RESUMEN
CONTEXT: Integrase (IN) is one of the three human immunodeficiency virus type 1 (HIV-1) enzymes that, together with a reverse transcriptase and protease, allow the virus to reproduce itself after infecting the host cells. Any new knowledge on inhibitors of this enzyme could provide essential clues for the development of anti-HIV drugs. OBJECTIVE: To evaluate the anti-HIV-1 IN activity of some Thai medicinal plant extracts, and to isolate the active compounds from the extract that possessed the strongest anti-HIV-1 IN activity. MATERIALS AND METHODS: Ethanol extracts of eight Thai medicinal plants (10-100 µg/mL) were evaluated for their inhibitory effect against HIV-1 IN. An extract of Mimusops elengi L. (Sapotaceae) leaves that possessed the strongest anti-HIV-1 IN activity was fractionated to isolate the active compounds by an anti-HIV-1 IN assay-guided isolation process. RESULTS AND DISCUSSION: The leaf extract from M. elengi had the strongest anti-HIV-1 IN activity with an IC50 value of 62.1 µg/mL. A bioassay-guided isolation of the active compounds from M. elengi leaf extract resulted in the isolation of active compounds, identified as a mixture of gallocatechin and epigallocatechin. This mixture of gallocatechin and epigallocatechin showed satisfactory anti-HIV-1 IN activity with an IC50 value of 35.0 µM. A flavanol glycoside, mearnsitrin was also isolated but was inactive at a concentration of 100 µM.