Phytochemical analysis and antioxidant activity of Alstonia scholaris

Abstract

The present study investigates the phytochemical constitution and antioxidant activity of various solvent (aqueous, butanol and ethyl acetate) extracts of the leaf and bark of Alstonia scholaris. The antioxidant assays performed include DPPH, ABTS and FRAP. the phytochemical screening revealed the presence of tannins, proteins, phenols and steroids in aqueous extracts of both leaf and bark of the plant. Butanol extract also showed moderate presence of the phytochemicals in the preliminary screening. The aqueous and butanol extracts showed significant antioxidant activity with DPPH, ABTS and FRAP assays when compared to the ethyl acetate extract. IC50 value of aqueous extract of bark and leaf were found to be 1.21 mg/ml and 2.83 mg/ml respectively in the DPPH assay and 210 µg/ml and 523 µg/ml in the ABTS assay. At 2 mg/ml concentration, the aqueous extract of bark and leaf showed ferric reducing power of 130.70 µmoles/mg and 109.52 µmoles/mg respectively in the FRAP assay. The TLC analysis of the aqueous extract of the bark, which showed highest antioxidant activity among the other extracts, was also performed.