Inhibition of HIV-1 Protease and RNase H of HIV-1 Reverse Transcriptase Activities by Long Chain Phenols from the Sarcotestas of Ginkgo biloba

Abstract

Nine long-chain phenols: four cardanols (1 - 4), two bilobols (5, 6) and three alkylsalicylic acids (7 B 9) were isolated from the CH₂Cl₂ extracts of the sarcotestas of Ginkgo biloba as HIV-1 protease (PR) inhibitors. From these phenols, the bilobols (IC₅₀, 2.6 - 5.8 μM) and alkylsalicylic acids (IC₅₀, 10.2 - 24.9 μM) exhibited dose-dependent potent inhibitory activities on HIV-1 PR, while the cardanols did not. On the other hand, only the alkylsalicylic acids (IC₅₀, 33.7 - 170.3 μM) inhibited the activities of RNase H of HIV-1 reverse transcriptase (RT), while all of the compounds failed to affect the RNA dependent DNA polymerase (RDDP) of HIV-1 RT. Therefore, we regard bilobols as a new class and selective inhibitors of HIV-1 PR; in addition, alkylsalicylic acids are elucidated as a new class of inhibitors against HIV-1 PR and RNase H of HIV-1 RT.

Key words

Ginkgo biloba - Ginkgoaceae - long-chain phenol - bilobol - alkylsalicylic acid - HIV-1 protease - RNase H of HIV-1 reverse transcriptase

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