Discovery of New Botanical Insecticides: Identification and Insecticidal Activity of Saponins from Clematis obscura Maxim and Insights into the Stress Response of Acyrthosiphon pisum Harris

• DOI: 10.1021/acs.jafc.3c06557
• Publication Date: 2024-02-22T13:34:44Z
• Authors: Nan Hao; Yinyin Qi; Long Zhao; Shuangshuang Liang; Wenjing Sun; Sunao Zhang; Xiangrong Tian
• Keywords: Acyrthosiphon pisum; Gossypol; Cuticle (hair)

To discover new botanical products-based insecticide candidates, 14 triterpenoid saponins (1–14) including four ones, obscurosides A-D (1–4), were isolated from Clematis obscura Maxim as potential agrochemicals against Acyrthosiphon pisum Harris and Plutella xylostella (L.). Compounds 1–3 characterized by a rare ribose substitution at C-3, 4 was bidesmoside glycosylated the C-23 C-28 positions of oleanane aglycone. 10 (median antifeeding concentration, AFC50 = 1.10 mg/mL; half-lethal LC50 1.21 mg/mL) 13 (AFC50 1.09 mg/mL, 1.37 showed significant insecticidal activities third larvae P. 72 h. All displayed antifeedant A. with deterrence index 0.20–1.00 400 μg/mL. Compound 8 optimal oral toxicity (LC50 50.09 μg/mL) pisum, followed compounds 1, 5–7, 9, 90.21–179.25 The shrinkage cuticle destruction intestinal structures microvilli, nucleus, endoplasmic reticulum, mitochondria toxic symptoms 8-treated pisum. significantly declined Chitinase activity in an inhibition rate 79.1% LC70 (70% lethal concentration) could be main reason for its toxicities. Molecular docking revealed favorable affinities 1 group I OfChtI (Group Ostrinia furnacalis) through conventional hydrogen bonds alkey/π-alkey interactions different patterns. These results will provide valuable information development novel pesticides management insect pests, especially