不同苦瓜品种皂苷含量组成及其抗氧化活性和α-葡萄糖苷酶的抑制活性

【目的】比较不同品种苦瓜果肉中皂苷总含量、7种单体组成含量及抗氧化性和α-葡萄糖苷酶抑制活性差异,为明确苦瓜中主要皂苷单体组成含量,筛选高皂苷含量及高活性的苦瓜品种提供科学参考。【方法】采用香草醛-高氯酸法测定13个苦瓜品种皂苷总含量,高效液相法测定7种皂苷单体含量、总抗氧化能力指数(ORAC),并评价其抗氧化活性,采用4-硝基酚-2-D吡喃葡萄糖苷法测定α-葡萄糖苷酶抑制率,同时分析组成含量和活性之间的相关性。【结果】13个不同品种苦瓜果肉皂苷总含量呈显著性差异,含量变幅为(0.52—1.20)g/100g DW,平均值为0.79 g/100g DW,变异系数为21.65%。7种皂苷单体含量的平均值依次为:苦瓜苷A(Momorcharaside A)5.32μg·g-1 DW,苦瓜皂苷A(Momordicoside A)25.42μg·g-1 DW,Karaviloside XI 3.96μg·g-1 DW,苦瓜皂苷F2(Momordicoside F2)66.95μg·g-1 DW,苦瓜皂苷K(Momordicoside K)183.70μg·g-1 DW,(23E)-3β,7β,25-trihydroxycucubita-5,23-dien-19-al 40.13μg·g-1 DW,Kuguacin N 3.87μg·g-1 DW。不同品种苦瓜总皂苷ORAC指数变幅为2 747.76—15 584.07μmol Trolox·g-1,平均值为8 879.48μmol Trolox·g-1,变异系数为34.91%;α-葡萄糖苷酶IC50值变幅为1.55—4.96 mg·m L-1。【结论】不同品种苦瓜果肉皂苷总含量、单体组成含量、抗氧化活性和α-葡萄糖苷酶抑制率有显著差异。皂苷是苦瓜抑制α-葡萄糖苷酶活性的主要物质基础,但并非苦瓜抗氧化活性主要贡献物质。(23E)-3β,7β,25-trihydroxycucubita-5,23-dien-19-al是主要活性单体。

Saponion Profiles and Antioxidant Activity, α-Glucosidase Inhibitory Activity of Momordica charantia of Different Varieties

【Objective】 The content and composition of saponion of 13 different M. charantia varieties as well as the antioxidant activity and inhibitory effect of α-glucosidase were studied. 【Method】 Perchloric acid-vanilin-glacial method was used to determine saponin content, while HPLC method was used to measure the contents of 7 saponin components. In addition, their antioxidant activity was evaluated by oxygen radical absorbance capacity (ORAC). The 4-nitrophenyl-2-β-D-glucopyranoside method was used to measure the α-glucosidase inhibitory activity and to analyze the relationship between the components and the corresponding activity. 【Result】There is a significant difference in contents of saponin in 13 different varieties of M. charantia.The content ranges of saponin were 0.52-1.20 g/100g DW, with an average value being 0.79 g/100g DW, and the coefficient of variability being 21.65%. The average contents of components were as follows: momorcharaside A 5.32 μg·g^-1 DW, momordicoside A 25.42 μg·g^-1 DW, karaviloside XI 3.96 μg·g^-1 DW, momordicoside F2 66.95 μg·g^-1 DW, momordicoside K 183.70 μg·g^-1 DW, (23E)-3β,7β,25-trihydroxycucubita-5,23-dien-19-al 40.13 μg·g^-1 DW, and kuguacin N 3.87 μg·g^-1 DW. ORAC values of the 13 M. charantia varieties varied from 2 747.76 to 15 584.07 μmol Trolox?g^-1, the average value being 8 879.48 mol Trolox·g^-1, the coefficient of variability being 34.91% and the IC₅₀ value of alpha glucosidase varied from 1.55 to 4.96 mg·mL^-1. 【Conclusion】Significant differences in the components of saponin and the antioxidant activity and the inhibitory effect on α-glucosidase of different varieties of M. charantia were detected. Saponin is the main active basis of α-glucosidase activity in M. charantia, but not the main antioxidant substance. (23E)-3β,7β,25-trihydroxycucubita-5,23-dien-19-al is the major active compound.