ABSTRACT
Two xanthones and 4-phenylcoumarins were isolated from the twigs of Mesua beccariana (Baill.) Kosterm. Among them, one new xanthone, beccarianin A (1), along with 7-isoprenyl-jacareubin (2), mammea A/ AA cyclo F (3), and mammea A/BA cyclo F (4). These structures were determined by spectrometric and spectroscopic methods, HRESIMS data, NMR, and UV spectra. Two xanthones (1-2) and two 4-phenylcoumarins (3-4) were evaluated for their cytotoxic effect on the HeLa cells. Compound 1 showed active activity (IC50 = 8.2 µM), and compounds 3-4 showed moderate activity (IC50 = 12.3 and 15.6 µM, respectively).
ABSTRACT
Three isoprenylated flavanones were isolated from the leaves of Flemingia lineata (L.) Aiton. Among them are two new flavanones, flemilineatins A and B (1 - 2), along with 6-isoprenyl eridioctyol (3). Their structures were determined using HRESIMS data and NMR spectra. Flavanones 1 - 3 were assayed in the HeLa cancer cells. Compound 1 showed moderate activity with an IC 50 value of 11.2 µM.
ABSTRACT
A new stilbene, malaysianol E (1), together with five known stilbenes namely gnetol (2), gnetucleistol C (3), gnetucleistol D (4), resveratrol (5) and E-viniferin (6) were successfully discovered from the acetone extract of the lianas of Gnetum microcapum. The structures of these stilbenes were determined on the basis of spectroscopic (1D and 2D NMR) and MS evidence. This paper describes the structural elucidation of the new compound, malaysianol E. The chemotaxonomic significance of this compound is briefly discussed.
