ABSTRACT
CONTEXT: HIV-1 integrase (HIV-1 IN) is a key enzyme involved in the replication cycle of the retrovirus. Any new knowledge on inhibitors of this enzyme could provide essential clues for the development of anti-HIV drugs. OBJECTIVE: To evaluate anti-HIV-1 IN activity of some Thai medicinal plant extracts, and the extract that possessed the strongest anti-HIV-1 IN activity was subjected to isolation of the active compounds. MATERIALS AND METHODS: Ethanol extracts of eight Thai medicinal plants were evaluated for their inhibitory effect against HIV-1 IN. An extract of Pometia pinnata J. R. Forst. & G. Forst (Sapindaceae) leaves that possessed the strongest anti-HIV-1 IN activity was fractionated to isolate the active compounds by anti-HIV-1 IN assay-guided isolation process. RESULTS AND DISCUSSION: The leaf extract from P. pinnata had the strongest anti-HIV-1 IN activity with an IC50 value of 8.8 µg/mL. An anti-HIV-1 IN assay-guided isolation of the active compounds from a leaf extract of P. pinnata resulted in the isolation of one active compound, identified as proanthocyanidin A2. Proanthocyanidin A2 showed satisfactory anti-HIV-1 IN activity with an IC50 value of 30.1 µM. Three flavonoids, epicatechin, kaempferol-3-O-rhamnoside, quercetin-3-O-rhamnoside; a glycolipid, 1-O-palmitoyl-3-O-[α-.-galactopyranosyl-(1 â 6)-ß-.-galactopyranosyl]-sn-glycerol; a steroidal glycoside; stigmasterol-3-O-glucoside; and a pentacyclic triterpenoid saponin, 3-O-α-.-arabinofuranosyl-(1 â 3)-[α-.-rhamnopyranosyl-(1 â 2)]-α-.-arabinopyranosyl hederagenin were also isolated but were inactive at a concentration of 100 µM.
