Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin 150500, China.
Gannan forest farm, Qiqihaer 162100, China.
Food Funct. 2020 Apr 30;11(4):3112-3125. doi: 10.1039/d0fo00012d.
Diabetes is the main chronic disease that greatly affects human life. Up to now, many measures have been taken to cope with the disease, among which natural products with hypoglycemic effects have aroused great interest. The objective of this study was to evaluate the hypoglycemic effects of Morus abla L. cv. longsang 1 leaf-derived water extract in vitro and in vivo. These leaves were firstly subjected to water extraction, and the obtained products were further isolated for polysaccharides, flavonoids and alkaloids. The α-glucosidase activity and anti-protein glycosylation activity of the aqueous extracts were examined in vitro. Hyperglycemic mouse models were used to evaluate the hypoglycemic effects of the aqueous extract by blood biochemical parameters, intestinal microbiota, and pathological changes to the kidneys. The results showed that the main hypoglycemic components in the aqueous extracts were flavonoids and alkaloids and their inhibition rates against α-glucosidase activity were 86.12 ± 1.79% and 87.29 ± 1.32%, respectively. High-dose mulberry leaf water extracts can reduce the blood glucose of diabetic mice by 28.17% and improve glucose tolerance by 19.02%. Furthermore, mulberry leaf water extracts could reduce the serum free fatty acid (FFA), tumor necrosis factor-α (TNF-α), insulin and glycated serum protein content, while alleviating kidney damage and improving intestinal microbiota. These results indicated that the synergistic effects among the different components of mulberry leaves might explain their alleviating effects on diabetic syndrome and thus provide a simple, convenient way to obtain the hypoglycemic components from mulberry leaves.
糖尿病是严重影响人类生命的主要慢性疾病。迄今为止，已经采取了许多措施来应对这种疾病，其中具有降血糖作用的天然产物引起了极大的兴趣。本研究的目的是评估 Morus abla L. cv. longsang 1 叶水提物的体外和体内降血糖作用。首先对这些叶子进行水提，然后对得到的产物进一步分离多糖、黄酮类化合物和生物碱。在体外检测水提物的α-葡萄糖苷酶活性和抗蛋白糖基化活性。使用高血糖小鼠模型，通过血液生化参数、肠道微生物群和肾脏病理变化来评估水提物的降血糖作用。结果表明，水提物中的主要降血糖成分是黄酮类化合物和生物碱，它们对α-葡萄糖苷酶活性的抑制率分别为 86.12±1.79%和 87.29±1.32%。高剂量桑叶水提取物可使糖尿病小鼠的血糖降低 28.17%，葡萄糖耐量提高 19.02%。此外，桑叶水提取物可以降低血清游离脂肪酸（FFA）、肿瘤坏死因子-α（TNF-α）、胰岛素和糖化血清蛋白含量，同时缓解肾脏损伤，改善肠道微生物群。这些结果表明，桑叶中不同成分的协同作用可能解释了它们对糖尿病综合征的缓解作用，从而为从桑叶中获得降血糖成分提供了一种简单、方便的方法。
