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-1IIIB,HIV-1A17,and HIV-19495,induced a cytopathic effect,with EC50 values ranging from 3.81 to 15.65 ng·mL-1.Wikstroelide M also had high inhibitory activities against HIV-2ROD and HIV-2CBL-20-induced cytopathic effects with EC50 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 EC50 values ranging from 15.16 to 35.57 ng·mL-1.Wikstroelide M also potently inhibited HIV-1IIIB induced cytolysis in MT-4 cells,with an EC50 value of 9.60 ng·mL-1.The mechanistic assay showed that wikstroelide M targeted HIV-1 reverse transcriptase and nuclear translocation of integrase through disrupting the interaction between integrase and LEDGF/p75.CONCLUSION:Wikstroelide 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 translocation through disrupting the interaction between integrase and LEDGF/p75.
