利用動物模式及細胞模式探討牛樟芝液態發酵酒精粗萃物對糖尿病延緩及預防之影響

Abstract

根據國際糖尿病聯盟最新數據顯示，全球糖尿病盛行率約為8.3%，反觀台灣糖尿病在十大死因中高居第五名，且罹病人口亦有逐漸攀升的趨勢。糖尿病主要分為三種型態，其中第二型糖尿病人口佔總糖尿病病患90%。其主要特徵為胰島素阻抗，造成胰島素阻抗的原因有許多，主要為缺乏活動力及營養過剩。許多文獻指出此二現象將啟動發炎現象及提升體內氧化壓力，導致胰島素阻抗進而造成第二型糖尿病。目前有研究顯示台灣特有牛樟芝具良好抗氧化及抗發炎之功效，但對於牛樟芝在糖尿病的研究極少。有鑑於野生品種不易取得導致價格昂貴，故本研究利用牛樟芝液態發酵酒精粗萃物進行預防或延緩糖尿病的大鼠試驗，並利用細胞模式探討機制。目前研究結果顯示，在動物實驗中發現牛樟芝液態發酵酒精粗萃物可部分延緩及預防血糖的上升，並可促使發炎物質TNF-α含量下降。在細胞實驗中，誘導L6肌肉細胞胰島素阻抗再投以牛樟芝液態發酵酒精粗萃物，結果顯示其可促使葡萄糖攝取的能力。本實驗材料為酒精萃取物，適合應用於生物體，因此本研究結果將提供糖尿病預防與延緩另一種選擇。

According to International Diabetes Federation Diabetes Atlas (IDF) in 2014, the worldwide prevalence of diabetes is 8.3% and there are about 4 billion people troubled by the disease. In Taiwan, diabetes ranks the fifth in the top ten causes of death and morbidity in the population is gradually rising. Among three types of diabetes, type II diabetes is the most encountered form, accounting for more than 90% of the total cases of diabetes. The major clinical outcome of type II diabetes is insulin resistance. Insulin resistance refers to the inability of the organism to respond to normal levels of circulating insulin, resulting in high blood glucose. There are various causes of insulin resistance, but the main reasons are the lack of exercise and over-nutrition. Many literature indicate that these two phenomena elicit inflammation and enhance oxidative stress, which cause insulin resistance leading to type II diabetes. The leading hypothesized mechanisms to explain insulin resistance in type II diabetes have been strongly linked to tissue inflammation. However, current antidiabetic therapy is based on synthetic drugs that very often produce side effects. For this reason, natural hypoglycaemic compounds may be attractive alternatives to interfere diabetes. Studies have shown Antrodia cinnamomea endemic to Taiwan exhibits potent antioxidant and anti-inflammatory function, but is not readily available because the wild species is rare and therefore expensive. There have been efforts to develop culture methods for A. cinnamomea in three different ways, of which liquid fermentation costs the least, although the active ingredients are quite different from that of wild species. Nonetheless, still an abundance of evidence reports that mycelia from liquid fermentation of A. cinnamomea shows antioxidant and anti-inflammatory ability. In lieu of the few numbers of studies about A. cinnamomea and diabetes, this present study attempts to discover whether alcohol crude extracts from A. cinnamomea liquid fermentation added to diet can prevent or delay the progression of diabetes in rats, and to reveal the underlying mechanism using cell model. The current results showed that A. cinnamomea liquid fermentation ethanol crude extracts can effectively delay and prevent the rise of blood sugar, promote the content of TNF-α and decrease inflammatory substances in vivo. In vitro, A. cinnamomea liquid fermentation ethanol crude extracts was able to stimulate glucose uptake in insulin resistant L6 muscle cell. Further research is needed to elucidate the precise mechanism behind A. cinnamomea’s anti-diabetic effects. The results of this study provide an insight into potential therapeutics for the prevention and amelioration of diabetes.