Prenylisoflavonoids from Erythrina senegalensis as Novel HIV-1 Protease Inhibitors

Eight compounds were isolated from the CH 2 Cl 2 extracts of ERYTHRINA SENEGALENSIS to assess HIV-1 protease (PR) activity inhibition. The prenylated isoflavone structures, identified by spectroscopic analysis, were 8-prenylluteone ( 1), auriculatin ( 2), erysenegalensein O ( 3), erysenegalensein D ( 4), erysenegalensein N ( 5), derrone ( 6), alpinumisoflavone ( 7), and 6,8-diprenylgenistein ( 8). The constituents showed dose-dependent inhibitory activities on HIV-1 PR with IC 50 values from 0.5 to 30.0 μM. Compounds 1 - 5 possessing two hydroxy groups in the 2′ and 4′ positions of the B ring, potently inhibited HIV-1 PR activity. In addition, 6,8-diprenylgenistein ( 8) with two prenyl groups in the 6 and 8 positions of the A ring and one hydroxy group in the 4′ position of B-ring was the most potent HIV-1 PR inhibitor.