Characterization of secondary metabolites from the berries of Ziziphus mucronata and their antioxidant properties

Abstract

Ziziphus mucronata is a medicinal plant used traditionally for treating various diseases. The antioxidant assay for the crude extracts obtained from the berries of Ziziphus mucronata was carried out using DPPH (2,2-diphenyl-1-picrylhydrazyl) method. Purified antioxidant compounds were obtained by chromatographic methods and were subjected to structure elucidation using nuclear magnetic resonance (NMR). Berries of Ziziphus mucronata were found to have high antioxidant activity since their ethyl acetate extract had an IC₅₀ value of 214.9 µg/mL and methanol extract had an IC₅₀ value of 8.9 µg/mL showing significant antioxidant activity in comparison to that of the standard ascorbic acid, which was found to have an IC₅₀ value of 1.5 µg/mL. Betulin, betulinic acid and ursolic acid were among the compounds isolated from the berries of Ziziphus mucronata and are known to possess significant antioxidant activity. They have not been known to be previously isolated from Ziziphus mucronata.

Keywords:

• Antioxidant
• DPPH
• ROS (reactive oxygen species)

Acknowledgements

The authors wish to acknowledge Prof S.T. Kariuki of Egerton University, Kenya for identifying the plant and University of Surrey, United Kingdom for carrying out NMR analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Research Foundation.