Phytochemical Screening, Polyphenol Content and Antioxidant Studies of Ethanol Leaf Extract of Combretum aculeatum vent.

Objectives: The present study aimed to identify the phytochemical groups of ethanol leaf extract of Combretum aculeatum Vent., and to evaluate the phenol content of extracts and their antioxidant activity.

Materials and Methods: Collected leaves were extracted with ethanol (95°). From the dried ethanol extract, 3 fractions were obtained after a liquid/liquid fractionation (hexane, ethyl acetate and water). Phytochemical screening of the raw extract was done using standard reactions. The phenol content was determined with Folin Denis reagent. Antioxidant activity was performed using 2, 2-diphenyl-picrylhydrazyl test (DPPH), ferric reducing antioxidant power (FRAP) and nitric oxide reducing tests.

Results: Tannins, flavonoids and mucilage were the main phytochemical constituents of the leaf extract. Antioxidant assay revealed ethanol extract and its polar fractions were more active. In DPPH assay, the aqueous fraction (IC50: 61.93±5.99 μg / ml) was more active than the ethanol extract, the ethyl acetate and hexane fractions with respective IC50 values 74.1±4.47 - 81.53±6.51 - 1710.33±71.15 µg/ml. In nitric oxide test the ethyl acetate fraction (IC50: 56.66±3.09 µg/ml) had shown a better ability to inhibit nitric oxide radical than the ethanol extract, the hexane and aqueous fractions (IC50: 84.33±9.80- 451.33±1.24- 101.33±4.10 µg/ml respectively). In FRAP assay the ethyl acetate and aqueous fractions had shown a better activity than the leaf extract.

Conclusion: Ethanol leaf extract had shown antioxidant activity in the different assays. This biological activity may be due to both polar and non polar compounds.