Phytochemical constituents and free radical scavenging activity of madang gatal (Schima wallichii) choisy stem bark

Abstract

Introduction: Madang gatal (Schima wallichii) Choisy is one of typical Indonesian plants that used traditionally as insomnia and hypertension drug. Background: The environment is highly polluted by free radicals which may contribute to the aging process of tissue and cause chronic diseases. The aims of the research were to study the phytochemical constituents and free radical scavenging activity of Schima wallichii stem bark. Materials and Methods: Extraction of S.wallichii stem bark was carried out by maceration method using methanol and then the methanol extract was partitioned using n-hexane, ethyl acetate and butanol successively. The methanol extract was then screened to determine the presence of different classes of secondary metabolites. The ethyl acetate fraction was subjected to silica column chromatography followed by exclusion chromatography on sephadex LH-20 to yield two partially purified isolates, SA and SE4. FTIR and GC-MS analyses indicated SA asa mixture of pentadecanoic acid, 14-methyl-, methyl ester and patchouli alcohol, while SE4 was made up predominantly of pentadecanoic acid, 14-methyl-, 13-hydroxy methyl ester. Free radical scavenging activity was performed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical oxidation method. Results: The phytochemical screening indicated the presence of alkaloids, flavonoids, tannins, saponins, terpenes and quinones. All tested samples, methanol, n-hexane, ethyl acetate and butanol extracts showed strong antioxidant activity with IC 50 values of 8.58, 17.36, 8.17 and 8.79 μg/mL, respectively. The isolates showed strong antioxidant activity with SE4 exhibiting an IC 50 value of about 5.5 times stronger than quercetin used as a standard antioxidant.