數種食材萃物對脂肪或肌肉細胞葡萄糖攝取之影響

The Effects of Several Food Extracts on Glucose Uptake in 3T3-L1 Adipocytes and C2C12 Myotubes

李天瑞(Tien-Jui Lee)

指導教授 ： 黃青真

國立臺灣大學/生命科學院/微生物與生化學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.00278

摘要

現今罹患代謝症候群的人口日益增加，有鑑於藥物治療所難以避免的副作用，傳統中草藥或食材的替代療法與其有效成分漸受重視。山藥與苦瓜長久以來被視為具有降血糖、改善糖尿病的食材，且於許多動物與人體試驗中獲得證實，但對於其中有效成分及作用機制卻不完全明瞭。因此本研究以C2C12肌肉細胞與3T3-L1脂肪細胞株的葡萄糖攝取模式，在正常無胰島素抗性的情況與以1 mM棕櫚酸誘發胰島素抗性下，探討山藥乙酸乙酯萃物與苦瓜乙酸乙酯萃物與其中不皂化物、乙醇萃物、水萃物是否有改善胰島素抗性的效果。結果發現山藥乙酸乙酯萃物對正常肌肉細胞具有類似胰島素效應，對於基礎與胰島素刺激下葡萄糖攝取均有促進效果，但對脂肪細胞則無促進效果。而苦瓜不皂化物可增進脂肪細胞葡萄糖攝取，但對胰島素抗性無改善。苦瓜以水萃物最有潛力，12小時處理下對於正常或有胰島素抗性的脂肪細胞，皆可隨劑量增進其葡萄糖攝取，卻會受熱破壞此一活性。此效果不會被compound c抑制，也無法完全被wortmannin所抑制，並不造成AMPK或Akt磷酸化增加。且苦瓜水萃物對長時間高胰島素所誘發的胰島素抗性沒有改善效果。而不同於先前研究的結果，發現3kDa以下小分子亦含有活性成分，顯示整體苦瓜水萃物改善胰島素抗性效應於低濃度時來自非蛋白質部分。針對於苦瓜水萃物發現的活性物質與其作用機制途徑值得進一步探討，具有改善胰島素抗性潛力。

關鍵字

胰島素抗性 ； 苦瓜 ； 山藥 ； 脂肪細胞 ； 肌肉細胞 ； 葡萄糖

並列摘要

Metabolic syndrome and insulin resistance have become worldwide epidemiological issues. Dietary supplement and traditional medicines may be a natural source of for the development of the treatment to counteract insulin resistance in stead of those widely used agents with many side effects. Yam and bitter gourd are common vegetable and tonic foods in Asian and have been shown to exert hypoglycemic effects in animal models and humans, but the mechanism and active constituents are not totally understood. Here we measured 3H-labeled 2-deoxyglucose uptake by normal and pamitate-induced insulin resistance 3T3-L1 adipocytes and C2C12 myotubes, and evaluated whether various extracts from yam and bitter gourd could improve. It is found that yam EA extract showed an insulin-like pattern in myotubes but not in adipocytes. Bitter gourd water extract is the most active fraction that showed a promotion of glucose uptake in both normal or insulin resistant 3T3-L1 adipocytes in a dose-dependent manner. This activity is diminished by heating the extract at 100℃ for 10 min. The activity was not inhibited by compound c but was partially inhibited by wortmannin. Neither AMPK phosphorylation nor Akt activation was changed. Interestingly, the water extract of bitter gourd could not improve the insulin resistance that induced by chronic insulin treatment. It has also been found that constituents with a MW less than 3 kDa were also active. The precise structure in bitter gourd water extract and mechanism of action of those active molecules are worth to be further examined. Bitter gourd thus has the potential for ameliorating insulin resistance.

並列關鍵字

insulin resistance ； bitter gourd ； yam ； adipocyte ； myotube ； glucose

參考文獻

吳夢婷 (2008). 數種具植物雌激素活性材料對卵巢剔除鼠代謝症候群及鈣代謝之影響. 國立台灣大學微生物與生化學研究所碩士論文.

張天鈞 (1994). 新陳代謝症 （metabolic syndrome）的歷史演進、定義和臨床意義. 當代醫學 31, 3.

鄭瑋宜 (2007). 山藥具雌激素活性成分之單離與鑑定研究. 國立台灣大學微生物與生化所博士論文.

陳永如 (2007). 數種植物雌激素食材萃物對PPAR、脂肪細胞生成及雌激素活性特質鑑定. 國立台灣大學微生物與生化學所碩士論文.

Ahmed, I., Adeghate, E., Cummings, E., Sharma, A.K., and Singh, J. (2004). Beneficial effects and mechanism of action of Momordica charantia juice in the treatment of streptozotocin-induced diabetes mellitus in rat. Mol Cell Biochem 261, 63-70.