title: Chemical profile and defensive function of the latex of Euphorbia peplus.
abstract: Plant latex is an endogenous fluid secreted from highly specialized laticifer cells and has been suggested to act as a plant defense system. The chemical profile of the latex of Euphorbia peplus was investigated. A total of 13 terpenoids including two previously unknown diterpenoids, (2S*,3S*,4R*,5R*,6R*,8R*,l1R*,13S*,14S*,15R*, 16R*)-5,8,15-triacetoxy-3-benzoyloxy-11,16-dihydroxy-9-oxopepluane and (2R*,3R*, 4S*,5R*,7S*,8S*,9S*,l3S*,14S*,15R*)-2,5,8,9,14-pentaacetoxy-3-benzoyloxy-15-hydroxy-7-isobutyroyloxyjatropha-6(17),11E-diene), ten known diterpenoids, and a known acyclic triterpene alcohol peplusol, were identified, using HPLC and UPLC-MS/MS analyses and through comparison with the authentic compounds isolated from the whole plant. The diterpenoids exhibited significant antifeedant activity against a generalist plant-feeding insect, the cotton bollworm (Helicoverpa armigera), with EC50values ranging from 0.36 to 4.60 μg/cm2. In particular, (2R*,3R*,4S*,5R*,7S*,8S*,9S*,l3S*,14S*,15R*)-2,5,9,14-tetraacetoxy-3-benzoyloxy-8,15-dihydroxy-7-isobutyroyloxyjatropha-6(17),11E-diene and (2R*,3R*, 4S*,5R*,7S*,8S*,9S*,l3S*,14S*,15R*)-2,5,14-triacetoxy-3-benzoyloxy-8,15-dihydroxy-7-isobutyroyloxy-9-nicotinoyloxyjatropha-6(17),11E-diene had EC50values of 0.36 and 0.43 μg/cm2, respectively, which were approximately 7-fold more potent than commercial neem oil (EC50= 2.62 μg/cm2). In addition, the major peplusol showed obvious antifungal activity against three strains of agricultural phytopathogenic fungi, Rhizoctonia solani, Colletotrichum litchi and Fusarium oxysporum f. sp. niveum. The results indicated that terpenoids in the latex of E. peplus are rich and highly diversified, and might function as constitutive defense metabolites against insect herbivores and pathogens for the plant.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Hua
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
authors.forename: Chao-Jiang
authors.initials: CJ
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China.
authors.forename: Shu-Xi
authors.initials: SX
authors.lastname: Jing
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China. Electronic address: luoshihong@mail.kib.ac.cn.
authors.forename: Shi-Hong
authors.initials: SH
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, PR China; Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming, 650201, PR China. Electronic address: shli@mail.kib.ac.cn.
authors.forename: Sheng-Hong
authors.initials: SH
authors.lastname: Li
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000302:isolation & purification* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D028481:Euphorbia / Q000737:chemistry*; D005247:Feeding Behavior / Q000187:drug effects*; D005670:Fusarium / Q000187:drug effects; D005989:Glycerides; D007840:Latex / Q000737:chemistry* / Q000494:pharmacology; D007915:Lepidoptera / Q000187:drug effects; D015394:Molecular Structure; D013729:Terpenes; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D004224:Diterpenes; D005989:Glycerides; D007840:Latex; D013729:Terpenes; D014315:Triterpenes; C002443:neem oil
keywords: Defensive function; Euphorbia peplus; Euphorbiaceae; Latex; Terpenoids