AIM： To evaluate the anti-HIV activity and mechanism of action of wikstroelide M, a daphnane diterpene from Daphne acutiloba Rehder （Thymelaeaceae）. METHOD： The anti-HIV activities of wikstroelide M against different HIV strains were evaluated by cytopathic effect assay and p24 quantification assay with ELISA. The inhibitory effect of wikstroelide M on HIV reverse transcription was analyzed by real-time PCR and ELISA. The effect of wikstroelide M on HIV-1 integrase nuclear translocation was observed with a cell-based imaging assay. The effect of wikstroelide M on LEDGF/p75-IN interaction was assayed by molecular docking. RESULTS： Wikstroelide M potently inhibited different HIV-1 strains, including HIV-lmn, HIV-1AI7, and HIV-19495, induced a cytopathic effect, with ECs0 values ranging from 3.81 to 15.65 ng.mL-I. Wikstroelide M also had high inhibitory activities against HIV-2noD and HIV-2cBL_20-induced cytopathic effects with ECs0 values of 18.88 and 31.90 ng.mL 1. The inhibitory activities of wikstroelide M on the three HIV-1 strains were further confirmed by p24 quantification assay, with ECs0 values ranging from 15.16 to 35.57 ng.mL-1. Wikstroelide M also potently inhibited HIV-lnm induced cytolysis in MT-4 cells, with an ECs0 value of 9.60 ng.mL ~. The mechanistic assay showed that wikstroelide M targeted HIV-I reverse transcriptase and nuclear translocation of integrase through disrupting the interaction between integrase and LEDGF/p75. CONCLUSION： Wikslroelide M may be a potent HIV-1 and HIV-2 inhibitor, the mechanisms of action may include inhibition of reverse trascriptase activity and inhibition of integrase nuclear Iranslocation through dismpting the interaction between integrase and LEDGF/p75.
