Chemical Investigation of Bioactive Substances from Medicinal Plants

This part deals with chemical investigation of compounds isolated from Anthocephalus cadamba (Roxb.) followed by DNA Topoisomerase IB activity pf the isolates. Chromatographic resolution of the methanolic and ethyl acetate extract of stem bark of Anthocephalus cadamba resulted in the isolation of a new indole alkaloid glycoside known as anthocephaline (1) with five known indole alkaloids (strictosamide, vincosamide, cadambine, 5-carboxystrictosidine and vallesiachotamine). Along with these indole alkaloids four triterpenoids viz., ursolic acid, quinovic acid 3-O-β-Lrhamnopyranoside, 3-O-[α-L-rhamnopyranosyl]-quinovic acid -28-O-[β-Dglucopyranosyl] ester, 3-O-[β-D-glucopyranosyl-(2→1) O-β-D-glucopyranosyl]-quinovic acid-28-O-[β-D-glucopyranosyl] ester and one iridoid glucoside (diderroside) were also isolated. Anthocephaline (1) was found to be an amorphous solid. It gave IR absorptions for hydroxyl and α, β-unsaturated carbonyl groups at 3420 cm-1 and 1653 cm-1 respectively. The UV spectrum exhibited absorptions which were found to be similar to an indole chromophore. The structure was established from detailed 1H and 13C NMR spectroscopic data, along with 2D NMR experiments (COSY, NOESY, HSQC, HMBC). The 1H and 13C NMR data of anthocephaline were very similar to those of naucleomide C, except for the resonances of aromatic protons, and trisubstituted olefinic and enolic protons. The 13C NMR data further indicated the presence of one carbomethoxy carbonyl group instead of an amide carbonyl