探討糙薏仁產品於人體降血糖功效並利用細胞實驗研究其功效成分

2018年台灣國民健康署公告指出，每3位19歲以上國民就有1人為代謝症候群。而美國糖尿病協會亦將代謝症候群視為預測糖尿病與心血管疾病的重要指標。但臨床使用的降血糖藥物仍伴隨各種副作用，因此使用天然食材也成為用藥前的替代療法。薏苡學名為Coix lacryma-jobi，屬禾本科。本實驗室選用台中4號薏仁，透過擠壓加工製造之即食產品，相較於市售薏仁產品有較高比例的慢性消化澱粉 (Slow digestive starch)，具有平穩飯後血糖的潛力。本研究透過人體試驗，將受試者分為實驗組或控制組，以前述糙薏仁產品或安慰劑取代早餐的澱粉類，觀察三個月中受試者空腹血糖與醣化血色素之變化。因薏苡組成中，以其固醇類的β-谷固醇 (β-sitosterol)、豆固醇 (Stigmasterol)為主要成分。本研究擬利用Cho-K1細胞，探討薏仁產品中的固醇類可能調節血糖的分子機制。人體試驗結果顯示，比較全部的受試者，與控制組相比，薏仁組無顯著調降血糖功效。但對於血糖值較高的受試者在第4週及第8週有較明顯調節的效果，此與過去曾有研究指出糙薏仁對第二型糖尿病患者有顯著調節血糖效果的結果相符。此外，細胞實驗結果顯示，薏仁產品中的固醇類含量可增加pAKT的表現量，可增加胰島素的感性。因此推測薏仁產品可至少可部分透過其中的植物固醇來調節血糖。

關鍵字

血糖調節；薏苡；慢性消化澱粉； β-谷固醇；豆固醇

並列摘要

According to the report from the Taiwan Health Promotion Administration in 2018, one out of every three people who are 19-year-old or older has metabolic syndrome. The American Diabetes Association also pointed out metabolic syndrome is one of the most important indicators of getting type 2 diabetes. However, clinical anti-diabetic agents combined with several side effects, natural foods are thus used as an interference. Adlay is a traditional Chinese herbal medicine. Previously, we employed a specific processing condition that remained the highest content of slowly digestive starch in the dehulled adlay product when compared with the commercial adlay products in marketing, which can lower post-meal blood glucose. We then conducted a clinical trial to compare the efficacy of the adlay product to the control product made of rice in modulating the blood glucose of people with high blood glucose levels for three months. Moreover, using the Cho-K1 cell line, we also investigated the glucose modulating effect of phytosterols in equal amount of the adlay product. We concluded that people who consumed the adlay product do not significantly lower their blood glucose levels than that of the white rice group. However, people with higher blood glucose baseline of the adlay product group approved more blood glucose than the white rice group at 4 and 8 weeks. This result was consistent with a previous study in which the author observed that dehulled adlay can significantly regulate blood glucose on subjects with type 2 diabetes mellitus. In the cell study, we approved that the major phytosterols in the adlay product can increase pAKT expression and insulin sensitivity. In conclusion, our adlay product can regulate blood glucose, at least partially through its phytosterols.