Screening of selected wood-damaging fungi for the HIV-1 reverse transcriptase inhibitors.

Extracts obtained using methanol and dichloromethane from 57 species of wood damaging fungi were investigated for their ability to inhibit HIV-1 reverse transcriptase activity in vitro using a non-radioactive assay. Sixty-three samples were tested all together; some species were represented more than one isolate. Thirteen methanolic extracts exhibited more than 40% inhibition and two among them inhibited the enzyme by more than 80%. All extracts obtained with dichloromethane were inferior to methanolic extracts in their inhibitory activity. The most active fungal species discovered in the first screening were Laetiporus sulphureus and Poria monticola, followed by Poria vaillanti and Chondrostereum purpureum. In the second screening, Laetiporus sulphureus was selected for detailed examination and different isolates were tested. Preliminary findings confirmed the presence of an acidic compound with the amino group in the most active fraction.