A weakly antimalarial biflavanone from Rhus retinorrhoea

The biflavanone (2S,2 "S)-7,7 " -di-O-methyltetrahydroamentoflavone and fiv e known flavonoids, 7-O-methylnaringenin, 7,3'-O-dimethylquercetin, 7-O-met hylapigenin, 7-O-methylluteolin, and eriodictyol were isolated from the lea ves of Rhus retinorrhoea Steud, Ex Olive. The biflavanone exhibited moderat e antimalarial activity with IC50 0.98 mug/ml against Plasmodium falciparum (W2 Clone) and weak activity against P. falciparum (D6 Clone) with IC50 2. 8 mug/ml. Nevertheless, it did not display any cytotoxicity. 7-O-Methylnari ngenin showed weak antimicrobial activity against Candida albicans, C. krus ei, Staphylococcus aureus, Mycobacterium smegmatis, M. intracellulare, and M. xenopi with MIC similar to 100 mug/ml. Characterization of each compound was based on spectral analysis and comparison with reported data. (C) 2001 Elsevier Science Ltd. All rights reserved.