Department of Entomology, University of Arkansas, 72701, Fayetteville, Arkansas.
J Chem Ecol. 1992 Apr;18(4):571-83. doi: 10.1007/BF00987820.
The fate of the tomato foliar phenolic, chlorogenic acid, in the digestive systems of Colorado potato beetleLeptinotarsa decemlineata (Coleoptera: Chrysomelidae) andHelicoverpa tea (Lepidoptera: Noctuidae) is compared. In larvalH. zea and other lepidopteran species previously examined, approximately 35-50% of the ingested chlorogenic acid was oxidized in the digestive system by foliar phenolic oxidases (i.e., polyphenol oxidase and peroxidase) from the tomato plant. The oxidized form of chlorogenic acid, chlorogenoquinone, is a potent alkylator of dietary protein and can exert a strong antinutritive effect upon larvae through chemical degradation of essential amino acids. In contrast, inL. decemlineata less than 4% of the ingested dose of chlorogenic acid was bound to protein. In vitro experiments to determine the influence of pH on covalent binding of chlorogenic acid to protein showed that 30-45% less chlorogenic acid bound to protein at pHs representative of the beetle midgut (pH 5.5-6.5) than at a pH representing the lepidopteran midgut (pH 8.5). At an acidic pH, considerably more of the alkylatable functional groups of amino acids (-NH2, -SH) are in the nonreactive, protonated state. Hence, polyphenol oxidases are unlikely to have significant antinutritive effects against the Colorado potato beetle and may not be a useful biochemical source of resistance against this insect. The influence of feeding by larval Colorado potato beetle on foliar polyphenol oxidase activity in tomato foliage and its possible significance to interspecific competition is also considered.
比较了番茄叶酚、绿原酸在科罗拉多马铃薯甲虫（鞘翅目：叶甲科）和茶尺蠖（鳞翅目：夜蛾科）消化系统中的命运。在之前研究过的幼虫 H.zea 和其他鳞翅目物种中，约 35-50%的摄入绿原酸被来自番茄植物的叶酚氧化酶（即多酚氧化酶和过氧化物酶）在消化系统中氧化。绿原酸的氧化形式，绿原醌，是膳食蛋白质的有效烷化剂，通过对必需氨基酸的化学降解，对幼虫产生强烈的抗营养作用。相比之下，在 L. decemlineata 中，少于 4%的摄入剂量的绿原酸与蛋白质结合。为了确定 pH 值对绿原酸与蛋白质共价结合的影响而进行的体外实验表明，在代表甲虫中肠的 pH 值（pH5.5-6.5）下，与在代表鳞翅目昆虫中肠的 pH 值（pH8.5）下相比，绿原酸与蛋白质结合的量减少了 30-45%。在酸性 pH 值下，更多的可烷基化氨基酸的功能基团（-NH2、-SH）处于非反应性、质子化状态。因此，多酚氧化酶不太可能对科罗拉多马铃薯甲虫产生显著的抗营养作用，也可能不是抵抗这种昆虫的有用生化来源。还考虑了幼虫科罗拉多马铃薯甲虫对番茄叶片中叶酚氧化酶活性的影响及其对种间竞争的可能意义。
