Vivekanandhan_2024_Toxicon__107737

Botanical essential oils are natural insecticides derived from plants, offering eco-friendly alternatives to synthetic chemicals for pest control. In this study, the essential oils were extracted from Acacia nilotica seed cotyledons, and their toxicity was tested against insect pests. Furthermore, the chemical components of the essential oils were identified through gas chromatography-mass spectrometry (GC-MS) analysis. The essential oil extracted from A. nilotica seeds exhibited the highest mortality rates of 60% and 98% in Culex quinquefasciatus, and 60% and 96.66% mortality in Plutella xylostella at 24 and 48 hours after treatment, respectively. The essential oils resulted in a lower LC(50) of 159.263 ppm/mL, and LC(90) of 320.930 ppm/mL within 24 hours. In 48 hours, the LC(50) was 52.070 ppm/mL and the LC(90) was 195.123 ppm/mL for C. quinquefasciatus. In the essential oil treatment of P. xylostella, the lower LC(50) was 165.900 ppm/mL, and the LC(90) was 343.840 ppm/mL 24 hours after the treatment. At 48 hours post-treatment, the LC(50) decreased to 62.965 ppm/mL, and the LC(90) decreased to 236.795 ppm/mL in P. xylostella. The study investigated the impact of essential oils on insect enzymes 24 hours after treatment. The study revealed significant changes in the levels of insect enzymes, including a decrease in acetylcholinesterase enzymes and an increase in glutathione S-transferase compared to the control group. Essential oils had minimal effects, resulting in mortality rates of 30.66% and 46% at 24 and 48 hours after treatment on Artemia salina. After 48 hours, minimal toxic effects of essential oils were observed on E. eugeniae, with a mortality rate of 11.33%. The GC-MS analysis of A. nilotica seed-derived essential oils revealed ten major chemical constituents, including 6-hydroxymellein, phthalic acid, trichloroacetic acid, hexadecane, acetamide, heptacosane, eicosane, pentadecane, 1,3,4-eugenol, and chrodrimanin B. Among these constituents, Heptacosane is the major chemical component, and this molecule has a high potential for involvement in insecticidal activity.