Extraction of Proanthocyanidins from Chinese Wild Rice ( Zizania latifolia ) and Analyses of Structural Composition and Potential Bioactivities of Different Fractions

• Published in: Molecules (Basel, Switzerland) Switzerland), 2019-04, Vol.24 (9), p.1681
• Main Authors: Chu, Mei-Jun, Du, Yong-Mei, Liu, Xin-Min, Yan, Ning, Wang, Feng-Zhong, Zhang, Zhong-Feng
• Format: Article
• Language: English
• Subjects: Antioxidants; bioactivities; Biological activity; Butanol; Catechin; Chemical Fractionation; Chromatography; Chromatography, High Pressure Liquid; Composition; Degree of polymerization; Enzyme Activation; Epicatechin; Ethanol; Experiments; extraction; Extraction procedures; Fractionation; Free Radical Scavengers - chemistry; Free Radical Scavengers - isolation & purification; Free Radical Scavengers - pharmacology; Functional foods & nutraceuticals; Glucosidase; Glycoside Hydrolase Inhibitors - chemistry; Glycoside Hydrolase Inhibitors - isolation & purification; Glycoside Hydrolase Inhibitors - pharmacology; Inhibitory Concentration 50; Molecular Structure; Oryza - chemistry; Pancreas; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Proanthocyanidins; Proanthocyanidins - chemistry; Proanthocyanidins - isolation & purification; Proanthocyanidins - pharmacology; purification; Resins; Scavenging; Variables; Variance analysis; wild rice; Zizania latifolia; α-Glucosidase
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules24091681

Due to the importance of proanthocyanidin bioactivity and its relationship with chemical structure, ultrasound-assisted extraction and purification schemes were proposed to evaluate the proanthocyanidin content and analyze the structural composition and potential bioactivities of different proanthocyanidin fractions from Chinese wild rice ( ). Following an optimized extraction procedure, the crude wild rice proanthocyanidins (WRPs) were purified using n-butanol extraction, chromatography on macroporous resins, and further fractionation on Sephadex LH-20 to yield six specific fractions (WRPs-1-WRPs-6) containing proanthocyanidin levels exceeding 524.19 ± 3.56 mg/g extract. Structurally, (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin were present as both terminal and extension units, and (-)-epicatechin was the major extension unit, in each fraction. This is the first preparation of WRP fractions with a different mean degree of polymerization (mDP), ranging from 2.66 ± 0.04 to 10.30 ± 0.46. A comparison of the bioactivities of these fractions revealed that fractions WRPs-1-WRPs-5 had significant DPPH radical scavenging activities, whereas fraction WRPs-6 with a high mDP showed better α-glucosidase and pancreatic lipase inhibitory effects. These findings should help define possible applications of WRPs to functional foods or nutraceuticals.