Evaluation of Total Phenolic Content and Antioxidant Activity of Three Leaf Extracts of Ziziphus spina-christi (Sedr) Grown in Jordan

摘要

Aims: The primary aims of this study were to evaluate the total phenolic content and In vitro antioxidant activity of three different leaves extracts (methanolic, ethanolic and aqueous) of Ziziphus spins-christi grown in Jordan. Methods: Total phenolic content of the methanolic, ethanolic and aqueous extracts of the leaves of Ziziphus spins-christi was determined spectrometrically according to the Folin-Ciocalteu procedure. The antioxidant activities of the leaves extracts of this plant at different concentrations were determined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity and reducing power methods. All the analyzes was made with the use of UV-Visible spectrophotometer, and ascorbic acid was used as a standard antioxidant. Place and Duration of Study: Department of Biological Science, Al-Bayt University, Al Mafraq, Jordan. Department of Nutrition and Food Technology, University of Jordan, Amman, Jordan, from April 2015 to December 2015. Results: The total phenolic content was ranged between 11.8 to 52.5 mg/g expressed in terms of Gallic acid equivalent (mg of GAE/g extract). In vitro antioxidant activity of the plant extracts revealed that all the extracts showed good antioxidant power with IC₅₀ values of 21.4, 24.2 and 54.3 μg/mL for methanolic, aqueous and ethanolic extracts, respectively. The reducing power of the extracts was found to be concentration dependent. The results of this study revealed that, the methanolic extract of leaves showed the highest phenolic concentration and largest antioxidant activity. Conclusion: From this study it may be concluded that Z. spina-christi leaves could have potential source of antioxidants for pharmaceutical drug preparations.