Phytochemical, antimicrobial and cytotoxic evaluation of Ziziphus spina-christi (L.) stem bark

Ziziphus spina-christi (L.), commonly called jujube, was evaluated for their phytochemical content in the stem bark as well as the antimicrobial and cytotoxic activities. Z. spina-christi bark was extracted with ethanol and the extract was partitioned between aqueous layer and ethyl acetate layer. The ethyl acetate extract was defatted using diethyl ether and used for GC-MS analysis. The aqueous layer was further extracted with ethyl acetate and drop wise addition ammonia solution to obtain alkaline ethyl acetate extract. Both ethyl acetate extract and alkaline ethyl acetate extract were tested for phytochemical content by qualitative analysis and evaluated for their biological activities such as antimicrobial (by agar well diffusion assay and minimum inhibitory concentration determination) and cytotoxic activities (by MTT assay in cell culture). Phytochemical analysis indicates the presence of tannins, flavonoids, terpernoids, saponin glycosides and alkaloids in Z. spina-christi. Ethyl acetate and alkaline ethyl acetate extracts showed antifungal (against Aspergillus fumigatus, Syncephalastrum racemosum and Geotricum candidum), antibacterial (against Streptococcus pneumoniae, Bacillis subtilis and Escherichia coli), and cytotoxic effects (against colon and breast carcinoma cells). In comparison, alkaline ethyl acetate extract showed significantly (p<0.05) higher antimicrobial activity (against A. fumigatus, S. racemosum and S. pneumoniae) and cytotoxic activities as compared to ethyl acetate extract (IC₅₀ of alkaline ethyl acetate and ethyl acetate extracts=196 and 400 μg/well against colon carcinoma cells and 164 and 397 μg/well against breast carcinoma cells, respectively).