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.
ABSTRACT
Objective: The purpose of this study was to evaluate the total phenol content and the antioxidant capacity of the hydro-alcoholic bark extract of Piliostigma reticulatum and its ethyl acetate, methanol and aqueous fractions. Materials and Methods: Powdered barks were extracted with ethanol (80%). From the crude extract, 3 fractions were obtained after fractionation by column chromatography with three different solvents (ethyl acetate, methanol and water). The polyphenol content was determined with Folin Denis reagent. Antioxidant activity was performed using DPPH (2, 2-diphenyl-picrylhydrazyl), ABTS (2,2’-azinobis (3-ethylbenzothiazoline 6-sulfonate) and FRAP (ferric reducing antioxidant potential) assays. Results: The total extract had higher polyphenol contents with 12.55 ± 0.12 mg tannic acid equivalent/ g of dried extract (TAE/g). For ethyl acetate, methanol and water fractions, respective polyphenol content of 7.67 ± 0.4 - 9.01 ± 0.05 and 5.56 ± 0.2 mg TAE / g were obtained. The DDPH test had revealed that the methanol fraction was more active (IC50: 30.83±0.22 μg/ml), while for ABTS assay the ethyl acetate fraction had shown better activity (IC50: 29.08±0.44 μg/ml). For the FRAP test, at all tested concentrations, the methanol fraction revealed highest efficient to reduce ferric ion with percentages of reduction varing from 38 ± 0.73% at 7.81 μg/ml to 93.21 ± 0.24% at 250 μg/ml. Conclusion: These studies showed that the methanol fraction exhibited the best antioxidant activity and that this activity may be related partially to its polyphenols content.