Metabolomics revealed metabolite biomarkers of antioxidant properties and flavonoid metabolite accumulation in purple rice after grain filling

• Published in: Food Chemistry: X 2023-06, Vol.18, p.100720-100720, Article 100720
• Main Authors: Xiong, Qiangqiang, Zhang, Jiao, Sun, Changhui, Wang, Runnan, Wei, Haiyan, He, Haohua, Zhou, Dahu, Zhang, Hongcheng, Zhu, Jinyan
• Format: Article
• Language: English
• Subjects: Flavonoids; Metabolite biomarker; Metabolomics; Purple rice; Total antioxidant capacity
• ISSN: 2590-1575; 2590-1575
• DOI: 10.1016/j.fochx.2023.100720

•The darker the colour of purple rice grain, the stronger the total antioxidant capacity.•The total antioxidant capacity at the early filling stage was lower than that at the middle and late filling stages.•Flavonoid synthesis in purple rice grains increased significantly 21 days after grain filling.•Phlorizin, myricetin 3-galactoside and trilobatin are metabolite biomarkers of antioxidant properties of purple rice grains. The correlation between flavonoids, phenolic metabolites and the total antioxidant capacity is well established. However, specific biomarkers of metabolites with antioxidant properties in purple rice grains remain unidentified. This study integrated nontargeted metabolomics, quantitative detection of flavonoids and phenolic compounds, and physiological and biochemical data to identify metabolite biomarkers of the antioxidant properties of purple rice grains after filling. The findings demonstrated a significant enhancement in the biosynthesis of flavonoids during the middle and late filling stages in purple rice grains. Additionally, the pathways involved in anthocyanin and flavonoid biosynthesis were significantly enriched. Catalase (CAT), phenylalanine ammonia-lyase (PAL), total phenols (TP), flavonoids (FD), and oligomeric proanthocyanidin (OPC) were significantly correlated with philorizin, myricetin 3-galactoside, and trilobatin. Phlorizin, myricetin 3-galactoside, and trilobatin were metabolite biomarkers of antioxidant properties in purple rice grains. This study provides new ideas for the cultivation of high-quality coloured rice varieties with high antioxidant activity.