Evaluation of Rubus grandifolius L. (wild blackberries) activities targeting management of type-2 diabetes and obesity using in vitro models
Abstract
Rubus grandifolius Lowe (wild blackberries) is an endemic species from Madeira Archipelago (Portugal) used in folk medicine for alleviating diabetic complications. In this work, R. grandifolius methanolic extracts were analysed for in vitro inhibitory effect on digestive enzymes linked to type-2 diabetes, as well as aldose reductase activity and protein glycation. The phenolic composition, antioxidant and cytotoxic activities were also determined. Methanolic extracts exhibited strong inhibition of glucosidases (α- and β), but were less potent for α-amylase and pancreatic lipase when compared to current pharmaceutical drugs. The total phenolic content determined by HPLC-DAD varied between 92.96 - 97.47 and 118.01–137.41 mg g−1 of dry extract for berries and leaves, respectively. Fifty polyphenols were quantified, anthocyanins and ellagitannins being the main compounds. Cyanidin-3-glucoside was identified as one of the main hypoglycaemic and hypolipidemic agents in all extracts. R. grandifolius also prevented glycation of bovine-serum albumin (BSA) and showed strong radical scavenging activity against tested free radicals. At low concentration, the extracts were not cytotoxic against Caco-2 cells. Based on the results of this study, wild blackberry extracts demonstrated a potential beneficial effect on the control/management of type-2 diabetes mellitus, validating their use in folk medicine.
野黑莓是葡萄牙马德拉群岛特有的一种，用于缓解糖尿病并发症的民间医学。本研究分析了黑莓甲醇提取物对2型糖尿病相关消化酶的体外抑制作用，以及醛糖还原酶活性和蛋白质糖化作用。同时测定了其酚类成分、抗氧化活性和细胞毒活性。与现有药物相比，甲醇提取物对α-和β -葡萄糖苷酶有较强的抑制作用，但对α-淀粉酶和胰脂肪酶的抑制作用较弱。HPLC-DAD测定浆果干提取物总酚含量为92.96 ~ 97.47，叶干提取物总酚含量为118.01 ~ 137.41 mg g−1。测定了50种多酚类化合物，主要化合物为花青素和鞣花单宁。花青素-3-葡萄糖苷在所有提取物中被鉴定为主要的降血糖和降血脂药物之一。黑莓对牛血清白蛋白(BSA)的糖基化也有一定的抑制作用，并表现出较强的自由基清除活性。在低浓度下，提取物对Caco-2 细胞无细胞毒性。本研究结果表明，野生黑莓提取物对2型糖尿病的控制和管理具有潜在的有益作用，验证了其在民间医学中的应用。
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https://www.sciencedirect.com/science/article/abs/pii/S0278691518308081
