以細胞與小鼠模式探討有色米萃取物對脂質代謝之影響

Abstract

本研究旨在探討有色米萃取物對高脂飲食（high fat diet, HFD）所誘導之代謝功能障礙相關脂肪肝疾病（metabolic dysfunction-associated steatotic liver disease, MASLD）的改善效果，並評估其對脂質代謝相關分子之調控作用。研究將有色米紅色SA0537（編號361）、紅棕色SA0536（編號363）、黑色SA0415（編號365）、淡褐色TNG67（編號367）、淡棕色SA0677.1（編號369）進行萃取，以1g米加12 mL 50%酒精萃取一晚後，凍乾成粉末，以二次水回溶後進行後續測試。首先以高效液相層析法（high Performance Liquid Chromatography, HPLC）測定有色米萃取物中矢車菊素-3-葡萄糖苷（cyanidin-3-glucoside, C3G）之含量，並以Folin–Ciocalteu法測定總酚含量。結果顯示，不同樣品之C3G與總酚含量存在差異，其中 黑米SA0415含量最高，因此選作後續實驗之主要處理組。於體外實驗中，先以棕櫚酸誘導HepG2細胞脂質累積，再以黑米SA0415萃取物進行處理。結果顯示，黑米SA0415萃取物可降低脂質沉積，並抑制脂肪酸所誘導之脂質累積。於體內實驗中，高脂飲食顯著增加小鼠體重與脂肪組織重量，促進肝臟脂質累積，並誘發血脂異常。相較之下，黑米SA0415萃取物處理可顯著降低脂肪組織重量，於Oil Red O染色結果中可觀察到肝臟脂質沉積較少。其作用方向並非完全一致，顯示可能涉及脂質運輸與代謝重新分配。進一步以即時聚合酶連鎖反應（real-time polymerase chain reaction, RT-qPCR） 進行脂質代謝相關基因分析，包含脂質新生相關基因FAS 與 SREBP-1c與脂肪酸氧化相關基因CPT1α 與 PPARα，黑米SA0415萃取物可調節脂質代謝相關基因的表現。總結而言，黑米萃取物可能透過降低脂質累積、改善血脂異常及調節脂質代謝相關基因表現，對高脂飲食所誘導之MASLD發揮保護作用。

This study investigated the ameliorative effects of colored rice extracts on high-fat diet (HFD)-induced metabolic dysfunction-associated steatotic liver disease (MASLD) and evaluated their regulatory roles on lipid metabolism-related molecular targets. Five varieties of colored rice were selected for extraction: red SA0537 (No. 361), reddish-brown SA0536 (No. 363), black SA0415 (No. 365), light brown TNG67 (No. 367), and light brownish SA0677.1 (No. 369). Each sample was extracted overnight using 12 mL of 50% ethanol per gram of rice, subsequently freeze-dried into powder, and reconstituted in double-distilled water prior to analysis. The content of cyanidin-3-glucoside (C3G) in the extracts was quantified by high-performance liquid chromatography (HPLC), and total phenolic content was determined using the Folin–Ciocalteu method. Significant variation in both C3G and total phenolic content was observed among samples, with black rice SA0415 exhibiting the highest levels; it was therefore selected as the primary treatment group for subsequent experiments. In vitro, palmitic acid-induced lipid accumulation in HepG2 cells was used as a cellular model. Treatment with the black rice SA0415 extract significantly reduced lipid deposition and attenuated fatty acid-induced lipid accumulation. In vivo, HFD-fed mice demonstrated significant increases in body weight and adipose tissue mass, along with pronounced hepatic lipid accumulation and dyslipidemia. In contrast, supplementation with the black rice SA0415 extract markedly reduced adipose tissue weight, and Oil Red O staining revealed notably diminished hepatic lipid deposition. The directional effects were not entirely consistent across parameters, suggesting potential involvement of lipid transport and metabolic redistribution mechanisms. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis of lipid metabolism-related genes—including the de novo lipogenesis-associated genes FAS and SREBP-1c, and the fatty acid oxidation-associated genes CPT1α and PPARα—demonstrated that the black rice SA0415 extract modulated the expression of these genes. Collectively, black rice extract may exert a protective role against HFD-induced MASLD by reducing lipid accumulation, alleviating dyslipidemia, and regulating the expression of lipid metabolism-related genes.