本研究以凤眼果壳为原料，提取凤眼果壳游离态和结合态多酚，通过不同极性有机溶剂萃取游离态多酚获得四相提取物，分别是正己烷相（HF），乙酸乙酯相（EAF），正丁醇相（BF）和水相（AqF）。测量游离态、结合态和萃取后的四相提取物的总多酚和总黄酮含量，结果表明游离态的多酚和黄酮含量均比结合态高。萃取后的四相提取物中，EAF的多酚和黄酮含量最高。通过DPPH自由基清除能力、ABTS自由基清除能力和还原力对结合态多酚和萃取后的四相提取物的抗氧化活性进行综合评价，EAF具有较好的抗氧化活性，其DPPH自由基清除率的EC50值为2.08 mg/mL，ABTS自由基清除率的EC50值为29.28 mg/mL，在10 mg/mL时，EAF的还原力达到0.81。采用HPLC技术分析，在EAF中鉴定出11种多酚类化合物：分别是表儿茶素、香草酸、异荭草素、阿魏酸、（反）阿魏酸、芦丁、槲皮苷、杨梅素、三叶苷、槲皮素和山奈酚。此外，EAF对人肺癌细胞A549的增殖具有剂量依赖性抑制作用，其抑制A549细胞增殖的EC50值为85.70 μg/mL。这项研究获得的结果表明，凤眼果壳多酚提取物具有较好的抗氧化和抗A549细胞增殖活性，有助于凤眼果壳的综合利用和开发新的功能性试剂。

In this study, the free and bound polyphenols were extracted from Sterculia nobilis Smith husk using Sterculia nobilis Smith husk as the raw materials. Then, the free polyphenols were extracted with organic solvents of different polaritiesto yield a four phase-extract, namely n-hexane phase (HF), ethyl acetate phase (EAF), n-butanol phase (BF) and aqueous phase (AqF). The total phenolic contentand total flavonoid content of the free polyphenol extract, bound polyphenol extract and four-phase extract were measured. The results showed that the free polyphenolextract had higher total phenolic content and total flavonoid content than the bound polyphenol extract. Among the four phases in the four-phase extract, the EAF had the highest phenolic and flavonoid contents.DPPH free radical scavenging ability, ABTS free radical scavenging ability and reducing power assays were used to evaluate comprehensively the antioxidant activities of the bound polyphenol extract and four-phase extract. EAF showed a higher antioxidant activity, with the EC50 values for DPPH and ABTS free radicals being 2.08 mg/mL and 29.28 mg/mL. The reducing power of EAF reached 0.81 at a concentration at 10 mg/mL. Eleven phenolic compounds (epicatechin, vanillic acid, isoorientin, ferulic acid, rutin, quercitrin, myricetin, trilobatin, quercetin and kaempferol) were identified in EAF by HPLC. In addition, EAF had a dose-dependent inhibitory effect on the proliferation of human lung cancer cell A549 with an EC50 value of 85.70 μg/mL. The results indicate that the polyphenol extract from Sterculia nobilis Smith husk has significant antioxidant activity and anti-proliferative activity towards A549 cells, which is helpful for the comprehensive utilization of Sterculia nobilis Smith husk and the development of new functional agents.

广东省水资源科学技术创新计划（201624）；111项目（B17018）；北京市食品营养与人类健康高级创新中心（20182004）