Reproductive Cell Biology Laboratory, National Institute of Immunology, New Delhi, India.
Indian J Med Res. 2013 Mar;137(3):540-8.
BACKGROUND & OBJECTIVES: Banaba (Lagerstroemia speciosa L.) extracts have been used as traditional medicines and are effective in controlling diabetes and obesity. The aim of this study was to evaluate the anti-HIV property of the extracts prepared from the leaves and stems of banaba, and further purification and characterization of the active components.
Aqueous and 50 per cent ethanolic extracts were prepared from leaves and stems of banaba and were evaluated for cytotoxicity and anti-HIV activity using in vitro reporter gene based assays. Further, three compounds were isolated from the 50 per cent ethanolic extract of banaba leaves using silica gel column chromatography and characterization done by HPLC, NMR and MS analysis. To delineate the mode of action of the active compounds, reverse transcriptase assay and protease assay were performed using commercially available kits.
All the extracts showed a dose dependent inhibition of HIV-1-infection in TZM-bl and CEM-GFP cell lines with a maximum from the 50 per cent ethanolic extract from leaves (IC 50 = 1 to 25 μg/ml). This observation was confirmed by the virus load (p24) estimation in infected CEM-GFP cells when treated with the extracts. Gallic acid showed an inhibition in reverse transcriptase whereas ellagic acid inhibited the HIV-1 protease activity.
INTERPRETATION & CONCLUSIONS: The present study shows a novel anti-HIV activity of banaba. The active components responsible for anti-HIV activity were gallic acid and ellagic acid, through inhibition of reverse transcriptase and HIV protease, respectively and hence could be regarded as promising candidates for the development of topical anti-HIV-1 agents.
罗望子（Lagerstroemia speciosa L.）提取物已被用作传统药物，对控制糖尿病和肥胖症有效。本研究旨在评估罗望子叶和茎提取物的抗 HIV 特性，并进一步纯化和鉴定活性成分。
从罗望子叶和茎中制备水提物和 50%乙醇提取物，并通过体外报告基因检测评估其细胞毒性和抗 HIV 活性。进一步采用硅胶柱色谱法从罗望子叶的 50%乙醇提取物中分离出三种化合物，通过 HPLC、NMR 和 MS 分析进行鉴定。为了阐明活性化合物的作用机制，使用市售试剂盒进行逆转录酶测定和蛋白酶测定。
所有提取物均表现出对 TZM-bl 和 CEM-GFP 细胞系中 HIV-1 感染的剂量依赖性抑制作用，其中来自罗望子叶的 50%乙醇提取物的抑制作用最强（IC 50 = 1 至 25 μg/ml）。当用提取物处理感染的 CEM-GFP 细胞时，通过病毒载量（p24）估计证实了这一观察结果。没食子酸显示出对逆转录酶的抑制作用，而鞣花酸则抑制 HIV-1 蛋白酶活性。
本研究表明罗望子具有新的抗 HIV 活性。负责抗 HIV 活性的活性成分是没食子酸和鞣花酸，分别通过抑制逆转录酶和 HIV 蛋白酶，因此可以被视为开发局部抗 HIV-1 药物的有前途的候选物。
