Institution of Plant Genetics and Breeding, Guizhou Normal University, Guiyang, 550001, China.
Guizhou Academy of Tobacco Science, Guiyang, 550003, China.
Sci Rep. 2023 Sep 29;13(1):16372. doi: 10.1038/s41598-023-43466-3.
Green glutinous rice is a unique genetic germplasm that has yet to be adequately studied. This study investigated antioxidant capacity and flavonoid metabolites in the bran layer of green glutinous rice (LvH) compared to purple (HeiH), red (HongH) and white (GJG) varieties. The results showed that LvH bran had significantly higher content of total flavonoids and anthocyanin than that of HongH (1.91-fold and 4.34-fold) and GJG (2.45-fold and 13.30-fold). LvH bran also showed significantly higher levels of vitamin B1 and vitamin E than that of HeiH (1.94-fold and 1.15-fold) and HongH (1.22-fold and 1.13-fold), indicating that green glutinous rice bran was rich in bioactive components. LvH bran showed significantly lower IC values for scavenging DPPH and ATBS radicals than GJG and even significantly lower IC value for scavenging DPPH radicals than HongH, highlighting its potential as an effective source of antioxidants. LvH bran had significantly different downstream metabolite synthesis in the flavonoid pathway compared to HeiH, HongH, and GJG, with 40, 26, and 22 different metabolites, 23, 20, and 33 up-regulated differentially expressed metabolites (DEMs), and 73, 50, and 13 down-regulated DEMs, respectively. Of the 139 flavonoid metabolites identified in colored rice bran, 26 metabolites showed significant positive correlation with both ABTS and DPPH radical scavenging capacity. Typically, quercetin derivatives showed potential for evaluating the antioxidant capacity of colored rice bran. These findings offer valuable insights into the antioxidant properties of green glutinous rice bran and provide references for better understanding of flavonoid metabolites in different colored rice bran.
绿糯米是一种独特的遗传种质资源，尚未得到充分研究。本研究比较了绿糯米（LvH）、紫米（HeiH）、红米（HongH）和白米（GJG）的糠层的抗氧化能力和类黄酮代谢物。结果表明，LvH 糠层总黄酮和花色苷的含量明显高于 HongH（1.91 倍和 4.34 倍）和 GJG（2.45 倍和 13.30 倍）。LvH 糠层还表现出比 HeiH（1.94 倍和 1.15 倍）和 HongH（1.22 倍和 1.13 倍）更高的维生素 B1 和维生素 E 水平，表明绿糯米糠层富含生物活性成分。LvH 糠层对 DPPH 和 ATBS 自由基的清除 IC 值明显低于 GJG，甚至明显低于 HongH，这突出了其作为有效抗氧化剂来源的潜力。LvH 糠层在类黄酮途径中的下游代谢产物合成与 HeiH、HongH 和 GJG 明显不同，分别有 40、26 和 22 种不同的代谢产物、23、20 和 33 种上调差异表达代谢物（DEM）和 73、50 和 13 种下调 DEM。在有色米糠中鉴定的 139 种类黄酮代谢物中，有 26 种代谢物与 ABTS 和 DPPH 自由基清除能力呈显著正相关。通常，槲皮素衍生物具有评估有色米糠抗氧化能力的潜力。这些发现为绿糯米糠层的抗氧化特性提供了有价值的见解，并为更好地了解不同有色米糠中的类黄酮代谢物提供了参考。
