Antibacterial activity of leaves and inter-nodal callus extracts of Mentha arvensis L

To determine the anti-bacterial efficacy of chloroform, ethanol, ethyl acetate and water extracts of inter-nodal and leaves derived calli extracts from Mentha arvensis (M. arvensis) against Salmonella typhi(S. typhi), Streptococcus pyogenes(S. pyogenes), Proteus vulgaris(P. vulgaris) and Bacillus subtilis(B. subtilis).

The inter-nodal and leaves segments of M. arvensis were cut into 0.5-0.7 cm in length and cultured on Murashige and Skoog solid medium supplemented with 3% sucrose, gelled with 0.7% agar and different concentration of 2, 4-Dichlorophenoxyacetie acid (2,4-D) either alone or in combinations. The preliminary phytochemical screening was performed by Brindha et al method. Antibacterial efficacy was performed by disc diffusion method and incubated for 24 h at 37 °C.

Maximum percentage of callus formation (inter-nodal segments 84.3 ± 0.78; leaves segments 93.8 ± 1.27) was obtained on Murashige and Skoog's basal medium supplemented with 3% sucrose and 1.5 mg/L of 2, 4-D. The ethanol extracts of leaves derived calli showed the maximum bio-efficacy than other solvents. The leaves and stem derived calli extracts on Proteus sp. showed that the plants can be used in the treatment of urinary tract infection associated with Proteus sp. Through the bacterial efficacy studies, it is confirmed that the in vitro raised calli tissue was more effective compared to in vivo tissue.

The bio-efficacy study confirmed that the calli mediated tissues showed the maximum zone of inhibition. The present study paved a protocol to establish high potential cell lines by in vitro culture.