Insecticidal, antimicrobial and antioxidant activities of bulb extracts of Allium sativum

Objective: To evaluate the insecticidal, antimicrobial and antioxidant activities of bulb extracts of Allium sativum (A. sativum). Methods: Dried bulbs of A. sativum were extracted with different solvents and evaluated for insecticidal, antimicrobial and antioxidant activities. Results: Aqueous and methanol extracts showed highest insecticidal activity (mortality rate of 81% and 64% respectively) against the larvae of Spodoptera litura (S. litura) at a concentration of I 000 ppm. With regard to antimicrobial activity, aqueous extract exhibited antibacterial activity against gram positive (Bacillus subtilis Staphylococcus aureu,) and gram negative (Escherichia coli and Klebsiella pneumonia) strains and antifungal activity against Candida alhicans. While methanol extract showed antimicrobial activity against all the tested micro organisms except two (Staphylococcus (wrens and Candida alhicans), the extracts of hexane, chloroform and ethyl acetate did not show any anti microbial activity. Minimum inhibitory concentration of aqueous and methanol extracts against tested bacterial and fungal strains was 100-150 mu g/mL Antioxidant activity of the bulb extracts was evaluated in terms of inhibition of free radicals by 2, 2'-diphenly-l-pierylhydrazyl. Aqueous and methanol extracts exhibited strong antioxidant activity (80%-90% of the standard). Conclusions: Antioxidant and antimicrobial activity of A. sativum against the tested organisms therefore, provides scientific basis for its utilization in traditional and folk medicine. Also, our results demonstrated the insecticidal efficacy of A. sativum against S. litura, a polyphagous insect.