Effects of Sterculia setigera Del. Stem Bark Extract on Hematological and Biochemical Parameters of Wistar Rats.

Africa is rich in a wide range of flora that are exploited as herbal medicines and remedies. Several diseases such as diabetes, diarrhea, dysentery and jaundice have been successfully managed using herbal medicines. Herbal decoctions or concoctions have been used as pain killers, antibiotics, and hematinics. This study evaluated the hematopoietic and biochemical properties of the stem bark of Sterculia setigera Del. in Wistar rats. Results showed that S. setigera decoction has copiously high tannin and cardiac glycoside levels. Ingestion of the decoction by rats over a 16-day period significantly (P < 0.05) increased the body weights of rats by 22.4% in the S. setigera-treated group. Hematological profiles showed raised levels of red blood cells, hemoglobin, packed cell volume, mean corpuscular volume, mean cell hemoglobin, mean cell hemoglobin concentration, and platelets, while biochemical parameters showed lower levels of alanine aminotransferase and aspartate aminotransferase, and slight increase in albumin and TP levels. We posit that the results justify the use of the stem bark of S. setigera as a hematinic by traditional medical practitioners and show its relative safety. Further experiments are needed to evaluate its safety.

Introduction

The rich floral biodiversity of Africa has provided herbal health practitioners with an impressive pool of natural pharmacy, which led to the prescription of herbal medicines for treatment, management, and/or control of several array of human ailments. The World Health Organization consultative group defined a medicinal plant as one which in single or more of its parts contains substances that can be used for therapeutic purposes, or which are precursors of useful drugs.1

In traditional African communities, majority of the population still use medicinal plants for observing primary health care.2 Natural products derived from plants contain physiologically active principles that have been exploited in traditional medical practice over the years for the treatment of various ailments.3 The use of Sterculia setigera Del. in the treatment of severe diarrhea,4,5 dysentery,6 and jaundice7 has been reported by several researchers over the years. Replacement for already existing pain killers, hematinics and antibiotics are soughted for globally due to the cost of already existing drugs and its associated side effects.8

S. setigera is one of the plants used in traditional medicine. It is a member of the family Sterculiaceae, a multipurpose savannah tree with a wide ecological spread in tropical Africa. It is found mostly in the wild.9 It is a deciduous plant that grows up to 40 feet high, with a smooth bark, and it peels off thin scales to expose yellowish patches.10 The plant S. setigera has been used in traditional medical practice by various communities in Africa.11 The gum is used in the treatment of snake bites, leprosy, syphilis, coughs, bronchitis, and rickets and to manage insanity.12 Previous reports indicated that S. setigera is used in the treatment of jaundice.5,7 The plant is also used as a hematinic (blood booster) by traditional medical practitioners for postpartum women, people with symptoms of anemia, or those recuperating from one form of ailment or another.13 Hamidu10 reported that it contains active metabolites such as tannins, flavonoids, saponins, phenolics, and glycosides. Analyses of several parts of S. setigera for their nutritional composition revealed that the plant has high crude protein, fiber, amino acids, minerals, carbohydrate, and fat contents. It is rich in sodium, iron, zinc, and manganese and contains different types of essential vitamins (vitamins A, B1, B2, B6, B12, and E).14–16 The aim of this research, therefore, is to study the effect of S. setigera aqueous extract on hematological parameters of Wistar rats.

Materials and Methods

Collection of S. setigera Del

Stem bark of S. setigera Del. was collected at the Mubi Farm of Adamawa State University located along Mubi-Sahuda road. The specimen was identified by Prof. Mohammed Saquib of the Department of Biological Science, Adamawa State University, Mubi, Nigeria. The stem bark was cut into small pieces and dried in an oven at 65°C. The dried sample was pulverized into a fine powder using an electric grinder and stored in air tight bottles until required.

Preparation of plant extract

From the dried powdered sample of S. setigera Del., 100 g was weighed and dissolved in 500 mL distilled water in a 1000-mL beaker by mixing using a hot magnetic stirrer at a temperature between 50°C and 60°C. The mixture was cooled to room temperature and filtered using muslin cloth. The filtrate was centrifuged at 2500 rpm for 10 minutes. The supernatant was collected and refiltered through Whatman No. 1 filter paper.

Phytochemical screening of S. setigera Del

Qualitative phytochemical screening of S. setigera Del. was carried out using standard methods.17,18

Experimental animals

Fifteen male adult Wistar rats weighing between 150 and 180 g were obtained from the animal house of Biochemistry Department, University of Maiduguri, Nigeria. The rats were acclimatized for two weeks to laboratory conditions and were fed food and water ad libitum. The rats were randomly distributed into three groups containing five rats per group.

Group 1: The control group was fed with normal feed and drinking water.

Group 2: The B complex-treated group was fed with normal feed and administered B complex in solution (Emzor Pharmaceutical Industries Limited).

Group 3: This group was fed normal feed and drinking water, and 50 mg/kg body weight of aqueous stem bark extract of S. setigera was orally administered.19 The administration of plant extract was done once daily between the hours of 8:00 and 9:00 am.

Treatment of animals

This research was conducted in accordance with Adamawa State University’s guidelines on the use of animals for research.

Animal weights and blood sample collection

Each group was weighed after every 4-day interval for a period of 16 days. The mean weight was computed and recorded for each group. The rats were subjected to an overnight fast after which blood samples (1.0–2.0 mL) were collected from the animal tails into EDTA-containing bottles and were used for analysis.

Hematological analysis

Hematological analysis was carried out using an Automatic Haematology Analyser (Coulter®) as described by the manufacturer.

Biochemical enzyme assay

Enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), total protein, albumin (ALB), and bilirubin were analyzed using VITROS DT 60, DTSC 11, DTE 11 device, model 2004 manufactured by Orthodox—Clinical Diagnostics.

Statistical analysis

All values are reported as mean ± SD and compared using one-way analysis of variance and further by Duncan multiple range test. Values were considered significant when P < 0.05.

Results

The results of phytochemical screening of aqueous stem bark extract of S. setigera showed that the plant contained tannins copiously; cardiac glycosides were in moderate amount, while saponins and anthraquinones were in low concentration (Table 1).

Table 1

Phytochemical analysis of stem extract of S. setigera.

PHYTOCHEMICALS	INFERENCE
Tannin	+++
Phlobatanin	−
Steroid	−
Saponin	+
Terpenoid	−
Flavonoid	−
Cardiac glycosides	++
Anthraquinone	+
Alkaloid	−

Notes: +++, highest concentration; ++, high concentration; +, low concentration; −, absent.

The results showed significant (P < 0.05) increase in body weight of Wistar rats after 16 days administration of aqueous stem bark extract of S. setigera compared to the control and B complex-treated group (Table 2). The body weights of rats treated with B complex increased by 22.56%, while the body weight of rats treated with aqueous S. setigera stem bark extract increased by 33.85% compared to the control group that increased by 13% only (Table 2).

Table 2

Body weights of Wistar rats treated with S. setigera bark extract.

TREATMENT GROUP(S)	WEIGHTS (G)
	DAY 1	DAY 4	DAY 8	DAY 12	DAY 16
No treatment (control)	192 ± 0.23a	203 ± 1.23a	207 ± 1.41a	214 ± 1.03a	217 ± 1.28a
B complex	210 ± 0.51b	223 ± 0.93b	230 ± 0.99b	214 ± 1.59a	236 ± 1.27b
Sterculia setigera aq. extract	210 ± 0.45b	223 ± 0.33b	248 ± 0.67c	248 ± 1.97b	257 ± 1.63c

Note: Values with different superscript down the row are significantly (P<0.05) different.

The hematological profile of rats treated with aqueous stem bark extract of S. setigera showed that levels of hemoglobin (HGB), packed cell volume (PCV), mean corpuscular volume (MCV), mean cell hemoglobin concentration (MCHC), platelets (PLT), and NEUT were significantly higher (P < 0.05) than those in both the control and B complex-treated rats. The B complex-treated group showed increase in the levels of red blood cells (RBCs), mean cell hemoglobin (MCH), and MCHC. White blood cell (WBC) count of the rats administered with the extract was not significantly different from that of the control. There was a significant decrease in the levels of neutrophils in both B complex and extract-treated groups when compared with the control (Table 3).

Table 3

The hematological profile of rats after administration of the aqueous bark extract of S. setigera.

	1	2	3
RBC (×106/uL)	7.1+±+0.51b	6.5+±+0.72a	7.5+±+0.56b
HGB (g/dl)	5.6+±+0.07a	5.9+±+0.09a	6.6+±+0.11b
PCV (%)	36.0+±+0.78a	38.7+±+1.89b	48.8+±+1.51c
MCV (f1)	56.3+±+2.51a	71.8+±+3.13b	74.7+±+3.59b
MCH (pg)	14.0+±+1.81a	16.1+±+2.55b	15.1+±+1.54b
MCHC (g/dl)	41.1 ±+2.34a	46.6 ±+2.66b	61.8 ±+3.01c
PLT (×1000)	1203+±+3.82a	1491+±+4.34b	1629+±+4.45c
WBC (×109/L)	5.4+±+0.01a	6.3+±+0.05c	5.6+±+0.08a
LYM (%)	64.4 ±+3.07a	67.3 ±+3.52b	66.9 ±+2.61b
NEUT ×103/Ul	10.3 ±+2.11c	5.1 ±+2.64a	6.5 ±+1.91b

Notes: Values with different superscript across the column are significantly (P < 0.05) different. Group(s) 1: control, 2: B complex, 3: S. setigera aq. extract treated, respectively.

Table 4 shows the effect of aqueous stem bark extract of S. setigera in rat liver biomarkers (ALB, total bilirubin [TB], ALT, and AST) after 16 days of administration. There was negligible increase in ALT level (0.03%), while AST level decreased by 8.88%. The levels of serum ALB and TB for both vitamin B complex and aqueous stem bark S. setigera-treated group of rats increased slightly compared to the control groups.

Table 4

Biochemical parameters of rats’ liver after the administration of the aqueous extract of S. setigera.

GROUP(S)	ALT (U/L)	AST (U/L)	ALB (g/dl)	TB (g/dl)
1.	70.8 ± 3.71a	74.2 ± 3.71b	4.1 ± 0.01a	0.8 ± 0.03a
2.	71.4 ± 2.96a	73.4 ± 3.40b	4.4 ± 0.02a	1.0 ± 0.01b
3.	68.3 ± 4.48a	71.8 ± 2.56a	4.4 ± 0.02a	0.9 ± 0.01b

Notes: Values with different superscript down the row are significantly (P < 0.05) different. Group 1: control, 2: B complex, 3: S. setigera aq. extract treated, respectively

Discussion

S. setigera Del. stem bark aqueous extract revealed that the plant contained copious levels of tannins and saponins and moderate levels of anthraquinones and cardiac glycosides, which is in agreement with previous studies,10,11 except for the absence of phenols and flavonoids observed in the present study. The presence of saponin (although in low concentration) is an important indicator and justifies the use of S. setigera in traditional medicine. This is due to the fact that saponin serves mainly as an important adjuvant in vaccines20 and was previously reported to have shown hematopoietic properties.21 Previous studies showed that the bactericidal properties of plants are attributed to the presence of active secondary metabolites such as alkaloids, flavonoids, and saponins.22–24 The absence of phenols and flavonoids in the present study could be attributed to the fact that aqueous stem bark extract of S. setigera Del. was used as against methanolic leaf extracts used in the previous work by Hamidu.10 The variations in bioactive metabolites of the same plant could also be attributed to the difference in their habitat.25 The absence of flavonoids in the stem bark extract of S. setigera Del. was also reported by Tor-Anyiin et al.11 However, the use of organic solvents such as acetone, ethanol, methanol, and petroleum ether could be investigated further to confirm the presence of these phytochemicals for possible development of novel drugs.

The B complex group showed an increase of 98.7% in weight than the untreated group of rats (86.0%). There was an unexplained decrease in weight on day 8, but the rats quickly regained their body weight by the 12th day. S. setigera-treated animals consistently gained weight all through the experiment.

Tor-Anyiin et al11 opined that these constituents may be responsible for the biological properties observed. Increase in body weight is an indication that the extract contains nutrients that are properly digested and utilized by the body.

The study showed that both S. setigera aqueous stem bark extract and B complex elicit an increase in the level of hematological profiles in white Wistar rats with S. setigera, showing a higher hematological effect. B complex has been previously reported to have hematopoietic-stimulating factor.26 S. setigera aqueous stem bark exhibited a better hematological effect than B complex. The increase in PCV and its related indices by the extract is an indication that the extract contains phytochemicals that can stimulate the secretion of erythropoietin—a glycoprotein hormone that stimulates stem cells in the bone marrow to produce RBCs.27 This may be attributed to the presence of saponin21 and its richness in iron and vitamins.14–16,28 Platelet is implicated in blood clotting and plays a crucial role in reducing blood loss and repair of vascular injury.29 The significant increase in platelet concentration by the plant extract indicates that it contains principles capable of stimulating the biosynthesis of blood clotting factors.30 The major functions of WBCs and its differential are to fight infections, defend the body by phagocytosis against invasion by foreign bodies or toxins, and produce or at least transport/distribute antibody in immune response. Insignificant difference in WBC count of the control group and S. setigera bark extract-treated group suggests that the plant does not possess toxins.

The results of 16 days’ evaluation of liver enzymes function showed negligible changes in both B complex and S. setigera groups, indicating that it has no observable adverse effect on the liver function when taken at a controlled dosage. The effect of the extract on the levels of both serum ALB and bilirubin was insignificant. This is indicative that the extract poses no damage to the rat’s liver and its use in traditional medical practice may pose no serious threat to the liver. However, 16 days only provide short-term safety evidence.

Conclusion

This study showed that the aqueous stem bark extract of S. setigera elevated hematological parameters in rats and also showed insignificant change in the level of disease biomarkers tested. The dose effect of S. setigera stem bark extracts on both hematological and biochemical parameters may be further studied for possible therapeutic applications in the management of hematological-related disorders because its use by tradomedical practitioners is justified.