Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
Functional Food Research Unit, Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200, Thailand.
Oxid Med Cell Longev. 2021 Apr 27;2021:5510230. doi: 10.1155/2021/5510230. eCollection 2021.
Rice bran oil (RBO) comprises various nutrients and phytochemicals which exhibit several health benefits. There are no studies regarding the functional effects of different colours of RBO. This study was aimed to compare the constituents and antioxidant activities of white rice bran oil (WRBO) and coloured rice bran oil (CRBO). Each RBO showed similar free fatty acid profiles. However, greater amounts of vitamin E, phytosterols, carotenoids, and chlorophylls were found in CRBO, which had lower -oryzanol content than WRBO. Oxidative stress was induced in male mice by an overdose of acetaminophen (APAP) at 300 mg/kg body weight. The mice were then fed with RBO at the equivalent dose to 100 mg/kg body weight of -oryzanol three hours later and sacrificed six hours after APAP treatment. The administration of 100 mg -oryzanol equivalent in CRBO ameliorated APAP-induced hepatotoxicity in mice more strongly than 100 mg -oryzanol equivalent in WRBO, as evidenced by the significant reduction of serum ALT, hepatocellular necrosis, and hepatic lipid peroxidation. CRBO could improve xenobiotic-metabolizing and antioxidant enzyme activities, including glutathione -transferase, superoxide dismutase, glutathione peroxidase, and glutathione reductase, and also increase mRNA expression of various antioxidant-responsive genes. Vitamin E, phytosterols, carotenoids, and chlorophyll might be the protective compounds in CRBO that alleviate APAP-induced hepatotoxicity through the interruption of APAP metabolism and the activation of antioxidant systems at both transcriptional and enzymatic levels. These findings might provide a protective role of CRBO on oxidative stress associated with several degenerative diseases.
米糠油（RBO）含有多种营养成分和植物化学物质，具有多种健康益处。目前尚无关于 RBO 不同颜色的功能效果的研究。本研究旨在比较白米糠油（WRBO）和有色米糠油（CRBO）的成分和抗氧化活性。两种 RBO 的游离脂肪酸谱相似。然而，CRBO 中含有更多的维生素 E、植物甾醇、类胡萝卜素和叶绿素，而 - 谷维素的含量则低于 WRBO。雄性小鼠经 300mg/kg 体重的对乙酰氨基酚（APAP）过量给药诱导氧化应激，三小时后给予相当于 100mg/kg 体重 - 谷维素的 RBO，并在 APAP 处理后六小时处死。与 WRBO 中相当于 100mg - 谷维素相比，CRBO 中相当于 100mg - 谷维素的给药能更显著地改善 APAP 诱导的小鼠肝毒性，这表现为血清 ALT、肝细胞坏死和肝脂质过氧化的显著减少。CRBO 可改善外源性代谢物和抗氧化酶活性，包括谷胱甘肽 - 转移酶、超氧化物歧化酶、谷胱甘肽过氧化物酶和谷胱甘肽还原酶，并增加各种抗氧化反应基因的 mRNA 表达。维生素 E、植物甾醇、类胡萝卜素和叶绿素可能是 CRBO 中的保护化合物，通过中断 APAP 代谢和在转录和酶水平上激活抗氧化系统来减轻 APAP 诱导的肝毒性。这些发现可能为 CRBO 在与几种退行性疾病相关的氧化应激中提供保护作用。
