Nishiyama Tozo, Mae Tatsumasa, Kishida Hideyuki, Tsukagawa Misuzu, Mimaki Yoshihiro, Kuroda Minpei, Sashida Yutaka, Takahashi Kazuma, Kawada Teruo, Nakagawa Kaku, Kitahara Mikio
Functional Foods Development Division, and Life Science Research Laboratories, Life Science RD Center, Kaneka Corporation, Takasago, Hyogo 676-8688, Japan.
J Agric Food Chem. 2005 Feb 23;53(4):959-63. doi: 10.1021/jf0483873.
Turmeric, the rhizome of Curcuma longa L., has a wide range of effects on human health. The chemistry includes curcuminoids and sesquiterpenoids as components, which are known to have antioxidative, anticarcinogenic, and antiinflammatory activities. In this study, we investigated the effects of three turmeric extracts on blood glucose levels in type 2 diabetic KK-A(y) mice (6 weeks old, n = 5/group). These turmeric extracts were obtained by ethanol extraction (E-ext) to yield both curcuminoids and sesquiterpenoids, hexane extraction (H-ext) to yield sesquiterpenoids, and ethanol extraction from hexane-extraction residue (HE-ext) to yield curcuminoids. The control group was fed a basal diet, while the other groups were fed a diet containing 0.1 or 0.5 g of H-ext or HE-ext/100 g of diet or 0.2 or 1.0 g of E-ext/100 g of diet for 4 weeks. Although blood glucose levels in the control group significantly increased (P < 0.01) after 4 weeks, feeding of 0.2 or 1.0 g of E-ext, 0.5 g of H-ext, and 0.5 g of HE-ext/100 g of diet suppressed the significant increase in blood glucose levels. Furthermore, E-ext stimulated human adipocyte differentiation, and these turmeric extracts had human peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand-binding activity in a GAL4-PPAR-gamma chimera assay. Also, curcumin, demethoxycurcumin, bisdemethoxycurcumin, and ar-turmerone had PPAR-gamma ligand-binding activity. These results indicate that both curcuminoids and sesquiterpenoids in turmeric exhibit hypoglycemic effects via PPAR-gamma activation as one of the mechanisms, and suggest that E-ext including curcuminoids and sesquiterpenoids has the additive or synergistic effects of both components.
姜黄，即姜黄属植物姜黄的根茎，对人体健康具有广泛影响。其化学成分包括姜黄素类化合物和倍半萜类化合物，已知这些成分具有抗氧化、抗癌和抗炎活性。在本研究中，我们调查了三种姜黄提取物对2型糖尿病KK-A(y)小鼠（6周龄，每组n = 5）血糖水平的影响。这些姜黄提取物通过乙醇提取（E-ext）获得，可同时得到姜黄素类化合物和倍半萜类化合物；通过己烷提取（H-ext）获得倍半萜类化合物；通过对己烷提取残渣进行乙醇提取（HE-ext）获得姜黄素类化合物。对照组喂食基础饲料，而其他组则喂食含有0.1或0.5 g H-ext或HE-ext/100 g饲料或0.2或1.0 g E-ext/100 g饲料的饲料，持续4周。尽管4周后对照组的血糖水平显著升高（P < 0.01），但喂食0.2或1.0 g E-ext、0.5 g H-ext和0.5 g HE-ext/100 g饲料可抑制血糖水平的显著升高。此外，E-ext刺激人脂肪细胞分化，并且在GAL4-PPAR-γ嵌合体分析中，这些姜黄提取物具有人过氧化物酶体增殖物激活受体-γ（PPAR-γ）配体结合活性。此外，姜黄素、去甲氧基姜黄素、双去甲氧基姜黄素和莪术酮具有PPAR-γ配体结合活性。这些结果表明，姜黄中的姜黄素类化合物和倍半萜类化合物均通过激活PPAR-γ作为一种机制发挥降血糖作用，并表明包含姜黄素类化合物和倍半萜类化合物的E-ext具有两种成分的相加或协同作用。
