Synthesis of thymyl esters and their insecticidal activity against Spodoptera litura (Lepidoptera: Noctuidae). Issue 3 (30th September 2019)

• Record Type: Journal Article
• Authors: Tharamak, Sorachat; Yooboon, Thitaree; Pengsook, Anchulee; Ratwatthananon, Atcharee; Kumrungsee, Nutchaya; Bullangpoti, Vasakorn; Pluempanupat, Wanchai
• Is Part Of: Pest management science. Volume 76:Issue 3(2020)
• Page Start: 928
• Page End: 935
• Publication Date: 2019-09-30
• Subjects: Spodoptera litura -- thymyl esters -- thymol -- detoxification enzymes -- structural modification; Pests -- Control -- Periodicals; Pesticides -- Periodicals; 632.9
• DOI: 10.1002/ps.5598
• Languages: English
• ISSNs: 1526-498X

Abstract

Abstract: BACKGROUND: Thymol, a natural phenolic monoterpene originating from Thymus vulgaris, is recognized as a safe and potent botanical insecticide to many insects. The structural modification of thymol into thymyl esters is a potential approach for the development of novel insecticides, which showed more toxicity than thymol. However, there are no reports on the insecticidal activity of thymyl esters to control Spodoptera litura . RESULTS: Thymol was structurally modified into ten thymyl esters by esterification using a new reagent, PPh3 /Br3 CSO2 Ph. The insecticidal activity of these compounds was examined against the second instars of Spodoptera litura using a topical application. Among the ten thymyl esters evaluated, thymyl cinnamate was the most toxic with LD50 = 0.41 and 0.34 μg/larva after 24 and 48 h posttreatment, respectively. In addition, thymyl cinnamate‐treated larvae showed increasing carboxylesterase and acetylcholinesterase activities in vivo experiment, whereas glutathione S ‐transferase activity showed no significant difference. CONCLUSION: Thymyl cinnamate were first reported to exhibit toxicity against S. litura 2.41–2.46 fold more efficient than thymol. However, the detailed biochemical interactions are necessary for further development of novel insecticides. © 2019 Society of Chemical Industry Abstract : Insecticidal activity of thymyl esters, derived from thymol, was first examined against Spodoptera litura using topical application. Thymyl cinnamate showed the most toxicity.