Antioxidant phytochemicals and antibacterial activities of sidr (Ziziphus spp.) leaf extracts

Leaves of the Ziziphus genus are recognized for their medicinal values. However, information about the bioactive compounds and phytochemical profile are very limited. Therefore, the objective of this study was to investigate the physicochemical characteristics, phytochemical composition, antioxidants and antibacterial activities of Ziziphus mauritiana Lamk. and Ziziphus spina-christi L. leaves. The results revealed the physicochemical and phytochemical composition of leaves from the two species were significantly influenced by species differences. Z. mauritiana leaf exhibited significantly higher moisture and oil contents than Z. spina-christi. Regardless of species, a total of 11 phenolic compounds were identified and quantified in leaf extracts by the HPLC analysis. Among the 11 individual phenolic compounds identified in leaf extracts, 8 compounds, namely 1,2-dihydroxy benzene, catechin, rutin, trans ferulic, p-coumaric, syringic, caffeic, and salicylic acid were found in both species' samples, while trans cinnamic acid and quercetin were unique to Z. spina-christ samples, and 4-hydroxy benzoic acid was only detected in Z. mauritiana samples. Z. mauritiana leaf had significantly higher phenolic and flavonoid contents, antioxidant and antibacterial activities as compared to Z. spina-christi. Based on their antioxidant composition, the investigated Zizyphus spp. leaves could be a valuable source of natural antioxidants against illnesses induced by oxidative stress. Z. mauritiana leaf extract could be used in the food and medicinal sectors. It may potentially provide a natural antibiotic with a low environmental effect.