Prenylated flavonoids from the stems and roots of Tripterygium wilfordii.

Phytochemical investigation on the stems and roots of Tripterygium wilfordii led to the isolation and characterization of three new prenylated flavanones, tripteryols A-C (1-3), along with (±)-5,4'-dihydroxy-2'-methoxy-6',6″-dimethypyraro-(2″,3″:7,8)-6-methyflavanone (4), and ((2S)-5,7,4'-trihydroxy-2'-methoxy-8,5'-di(3-methyl-2-butenyl)-6-methylflavanone (5). Structures of the compounds 1-5 were elucidated using spectroscopic techniques, such as UV, IR, NMR (1D and 2D), and HRESI-MS. Tripteryols B (2) was found active in the antimicrobial assay against Cryptococcus neoformans, Pseudomonas aeruginosa, vancomycin-resistant Enterococcus faecalis (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) with IC50 values in the range of 2.95-8.59μg/mL. Compounds 4 and 5 showed significant antimicrobial activities against C. neoformans, MRSA and Staphylococcus aureus with IC50 values in the range of 1.06-2.60μg/mL. Additionally, significant antimalarial activities of tripteryols A-B (1-2) against chloroquine-sensitive D6 and resistant W2 clones of Plasmodium falciparum were observed and none of the compounds 1-5 were cytotoxic to Vero cells.