فعالیت مهارکنندگی اسانس سه گیاه روی آنزیم استیل کولین استراز لارو سوم کرم غوزه پنبه Helicoverpa armigera (Lepidoptera, Noctuidea)

Acetylcholinesterase (AChE) is a critical enzyme in insects that hydrolyzes the neurotransmitter acetylcholine at cholinergic synapses. It plays a key role in regulating nerve impulse transmission and is an important target for many insecticides. Essential oils extracted from different plant species have gained recognition for their potential as acetylcholinesterase (AChE) inhibitors, which can be advantageous in pest control. In this study, we examined the anti-acetylcholinesterase (CHE) activity of various extracts from Salvia rosmarinus (Lamiaceae), Origanum majorana (Lamiaceae) and Artemisia persica (Asteraceae). The whole body of 3rd instar larvae was homogenized and then centrifuged at 10,000 rpm for 10 minutes at 4°C. The supernatant was used as the enzyme source. To measure the activity of the acetylcholinesterase enzyme, a special diagnostic kit (Biorexfars®-Iran) was used. This kit contains two reagents, R1 and R2. The first reagent contains Pyrophosphate Buffer pH7.6 (75 mmol/l) and Potassium hexacyanoferrate (2.0 mmol/l). The second reagent contains s-Butyrylthiocholine iodide (15 mmol/l), which is the substrate of the reaction and is used in a ratio of 5 to 1 (R1 to R2). To investigate the inhibitory effect of plant essential oils, 960 μL of buffer and 60 μL of enzyme samples from cotton bollworm larvae were mixed in a test tube and incubated at 37 °C for 15 minutes. The absorbance of the sample was then measured at 405 nm using an ELISA reader. Next, 200 μL of substrate (R2) was added to the solution and the absorbance was measured again. The difference between the two absorbance readings indicates the activity of the acetylcholinesterase enzyme in the samples. By comparing the activity in the control and the inhibiting sample, the inhibition rate can be calculated. The results suggest that the 10% concentration of A. persica essential oil had the most potent inhibitory effect, while the 2.5% concentration of O. majorana essential oil had the least. Furthermore, there was no notable difference in the inhibitory effects between the 2.5% concentration of S.rosmarinus and the 5% concentration of O. majorana. In this study, we have selected aromatic medicinal plants that have shown significant inhibitory effects. However, in order to fully understand the potential of these plants, it is necessary to identify their secondary compounds and analyze their structures. The use of medicinal plants shows promise in identifying effective biological agents against pests such as the cotton bollworm and other plant pests