Protective effect of Enicostema axillare on mutagenicity of Salmonella typhimurium by increasing free radical scavenging abilities.

CONTEXT

Enicostema axillare A. Raynal (Gentianaceae) has been used in the traditional Indian system of medicine as a depurative and for the treatment of skin diseases, tumors, intermittent fever, and helminthiasis.

OBJECTIVE

E. axillare was investigated for antimutagenic and antioxidant effects.

MATERIALS AND METHODS

The antioxidant and antimutagenic activities of E. axillare fractions were determined by 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging assay and Ames test using Salmonella typhimurium tester strains TA98 and TA100 against direct-acting mutagens, such as sodium azide (NaN₃), 4-nitro-O-phenylene diamine (NPD), and mutagen needing activation, such as 2-aminofluorene (2AF). Toxicity study of these fractions was also performed.

RESULTS AND DISCUSSION

The ethyl acetate fraction showed maximum antimutagenic effect by 88.25 and 84.46% (preincubation) and 85.13 and 84.47% (coincubation) of inhibition against NaN₃ and NPD-induced mutagenicity, respectively. Inhibition of S9-dependent mutagens such as 2AF was higher than direct-acting mutagens by the ethyl acetate fraction of E. axillare. It showed 90.25 and 92.00% of inhibition in the preincubation and coincubation experiments. The ethyl acetate fraction showed higher total antioxidant capacity (24.79 ± 0.29 µg) and low IC₅₀ value for DPPH radical scavenging assay (192.27 ± 3.67 µg). The overall effect of E. axillare fractions was found to be in the order: ethyl acetate > methanol > hexane in these assays. In subacute toxicity study, with oral administration of these fractions, no marked biochemical and histopathologic changes were observed.

CONCLUSION

The significant antimutagenic and antioxidant activities of E. axillare might provide a scientific validation for the traditional use of this plant.