De-Oliveira A C, Ribeiro-Pinto L F, Otto S S, Gonçalves A, Paumgartten F J
Department of Biological Sciences, The National School for Public Health, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
Toxicology. 1997 Dec 26;124(2):135-40. doi: 10.1016/s0300-483x(97)00144-3.
Beta-Myrcene (MYR) is an acyclic monoterpene found in the essential oils of a variety of useful plants such as lemongrass (Cymbopogon citratus), hop, verbena, bay and others. MYR and essential oils containing this olefinic monoterpene are widely used as flavoring food additives, as fragrances in cosmetics and as scents in household products. The present study was undertaken to investigate the induction of liver monooxygenases by MYR. Female Wistar rats were treated by gavage with MYR (1000 mg/kg body weight) or corn oil (vehicle) for 1 or 3 consecutive days. Activities of ethoxycoumarin-O-deethylase (ECOD) and alkoxy-resorufin O-dealkylases (methoxy- (MROD), ethoxy- (EROD), pentoxy- (PROD) and benzyloxy-resorufin-O-dealkylation (BROD)) were determined fluorimetrically in the hepatic microsomal fraction. Exposure to MYR, either for 1 or 3 days, produced marked (13-34-fold) increases in the activities of PROD and BROD and only minor changes in ECOD, EROD and MROD. Since PROD and BROD are metabolized mainly by CYP2B isoenzymes, these results suggest that MYR induces this phenobarbital-inducible P450 subfamily. The induction of CYP2B isoenzymes was confirmed by SDS-PAGE and immunoblotting. Levels of apoproteins CYP2B1/2B2 were increased 8.2-fold after treatment with MYR (1000 mg/kg body wt, 3 days). Results from this study therefore indicate that MYR is an inducer of isoenzymes belonging to CYP2B subfamily.
β-月桂烯（MYR）是一种无环单萜，存在于多种有用植物的精油中，如柠檬草（香茅）、啤酒花、马鞭草、月桂等。MYR以及含有这种烯类单萜的精油被广泛用作调味食品添加剂、化妆品香料和家用产品香精。本研究旨在调查MYR对肝脏单加氧酶的诱导作用。雌性Wistar大鼠连续1天或3天经口灌胃给予MYR（1000mg/kg体重）或玉米油（赋形剂）。采用荧光法测定肝微粒体部分乙氧香豆素-O-脱乙基酶（ECOD）和烷氧基试卤灵O-脱烷基酶（甲氧基-（MROD）、乙氧基-（EROD）、戊氧基-（PROD）和苄氧基试卤灵-O-脱烷基化酶（BROD））的活性。暴露于MYR 1天或3天，可使PROD和BROD的活性显著增加（13 - 34倍），而ECOD、EROD和MROD仅有轻微变化。由于PROD和BROD主要由CYP2B同工酶代谢，这些结果表明MYR可诱导这种苯巴比妥诱导型P450亚家族。通过SDS - PAGE和免疫印迹法证实了CYP2B同工酶的诱导作用。用MYR（1000mg/kg体重，3天）处理后，载脂蛋白CYP2B1/2B2水平增加了8.2倍。因此，本研究结果表明MYR是CYP2B亚家族同工酶的诱导剂。
