INHIBITORY EFFECTS OF EGYPTIAN FOLK MEDICINES ON HUMAN-IMMUNODEFICIENCY-VIRUS (HIV) REVERSE-TRANSCRIPTASE

Extracts of 41 medicinal plants used in Egyptian folk medicine were sc reened for their inhibitory effects on human immunodeficiency virus-1 reverse transcriptase. The extracts of fruits of Phyllanthus emblica, Quercus pedunculata, Rumex cyprius, Terminalia bellerica, Terminalia c hebula and Terminalia horrida showed significant inhibitory activity w ith IC(50)less than or equal to 50 mu g/ml. Through a bioassay guided- fractionation of the methanol extract of the fruit of P. emblica, putr anjivain A (1) was isolated as a potent inhibitory substance with IC50 =3.9 mu M, together with 1,6-di-O-galloyl-beta-D-glucose (2), 1-O-gall oyl-beta-D-glucose (3), kaempferol-3-O-beta-D-glucoside (4), quercetin -3-O-beta-D-glucoside (5) and digallic acid (6). The inhibitory mode o f action by 1, 2 and 6 was non-competitive with respect to the substra te but competitive with respect to a template-primer. Furthermore, the stereochemistry of 1 was established in this paper by nuclear magneti c resonance spectroscopy.