Pesticidal Potency With Dynamic Chemical Profiles: A Comprehensive Seasonal Study of <i>Alpinia nigra</i> (Gaertn.) Burtt Essential Oils With Possible Mechanistic Approach

This study investigates the seasonal variation in chemical composition, yield, and biological activities of Alpinia nigra essential oil (ANEO) collected monthly from October 2021 to September 2022. The highest oil yield (0.40%) was recorded in January. GC-MS analysis identified 1,8-cineole as the dominant compound, alongside seasonal fluctuations in β-pinene, α-caryophyllene, and caryophyllene oxide. The biological activities exhibited significant seasonal variation: nematicidal activity against Meloidogyne incognita peaked in September, October and February, achieving up to 100% mortality at 1.0 µL/mL within 96 h; herbicidal activity against Raphanus raphanistrum was strongest in winter, with 100% inhibition of seed germination, root, and shoot growth; while antifeedant activity against Spodoptera litura was maximum in February, March and September (up to 82% feeding inhibition). Molecular docking studies highlighted strong binding of caryophyllene oxide to target proteins-acetylcholinesterase for nematicidal activity (8.6 kcal/mol), acyl-ACP thioesterase for herbicidal activity (7.3 kcal/mol), and ACh-binding protein for antifeedant activity (7.0 kcal/mol)-underscoring its broad-spectrum bioactivity. Based on these findings, it can be inferred that linking ANEO into integrated pest management systems could revolutionize sustainable agriculture by offering a possible effective alternative to synthetic agrochemicals, which can contribute to global efforts in reducing chemical pesticide reliance and to the development of eco-friendly botanical pesticides.