Zhang Wen, Li Lingyu, Ma Yue, Chen Xiaole, Lan Tao, Chen Long, Zheng Zhenjia
Key Laboratory of Food Processing Technology and Quality Control of Shandong Higher Education Institutes, College of Food Science and Engineering, Shandong Agricultural University, 61 Daizong Street, Tai'an 271018, China.
Institute of Agri-Food Processing and Nutrition, Beijing Academy of Agriculture and Forestry Sciences, Beijing Key Laboratory of Agricultural Products of Fruits and Vegetables Preservation and Processing, Key Laboratory of Vegetable Postharvest Processing, Ministry of Agriculture and Rural Affairs, Beijing 100097, China.
Foods. 2022 Jun 21;11(13):1821. doi: 10.3390/foods11131821.
The aim of our study was to synthesize a pumpkin peel polysaccharide (PPP)-Cr(III) complex and investigate its hypoglycemic activity. Firstly, a novel PPP-Cr(III) complex with a Cr content of 23.77 mg/g was synthesized and characterized. Physicochemical characterization indicated that PPP-Cr(III) had some changes in chemical composition, monosaccharide composition, and morphological structure compared with PPP. The molecular weights of PPP-Cr(III) and PPP were 1.398 × 10 g/mol and 3.386 × 10 g/mol, respectively, showing a lower molecular weight after the introduction of Cr(III). Fourier transform infrared spectroscopy showed that a new characteristic absorption peak of Cr-O appeared at 534 cm in PPP-Cr(III), indicating that Cr(III) was successfully complexed with PPP. Secondly, the hypoglycemic activity of PPP-Cr(III) based on α-glucosidase inhibitory and insulin resistance (IR)-HepG2 cells was evaluated. Compared with PPP, PPP-Cr(III) exhibited a more significantly α-glucosidase inhibitory activity. The IR-HepG2 cells confirmed an obvious increase in glucose consumption. Western blot analysis demonstrated that the treated IR-HepG2 cells were able to increase the protein levels of p-AMPK and p-GSK-3β, indicating that IR-HepG2 cells exerted hypoglycemic activity via the AMPK/GSK-3β signaling pathway. These results suggested that PPP-Cr(III) had good hypoglycemic activity, which could provide theoretical support for the development of novel hypoglycemic products.
我们研究的目的是合成一种南瓜皮多糖（PPP）-铬（III）复合物，并研究其降血糖活性。首先，合成并表征了一种铬含量为23.77 mg/g的新型PPP-铬（III）复合物。物理化学表征表明，与PPP相比，PPP-铬（III）在化学成分、单糖组成和形态结构上有一些变化。PPP-铬（III）和PPP的分子量分别为1.398×10 g/mol和3.386×10 g/mol，在引入铬（III）后分子量降低。傅里叶变换红外光谱表明，PPP-铬（III）在534 cm处出现了新的Cr-O特征吸收峰，表明铬（III）成功地与PPP络合。其次，基于α-葡萄糖苷酶抑制和胰岛素抵抗（IR）-HepG2细胞对PPP-铬（III）的降血糖活性进行了评价。与PPP相比，PPP-铬（III）表现出更显著的α-葡萄糖苷酶抑制活性。IR-HepG2细胞证实葡萄糖消耗明显增加。蛋白质印迹分析表明，处理后的IR-HepG2细胞能够增加p-AMPK和p-GSK-3β的蛋白水平，表明IR-HepG2细胞通过AMPK/GSK-3β信号通路发挥降血糖活性。这些结果表明，PPP-铬（III）具有良好的降血糖活性，可为新型降血糖产品的开发提供理论支持。
