Bioassay guided fractionation, isolation and characterization of hepatotherapeutic 1, 3-di-ortho-galloyl quinic acid from the methanol extract of the leaves of Pterocarpus santalinoides

Leaf extracts of Pterocarpus santalinoides DC are traditionally used to ameliorate ageing-related ailments such as heart and liver diseases, and have been reported to be protective against toxic injuries to the liver.This study aimed to isolate and characterize the hepatoprotective/hepatotherapeutic principle in the methanol leaf extract of P. santalinoides.Fresh leaves of P. santalinoides were dried under shade and ground into powder. The ground leaves (2 Kg) were extracted with 80% methanol by maceration. Fractionation was carried out using column and thin layer chromatography techniques. Bioassay of fractions and sub-fractions was done using carbon tetrachloride (CCl4)-induced hepatotoxicity model in albino rats. Phytochemical analysis was carried out on the active compound. Characterization and structural elucidation of the active compound using high performance liquid chromatography and nuclear magnetic resonance spectroscopy was done.Extraction yielded 260 g dry extract. Six fractions (F1, F2, F3, F4, F5 and F6) were obtained after column and thin layer chromatography, with F6 (Rf = 0.78; Yield = 2.13 g) being the most active hepatotherapeutic fraction that significantly (p < 0.05) lowered serum ALT activity and increased serum albumin levels in CCl4-induced hepatopathy in albino rats. Further separation of F6 yielded four sub-fractions (F61, F62, F63 and F64), of which F61 with an Rf of 0.85 and a yield of 30.0 mg was isolated as the active hepatotherapeutic compound. Stiasny and ferric chloride test of F61 showed the presence of tannins in the fraction. Characterization of F61 revealed 1, 3-di-ortho-galloyl quinic acid.The hepatoprotective/hepatotherapeutic principle in the methanol extract of the leaves of P. santalinoides was identified as 1, 3-di-ortho-galloyl quinic acid.