Ting Wang, Guangying Chen, Ying Liu, Xiaoping Song, Changri Han and Johnny J He
Background: Highly active antiretroviral therapy (HAART) is the current treatment for HIV/AIDS and contains a combination of anti-HIV reverse transcriptase inhibitors and protease inhibitors. It is effective in suppressing HIV replication and subsequently improving the patients’ survival. However, the issues associated with use of HARRT such as the high cost, severe side effects, and drug resistance has called for development of alternative anti-HIV therapeutic strategies. In this study, we screened several traditional Chinese medicinal herbal extracts for their anti- HIV activities and determined their anti-HIV mechanisms.
Materials and Methods: Nine traditional Chinese medicinal (TCM) herbal plants and their respective parts derived from Hainan Island, China were extracted using a series of organic solvents, vacuum dried, and dissolved in dimethyl sulfoxide. Initial anti-HIV activity and cytotoxicity of these extracts were evaluated in HIV-infected human CD4+ T lymphocytes Jurkat. Extracts of higher anti-HIV activities and lower cytotoxicity were selected from the initial screening, and further examined for their effects on HIV-1 entry, post-entry, reverse transcriptase, gene transcription and expression using a series of virology and biochemistry strategies.
Results: Four extracts derived from two different herbal plants completely blocked HIV-1 replication and showed little cytotoxicity at a concentration of 10 μg/ml. None of these four extracts had any inhibitory effects on HIV-1 long terminal repeat promoter. Two of them exhibited direct inhibitory activity against HIV-1 reverse transcriptase (RT). All four extracts showed significant blocking of HIV-1 entry into target cells.
Conclusions: These results demonstrated that four TCM extracts were capable of preventing HIV-1 infection and replication by blocking viral entry and/or directly inhibiting the RT activity. These results suggest the possibility of developing these extracts as potential anti-HIV therapeutic agents.