title: Triterpene acids from apple peel inhibit lepidopteran larval midgut lipases and larval growth.
abstract: Fruit extracts from apple, kiwifruit, feijoa, boysenberry, and blueberry were screened for the presence of lipase inhibitory compounds against lepidopteran larval midgut crude extracts. From 120 extracts, six showed significant inhibition with an extract from the peel of Malus × domestica cv. "Big Red" showing highest levels of inhibition. Because this sample was the only apple peel sample in the initial screen, a survey of peels from seven apple cultivars was undertaken and showed that, despite considerable variation, all had inhibitory activity. Successive solvent fractionation and LC-MS of cv. "Big Red" apple peel extract identified triterpene acids as the most important inhibitory compounds, of which ursolic acid and oleanolic acid were the major components and oxo- and hydroxyl-triterpene acids were minor components. When ursolic acid was incorporated into artificial diet and fed to Epiphyas postvittana Walker (Tortricidae: Lepidoptera) larvae at 0.16% w/v, a significant decrease in larval weight was observed after 21 days. This concentration of ursolic acid is less than half the concentration reported in the skin of some apple cultivars.
authors.affiliation: The New Zealand Institute for Plant & Food Research, Palmerston North, New Zealand; Institute of Plant Sciences and Resources, Okayama University, Kurashiki, Okayama, Japan.
authors.forename: John T
authors.initials: JT
authors.lastname: Christeller
authors.forename: Tony K
authors.initials: TK
authors.lastname: McGhie
authors.forename: Joanne
authors.initials: J
authors.lastname: Poulton
authors.forename: Ngaire P
authors.initials: NP
authors.lastname: Markwick
mesh_terms: D000818:Animals; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D005638:Fruit / Q000737:chemistry*; D041981:Gastrointestinal Tract / Q000201:enzymology; D007814:Larva / Q000187:drug effects* / Q000201:enzymology* / Q000254:growth & development; D008049:Lipase / Q000037:antagonists & inhibitors; D027845:Malus / Q000737:chemistry*; D009036:Moths / Q000187:drug effects* / Q000201:enzymology* / Q000254:growth & development; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology; D014315:Triterpenes / Q000737:chemistry* / Q000494:pharmacology; D000097245:Ursolic Acid
chemical_list: D004791:Enzyme Inhibitors; D008049:Lipase; D010936:Plant Extracts; D014315:Triterpenes; D000097245:Ursolic Acid
keywords: bioassay; lepidoptera; lipase; phyllophagy; triterpene; ursolic acid