Ghostin J, Habib-Jiwan JL, Rozenberg R, Daloze D, Pasteels JM, Braekman JC. Triterpene saponin hemi-biosynthesis of a leaf beetle’s (Platyphora kollari) defensive secretion.
Naturwissenschaften 2007;
94:601-5. [PMID:
17354008 DOI:
10.1007/s00114-007-0223-5]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 12/19/2006] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
The adults of the leaf beetle Platyphora kollari (Chrysomelidae) are able to metabolise the oleanane triterpene beta-amyrin (1) into the glycoside 3-O-beta-D: -glucopyranosyl-(1-->4)-beta-D: -glucuronopyranosyl-hederagenin (2) that is stored in their defensive glands. The aim of this study was to test the hypothesis that oleanolic acid (3) is an intermediate in the conversion of 1 into 2 and to check whether the sequestration of pentacyclic triterpenes is selective in favour of beta-amyrin (1). To this end, adults of P. kollari were fed with Ipomoea batatas leaf disks painted with a solution of [2,2,3-(2)H(3)]oleanolic acid or [2,2,3-(2)H(3)]alpha-amyrin and the secretion of their defensive glands analysed by HPLC-ESIMS. The data presented in this work indicated that the first step of the transformation of beta-amyrin (1) into the sequestered glycoside 2 is its oxidation into oleanolic acid (3) and that this conversion is selective but not specific in favour of beta-amyrin (1).
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