ABSTRACT
Objectives: The aim of this study was to identify the phytochemical groups of hydroethanolic leaf extract of Senna sieberiana DC and its fractions and to investigate their free radical scavenging activity. Methods: S. sieberiana leaves were extracted with hydroethanolic solvent. From the hydroethanolic extract 3 fractions were obtained after a liquid/liquid fractionation (dichloromethane, ethyl acetate and water). Phytochemical screening of the leaf extract and its fractions was done using standard reactions. Free radical scavenging activity was assessed using DPPH and ABTS assays. Results: Tannins, flavonoids, anthracenic derivatives, sterols and triterpenoids were the main phytochemical constituents of the leaf extract and fractions. The hydro-ethanolic leaf extract of Senna sieberiana, its dichloromethane, ethyl acetate and aqueous fractions and ascorbic acid had respective IC50 values of 191.6±3.82 - 495.73±8.96 - 165.8±4.85 - 50.40±2.65 - 19.53±0.13 µg/ml in ABTS assay. In DPPH assay, the IC50 values were 44.8 ± 1.22 - 218.93±9.01 - 32.13 ± 1.8 - 26.4±0.11- 4.66±0.07 µg/ml respectively for the leaf extract, dichloromethane, ethyl acetate and aqueous fractions and ascorbic acid. Conclusion: The hydroethanolic leaf extract of S. sieberiana had shown free radical scavenging activity. The aqueous fraction was more active among plant tested samples.