Evaluation of antibacterial and antioxidant activities of Ziziphus vulgaris (Rhamnaceae)

Zizyphus vulgaris Lam. is a deciduous shrub, native of the Mediterranean region and used to treat sore throats, alleviate stress and helps in the common colds. In present work 10g of the dried plant material was soaked in 100ml methanol and shaken for 24h and clear filtrate was obtained. The fresh methanolic crude extracts were qualitatively screened for secondary metabolites. Results showed that: flavonoids, hydrolysable tannins, alkaloids, terpenes and saponins had reasonably high contents but anthraquinones and coumarines were low. In vitro antimicrobial assay and MIC determination growth inhibition activities of methanolic leaves extract of Z. vulgaris against gram-positive and gram-negative bacterial species using the conventional paper disc assay showed good inhibitory effects only against gram-positive with no antagonistic effects against gram-negative bacterial species testedThe MIC values of the crude methanolic Z. vulgaris extract on gram-positive was in range to 12.5–25.0µg/ml, whereas extract exhibited very weak antimicrobial activity against gram-negative with very high values (1000µg/ml) of MICs. Total phenolics assay by the Folin-Ciocalteu method in plant extract also showed reasonably high contents of polyphenolics (300mg/ml extract). Results collectively suggest that Z. vulgaris is not only reliable natural sources of antimicrobials but also potential sources of phenolic antioxidants and hence could be nominated for future intensive studies.

Keywords: Ziziphus vulgaris, antimicrobials, phenolic antioxidants