The study explores Paulownia flowers as an emerging resource in medicine, food, health supplements, cosmetics, and animal feed, despite a lack of characterization of their secondary metabolite accumulation mechanisms. We conducted a comprehensive investigation into the biological activities, metabolite profiles, and gene expression patterns of flavonoids in Paulownia flowers. Our results, obtained using ABTS/FRAP/DPPH assays, MTT assays, and colorimetric analyses, demonstrate the potent antioxidant, antibacterial, hypolipidemic, and antiproliferative activities of Paulownia flower flavonoid (PFF) extracts. Notably, the Paulownia elongata tetraploid (M4) exhibited particularly notable effects. HPLC fingerprinting, molecular docking, and density functional theory calculations led to the identification of rhoifolin and luteolin as key bioactive flavonoids. UV-Vis, fluorescence, and circular dichroism spectroscopy confirmed PFF's role as a reversible and mixed inhibitor of xanthine oxidase (XOD). Transcriptome and metabolomic analyses further revealed substantial enrichment in phenylpropanoid, flavonol, and flavonoid biosynthetic pathways, with PfPP2C, PfPYR, PfPYL, PfNPR1, PfMYBs, and PfbHLHs identified as crucial regulators. This work provides a foundational understanding of flavonoid biosynthesis in Paulownia flowers, paving the way for targeted genetic modification and biotechnological interventions aimed at enhancing flavonoid accumulation for industrial applications.

中文翻译：

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泡桐花中生物活性黄酮类化合物的综合研究：揭示工业应用的代谢途径、有效成分和调控基因


该研究探索了泡桐花作为药物、食品、保健品、化妆品和动物饲料中的新兴资源，尽管缺乏对其次生代谢物积累机制的表征。我们对泡桐花中黄酮类化合物的生物活性、代谢物谱和基因表达模式进行了全面调查。我们使用 ABTS/FRAP/DPPH 测定、MTT 测定和比色分析获得的结果证明了泡桐花类黄酮 （PFF） 提取物具有强大的抗氧化、抗菌、降血脂和抗增殖活性。值得注意的是，Pauloniia elongata tetraploid （M4） 表现出特别显着的效果。HPLC 指纹图谱、分子对接和密度泛函理论计算导致 rhoifolin 和 luteolin 被鉴定为关键的生物活性类黄酮。UV-Vis、荧光和圆二色谱光谱证实了 PFF 作为黄嘌呤氧化酶 （XOD） 的可逆和混合抑制剂的作用。转录组和代谢组学分析进一步揭示了苯丙烷、黄酮醇和类黄酮生物合成途径的大量富集，其中 PfPP2C 、 PfPYR 、 PfPYL、 PfNPR1 、 PfMYBs 和 PfbHLHs 被确定为关键调节因子。这项工作为泡桐花中类黄酮的生物合成提供了基础认识，为靶向基因改造和生物技术干预铺平了道路，旨在增强工业应用中的类黄酮积累。