The structure of antrocarine E, an ergostane isolated from Antrocaryon klaineanum Pierre (Anacardiaceae).

Eight compounds were isolated from the stem bark of Antrocaryon klaineanum, and their structures determined by chemical and spectroscopic methods. Among these compounds, the ergostane-type antrocarine E (1a) is a new compound, although the structure had already been published by mismatching the spectroscopic data with those of 2. In this paper, we are reporting the valid spectroscopic values for antrocarine E and X-ray diffraction results.

Norbergenin derivatives from Diospyros crassiflora (Ebenaceae).

From the ethyl acetate extract of the stems of Diospyros crassiflora Hiern, three new norbergenin derivatives, 4,11-di-O-galloylnorbergenin (1), 3-O-galloylnorbergenin (2), and 4-O-(4'-hydroxy-3'-methoxybenzoyl)-norbergenin (3), were isolated along with ten known compounds (4-13). Their structures were established by mean of spectroscopic techniques namely 1- and 2-D NMR experiments, mass spectrometry and comparison with reported data. Isolates 1-9 were evaluated for their ability to protect PC12 cells against hydrogen peroxide induced injury. Compounds with a galloyl group in their structure were found to prevent toxicity induced by H2O2 in PC12 cells.

New coumarin glycosides from the leaves of Diospyros crassiflora (Hiern).

Two new 5-methylcoumarin glycosides named diosfeboside A (1) and B (2) and five known compounds namely kaempferol 3-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranoside (3), ursolic acid (4), betulinic acid (5), stigmasterol (6) and stigmasterol 3-O-ß-D-glucopyranoside (7) were isolated from the leaves of Diospyros crassiflora (Hiern). Their structures were established through interpretation of 1 and 2D NMR, mass spectra analysis and comparison with reported data. In vitro cytotoxic activity of the new compounds against human carcinoma cell lines (HL-60, Bel-7402, BGC-823, and KB) was evaluated and no cytotoxicity was observed for each of them.