Evaluation of Antimicrobial and Antioxidant Activities of Psidium guajava L growing in Libya

The aim of this study was to evaluate quantitatively the antimicrobial and antioxidant potentials of the leaves extracts of Guava (Psidium guajava Linn.),belonging to the Myrtaceae family. The plant samples were collected from Tajoura eastern part of Tripoli in Libya. Methanol and water were used as solvents in the extraction. The phytochemical screening showed that the ethanolic and aqueous extracts had tannins, flavonoids, alkaloids, saponins, terpenes in varying proportions while alkaloid was the only exclusion in the methanolic extract. The water, methanol crude extracts as well as flavonoids extract were effective against both Gram- positive and Gram-negative bacteria: Buscillis subtils , Staphylococcus aureus, Escherichia coli and Salmonella typhi. The minimum inhibitory concentration MIC for flavonoids extract was 2.5 mg/ml .It was also found that both extracts (aqueous and methanolic) of the Guajava leaves showed reasonably high content of polyphenols. These results suggest that Psidium guajava L. is not only reliable natural source of antimicrobials but also potential sources of phenolic antioxidants and hence could be nominated for further intensive studies