Toxicity, antifeedant and biochemical efficacy of Mentha piperita L. essential oil and their major constituents against stored grain pest

The efficiency of chemically characterized Mentha piperita L. essential oil (EO), a plant based insecticide was tested for acetylcholinesterase activity (AChE) and antioxidant enzyme system (SOD, CAT, GSH and GSSH) in Sitophilus oryzae (L.) and Tribolium castaneum (Herbst.). GC-MS results evidenced for menthone and menthol as the major compounds of EO. As a fumigant, EO and its major component showed 100% mortality at 75.0 mu L/L air and 100.0 mu L/L air against S. oryzae and T. castaneum at 24 h of exposure. Antifeedant activity exhibited 100% lethal activity against pests in comparison to sub lethal doses. In vivo percent inhibition of AChE activity ranged between S. oryzae (29.68%, 18.81% and 14.34%) and T. castaneum (20.67%, 13.73% and 9.19%). Significant changes in antioxidant defense system studied for SOD, CAT, GSH and GSSH were noticed. Results revealed the toxicity of EO associations with the inhibition of AChE activity accompanied by oxidative imbalance. Therefore, M. piperita EO has a noteworthy role in insecticidal properties and could be recommended as an eco-friendly alternative to synthetic insecticides.