Perera Handunge Kumudu Irani, Premadasa Walgama Kankanamlage Vindhya Kalpani, Poongunran Jeyakumaran
Department of Biochemistry, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka.
Postgraduate Institute of Science, University of Peradeniya, Peradeniya, Sri Lanka.
BMC Complement Altern Med. 2016 Jan 5;16:2. doi: 10.1186/s12906-015-0982-z.
Hyperglycaemia is a salient feature of poorly controlled diabetes mellitus. Rate of protein glycation is increased with hyperglycaemia leading to long term complications of diabetes. One approach of controlling blood glucose in diabetes targets at reducing the postprandial spikes of blood glucose. The objectives of this study were to assess the in vitro inhibitory effects of Costus speciosus (COS) leaves on α-amylase and α-glucosidase activities, fructosamine formation, protein glycation and glycation-induced protein cross-linking.
Methanol extracts of COS leaves were used. Inhibitory effects on enzyme activities were measured using porcine pancreatic α-amylase and α-glucosidase from Saccharomyces cerevisiae in the presence of COS extract. Percentage inhibition of the enzymes and the IC50 values were determined. In vitro protein glycation inhibitory effect of COS leaves on early and late glycation products were measured using bovine serum albumin or chicken egg lysozyme with fructose. Nitroblue tetrazolium was used to assess the relative concentration of fructosamine and polyacrylamide gel electrophoresis was used to assess the degree of glycation and protein cross-linking in the reaction mixtures.
α-Glucosidase inhibitory activity was detected in COS leaves with a IC50 of 67.5 μg/ml which was significantly lower than the IC50 value of Acarbose (p < 0.01). Amylase inhibitory effects occurred at a comparatively higher concentration of extract with a IC50 of 5.88 mg/ml which was significantly higher than the IC50 value of Acarbose (p < 0.01). COS (250 μg/ml) demonstrated inhibitory effects on fructosamine formation and glycation induced protein cross-linking which were in par with 1 mg/ml aminoguanidine were detected.
Methanol extracts of COS leaves demonstrated in vitro inhibitory activities on α-glucosidase, fructosamine formation, glycation and glycation induced protein cross-linking. These findings provide scientific evidence to support the use of COS leaves for hypoglycemic effects with an added advantage in slowing down protein glycation.
高血糖是糖尿病控制不佳的一个显著特征。随着高血糖导致糖尿病的长期并发症，蛋白质糖基化速率增加。控制糖尿病血糖的一种方法是针对降低餐后血糖峰值。本研究的目的是评估闭鞘姜（COS）叶对α-淀粉酶和α-葡萄糖苷酶活性、果糖胺形成、蛋白质糖基化和糖基化诱导的蛋白质交联的体外抑制作用。
使用闭鞘姜叶的甲醇提取物。在COS提取物存在的情况下，使用猪胰α-淀粉酶和酿酒酵母的α-葡萄糖苷酶来测量对酶活性的抑制作用。测定酶的抑制百分比和IC50值。使用牛血清白蛋白或鸡卵溶菌酶与果糖来测量闭鞘姜叶对早期和晚期糖基化产物的体外蛋白质糖基化抑制作用。用硝基蓝四唑来评估果糖胺的相对浓度，并使用聚丙烯酰胺凝胶电泳来评估反应混合物中的糖基化程度和蛋白质交联。
在闭鞘姜叶中检测到α-葡萄糖苷酶抑制活性，IC50为67.5μg/ml，显著低于阿卡波糖的IC50值（p<0.01）。淀粉酶抑制作用在相对较高浓度的提取物下出现，IC50为5.88mg/ml，显著高于阿卡波糖的IC50值（p<0.01）。COS（250μg/ml）对果糖胺形成和糖基化诱导的蛋白质交联表现出抑制作用，与检测到的1mg/ml氨基胍相当。
闭鞘姜叶的甲醇提取物对α-葡萄糖苷酶、果糖胺形成、糖基化和糖基化诱导的蛋白质交联具有体外抑制活性。这些发现提供了科学证据来支持使用闭鞘姜叶产生降血糖作用，并在减缓蛋白质糖基化方面具有额外优势。
