Antioxidant, antibacterial and cytotoxic effects of the phytochemicals of whole Leucas aspera extract

Objective: To investigate the antioxidant, antibacterial and cytotoxic activity of whole Leucas aspera (Labiatae) (L. aspera) alcoholic extract. Methods: Whole L. aspera powder was extracted by absolute ethanol (99.50%). The ethanolic extract was subjected to antioxidant, antibacterial and brine shrimp lethality assay. Results: The extract showed potent radical scavenging effect (antioxidant) with IC50 value of (99.58±1.22) μg/mL which was significant (P<0.01) in comparison to ascorbic acid with IC50 value of (1.25±0.95) μg/mL. In case of antibacterial screening, the extract showed notable antibacterial effect against the tested microbial strains. Significant (P<0.05) zone of inhibitions against Gram positive Bacillus subtilis [(12.00±1.32) mm] and Bacillus megaterium [(13.00±1.50) mm], Staphylococcus aureus [(8.00±0.50) mm] and Gram negative Salmonella typhi [(6.00±0.50) mm], Salmonella paratyphi [(8.00±1.00) mm], Shigella dysenteriae [(9.00±1.32) mm] and Vibrio cholerae [(9.00±0.66) mm] was observed. In brine shrimp lethality bioassay, the extract showed the LC50 value as (181.68±2.15) μg/mL which was statistically significant (P<0.01) compared to positive control vincristine sulfate [LC50=(0.76±0.04) μg/mL]. Conclusions: The results demonstrate that the ethanolic extract of L. aspera could be used as antibacterial, pesticidal and various pharmacologic actives. © 2013 Asian Pacific Tropical Biomedical Magazine.