Antibacterial activity of sequentially extracted organic solvent extracts of fruits, flowers and leaves of Lawsonia inermis L. from Jaffna.

OBJECTIVE: To reveal the antibacterial activity of sequentially extracted different cold organic solvent extracts of fruits, flowers and leaves of Lawsonia inermis (L. against) some pathogenic bacteria.

METHODS: Powders of fruits, flowers and leaves of L. inermis were continuously extracted with dichloromethane (DCM), ethyl acetate and ethanol at ambient temperature. The dried extracts were prepared into different concentrations and tested for antibacterial activity by agar well diffusion method, and also the extracts were tested to determine the available phytochemicals.

RESULTS: Except DCM extract of flower all other test extracts revealed inhibitory effect on all tested bacteria and their inhibitory effect differed significantly (P<0.05). The highest inhibitory effect was showed by ethyl acetate extract of flower against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa), and ethyl acetate extract of fruit on Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis). The ethyl acetate and ethanol extracts of flower, fruit and leaf expressed inhibition even at 1 mg/100 µl against all test bacteria. Among the tested phytochemicals flavonoids were detected in all test extracts except DCM extract of flower.

CONCLUSIONS: The study demonstrated that the ethyl acetate and ethanol extracts of fruit and flower of L. inermis are potentially better source of antibacterial agents compared to leaf extracts of respective solvents.