Hepatoprotective and in-vitro anti-HIV-1 effect of Alectryon tomentosus F. Muell leaf extract and its phytochemical profile

Abstract

ObjectivesThis work was designed to evaluate the therapeutic efficacy of Alectryon tomentosus F. Muell leaf extract against CCl 4 -induced hepatic injury in albino rats and anti-HIV effect in vitro. Proximate analysis, phytochemical screening and assay of total flavonoid (TFC) and phenolic contents (TPC), were carried out according to standard methods.Materials and methodsThe TPC and TFC were estimated spectrophotometrically. The median lethal dose (LD 50 ) of the total ethanol extract of A. tomentosus F. Muell leaves was evaluated. The effect on acute HIV-1 infectivity was measured with the syncytium formation assay using AZT (3΄-azido-3΄-deoxythymidine) as a positive control. Moreover, carbon tetrachloride-induced acute hepatic damage was used to evaluate the hepatoprotective effect of the leaves.Results and conclusionProximate analysis of air-dried leaves of A. tomentosus F. Muell revealed 8.3% moisture content, 9.2% total ash, 0.48% water-soluble ash and 2.56% acid-insoluble ash. Preliminary phytochemical screening revealed that the dried powdered leaves of A. tomentosus F. Muell are rich in carbohydrates and/or glycosides, volatile constituents, sterols and/or triterpenes and tannins; however, flavonoids (free and combined) and coumarins are present in a lesser concentration. Alkaloids, saponins, cardiac glycosides and anthraquinones are absent. The evaluated TPC was 71.59 mg gallic acid equivalent/g dry weight, whereas TFC was 63.64 mg quercetin equivalent/g plant dry weight. The median lethal dose (LD 50 ) of the total ethanol extract was found to be 9.2 g/kg body weight, indicating the safety of the leaves of the plant. In carbon tetrachloride-induced acute hepatic damage model, the methylene chloride extract showed the highest protection percentage as shown by reduction in the level of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase levels, followed by aqueous extract. These may be attributed to their phenolic and flavonoidal content. The anti-HIV-1 activity was assessed by evaluating syncytium formation. The results showed that the extract was minimally toxic and showed a weak anti-HIV-1 activity in comparison with AZT.