Emergence of drug resistance demands new therapeutic strategies against the human immunodeficiency virus (HIV). Currently, there is an increasing research focus on targeting gene expression—the crucial step wherein new viruses and new viral strains are amplified. Moreover, natural products are also being considered as potential candidates for new antivirals. We screened the extract obtained from a Philippine medicinal plant, Mentha cordifolia (Mc). In this study, we demonstrated that Mc ammonium sulfate extract has antiretroviral activity against HIV. HIV-1 latently infected cells (OM10.1) were pretreated with Mc extract and activated with TNFα. In treated cells, viral replication was inhibited in both cell culture supernatant and whole cell lysates. The level of viral production, as measured by the viral p24 protein concentration, was very much inhibited under noncytotoxic concentrations to the similar level without addition of TNFα. Luciferase assays, however, showed that Mc does not inhibit the HIV-1 long terminal repeat-driven gene expression. IκBα degradation and p65 nuclear translocation was also not affected as visualized through Western blot and immunofluorescence. These observations demonstrated that Mc possessed an antiviral component against HIV-1 and warrant further work to explore its target of action at a later step of gene expression. Our study introduces a potential source of a lead compound that targets steps in the HIV life cycle.

中文翻译：

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使用已建立的人类细胞系在 HIV-1 潜伏感染细胞中薄荷植物提取物的体外抗病毒活性

耐药性的出现需要针对人类免疫缺陷病毒 (HIV) 的新治疗策略。目前，越来越多的研究关注靶向基因表达——这是扩增新病毒和新病毒株的关键步骤。此外，天然产物也被认为是新抗病毒药物的潜在候选者。我们筛选了从菲律宾药用植物Mentha cordifolia中获得的提取物（麦克）。在这项研究中，我们证明了 Mc 硫酸铵提取物具有抗 HIV 的抗逆转录病毒活性。HIV-1 潜伏感染细胞 (OM10.1) 用 Mc 提取物预处理并用 TNFα 激活。在处理过的细胞中，病毒复制在细胞培养上清液和全细胞裂解物中均受到抑制。通过病毒 p24 蛋白浓度测量的病毒产生水平在不添加 TNFα 的非细胞毒性浓度下受到非常大的抑制，达到相似水平。然而，荧光素酶测定表明，Mc 不抑制 HIV-1 长末端重复驱动的基因表达。通过蛋白质印迹和免疫荧光可见，IκBα 降解和 p65 核转位也没有受到影响。这些观察结果表明，Mc 具有抗 HIV-1 的抗病毒成分，需要进一步的工作来探索其在基因表达后期的作用目标。我们的研究介绍了一种针对 HIV 生命周期各个步骤的先导化合物的潜在来源。