Insecticidal potential of l-isoleucine, N-allyloxycarbonyl-, dodecyl ester from Actinokineospora fastidiosa against Plutella xylostella.

Insect pests like Plutella xylostella cause significant crop losses, and the overuse of synthetic pesticides has led to resistance and ecological imbalance. This study evaluated the insecticidal properties of 1-isoleucine, N-allyloxycarbonyl-, dodecyl ester, isolated from Actinokineospora fastidiosa. The compound showed strong antifeedant (89.19%), larvicidal (83.53%), and pupicidal (90.00%) activity at 25 µg/mL, with LC50 and LC90 values of 9.82 and 47.72 µg/mL, respectively. In addition, treated larvae exhibited delayed development, elevated antioxidant enzyme levels (SOD, CAT), DNA damage, and severe midgut histological alterations. Furthermore, molecular docking revealed strong binding affinities to key insect proteins, indicating multiple potential modes of action. Meanwhile, no adverse effects were observed on non-target soil organisms (E. eugeniae), and the compound showed no antagonism toward rhizospheric microbes. These results suggest that this actinobacterial metabolite is a promising, eco-friendly candidate for integrated pest management.