Extracts from Acacia catechu suppress HIV-1 replication by inhibiting the activities of the viral protease and Tat.

BACKGROUND: Acacia catechu (Mimosa family) stem bark extracts have been used traditionally as a dietary supplement as well as a folk medicine given its reported anti-inflammatory, immunomodulatory, hepatoprotective, antioxidant, anti-microbial and anti-tumor activities. The present study was undertaken to evaluate the anti-HIV-1 activity of the extracts from stem bark of A. catechu. METHODS: The aqueous and 50% ethanolic extracts of A. catechu stem bark were prepared and 50% ethanolic extract was further fractioned by successively partitioning with petroleum ether, chloroform and n-butanol. All the extracts and fractions were evaluated for cytotoxicity and anti-HIV-1 activity using different in vitro assays. The active n-butanol fraction was evaluated for its inhibition against HIV-1 reverse transcriptase, integrase, protease, pro-viral genome integration and viral Tat protein mediated transactivation. The effect of n-butanol fraction on the induction of pro-inflammatory cytokines secretion in Vk2/E6E7 cells and transepithelial resistance in Caco-2 and HEC-1A cells was investigated. RESULTS: The aqueous and 50% ethanolic extracts of A. catechu showed IC50 values of 1.8 ± 0.18 µg/ml and 3.6 ± 0.31 µg/ml, respectively in cell-free virus based assay using TZM-bl cells and HIV-1NL4.3 (X-4 tropic). In the above assay, n-butanol fraction exhibited anti-HIV-1 activity with an IC50 of 1.7 ± 0.12 µg/ml. The n-butanol fraction showed a dose-dependent inhibition against HIV-1NL4.3 infection of the peripheral blood lymphocytes and against HIV-1BaL(R-5-tropic) as well as two different primary viral isolates of HIV-1 infection of TZM-bl cells. The n-butanol fraction demonstrates a potent inhibitory activity against the viral protease (IC50 = 12.9 µg/ml), but not reverse transcriptase or integrase. Further, in Alu-PCR no effect on viral integration was observed. The n-butanol fraction interfered with the Tat-mediated Long Terminal Repeat transactivation in TZM-bl cells, mRNA quantitation (qRT-PCR) and electrophoretic mobility shift assay (EMSA). The n-butanol fraction did not cause an enhanced secretion of pro-inflammatory cytokines in Vk2/E6E7 cells. Additionally, no adverse effects were observed to the monolayer formed by the Caco-2 and HEC-1A epithelial cells. CONCLUSIONS: The results presented here show a potential anti-HIV-1 activity of A. catechu mediated by the inhibition of the functions of the viral protein and Tat.

Ellagic acid & gallic acid from Lagerstroemia speciosa L. inhibit HIV-1 infection through inhibition of HIV-1 protease & reverse transcriptase activity.

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. METHODS: 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. RESULTS: 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.

Estimation of heavy metals in different berberis species and its market samples.

Popularity of herbal drugs is increasing all over the world because of lesser side effects as compared to synthetic drugs. Besides, it costs less and easily available to poor people particularly in developing countries. But quality assurance of herbal drugs is very necessary prior to its use. Because in today's polluted environment, even herbal drugs are not safe. Berberis spp. is very important medicinal plant, having various medicinal properties. It is also included in Indian and British pharmacopoeias. Its demand is quite high in herbal drug market. So, to check the quality of market samples of this drug, ten different samples were procured from different drug markets of India for heavy metal estimation. Besides, genuine samples of four species of Berberis viz. B. aristata, B. chitria, B. lycium, B. asiatica were also collected from natural habitats to compare heavy metal concentration in both market and genuine samples. It was found that market samples were much more contaminated than genuine samples. Lead (Pb) concentration is far beyond from WHO permissible limit (10 ppm) for herbal drugs, reaching to maximum 49.75 ppm in Amritsar market sample. Likewise, concentration of all other metals like Cd, Cr and Ni were also very high in market samples as compared to genuine samples.