Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Korea.
Br J Nutr. 2010 Jul;104(2):180-8. doi: 10.1017/S0007114510001765. Epub 2010 May 21.
The antioxidant activity of lemon balm (Melissa officinalis) essential oil (LBEO) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and its hypoglycaemic effect in db/db mice were investigated. LBEO scavenged 97 % of DPPH radicals at a 270-fold dilution. Mice administered LBEO (0.015 mg/d) for 6 weeks showed significantly reduced blood glucose (65 %; P < 0.05) and TAG concentrations, improved glucose tolerance, as assessed by an oral glucose tolerance test, and significantly higher serum insulin levels, compared with the control group. The hypoglycaemic mechanism of LBEO was further explored via gene and protein expression analyses using RT-PCR and Western blotting, respectively. Among all glucose metabolism-related genes studied, hepatic glucokinase and GLUT4, as well as adipocyte GLUT4, PPAR-gamma, PPAR-alpha and SREBP-1c expression, were significantly up-regulated, whereas glucose-6-phosphatase and phosphoenolpyruvate carboxykinase expression was down-regulated in the livers of the LBEO group. The results further suggest that LBEO administered at low concentrations is an efficient hypoglycaemic agent, probably due to enhanced glucose uptake and metabolism in the liver and adipose tissue and the inhibition of gluconeogenesis in the liver.
研究了香蜂草（ Melissa officinalis ）精油（ LBEO ）对 2,2-二苯基-1-苦基肼（ DPPH ）自由基的抗氧化活性及其对 db/db 小鼠的降血糖作用。LBEO 在 270 倍稀释下可清除 97%的 DPPH 自由基。与对照组相比，给予 LBEO（0.015 mg/d）6 周的小鼠血糖（65%；P<0.05）和 TAG 浓度显著降低，口服葡萄糖耐量试验评估的葡萄糖耐量改善，血清胰岛素水平显著升高。通过 RT-PCR 和 Western blot 分别进行基因和蛋白质表达分析，进一步探讨了 LBEO 的降血糖机制。在所研究的所有与葡萄糖代谢相关的基因中，肝葡萄糖激酶和 GLUT4 以及脂肪细胞 GLUT4 、 PPAR-γ 、 PPAR-α 和 SREBP-1c 的表达均显著上调，而肝葡萄糖-6-磷酸酶和磷酸烯醇丙酮酸羧激酶的表达下调。结果进一步表明，低浓度 LBEO 是一种有效的降血糖剂，可能是由于增强了肝脏和脂肪组织中的葡萄糖摄取和代谢，以及抑制了肝脏中的糖异生。
