Inhibition of HIV-1 entry by extracts derived from traditional Chinese medicinal herbal plants

In-Woo Park,Ying Liu,Johnny J He,Xiaoping Song,Guangying Chen,Changchun Cen,Changri Han,Linden A Green,Xinming Song,Ting Wang,Biao Yang

doi:10.1186/1472-6882-9-29

Abstract

BackgroundHighly active anti-retroviral therapy (HAART) is the current HIV/AIDS treatment modality. Despite the fact that HAART is very effective in suppressing HIV-1 replication and reducing the mortality of HIV/AIDS patients, it has become increasingly clear that HAART does not offer an ultimate cure to HIV/AIDS. The high cost of the HAART regimen has impeded its delivery to over 90% of the HIV/AIDS population in the world. This reality has urgently called for the need to develop inexpensive alternative anti-HIV/AIDS therapy. This need has further manifested by recent clinical trial failures in anti-HIV-1 vaccines and microbicides. In the current study, we characterized a panel of extracts of traditional Chinese medicinal herbal plants for their activities against HIV-1 replication.MethodsCrude and fractionated extracts were prepared from various parts of nine traditional Chinese medicinal herbal plants in Hainan Island, China. These extracts were first screened for their anti-HIV activity and cytotoxicity in human CD4+ Jurkat cells. Then, a single-round pseudotyped HIV-luciferase reporter virus system (HIV-Luc) was used to identify potential anti-HIV mechanisms of these extracts.ResultsTwo extracts, one from Euphorbiaceae, Trigonostema xyphophylloides (TXE) and one from Dipterocarpaceae, Vatica astrotricha (VAD) inhibited HIV-1 replication and syncytia formation in CD4+ Jurkat cells, and had little adverse effects on host cell proliferation and survival. TXE and VAD did not show any direct inhibitory effects on the HIV-1 RT enzymatic activity. Treatment of these two extracts during the infection significantly blocked infection of the reporter virus. However, pre-treatment of the reporter virus with the extracts and treatment of the extracts post-infection had little effects on the infectivity or gene expression of the reporter virus.ConclusionThese results demonstrate that TXE and VAD inhibit HIV-1 replication likely by blocking HIV-1 interaction with target cells, i.e., the interaction between gp120 and CD4/CCR5 or gp120 and CD4/CXCR4 and point to the potential of developing these two extracts to be HIV-1 entry inhibitors.

Highlights

Active anti-retroviral therapy (HAART) is the current HIV/acquired immune deficiency syndrome (AIDS) treatment modality
Human immunodeficiency virus type 1 (HIV-1) life cycle begins with binding of HIV-1 gp120 to cellular receptors CD4 and chemokine receptors CCR5 or CXCR4 that are expressed on the surface of HIV-1 target cells, followed by gp41 conformational change, which in turn leads to virus-cell membrane fusion and entry of the viral core into the cytoplasm [4,5,6]
We included the solvent dimethyl sulfoxide (DMSO) of the extracts and an HIV-1 reverse transcriptase (RT) inhibitor AZT in these experiments

Summary

Introduction

Active anti-retroviral therapy (HAART) is the current HIV/AIDS treatment modality. The high cost of the HAART regimen has impeded its delivery to over 90% of the HIV/AIDS population in the world. This reality has urgently called for the need to develop inexpensive alternative anti-HIV/AIDS therapy. Concomitant with budding, a third virally encoded enzyme protease (PR) processes the core proteins into their final forms, and the virion undergoes a morphologic change known as maturation [7,13]. This final step primes the progeny viruses for the round of infection

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Conclusion