Phytotoxic and antibacterial assays of crude methanolic extract of Mentha longifolia (Linn.)

Mentha longifolia (Horse Mint; syn. M. sylvestris L.) is a well known species in the genusMentha (mint) widely applied in medicine as a constituent of various drugs, and is often used in aromatherapy. The current study was designed to investigate the antibacterial and phytotoxic capacity of methanolic extract of M. longifolia. Five hundred gram of shade dried whole plant in powdered form was subjected to extract in methanol, which yielded approximately 80 g of plant extract. The extract was evaluated for in vitro bioassay including antibacterial activity againstStaphylococcus aureus, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa,through agar well diffusion technique. The herbicidal potency of the extract was also evaluated by phytotoxic assay in two modes. The extract showed maximum antibacterial potential in various concentrations, and also showed a significant inhibition in growth of shoot and root in both modes of phytotoxic assay, that is, plate and field study might be due to the presence of bioactive constituents in extract.