5种莲副产物中活性成分及其抗氧化、α-葡萄糖苷酶抑制活性比较

Comparison of Bioactive Compounds, Antioxidant Activity and α-Glucosidase Inhibition Activity of Five By-Products from Lotus Seed Production

每年大量的莲叶、莲蓬壳、莲壳和莲衣因被丢弃而没有得到有效利用,因此,本研究旨在通过比较莲叶、莲蓬壳、莲壳、莲衣和莲心提取物中主要活性成分的含量及其抗氧化和α-葡萄糖苷酶活性抑制能力,探讨其高值化利用潜力。结果表明:莲蓬壳提取物中的总酚含量(232.50 mg GAE/g)和总三萜含量(423.75 mg OAE/g)最高,而莲叶和莲衣提取物分别具有最高的总黄酮含量(41.48 mg Qu E/g)和总缩合单宁含量(36.13 mg Ca E/g)。同时,莲蓬壳提取物具有最高的抗氧化和α-葡萄糖苷酶活性抑制能力,其1,1-二苯基-2-苦基肼自由基、2,2’-联氮基-双(3-乙基苯并噻唑啉-6-磺酸)自由基清除能力和α-葡萄糖苷酶活性抑制能力分别为阳性对照的2.64、1.17、85倍。莲衣的抗氧化能力次之,莲叶、莲蓬壳、莲壳和莲衣的α-葡萄糖苷酶活性抑制能力均高于阿卡波糖。相关性分析显示,多酚类和缩合单宁类化合物为莲副产物中主要的自由基清除剂和α-葡萄糖苷酶抑制剂,而黄酮类化合物对铁离子还原能力的贡献最大。因此,莲蓬壳具有很好的抗氧化和抑制α-葡萄糖苷酶活性的能力,多酚、黄酮和缩合单宁为其主要活性成分,具有进一步研究其体内降血糖、抗糖尿病及其并发症的价值。

A large amount of lotus receptacle, epicarp, and seed skin are discarded every year without any further utilization. Thus, this study was designed to compare the potentials in high-value utilization of lotus leaf, receptacle, epicarp, seed skin and plumule. The contents of major bioactive compounds in extracts from these materials were measured, and the antioxidant activities and hypoglycemic potential were analyzed with three antioxidant models and α-glucosidase inhibitory assay, respectively. The results indicated that lotus receptacle extract had the highest contents of phenols （232.50 mg GAE/g） and triterpenoids （423.75 mg OAE/g）, while the highest content of ？avonoids （41.48 mg QuE/g） and condensed tannins （36.13 mg CaE/g） was found in lotus leaf and lotus seed skin extract, respectively. In addition, lotus receptacle extract showed the strongest antioxidant and α-glucosidase inhibition. The 1,1-diphenyl-2-picrylhydrazyl scavenging ability, 2,2’-azino-bis-（3-ethylbenzthiazoline-6-sulphonate） scavenging ability and α-glucosidase inhibition were 2.64, 1.17 and 85 folds higher than that of the positive control, respectively. Furthermore, lotus seed skin extract had the second highest antioxidant ability; the α-glucosidase inhibition of lotus leaf, lotus receptacle, lotus epicarp, and lotus seed skin was higher than that of acarbose. Correlation analysis indicated that phenolics and condensed tannins contributed the most to free radical scavenging and α-glucosidase inhibitory activity, whereas avonoids contributed the most to reducing power. Thus, lotus receptacle has considerable antioxidant and hypoglycemic activities, and phenolics, avnoids and condensed tannins are the major bioactive compounds, and therefore it needs to be further investigated for in vivo activity against hyperglycaemia, diabetes and diabetic complication.