RT Journal Article SR Electronic T1 Antiviral Activities of Extracts of Euphorbia hirta L. against HIV-1, HIV-2 and SIVmac251 JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 429 OP 432 VO 23 IS 3 A1 GYURIS, ÁGNES A1 SZLÁVIK, LÁSZLÓ A1 MINÁROVITS, JÁNOS A1 VASAS, ANDREA A1 MOLNÁR, JOSEPH A1 HOHMANN, JUDIT YR 2009 UL http://iv.iiarjournals.org/content/23/3/429.abstract AB The antiretroviral activities of extracts of Euphorbia hirta were investigated in vitro on the MT4 human T lymphocyte cell line. The cytotoxicities of the extracts were tested by means of the MTT cell proliferation assay, and then the direct effects of the aqueous extract on HIV-1, HIV-2 and SIVmac251 reverse transcriptase (RT) activity were determined. A dose-dependent inhibition of RT activity was observed for all three viruses. The HIV-1 inhibitory potency of E. hirta was studied further, and the activities of the aqueous and 50% methanolic extracts were compared. The 50% methanolic extract was found to exert a higher antiretroviral effect than that of the aqueous extract. The 50% MeOH extract was subjected to liquid-liquid partition with dichloromethane, ethyl acetate and water. Only the remaining aqueous phase exhibited significant antiviral activity; all the lipophilic extracts appeared to be inactive. After removal of the tannins from the aqueous extract, the viral replication inhibitory effect was markedly decreased, and it was therefore concluded that tannins are most probably responsible for the high antiretroviral activity.