Glycosides of ursane-type triterpenoid, benzophenone, and iridoid from Vangueria agrestis (Fadogia agrestis) and their anti-infective activities

Abstract

Four ursane-type triterpenoid glycosides (1-4), two benzophenone glycosides (5 and 6), and one iridoid glucoside (7) were isolated and characterized from the dried roots of Vangueria agrestis. Compounds 1 (3-O-[α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl]pomolic acid 28-O-β-D-glucopyranosyl ester) and 5 (2-O-[β-D-apiofuranosyl-(1→6)-β-D-glucopyranosyl]-6,4′-dihydroxy-4-methoxy benzophenone) were found to be new metabolites. The identity of all compounds has been accomplished, primarily, based on 1 D and 2 D NMR and HRESMS analysis. Compounds 6 and 2, showed inhibitory effect against Trypanosoma brucei with IC₅₀ 22.3 µM for 6 and IC₅₀ 11.1 µM, IC₉₀ 12.3 µM for 2.

Keywords:

• Vangueria agrestis
• Fadogia agrestis
• Rubiaceae
• glycosides
• ursane-triterpenoid
• benzophenone
• iridoid
• anti-infective activities

Acknowledgements

The authors are grateful to Dr. Melissa Jacob and Dr. Babbo Takwani for carrying out the antimicrobial and the antileishmanial bioactivity assays, respectively. Thanks to Dr. Avula for acquiring the accurate mass data.