-(S-Pro-R-Leu) (130), callysponine A (131), cyclo-(Gly-Pro) (132), cyclo-(Ile-Pro) (133), cyclo-(Pro-Pro) (134), cyclo-(Thr-Pro) (135), cyclo-(R-Pro-6-hydroxyl-R-Ile) (136), cyclo-(R-Pro-R-Phe) (137), cyclo-(R-Tyr-R-Phe) (138), cyclo-(S-Pro-S-Phe) (139), Staphyloamide A (140), dysamide A (141), callyspongidipeptide A (142), cyclo-((S)-Pro-(R)-Ile) (143), seco-((S)-Pro-(R)-Val) (144), (3R)-methylazacyclodecane (145), and callyazepin (146) (Figure 3 and Table S3). The analyzed metabolites were obtained from the following extracts: EtOH for 126–130 [70] and 141 [6], EtOH 95% for 129 and 130 [66,71], 136–140 [66] and 142–144 [71], EtOH/H2O 9:1 for 131–135 [72,73,74,75,76,77,78,79], and MeOH + CH2Cl2 for 145 and 146 [5]. Only 126, 130, 131, 136, 141, 142, and 144–146 present 1H and 13C NMR data. The structures of 138, 141, 144, and 145 are monocyclic, while 126–137, 139, 140, 142, 143, and 146 are bicyclic.

2.4. Simple Phenols and Phenylpropanoids

2-Phenylacetamide (147) and ρ-methoxyphenylacetic acid (148) were isolated from the 95% ethanolic extract of Callyspongia sp. [67] and 4-hydroxybenzoic acid (149) from the mixture of 95% MeOH/CH2Cl2 1:1 and EtOH extracts of Callyspongia fibrosa [45]. The metabolites 147–149 were elucidated by 1H NMR, but only 1 by 13C NMR (Table S4). All benzenoids have a substituted aromatic monocyclic structure (Figure 4).

Figure 4

Structures of simple phenols and phenylpropanoids isolated from Callyspongia species.

Other metabolites were isolated from Callyspongia’s species: 4-hydroxyphenylacetic acid (150), (E)-4-(4-hydroxyphenyl)-3-buten-2-one (151), phenylalanine (152), 3,5-dibromo-4-methoxyphenylacetic acid (153), 3,5-dibromo-4-methoxyphenylpyruvic acid (154), callyspongic acid (155), N-acetyl-3,5-dibromo-4-hydroxyl phenylethamine (156), and N-acetyl-3-bromo-4-hydroxyphenylethamine (157). The metabolites 150–152 were obtained from 95% hydroalcoholic extracts [67] and 153–157 from combination of extracts MeOH/CH2Cl2 [80], all from Callyspongia sp. The metabolites were elucidated by 1H and 13C NMR; however, only 151, 153–155, and 157, present the spectroscopic data. The compounds 150 and 151 are phenol derivatives, 152 is an amino acid, and 153–157 are bromotyrosine derivatives (Figure 4 and Table S4).

2.5. Nucleosides

A total of 11 nucleosides was obtained from Callyspongia species (Figure 5 and Table S5): the diazines 1H-pyrimidine-2,4-dione (158) and 5-methylpyrimidine-2,4 (1H, 3H)-dione (159), the pyrimidine nucleosides 1-(4-hydroxy-5-hydroxymethyl-tetrahydro-furan-2-yl)-5-methyl-1H-pyrimidine-2,4-dione (160), 1-(2’-deoxy-α-D-ribofuranosyl)thymine (161), 2’-deoxyuridine (162), spongothymidine (163) and spongouridine (164), the purine nucleosides 2’-deoxyadenosine (165) and 2’-deoxyinosine (166), and the triazole ribonucleosides 1-(2’-deoxy-β-D-erythro-pentofuranosyl)-1H-1,2,4-triazole (167) and 1-(β-D-ribofuranosyl)-1H-1,2,4-triazole (168). The metabolites 158–160 were isolated from the mixture of EtOH 95% and CH2Cl2/MeOH extracts of Callyspongia fibrosa [45], while 161–168 were isolated from EtOH 90% extract of Callyspongia sp. [20]. The structures were elucidated based on 1H and 13C NMR data. Nucleosides 158–164 were characterized by the presence of pyrimidine (or 1,3-diazine) units, while 165 and 166 contain purine units in their structures, and 167, 168 were characterized as 1,2,4-triazole derivatives.

Figure 5

Structures of nucleosides isolated from Callyspongia species.

2.6. Cyclic Peptides and Cyclic Depsipeptides

The structures of a series of 16 Callyaerins were elucidated by 1H and 13C NMR in research exploring Callyspongia aerizusa: callyaerins A (169), B (170), C (171), D (172 and 173), E (174), F (175 and 176), G (177 and 178), H (179), I (180), J (181), K (182), L (183), and M (184). Compounds 169–172, 174, 175, and 179 were isolated from EtOAc extract [4], and 169–171, 173, 174, and 176–178 as well as 180–184 were obtained from MeOH extract [22,81,82]. Cyclic peptides 169–184 (Figure 6 and Table S6) have long chains, and for the callyaerins D (172 and 173), F (175 and 176) and G (177 and 178), more than one structure has been associated with the same metabolite name. In addition, callynormine A (185) was isolated from Callyspongia abnormis [83] (but no information was found on the extract used), callyptide A (186) from CH2Cl2/MeOH 1:1 extract of Callyspongia sp. [84], and the phoriospongins A (187) and B (188) were isolated from the EtOH extract of Callyspongia bilamellata [85]. Structures 185–188 are characteristic of cyclic peptides, and 187–188 are cyclic depsipeptides (Figure 6 and Table S6).

Figure 6

Structures of cyclic peptides and cyclic depsipeptides isolated from Callyspongia species.

2.7. Polyketides

Callystatin A (189) were characterized from the acetone extract of Callyspongia truncata [86,87], comantherin (190) from the mixture of MeOH/CH2Cl2 (1:1) and MeOH extracts of Callyspongia sp. [80], and callyspongiolide (191) from MeOH extract of Callyspongia sp. [88,89,90]. Compounds 189 and 190, despite being structurally different, have common characteristics, such as the presence of dihydropyranone cycle derivatives and unsaturated bonds, as well as carbonyl, hydroxyl, and heteroatom units (Figure 7 and Table S7). In addition, butenolide 5-hydroxy-3-methyl-5-pentyl-2,5-dihydrofuran-2-one (192) was isolated from the acetone extract of Callyspongia vaginalis [9], and furans hydroxydihydrobovolide (193) as well as (−)-Loliolide (194) from the EtOH 95% extract of Callyspongia sp. [67]. Structures 192–194 were proposed as furanone derivatives (Figure 7 and Table S7). The elucidation of these compounds was performed by NMR; however, only 189, 191, and 192 present the data of 1H and 13C NMR.

Figure 7

Structures of polyketides isolated from Callyspongia species.

2.8. Miscellanous

Callyspongidic acids C12:0 (195), C13:0 (196), C14:0 (197), and C14:1 (198) were isolated from MeOH/CH2Cl2 1:1 extract from Callyspongia californica and characterized as phenol derivatives bearing carbonyl and hydroxyl groups (Figure 8 and Table S8) [12].

Figure 8

Structures of miscellaneous compounds isolated from Callyspongia species.

Other compounds were isolated from species of the genus Callyspongia: 2-(3-methyl-dec-3-enamido)ethanesulfonic acid (199); the Callyspongiamides A (200) and B (201); the bastadins 6 (202), 7 (203), 8 (204), 9 (205), 16 (206), 18 (207) and 24 (208); [(3S,4Z,6S)-6-butyl-6-ethyl-4-ethylidene-1,2-dioxan-3-yl]acetic acid (209); [(3S,4R)-6-butyl-4,6-diethyl-1,2dioxan-3-yl]acetic acid (210); and the callypyrones A (211) and B (212). Except for substances 211 and 212 that were isolated from an EtOAc/MeOH 1:1 of Callyspongia diffusa [26], these metabolites were obtained from ethanolic extract of Callyspongia sp. (200 and 201) [6], as well as 90% (199) hydroalcoholic [91] extracts. Also, the combination of extracts MeOH + CHCl3/MeOH provided 209–210 [92,93,94,95] while MeOH + CH2Cl2 afforded 202–208 [80]. The metabolites were elucidated by 1H and 13C NMR; however, only 195–201, and 209–212 present the spectroscopic data. The structures of 199–212 are varied (Figure 8 and Table S8), but some of the metabolites can be grouped by structural similarity: polychlorine-containing modified dipeptides 200 and 201, bastadins 202–208, cyclic peroxides 209–210, and the callypyrones 211–212.

3. Biological Aspects of Metabolites Isolated in Callyspongia species

The biological activities of metabolites 1–212 were investigated by considering any research involving these substances, including the articles about Callyspongia species. In this sense, 108 compounds (including isomers 16a,b and 116a,b) have been associated with some type of biological action, including anti-hiv, antimalarial, antioxidant, antihypertensive, anti-angiogenic, anti-tuberculosis, antimicrobial, antiproliferative, antifouling, modulatory, inhibitory (enzyme), and cytotoxic, for example. This information is also complemented in Table 1, and discussed in the topics below.

Table 1

Biological aspects in active metabolites of Callyspongia species.

Metabolite Name	Biological Activity	Ref.
Aikupikanyne E (5)	Cytotoxicity {(P-388, ATCC: CCL 46), (A-549, ATCC: CL 8) and (HT-29, ATCC: HTB 38)}	[27]
Aikupikanyne F (6)	Cytotoxicity {(P-388, ATCC: CCL 46), (A-549, ATCC: CL 8) and (HT-29, ATCC: HTB 38)}	[27]
Callyberyne A (Callypentayne) (9)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
Callyberyne C (Callytetrayne) (11)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
14,15-Dihydrosiphonodiol (Dihydrosiphonodiol) (13)	Antiproliferative activity (HL-60 and HCT-15 cell lines)	[31]
	Inhibitory activity (gastric H,K-ATPase)	[32,96]
Callyspongidiol (14)	Antiproliferative activity (HL-60 and HCT-15 cell lines)	[31]
Siphonodiol (15)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)	[29]
	Antiproliferative activity (HL-60 and HCT-15 cell lines)	[31]
	Antibacterial (Staphylococcus aureus and Streptococcus pyogenes)	[33,96]
	Antifungal (Trichophyton asteroides)	[33,96]
	Inhibitory activity (gastric H,K-ATPase)	[32,96]
(+)-(4E,16E)-icosa-4,16-diene-1,19-diyne-3,18-diol (16a)	Cytotoxic (TR-LE and HeLa cell lines)	[35]
(−)-(4E,16E)-icosa-4,16-diene-1,19-diyne-3,18-diol (16b)	Cytotoxic (TR-LE and HeLa cell lines)	[35]
Callyspongendiol (17)	Cytotoxicity (HCT-166 and MCF-7 cell lines)	[8,36]
Tetrahydrosiphonodiol (18)	Inhibitory activity (gastric H,K-ATPase)	[29,96]
(3R,4E,28Z)-Hentriacont-4,28-diene-1,23,30-triyn-3-ol (19)	Cytotoxicity (NBT-II cell line)	[37]
Callyspongenol A (20)	Cytotoxicity (P388 and HeLa cell lines)	[38]
Callyspongenol B (21)	Cytotoxicity (P388 and HeLa cell lines)	[38]
Callyspongenol C (22)	Cytotoxicity (P388 and HeLa cell lines)	[38]
Callyspongenol D (23)	Cytotoxicity (MCF-7 and HCT-116 cell lines)	[8,36]
Callysponyne A (24)	Cytotoxicity (MOLT-4, K-562, T-47D and HCT 116 cell lines)	[39]
Callysponyne B (25)	Cytotoxicity (MOLT-4, K-562, MDA-MB-231 and HCT 116 cell lines)	[39]
Dehydroisophonochalynol (Dehydrosiphonochalynol) (26)	Cytotoxicity (P388, HeLa, MCF-7 and A549 cell lines)	[36,38,40]
Siphonellanol A (27)	Cytotoxicity (HeLa, MCF-7 and A549 cell lines)	[40]
Siphonellanol B (28)	Cytotoxicity (HeLa, MCF-7 and A549 cell lines)	[40]
Siphonellanol C (29)	Cytotoxicity (HeLa, MCF-7 and A549 cell lines)	[40]
Siphonchalynol (30)	Cytotoxicity (HeLa, MCF-7 and A549 cell lines)	[40]
Callysponginol sulfate A (31)	Inhibitor of MT1-MMP	[41]
Callyspongin A (Siphonodiol disulfate) (32)	Inhibitor of fertilization of starfish gametes	[42]
	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)	[29]
Callyspongin B (Siphonodiol sulfate) (33)	Inhibitor of fertilization of starfish gametes	[42]
	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)	[29]
Callytriol A (34)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)
Callytriol B (35)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)
Callytriol C (36)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)
Callytriol D (37)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)
Callytriol E (38)	Metamorphosis-inducing (Ascidian Halocynthia roretzi larvae)	[29]
	Antifouling activity (Barnacle Balanus Amphitrite larvae)
Callyspongynic Acid (44)	α-glucosidase inhibitor	[44]
Batyl alcohol (46)	Biofilm inhibition (Alteromona macleodii, Ochrobactrum pseudogrignonense, Vibrio harveyi and Staphylococcus aureus)	[97]
Callyspongamide A (47)	Cytotoxicity (HeLa cell lines)	[46]
Isocopalanol (49)	Cytotoxicity (PANC-1 cell line)	[50]
Akaterpin (50)	Enzyme Inhibitor (PI-PLC and neural sphingomyelinase)	[51]
Ilhabelanol (51)	Inhibitor of L-APRT	[11]
Ilhabrene (52)	Inhibitor of L-APRT	[11]
Isoakaterpin (53)	Inhibitor of L-APRT	[11]
(2S,4aS,5S,6R,8aS)-5-(2-((1S,3aS,5R,8aS,Z)-1-hydroxy-1,4,4,6-tetramethyl-1,2,3,3a,4,5,8,8a-octahydroazulen-5-yl)-ethyl)-4a,6-dimethyloctahydro-2H-chromene-2,6-diol (54)	Cytotoxicity (KB-3-1 and KB-C2)	[52]
Neviotine A (56)	Inhibitory activity (RANKL induced osteoclastogenesis)	[57]
	Cytotoxicity (PC-3, A549, MCF-7 and HepG-2 cell lines)	[55,56]
	Antibacterial activity (Staphylococcus aureus, Bacillis subtilis and Escherichia coli)	[56]
	Antiviral activity (HAV-10)	[56]
Neviotine C (58)	Cytotoxicity (PC-3 and A549 cell lines)	[55]
Neviotine D (59)	Inhibitory activity (RANKL induced osteoclastogenesis)	[57]
Sipholenol A (15-sipholen-4,10,19-triol) (60)	Cytotoxicity (KB-3-1, KB-C2, HepG-2, PC-3, A549, MCF-7 and HCT-116 cell lines)	[8,36,52,55,56,58,59]
	Inhibitor of P-gp	[98]
	Antiproliferative activity (+SA mouse mammary epithelial cells)	[58]
	Antiviral (HAV-10)	[56]
Sipholenol L (71)	Cytotoxicity (MCF-7 and HepG-2 cell lines)	[56]
	Antibacterial activity (Staphylococcus aureus and Bacillis subtilis)	[56]
	Antiviral (HAV-10 and HSV-1)	[56]
Sipholenol L (72)	Cytotoxicity (HCT-116, KB-3-1 and KB-C2 cell lines)	[8,52]
Sipholenol M (73)	Cytotoxicity (KB-3-1 and KB-C2 cell lines)	[52]
Sipholenone A (15-sipholen-10,19-diol-4-one) (76)	Cytotoxicity (HCT-116, PC-3, A549, MCF-7 and HepG-2 cell lines)	[8,55,56,58]
	Antibacterial activity (Staphylococcus aureus, Bacillis subtilis and Escherichia coli)	[56]
	Reversal effects for KB-C2	[59]
	Antiproliferative activity (+SA mouse mammary epithelial cells)	[58]
	Anti-angiogenic activity (CAM assay)	[58]
Sipholenone E (80)	Cytotoxicity (KB-3-1 and KB-C2 cell lines)	[52]
Siphonellinol C (85)	Reversal effects for KB-C2	[59]
Siphonellinol D (87)	Cytotoxicity (KB-3-1 and KB-C2 cell lines)	[52]
Siphonellinol E (88)	P-gp modulatory activity	[52]
24S-24-methyl-cholestane-3β,5α,6β,25-tetraol-25-mono acetate (89)	Antimalarial (Plasmodium falciparum)	[23]
24S-24-methyl chelestane-3β,5α,6β,12β,25-pentaol-25-O-acetate (90)	Antimalarial (Plasmodium falciparum)	[23]
24S-24-methyl cholest-25-ene-3β,5α,6β,12β-tetrol (91)	Antimalarial (Plasmodium falciparum)	[23]
24S-24-methyl cholestane-3β,6β,25-triol-25-O-acetate (92)	Antimalarial (Plasmodium falciparum)	[23]
Callysterol (ergosta-5,11-dien-3β-ol) (97)	Anti-inflammatory	[19]
Cholestenone (4-cholesten-3-one) (98)	Anti-metastasis of lung adenocarcinoma	[99]
Gelliusterol E (101)	Antichlamydial (Chlamydia trachomatis)	[28]
β-sitosterol (102)	Analgesic	[100,106]
	Angiogenic	[101]
	Anthelminthic	[100]
	Antibacterial (Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhii, Corynebacterium diphtheria and Klebsiella pneumoniae)	[102,103,104]
	Antidiabetic	[102,105]
	Antifungal (Fusarium spp.)	[104]
	Anti-inflammatory	[100,106,107,108]
	Antimutagenic	[100]
	Antipyretic	[107]
	Cytotoxicity (MCF-7, HT-29, U937, MDA-MB-231, SGC-7901 and LNCaP)	[108,109,110,111,112,113,114]
	Hypocholesterolemic	[115]
	Immunomodulatory (pigs imune)	[116]
Siphonocholin (103)	Anti-QS (inhibit the production of violacein)	[63]
	Anti-biofilm (Paracoccus sp., Pseudomonas aeruginosa, Pseudoalteromonas sp. and Bacillus sp.)	[63]
Ergosta-5,24(28)-dien-3β-ol (104)	Cytotoxicity (HCT-116 cell line)	[8]
2-bromoaldisine (105)	Anti-HIV-1	[117]
	Inhibitory (Raf/MEK-1/MAPK cascade)	[118]
	Inhibitory (GSK-3, DYRK1A, CK-1)	[119]
Hymenialdisine (110)	Cytotoxicity (SW620 and KB-3-1 cell lines)	[65]
	Kinase inhibitor (CK1, CDK5 and GSK-3β)	[65,120]
3-(2-(4-hydroxyphenyl)-2-oxoethyl)-5,6-dihydropyridin-2(1H)-one (115)	Anti-allergic	[121]
(1R,3R)-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (116a)	Anti-oxidant	[122]
(1R,3S)-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (116b)	Anti-oxidant	[122]
1H-indole-3-carbaldehyde (119)	Inhibitor (Tyrosinase)	[123]
5-bromo trisindoline (120)	Antibacterial (Staphylococcus aureus and Bacillus subtilis)	[7]
	Biofilm inhibitory (Pseudomonas aeruginosa)	[7]
	Antitrypanosomal	[7]
	Cytotoxicity (HT-29, OVCAR-3 and MM.1S)	[7]
6-bromo trisindoline (121)	Antibacterial (Staphylococcus aureus and Bacillus subtilis)	[7]
	Biofilm inhibitory (Pseudomonas aeruginosa)	[7]
	Antitrypanosomal	[7]
	Cytotoxicity (HT-29, OVCAR-3 and MM.1S)	[7]
Untenine A (122)	Anti-microfouling	[68]
Untenine B (123)	Anti-microfouling	[68]
Untenine C (124)	Anti-microfouling	[68]
Niphatoxin C (125)	Cytotoxicity (THP-1 cell line)	[69]
Cyclo-(S-Pro-R-Ala) (129)	Antifouling (Cyprid larvae of the barnacle)	[66]
Cyclo-(S-Pro-R-Leu) (Cyclo-((S)-Pro-(R)-Leu)) (130)	Antifouling (Cyprid larvae of the barnacle)	[66]
Dysamide A (141)	Inhibitor of the SOAT1 and SOAT2 isozymes	[6]
(3R)-methylazacyclodecane (145)	Cytotoxic (K562 and A549 cell lines)	[5]
Callyazepin (146)	Cytotoxic (K562 and A549 cell lines)	[5]
2-phenylacetamide (147)	Estrogenic activities	[124]
	Inhibitory effect to the growth (rice, lettuce, barnyard millet and rape)	[125]
4-hydroxybenzoic acid (149)	Antimicrobial Activity (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Lactobacillus plantarum, Leuconostoc mesenteroides, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Pseudomonas. Syringae, Pseudomonas. syringae pv. Tobaci, Ewinia carotovora subsp. carotovora, Xanthomonas campestri and Agrobacterium)	[126]
	Fungitoxicity (inhibited the growth of Ganoderma boninense)	[127]
	Hypoglycemic activity	[128]
3,5-dibromo-4-methoxyphenylpyruvic acid (154)	ApoE modulatory (CCF-STTG1 cell line)	[80]
2’-Deoxyadenosine (165)	Inhibitor of keratinocyte proliferation	[129]
	Toxic to E3 embryos	[130]
Callyaerin A (169)	Anti-Tuberculosis	[22,131]
	Antibacterial (Escherichia coli and Staphylococcus aureus)	[4]
	Antifungal (Candida albicans)	[4]
	Cytotoxicity (L5178Y cell line)	[4]
Callyaerin B (170)	Anti-Tuberculosis	[22]
	Antibacterial (Escherichia coli and Staphylococcus aureus)	[4]
	Antifungal (Candida albicans)	[4]
	Cytotoxicity (L5178Y, THP-1 and MRC-5 cell lines)	[4,22]
Callyaerin C (171)	Cytotoxicity (L5178Y cell line)	[4]
Callyaerin D (172)	Cytotoxicity (L5178Y cell line)	[4]
Callyaerin E (174)	Cytotoxicity (L5178Y cell line)	[4]
	Antimicrobial (Escherichia coli, Staphylococcus aureus Candida albicans and Bacilus subtilis)	[4]
Callyaerin F (175)	Cytotoxicity (L5178Y cell line)	[4]
Callyaerin G (178)	Cytotoxicity (L5178Y and HeLa cell lines)	[4,82]
Callyaerin H (179)	Cytotoxicity (L5178Y cell line)	[4]
Callyptide A (186)	Cytotoxicity {MDA-MB-231; ATCC: HTB 38, A549 (ATCC: CCL-185) and HT-29 (ATCC: HTB 38) cell lines}	[84]
Callystatin A (189)	Cytotoxicity (KB cell line)	[86,87]
Callyspongiolide (191)	Cytotoxicity (L5178Y cell line and Jurkat J16 T and Ramos B lymphocytes)	[88]
	Inhibitor (Vacuolar ATPase)	[132]
Hydroxydihydrobovolide (193)	Anti-HIV	[67,133]
	Cytotoxicity (SH-SY5Y cell line)	[134]
	Plant growth inhibitor	[135]
(–)-loliolide (194)	Antibacterial (Bacillus subtilis, Neisseria gonorrhoeae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Enterobacter cloacae and Klebsiella pneumoniae)	[136,137,138]
	Antidepressant	[138,139]
	Antifungal (Candida albicans and Aspergillus niger)	[137,138]
	Antimutagen	[138,140]
	Antioxidant (DPPH, H2O2 radicals and intercellular ROS)	[138,141]
	Cytotoxicity (L5187Y cell line)	[136,138]
	Germination inhibitor (lettuce and alfalfa seeds)	[138,142]
	Repellent for ants (Atta cephalotes)	[67,138]
Callyspongidic acid C13:0 (196)	Cytotoxicity (A2058 cell line)	[12]
Callyspongiamide A (200)	Inhibitors of the SOAT1 and SOAT2 isozymes	[6]
Callyspongiamide B (201)	Inhibitors of the SOAT1 and SOAT2 isozymes	[6]
Bastadin 6 (202)	Anti-angiogenic activity (inhibit VEGF and bFGF of HUVECs)	[143]
	Cytostatic and/or cytotoxic effects (L5178Y, MCF-7, A549, Hs683, U373, B16F10 and SKMEL 28)	[144,145]
Bastadin 7 (203)	Cytotoxicity (L5178Y)	[145]
	Inhibitor (the serum + hEGF-induced tubular formation of HUVEC)	[94]
Bastadin 8 (204)	Inhibitor (IMPDH)	[95]
Bastadin 9 (205)	Cytostatic and/or cytotoxic effects (MCF-7, A549, Hs683, U373, B16F10 and SKMEL 28)	[144]
Bastadin 16 (206)	Cytostatic and/or cytotoxic effects (L5178Y, MCF-7, A549, Hs683, U373, B16F10 and SKMEL 28)	[144,145]
Bastadin 24 (208)	Cytotoxicity (CNXF SF268, LXFA 629L, MAXF 401NL, MEXF 276L and PRXF 22RV1)	[94]
[(3S,4Z,6S)-6-butyl-6-ethyl-4-ethylidene-1,2-dioxan-3-yl]acetic acid (209)	Cytotoxicity (P-388 cell line)	[92]
[(3S,4R)-6-butyl-4,6-diethyl-1,2dioxan-3-yl]acetic acid (210)	Cytotoxicity (P-388 cell line)	[92]
Callypyrone A (211)	Antihypertensive	[26]
	Antioxidant	[26]
Callypyrone B (212)	Antihypertensive	[26]
	Antioxidant	[26]

3.1. Polyacetylenes

The aikupikanynes E (5) and F (6) from Callyspongia sp. showed moderate activity (with IC50 values of 5 and 10 μg/mL) against the cancer cell lines studied (Table 1) [27]. Other polyacetylenes obtained from Callyspongia truncata showed a potent metamorphosis-inducing activity in the ascidian Halocynthia roretzi larvae (with ED100 values of 0.13–1.3 μg/mL) for 9, 11, 15, and 32–38, and antifouling activity against the barnacle Balanus amphitrite larvae (with ED50 values of 0.24–4.5 μg/mL) for 15 and 32–38 [29]. In addition, the inhibitory effect of the fertilization of starfish gametes of 32 and 33 in concentrations of 6.3 and 50 μM, respectively, [42].

Three polyacetylene diols were isolated from Callyspongia sp. and have driving Th1 polarization and antiproliferative effect against HL-60 (IC50 values: 6.5 μg/mL for 13,14 and 2.8 μg/mL for 15) and HCT-15 (IC50 values: 21 μg/mL for 13, 22 μg/mL for 14 and 34 μg/mL for 15) [31]. 13, 15 and 18 exhibited strong inhibitory activity against gastric H,K-ATPase (IC50 1.0 × 10−5 M) [32,96]. The 16a and 16b isomers are weakly cytotoxic, with IC50 values of 0.47 for 16a natural, 1.5 (± 0.29) for 16a synthetic, 0.11 for 16b natural and 0.35 (± 0.13) for 16b synthetic against TR-LE and 1.8 (± 5.0) for 16a and 5.3 (± 1.1) for 16b synthetics against HeLa [35]. Other activities have been attributed to siphonodiol (15): medium antibacterial effect against S. aureus (MIC 12.5 μg/mL) and S. pyrogenes C-203 (MIC 6.2 μg/mL), and weak antifungal activity against T. asteroids (MIC 25.0 μg/mL) [33,96].

The metabolites 17 and 23 from Callyspongia siphonella proved to be weakly cytotoxic active against HCT-116. In addition, 17 and 26 were found to be weak cytotoxic against cells of MCF-7 with IC50 values of 65.7 and 73.6 μM, respectively, while 23 (IC50: 11.7 μM) presented greater activities [36].

The compound (3R,4E,28Z)-hentriacont-4,28-diene-1,23,30-triyn-3-ol (19) has been reported to be cytotoxic against the NBT-II cell line at concentrations of 5 and 10 μg/mL [37]. The metabolites 20–22 and 26 are moderately cytotoxic against the P388 cell lines (IC50 values in μg/mL: 2.2 for 20, 22, and 26 and 10.0 for 21) and HeLa (IC50 values in μg/mL: 4.5 for 20, 10.0 for 21, 3.9 for 22, and 5.1 for 26) [38]. Cytotoxic compounds 26–30 also have moderate activity against HeLa (IC50 values 23.9–26.5 μM), MCF-7 (IC50 values 54.9–69.2 μM), and A549 (IC50 values 58.5–63.4 μM) cell lines [40]. In vitro cytotoxicity activities of compounds 24 and 25 were evaluated and verified to fight MOLT-4 cell lines (IC50 values: 1.9 μM for both), K-562 (IC50 values 5.6–6.1 μM), and HCT 116 (IC50 values 5.4–7.0 μM), only 24 against T-47D (IC50 value: 8.9 μM) and 25 against MDA-MB-231 (IC50 value: 9.9 μM) [39].

Two interesting compounds were isolated from Callyspongia truncata, the Callysponginol sulfate A (31), which was found to inhibit MT1-MMP with an IC50 of 15.0 μg/mL [41], and Callyspongynic Acid (44), a α-glucosidase inhibitor with an IC50 of 0.25 μg/mL [44]. The glycerolipid Batyl alcohol 46 showed biofilm inhibition capacity for Alteromona macleodii, Ochrobactrum pseudogrignonense, Vibrio harveyi, and Staphylococcus aureus at 0.5 and 0.025 mg/mL [97]. The polyacetylenic amide callyspongamide A (47) was shown to be moderately cytotoxic against HeLa (IC50 of 4.1 μg/mL) [46].

3.2. Terpenoids and Steroids

The metabolites 60, 72, 76, and 104, from Callyspongia siphonella, proved to be weakly cytotoxic active against HCT-116, but 60, 72, and 76 were found to have moderate activity (at the respective IC50 values of 14.8 ± 2.33, 19.8 ± 3.78, and 95.8 ± 1.34 μM) [8]. In addition, 60 presented high cytotocix activity against cells of MCF-7 with IC50 values of 8.8 μM [36]. The effects on Reversing P-gp-Mediated MDR to colchicine involving the KB-3-1 cell lines were also tested (IC50 values in μM: 5.6 ± 0.5 for 54, 4.8 ± 0.1 for 60, 5.1 ± 0.3 for 72, 4.7 ± 0.3 for 73, 4.7 ± 0.4 for 80, 4.2 ± 0.1 for 87 and 4.6 ± 0.6 for 88) and KB-C2 (IC50 values in μM: 390 ± 40 for 54, 140 ± 30 for 60, 150 ± 10 for 72, 780 ± 60 for 73, 62 ± 11 for 80, 180 ± 10 for 87 and 560 ± 50 for 88) [52].

The isocopalanol (49) showed inhibition ability for the PANC-1 cell line with an IC50 of 0.1 μg/mL [50]. akaterpin (50) has been proven to inhibit PI-PLC (IC50 of 0.5 μg/mL) and neural sphingomyelinase (IC50 of 30 μg/mL) [51]. The sulfated meroterpenoids 51–53 are inhibitors of L-APRT at IC50 of 0.7, 0.7 and 1.05 μM, respectively, [11].

The metabolites 56, 58, 60, and 71 showed activity against PC-3 (IC50 7.9 ± 0.12–71.2 ± 0.34 μM) and A549 (IC50 8.9 ± 0.01–87.2 ± 1.34 μM) cell lines, with compound 60 being the most active [55]. The cell lines MCF-7 (IC50 3.0 ± 0.4–19.2 ± 0.6 μM) and HepG-2 (IC50 2.8 ± 0.4–18.7 ± 0.9 μM) were tested for 56, 60, 71, and 76, and 76 had the most significant effect [56] (also obtained MCF-7 IC50 values of 1.162 for 60 and 0.9 μM for 76 [58]). In the same study, antiviral activity against HAV-10 was also weak for 56 and 71 (which also showed weak effectiveness against HSV-1) and moderate for 60 [56] (60 is an inhibitor of P-gp too) [98]. In addition, the antimicrobial activities of 56 and 71 were measured (Table 1), in which 56 obtained the greater result (12.7 ± 0.58–17.2 ± 0.58 mm) and 71 obtained a moderate one against gram positive bacteria only (12.3 ± 0.72–14.5 ± 0.72 mm) [56]. Compounds 56 and 59 also strongly inhibit RANKL-induced osteoclastogenesis with IC50 values of 32.8 and 12.8 μM, respectively, [57].

Sipholenol A (60) and sipholenone A (76) exhibited antiproliferative activity against +SA mouse mammary epithelial cells. While compound 76 was found to be a potential inhibitor (IC50 20–30 μM), 60 had lower activity (IC50 70 μM) [58]. Substances 60 and 76, in addition to 85, showed Reversal effects for KB-C2 [59], and 76 had both anti-angiogenic activity in CAM assay (0.026 μM per pellet) [58] and antibacterial activity (Table 1) [56]. In another study, substances 89–92 were associated with moderate antimalarial activity against Plasmodium falciparum [23], in which 89 showed the best result. Callysterol (97) showed an anti-inflammatory effect [19] and cholestenone (98) had an anti-metastatic effect on lung adenocarcinoma [98,99]. Gelliusterol E (101) inhibited the formation and growth of chlamydial trachomatis (IC50 value 2.3 μM) [28], and siphonocholin (103) inhibited the production of violacein, being an Anti-QS and Anti-biofilm compound (Table 1) [63]. β-Sitosterol (102) was found to exhibit anthelminthic [100], antimutagenic (at 0.5 mg/kg inhibited the mutagenicity of tetracycline) [100], angiogenic [101], antibacterial (Table 1) [102,103,104], antifungal against Fusarium spp. [104], antidiabetic [102,105], analgesic [100,106], antipyretic [107], anti-inflammatory [100,106,107,108,109,110,111,112,113,114], cytotoxic (Table 1) [108,109,110,111,112,113,114], hypocholesterolemic [115], and immunomodulatory activities [116].

3.3. Alkaloids

Furthermore, 2-Bromoaldisine (105) was evaluated as a potential compound for anti-HIV action, by inhibiting type 1 of this virus with an infection vector to 1/3 at 200 nM in a 96-well plate [117]. Compound 105 also inhibited MEK-1 reasonably [118], and GSK-3 (IC50 > 41.2 μM), DYRK1A (IC50 > 41.2 μM), and CK-1 significantly (IC50 1.6 μM) [119]. Hymenialdisine (110) was reported as inhibitor kinase, acting against CK1δ (IC50 0.03 μM), CDK5/p25 (IC50 0.16 μM), and GSK-3β (IC50 0.07 μM) [65,120], as well as being also moderately cytotoxic against SW620 (IC50 3.1 μM) and KB-3-1 (IC50 2.0 μM) cell lines [65].

3-(2-(4-Hydroxyphenyl)-2-oxoethyl)-5,6-dihydropyridin-2(1H)-one (115) had an in vitro anti-allergic effect predicted by in silico computational chemistry approaches [121]. The 116a–116b isomers showed antioxidant activity [122] and 1H-indole-3-carbaldehyde (119) antifungal effect against the YL185 fungus [123]. The nitroalkyl pyridine alkaloids 122–123 exhibited a potent anti-microfouling action with IC100 values of 3.0, 6.1, and 5.8 mg/cm2, respectively, [68]. In addition, niphatoxin C (125) was shown to be cytotoxic against THP-1 cells and exhibited the ability to form a permeable ion [69].

The brominated oxindole alkaloid isomers 120 and 121 exhibited the following activities with the values, respectively, grouped: potent antibacterial effect against Staphylococcus aureus (MIC: 8 and 4 μg/mL) and Bacillus subtilis (MIC: 16 and 4 μg/mL), moderate biofilm inhibitory with 49.32% and 41.76% inhibition (Table 1), moderate in vitro antitrypanosomal (13.47 and 10.27 μM), and strong cytotoxicity against HT-29 (IC50 8 ± 0.8 and 12.5 ± 0.3 μM), OVCAR-3 (IC50 7 ± 0.3 and 9 ± 0.6 μM), and MM.1S (IC50 9 ± 0.7 and 11 ± 0.9 μM) [7].

Diketopiperazines 129 and 130 have been associated with antifouling activity against cyprid larvae of the barnacle (LC50 6.0 μg/cm2 and 3.5 μg/cm2) [66], while 141 has been reported as SOAT isozymes [6]. 145 and 146 are moderately cytotoxic against K562 (IC50 values 3.2 and 7.4 μg/mL, respectively) and A549 cell lines (IC50 values 3.8 and 3.0 μg/mL, respectively) [5].

3.4. Simple Phenols and Phenyl Propanoids

The compound 2-phenylacetamide (147) presented estrogenic activities in a study involving the seeds of Lepidium apetalum, indicating a potential for the treatment of perimenopause syndrome [124]. It was also produced by Actinomyces with an inhibitory effect on the plant growth of rice, lettuce, barnyard millet, and rape [125]. 4-hydroxybenzoic acid (149) was identified as an antimicrobial substance from Rice Hull sensitive for the tested fungi and bacteria (Table 1), in which gram-positive bacteria were inhibited (IC50 values ranging from 100 to 1000 µg/mL) more efficiently than the gram-negative [126]. Other studies have shown the inhibition of the growth of Ganoderma boninense [127] and the hypoglycemic activity [128] from 149. In addition, 3,5-dibromo-4-methoxyphenylpyruvic acid (154) is weakly active in increasing the apolipoprotein E secretion from human CCF-STTG1 cells at (40 μM) [80].

3.5. Nucleosides

The only nucleoside from Callyspongia found to be biologically a is 2′-deoxyadenosine (165), which inhibited the keratinocyte outgrowth [129] and is toxic to E3 embryos [130] (Table 1).

3.6. Cyclic Peptides and Cyclic Depsipeptides

Cyclic peptides 169–172, 174–175, and 178–179 exhibited cytotoxic activity against the L5178Y cell line, especially 174 and 179, which were potent with the respective ED50 of 0.39 and 0.48 μM values, respectively, while 169–172, 175, and 178 were less active (ED50 2.92 to 4.14 μM) [4,22]. Still, in the same study, antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and Bacilus subtilis were associated with the molecules 169, 170 and 174 (Table 1) [4].

Other bioactivities have been reported among callyaerins, including potent anti-tuberculosis for 169 [22,131] and 170 [22], and moderate cytotoxicity against THP-1 (IC50 5 μM), MRC-5 (IC50 2 μM), and HeLa (ED50 5.4 μg/mL) cell lines for 178 [22,82]. In this sense, callyptide A (186) was also shown to be cytotoxic, but against MDA-MB-231; ATCC: HTB 38, A549 (ATCC: CCL-185), and HT-29 (ATCC: HTB 38) cell lines [84].

3.7. Polyketides

Callystatin A (189) are moderately cytotoxic against A2058 (IC50 3.2 μM) [12] and KB (IC50 0.01 ng/mL) [86,87] cell lines. Callyspongiolide (191) has been shown to be a potent vacuolar ATPase inhibitor (IC50 10 nM) [131,132] and also has a high cytotoxicity against the L5178Y cell line (IC50 320 nM), Jurkat J16 T (IC50 70 nM), and Ramos B lymphocytes (IC50 60 nM) [88].

Hydroxydihydrobovolide (193) has been reported as a type 1 anti-HIV substance (IC50 122.7 μM) [67,133], significantly cytotoxic against the SH-SY5Y cell line (50 μM) [134] and inhibitor of hypocotyl growth of cress seedlings (100 μM) [135]. Compound (−)-Loliolide (194) has a broad spectrum of bioactivity, including antibacterial (Table 1) [136,137,138], antidepressant [138,139], antifungal (Table 1) [137,138], antimutagen [138,140], moderately antioxidant (Table 1) [138,141], germination inhibitor [138,142], repellent for ants Atta cephalotes [67,138] and cytotoxicity against cell line L5187Y (ED50: 4.7 mg/mL) [136,138].

3.8. Miscellanous

Callyspongidic acid C13:0 (196) is effective against A2058 (IC50 3.2 μM) [12]. Callyspongiamides 200 and 201 inhibited the SOAT1 and SOAT2 isozymes [6]. Bastadin 6 (202) inhibited tumor angiogenesis by inducing selective apoptosis to endothelial cells (Table 1) [143]; compounds 205 and 206 exhibited in vitro cytostatic and/or cytotoxic effects against MCF-7 (IC50 4 to 8 μM), A549 (IC50 3 to 8 μM), Hs683 (IC50 3 to 4 μM), U373 (IC50 3 to 11 μM), B16F10 (IC50 4 to 6 μM), and SKMEL 28 (IC50 4 to 7 μM) cells, and only 202 and 206 against L5178Y (IC50 1.5 to 1.9 μM, respectively) [144,145]. Bastadin 7 (203) is also cytotoxic against L5178Y, however, with IC50 5.3 μM [145]; and also significantly inhibited the serum + hEGF-induced tubular formation of HUVEC (1 μg/mL) [94]. Bastadin 8 (204) showed moderate inhibitory activity of IMPDH [95], while bastadin 24 (208) had cytotoxicity against CNXF SF268, LXFA 629L, MAXF 401NL, MEXF 276L, and PRXF 22RV1 [94]. Other compounds have been proven to be cytotoxic: 209 and 210 against the P-388 cell line (ED50 values 5.5 and 2.6 μg/mL, respectively) [92]. Lastly, 211 and 212 exhibited antihypertensive and antioxidant activity [26].

4. Discussion

The genus Callyspongia is composed of various species of sponges, in which 261 have been described and approximately 180 accepted by reviews of taxonomists [3,4]. Although only 15 species were identified in this review, these metabolites were isolated and properly characterized by NMR. Callyspongia sp. species were also considered in the bibliographic survey, but their non-identification makes the distinction between them impossible, allowing only a speculative approach based on localities of origin of these sponges. However, these results suggest that there are still many Callyspongia sponges that can be studied.

The first study about the isolation of metabolites from Callyspongia was published in 1981 [25] and the most recent ones have been published in 2020 [26,63]. Analyzing this time range, the expansion in the rate of publications is notable, especially if publications of the last decade are taken into account, indicating the increased interest in researching Callyspongia species. Still, during this period, two species of Shiphonochalina have been taxonomically reclassified and are currently known as Callyspongia lindgreni (Siphonochalina truncata) [32,33] and Callyspongia siphonella (Siphonochalina siphonela) [25,36,40,53,54,55,56,57,60,61,62,63].

In total, 212 metabolites were identified from Callyspongia, in which 103 are categorized in two classes, polyacetylenes (1–47), and terpenoids and steroids (48–104), in agreement with previous studies that present substances of this class as characteristic in the genus. In this sense, because of the greater number of isolations in different species, polyacetylenes could be classified as chemical markers for Callyspongia [9,27].

The sipholane triterpenoids (54–88) were also extensively documented, being the first isolated metabolites according to the investigations of this review [25], but they are only associated with Callyspongia siphonella. In addition, most of isolated compounds were collected from sponges of Red Sea regions, China, Japan, Indonesia, and Australia. This fact highlights the potential for further research in regions where the genus is less explored, such as Brazil, Ecuador, and Barbados, for example. It is also important to note that in some studies, no trace was found on the place of origin of the marine material studied [20,33,51,87].

Molecules 1–212 are structurally varied, and because of this, confusion such as the changing names of metabolites [29,42] and the attribution of different structures to the same compound can occur, for example, the Callyaerins D [4,22], F [4,22] and G [22,82]. The unavailability of 1H and 13C NMR data was also identified in some articles, but it is still possible to obtain spectroscopic information from other studies. The number of isolated compounds confirms the interest in the genus, but other investigations not covered in the review also contribute to this aspect: isolation accompanied by characterization [10], identification by dereplication [7], Mass Spectrometry [146,147] (process also present in some of the metabolites 1–212), and the isolation of compounds from beings that establish symbiotic relationships with Callyspongia species [148,149]. Thus, it can be said that this genus has been widely explored through different types of research.

Some of the 212 metabolites reported herein were described in original reviews and articles as biologically relevant. Among these compounds, 109 molecules (including isomers 16a–16b and 116a–116b) have been reported as bioactive (Table 1), corresponding to approximately half of the metabolites elucidated in Callyspongia. The absence of biological approaches for some substances in the studies indicates a great opportunity for future research and advances in the field. In addition, polyacetylenes correspond to the largest class of bioactive metabolites in the genus, and the most frequent biological activities were cytotoxicity and antimicrobial (antibacterial and antifungal). In this sense, the results are in agreement with the data that prove the relevance of the metabolites in the genus with anticancer action [24,40,58,94,98,109,111,113,144].

Future perspectives are encouraging, with regard to the emergence of new chemical contributions to the genus Callyspongia. However, there are still limitations in the study of sponges, some of the most significant are: the geographical location in the collection of species, the high concentration of marine salts in samples and extracts, the high cost of carrying out the experimental procedures and the probability of isolating metabolite with low yield. Some of the patterns observed in the methodologies of the articles can be pointed out the procedures used to minimize research problems in marine beings; Because of this, the frequent collection of sponges in regions close to places with anthropogenic action and the predominance in the isolation of non-polar compounds was observed. Consequently, we believe that the exploitation of Callyspongia species will expand.

5. Materials and Methods

The literature review on the genus Callyspongia was based on the theme: “metabolites isolated from Callyspongia species and characterized by the NMR spectroscopic technique”. This systematic secondary study was adopted through the qualitative and quantitative approach to information on the topic and conducted in electronic scientific databases and in websites of the selected journals, such as as: ACS Publications, Google Scholar, PubMed, ResearchGate, SciELO, Science Direct, SciFinder, Semantic Scholar, Springer Link, Taylor & Francis Online and Wiley Online Library. The only word investigated in isolation was “Callyspongia”, but “activity”, “biological”, “biological activity”, “NMR” was also used.

The knowledge about the species existing in the genus Callyspongia was obtained through the World Marine Species Register (WoRMS). The species were classified by nomenclature and researched individually. Additional information was obtained by searching for the term “Callyspongia” accompanied by keywords specific to the articles, such as the species name, the collection site, the name of the isolated metabolites and the types of biological activity. In addition, the data of biological activities of metabolites were searches by the name of the structures accompanied by the terms “biological”, “activity” and “biological activity”.

The selection of articles proceeded using inclusion criteria, i.e., the characterization of molecules by NMR as the primary criterion and the presence of biological activity as the secondary. The articles were identified by means of a summarized reading of the published content. The investigations reached a total of 973 articles, of which, 145 were considered compatible with the inclusion criteria, and selected for the review.

Through NMR data, 212 metabolites were identified from genus Callyspongia (15 species and Callyspongia sp.), which were classifying into the following groups: polyacetylenes, polyketides, terpenoids and steroids, simple phenols and phenylpropanoids, alkaloids, nucleosides, cyclic peptides and cyclic depsipeptides, and miscellaneous (Figure 9).

Figure 9

Classes of compounds isolated from Callyspongia species.

6. Conclusions

Sponges of the Callyspongia genus are producers of several classes of primary and secondary metabolites, mainly polyacetylenes and lipids. In addition, many of these compounds are biologically active and have activities that may prove to be promising in fighting diseases. Thus, this literature review gathered essential information for the emergence of new research on the species of the genus.