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INHIBITION OF INSECT GLUTATHIONE S‐TRANSFERASE (GST) BY CONIFER EXTRACTS
Author(s) -
Wang Zhiling,
Zhao Zhong,
AbouZaid Mamdouh M.,
Arnason John T.,
Liu Rui,
WalsheRoussel Brendan,
Waye Andrew,
Liu Suqi,
Saleem Ammar,
Cáceres Luis A.,
Wei Qin,
Scott Ian M.
Publication year - 2014
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21192
Subject(s) - biology , biochemistry , glutathione , botany , flavonoid , bark (sound) , abies balsamea , taxifolin , enzyme assay , enzyme , antioxidant , balsam , ecology
Insecticide synergists biochemically inhibit insect metabolic enzyme activity and are used both to increase the effectiveness of insecticides and as a diagnostic tool for resistance mechanisms. Considerable attention has been focused on identifying new synergists from phytochemicals with recognized biological activities, specifically enzyme inhibition. Jack pine ( Pinus banksiana Lamb.), black spruce ( Picea mariana (Mill.) BSP.), balsam fir ( Abies balsamea (L.) Mill.), and tamarack larch ( Larix laricina (Du Roi) Koch) have been used by native Canadians as traditional medicine, specifically for the anti‐inflammatory and antioxidant properties based on enzyme inhibitory activity. To identify the potential allelochemicals with synergistic activity, ethanol crude extracts and methanol/water fractions were separated by Sephadex LH‐20 chromatographic column and tested for in vitro glutathione S‐transferase (GST) inhibition activity using insecticide‐resistant Colorado potato beetle, Leptinotarsa decemlineata (Say) midgut and fat‐body homogenate. The fractions showing similar activity were combined and analyzed by ultra pressure liquid chromatography‐mass spectrometry. A lignan, (+)‐lariciresinol 9′‐p‐coumarate, was identified from P. mariana cone extracts, and L. laricina and A. balsamea bark extracts. A flavonoid, taxifolin, was identified from P. mariana and P. banksiana cone extracts and L. laricina bark extracts. Both compounds inhibit GST activity with taxifolin showing greater activity compared to (+)‐lariciresinol 9′‐p‐coumarate and the standard GST inhibitor, diethyl maleate. The results suggested that these compounds can be considered as potential new insecticide synergists.