Studies On Anti-HIV-1 Activity Of Fungi Extracts

Finding anti-HIV drugs from Chinese traditional medicine was always a good method in new drugs research. In recent years some researches indicated that several endophytic fungi of medicinal plants had the same or similar active components to their hosts. In order to find anti-HIV agents from natural products, 97 extracts of 90 fungi were tested for their inhibitory activity on human immunodeficiency virus type 1 (HIV-1). Most of the extracts tested were relatively nontoxic to human lymphocytic MT-4 cells, but only the extracts of No. 1, No. 3, No. 9, No. 23, No. 35, No.36, No. 43, No. 68, No. 70, No. 93, No. 105 fungus exhibited potent anti-HIV activity in an in vitro MTT assay. The mycelium extract of No. 1 (Ml) was selected to study detailedly and the strain was isolated from root of Dendrobium condidum. and identified as Epulorhiza sp..M1 had low cytotoxicity to MT-4 cells in vitro which CC50 was >1000μ g/ml. M1 inhibited acute HIV infection in vitro which IC50 for p24 antigen was <31.25μg/ml and was effective when it was added 12 h after infection. PCR analysis of infected cells demonstrated that Ml delayed the appearance of late product of reverse transcription and HIV was blocked before its RNA expression. Ml did not inhibite HIV-1 reverse transcriptase, integrase and protease. Ml did not inhibite HIV-1 adsorpting and entry into MT-4 cells either. The target of Ml is post-integration of proviral DNA. When combined with AZT, Ml showed an additive effect at tested concentrations.Ml had low anti- oxidation activity and eliminating oxygen free radical ability, but the culture supernatants of M1 and MT-4 cells had higher ability to eliminate oxygen free radical. Ml inhibited apoptosis of MT-4 cells induced by dexamethasone and increased the live cell counts of MT-4 cells.Advances in the research of anti-HIV products were reviewed.