三华李叶抗氧化活性物质的分离鉴定

Isolation and Identification of Bioactive Compounds with Antioxidant Activities from Sanhua Plum (Prunus salicina Lindl.)

摘要:

对比研究了三华李果肉、果核及叶乙醇提取物的总酚、总黄酮含量及其抗氧化活性。三华李叶提取物总酚、总黄酮含量最高，分别为14.75 g没食子酸当量/100 g提取物和5.45 g儿茶素当量/100 g提取物，且三华李叶具有最强的DPPH自由基清除能力（IC50值为79.75 μg/mL）及氧自由基吸收能力（ORAC值为6521.74 μmol trolox equiv/g）。采用柱层析法，从三华李叶中分离得到三个黄酮类化合物，通过核磁共振法（NMR）及电喷雾质谱法（ESI-MS），鉴定为山柰酚-3,7-二-O-α-L-鼠李糖苷，山柰酚-3-O-α-L-鼠李糖苷以及山柰酚-7-O-α-L-鼠李糖苷，三个化合物均为首次从三华李叶中分离得到。其中，山柰酚-7-O-α-L-鼠李糖苷具有最强的DPPH自由基清除能力（IC50为12.93 μg/mL）及氧自由基吸收能力（ORAC，8.83 μmol trolox equiv/μmol）。山柰酚-3,7-二-O-α-L-鼠李糖苷是三华李叶中含量最多的化合物。因此，三华李叶可作为有效的抗氧化剂用于保健食品。

Abstract:

The total phenol and flavonoid content as well as the antioxidant activities of extracts from the fruit pulp, pit, and leaf of Sanhua plum (Prunus salicina Lindl.) were comparatively studied. The plum leaf extract had the highest total phenolic content (14.75 g gallic acid equiv/100 g extract) and total flavonoid content (5.45 g catechin equiv/100 g extract), and possessed the strongest 2,2-diphenyl-1-picrylhydrazyl (DPPH?) radical scavenging activity (half maximal inhibitory concentration (IC50) value = 79.75 μg/mL) and oxygen radical absorbance capacity (6521.74 μmol trolox equiv/g). Using column chromatography, three flavonoids were separated from Sanhua plum leaves for the first time; they were identified as kaempferol-3,7-O-α-L-dirhamnoside, kaempferol-3-O-α-L-rhamnoside, and kaempferol-7-O-α-L-rhamnoside by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI-MS). Among them, kaempferol-7-O-α-L-rhamnoside possessed the strongest DPPH? radical scavenging activity (IC50 value = 12.93 μg/mL) and oxygen radical absorbance capacity (8.83 μmol trolox equiv/μmol). The compound with the highest content in the plum leaf extract was kaempferol-3,7-O-α-L-dirhamnoside (6.40 g/100 g extract). Therefore, plum leaf extract can be an effective antioxidant for use in health care products.