Sericultural & Agri-Food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs/Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, PR China.
Sericultural & Agri-Food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs/Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, PR China.
Food Chem. 2021 Oct 1;358:129872. doi: 10.1016/j.foodchem.2021.129872. Epub 2021 Apr 20.
Chemical profiles, distribution, and antioxidant activity of bound phenolics from brown rice were investigated. Four new dehydrodiferulic acid dimers (DFA) along with eighteen known phenolics were isolated from brown rice bound phenolic extracts and their structures were determined by multiple spectroscopic methods. Among them, ferulic acid and 8-5' DFA were the most abundant monomeric and dimeric bound phenolics in brown rice, rice bran and polished rice. In whole brown rice, polished rice contributed more than 50% of three phenolic monomers and six phenolic dimers, while rice bran contributed more than half of the other thirteen phenolics including eight monomers, four dimers, and one trimer. All the isolated compounds exhibited oxygen radical absorbance capacity. Thomasidioic acid, caffeic acid, methyl caffeate, and 8-5' DC DFA displayed potent peroxyl radical scavenging capacity, and the last three compounds also showed moderate cellular antioxidant activity.
研究了糙米中结合型酚类化合物的化学特征、分布及其抗氧化活性。从糙米结合型酚类提取物中分离得到四个新的去氢二阿魏酸二聚体（DFA）和十八个已知酚类化合物，并通过多种光谱方法确定了它们的结构。其中，阿魏酸和 8-5' DFA 是糙米、米糠和精米中含量最丰富的单体和二聚体结合型酚类化合物。在整个糙米中，精米中三种酚类单体和六种酚类二聚体的含量超过 50%，而米糠中则含有除这三种之外的另外 13 种酚类化合物，包括 8 种单体、4 种二聚体和 1 种三聚体。所有分离得到的化合物均表现出氧自由基吸收能力。托马斯酸、咖啡酸、甲基咖啡酸和 8-5' DC DFA 具有较强的过氧自由基清除能力，后三种化合物还表现出适度的细胞抗氧化活性。
