[Inhibition of HIV-1 mediated cell-cell fusion by saponin fraction from Psidium guajava leaf].

ABSTRACT

OBJECTIVE: To investigate the effects of the total saponin of Psidium guajava leaf (TSGL) on HIV-1 envelop proteins (env) mediated virus entry into target cells. METHODS: The TSGL was purified and concentrated using SA-1 macropore resin. The effect of TSGL on HIV-1 entry into target cells was tested using a cell-cell fusion assay by mixing CHO-WT and MT-2 cells. The cytotoxicity of TSGL was measured by MTT assay. The activity of TSGL on blocking the HIV-1 gp41 six helical bundle (6-HB) formation was analyzed by ELISA and Native-PAGE (N-PAGE). RESULTS: The TSGL could inhibit HIV env mediated cell-cell fusion with an IC50 of (7.33 +/- 0.40) microg/mL, and displayed little cytotoxicity at that concentration. ELISA assay showed that the TSGL could prevent gp41 6-HB formation with inhibitory activity of 95.93% at 25 microg/mL. N-PAGE study confirmed the inhibitory effect of TSGL on gp41 6-HB formation. CONCLUSIONS: The TSGL can inhibit HIV entry target cells by interfering the envelop subunit gp41 form the critical 6-HB structure.