Phytochemical Screening, and Antioxidant Activity of Methanolic Extract and Solvent Fractions of the Stem Bark of Moringa Stenopetala Bak. Cuf.

Abstract

Ageze Hailu, Terfo Yilma and Abraham Nigusse

Background: Moringa stenopetala Bak. Cuf. is a medicinal plant that has been used extensively in Traditional Medicine in both Ethiopia and East Africa. Many studies have been conducted regarding the pharmacological properties of the leaves of this plant. However, very little research has been done on the bioactive potential of the stem bark of M. stenopetala.

Objectives: The main objective of this study was to determine the phytochemical make-up and antioxidant activity of the methanolic extract and solvent fractions of the stem bark of M. stenopetala.

Methods: The extraction of the dried stem bark with absolute methanol, further extractions were performed using fractions of the extract with solvents of chloroform, acetone and water. The preliminary phytochemical screening was done to the extract and solvent fractions using standard methods. The antioxidant activity of all three solvent fractions of the stem bark were evaluated using the DPPH radical scavenging assay.

Results: The preliminary phytochemical screening of the solvent fractions revealed that each fraction contained a variety of secondary metabolites, including flavonoids, phenols, tannins, saponins, terpenoids, alkaloids, phytosterols and cardiac glycosides; the quantity of these compounds varied between fractions. The DPPH assay indicate the aqueous and the acetone fractions at a concentration of 100μg/mL showed a strong percentage inhibition of 73.63% and 72.53%, respectively. The chloroform fraction showed moderate activity of 69.23%. When compared to the results of ascorbic acid as a reference standard, which showed a 98.59% percentage inhibition at the same concentration. The antioxidant activity of the crude extract and both solvent fractions is likely due to the presence of phenolic and flavonoid compounds.

Conclusion: In conclusion, the results obtained in this study support the traditional use of the stem bark of M. stenopetala as a natural source of antioxidant phytochemicals, as well as providing the necessary justification for future quantitative and bioactivity-guided studies on M. stenopetala.

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