Total phenolic, flavonoid contents, in-vitro antioxidant activities and hepatoprotective effect of aqueous leaf extract of Atalantia ceylanica

BACKGROUND Decoction prepared from leaves of Atalantia ceylanica is used in traditional medicine in Sri Lanka for the treatment of various liver ailments since ancient times. Lyophilized powder of the water extract of A. ceylanica leaves was investigated for its phytochemical constituents, antioxidant and hepatoprotective activity in-vitro. METHODS The total phenolic and flavonoid contents were determined using Folin Ciocalteu method and aluminium chloride colorimetric assay respectively. The antioxidant activities of the decoction were investigated using 1,1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical, nitric oxide scavenging assays and ferric ion reducing power assay. Hepatotoxicity was induced on porcine liver slices with ethanol to study hepatoprotective activity. Porcine liver slices were incubated at 37°C with different concentrations of the water extract of A. ceylanica in the presence of ethanol for 2 hours. The hepatoprotective effects were quantified by the leakage of alanine transaminase (ALT), aspartate transaminase (AST) and lactate dehydrogenase (LDH) to the medium. Thiobarbituric acid reactive substances (TBARS) assay was performed to examine the anti-lipid peroxidation activity caused by the plant extract. RESULTS The mean ± SD (n =9) for the levels of total phenolics and flavonoids were 4.87 ± 0.89 w/w% of gallic acid equivalents and 16.48 ± 0.63 w/w% of (-)-Epigallocatechin gallate equivalents respectively. The decoction demonstrated high antioxidant activity. The mean ± SD values of EC50 were 131.2 ± 36.1, 48.4 ± 12.1, 263.5 ± 28.3 and 87.70 ± 6.06 μg/ml for DPPH, hydroxyl radical, nitric oxide scavenging assays and ferric ion reducing power assay respectively.A significant decrease (p <0.05) was observed in ALT, AST and LDH release from porcine liver slices treated with A. ceylanica extract at a concentration of 2 mg/ml in the presence of ethanol (5 M) compared to that of ethanol (5 M) treated slices. Furthermore, a reduction in lipid peroxidation was also observed in liver slices treated with the leaf extract of A. ceylanica (2 mg/ml) compared to that of ethanol induced liver toxicity (p <0.05). CONCLUSIONS The results suggest that aqueous extract of A. ceylanica exerts hepatoprotective activity against ethanol induced liver toxicity of porcine liver slices which can be attributed to the antioxidant properties possessed by the plant material.