Laboratory of Biomedical and Environmental Sciences, University of California, Los Angeles, 900 Veteran Avenue, 90024, Los Angeles, California.
J Chem Ecol. 1990 Mar;16(3):887-99. doi: 10.1007/BF01016498.
Plant chemicals naturally exist in complex mixtures, which can interact either additively, synergistically, or antagonistically. We investigated the potential interactions of three naturally occurring antioxidants- nordihydroguaiaretic acid (NDGA), safrole, and α-tocopherol-with the general insecticide carbarayl to affect the performance of cabbage looper larvae (Trichoplusia ni). The cabbage looper is known to produce a mixed-function oxidase enzyme system in response to the presence of carbaryl. We proposed that plant antioxidants would interfere with enzymatic oxidation, enhancing the susceptibility of this insect to carbaryl. Insects were fed artificial diets containing each antioxidant alone or in pairwise combinations with the insecticide carbaryl to test for their effects on the insect's nutritional measurement indices. The three antioxidants tested were not equally effective individually against insect survivorship and interacted differentially in combination with the insecticide. The nutritional indices were measured on insects fed diets containing the chemicals at nonlethal doses. Insects fed 0.001 % wet wt NDGA diets grew 1.62 times less, and had gross and net conversion efficiencies reduced 3.20 and 3.63 times, respectively, compared to the control larvae. Carbaryl (0.002% wet wt) in combination with NDGA acts as an antagonist to the effects mentioned above, while safrole (1 × 10(-4) wet wt) had an additive effect when combined with the insecticide, reducing 1.76 times larval relative growth rate and efficiency of conversion of ingested food in respect to the control. The larvae fed significantly more (1.2 times) on both insecticide and safrole diets than on the controls or their combined diets. Larvae fed α-tocopherol alone or in combination with carbaryl had similar growth and conversion efficiencies as controls. We conclude that the effects of different combinations of compounds cannot be predicted a priori and must be determined experimentally.
植物化学物质天然存在于复杂的混合物中，它们可以相互作用，要么是相加的，要么是协同的，要么是拮抗的。我们研究了三种天然存在的抗氧化剂——北美圣草次甲素（NDGA）、黄樟素和 α-生育酚——与一般杀虫剂carbaryl 的潜在相互作用，以影响小菜蛾幼虫（Trichoplusia ni）的表现。众所周知，小菜蛾会产生一种混合功能氧化酶系统，以应对 carbaryl 的存在。我们提出，植物抗氧化剂会干扰酶的氧化作用，增强这种昆虫对 carbaryl 的敏感性。昆虫被喂食含有单独抗氧化剂或与杀虫剂 carbaryl 成对组合的人工饲料，以测试它们对昆虫营养测量指数的影响。测试的三种抗氧化剂对昆虫存活率的单独作用并不相同，并且与杀虫剂的相互作用也不同。在非致死剂量下，用含有这些化学物质的饲料喂养昆虫，测量营养指数。与对照幼虫相比，喂食 0.001%湿重 NDGA 饲料的昆虫生长速度慢了 1.62 倍，总转化率和净转化率分别降低了 3.20 倍和 3.63 倍。与对照幼虫相比，与 NDGA 组合的 carbaryl（0.002%湿重）作为上述作用的拮抗剂，而黄樟素（1×10（-4）湿重）与杀虫剂结合时具有相加作用，降低了 1.76 倍幼虫的相对生长率和摄入食物的转化效率。与对照幼虫相比，喂食昆虫和黄樟素的幼虫显著吃得更多（1.2 倍）。单独喂食 α-生育酚或与 carbaryl 组合喂食的幼虫与对照幼虫的生长和转化效率相似。我们得出结论，不同化合物组合的影响不能先验预测，必须通过实验确定。
