School of Food and Biological Engineering, Jiangsu University, Zhenjiang, People's Republic of China.
Institute of Food Physical Processing, Jiangsu University, Zhenjiang, People's Republic of China.
J Sci Food Agric. 2024 Jan 15;104(1):63-74. doi: 10.1002/jsfa.12890. Epub 2023 Aug 12.
Our previous studies have shown that ultrasound-treated γ-aminobutyric acid (GABA)-rich coffee leaves have higher angiotensin-I-converting enzyme inhibitory activity than their untreated counterpart. However, whether they have antidiabetic activity remains unknown. In this study, we aimed to investigate the inhibitory activities of coffee leaf extracts (CLEs) prepared with ultrasound (CLE-U) or without ultrasound (CLE-NU) pretreatment on α-amylase and α-glucosidase. Subsequently, we evaluated the binding interaction between CLE-U and both enzymes using multi-spectroscopic and in silico analyses.
Ultrasound pretreatment increased the inhibitory activities of CLE-U against α-amylase and α-glucosidase by 21.78% and 25.13%, respectively. CLE-U reversibly inhibits both enzymes, with competitive inhibition observed for α-amylase and non-competitive inhibition for α-glucosidase. The static quenching of CLE-U against both enzymes was primarily driven by hydrogen bond and van der Waals interactions. The α-helices of α-amylase and α-glucosidase were increased by 1.8% and 21.3%, respectively. Molecular docking results showed that the key differential compounds, including mangiferin, 5-caffeoylquinic acid, rutin, trigonelline, GABA, caffeine, glutamate, and others, present in coffee leaves interacted with specific amino acid residues located at the active site of α-amylase (ASP197, GLU233, and ASP300). The binding of α-glucosidase and these bioactive components involved amino acid residues, such as PHE1289, PRO1329, and GLU1397, located outside the active site.
Ultrasound-treated coffee leaves are potential anti-diabetic substances, capable of preventing diabetes by inhibiting the activities of α-amylase and α-glucosidase, thus delaying starch digestion. Our study provides valuable information to elucidate the possible antidiabetic capacity of coffee leaves through the inhibition of α-amylase and α-glucosidase activities. © 2023 Society of Chemical Industry.
我们之前的研究表明，经过超声处理的富含γ-氨基丁酸（GABA）的咖啡叶比未经处理的咖啡叶具有更高的血管紧张素转化酶抑制活性。然而，它们是否具有抗糖尿病活性尚不清楚。在这项研究中，我们旨在研究经超声（CLE-U）或未经超声（CLE-NU）预处理的咖啡叶提取物（CLEs）对α-淀粉酶和α-葡萄糖苷酶的抑制活性。随后，我们使用多光谱和计算分析评估了 CLE-U 与两种酶的结合相互作用。
超声预处理使 CLE-U 对α-淀粉酶和α-葡萄糖苷酶的抑制活性分别提高了 21.78%和 25.13%。CLE-U 可逆地抑制两种酶，对α-淀粉酶表现为竞争性抑制，对α-葡萄糖苷酶表现为非竞争性抑制。CLE-U 对两种酶的静态猝灭主要由氢键和范德华相互作用驱动。α-淀粉酶和α-葡萄糖苷酶的α-螺旋分别增加了 1.8%和 21.3%。分子对接结果表明，咖啡叶中存在的关键差异化合物，包括芒果苷、5-咖啡酰奎宁酸、芦丁、瓜氨酸、GABA、咖啡因、谷氨酸等，与位于α-淀粉酶活性位点的特定氨基酸残基相互作用（ASP197、GLU233 和 ASP300）。α-葡萄糖苷酶与这些生物活性成分的结合涉及到位于活性位点以外的氨基酸残基，如 PHE1289、PRO1329 和 GLU1397。
超声处理过的咖啡叶是潜在的抗糖尿病物质，通过抑制α-淀粉酶和α-葡萄糖苷酶的活性来预防糖尿病，从而延缓淀粉的消化。我们的研究提供了有价值的信息，通过抑制α-淀粉酶和α-葡萄糖苷酶的活性来阐明咖啡叶可能具有的抗糖尿病能力。© 2023 化学工业协会。
