Castanea sativa shells (CSS), an abundant and underexploited agro-residue in chestnut producing countries, are an excellent source of bioactive compounds with outstanding health-promoting properties. The aim of this study was to recover bioactive compounds from CSS employing Supercritical Fluid Extraction-CO₂ (SC-CO₂). The optimization of the extraction was performed based on the antioxidant activity of CSS extracts evaluated by FRAP, DPPH and ABTS assays. The optimal CSS extract was further characterized regarding in vitro radical scavenging capacity, phenolic profile and intestinal cell effects. The optimal conditions were 60 °C, 350 bar and 15% of co-solvent. The results demonstrated that CSS extract was an effective scavenger of NO (IC₅₀ = 0.76 μg/mL) and HOCl (IC₅₀ = 1.57 μg/mL). The IC₅₀ calculated for Caco-2 and HT29-MTX were, respectively, 477.94 μg/mL and 3.71 μg/mL. Indeed, the phenolic profile revealed the presence of phenolic acids (particularly ellagic acid and caffeic acid derivative) and flavonoids (epigallocatechin and catechin/epicatechin). Overall, this work suggests the valorization of CSS extracted by SC-CO₂ as promising nutraceutical ingredient based on its bioactivity and safety. To the best of our knowledge, this is the first study that employed SC to recover bioactive compounds from CSS.

栗壳国家的栗渣（Castanea sativa shells，CSS）是一种丰富而未被充分利用的农业残留物，是生物活性化合物的极佳来源，具有促进健康的特性。这项研究的目的是采用超临界流体萃取CO ₂（SC-CO ₂）从CSS中回收生物活性化合物。基于通过FRAP，DPPH和ABTS分析评估的CSS提取物的抗氧化活性，对提取物进行了优化。关于体外自由基清除能力，酚类和肠道细胞作用，进一步对最佳CSS提取物进行了表征。最佳条件为60°C，350 bar和15％的助溶剂。结果表明CSS提取物是有效的NO清除剂（IC ₅₀  = 0.76μg/ mL）和HOCl（IC ₅₀  = 1.57μg/ mL）。计算得出的Caco-2和HT29-MTX的IC ₅₀分别为477.94μg/ mL和3.71μg/ mL。实际上，酚类特征表明存在酚酸（特别是鞣花酸和咖啡酸衍生物）和类黄酮（表没食子儿茶素和儿茶素/表儿茶素）。总的来说，这项工作表明基于SC-CO ₂的生物活性和安全性，它们被SC-CO ₂提取为有希望的营养成分的价值。据我们所知，这是第一项使用SC从CSS回收生物活性化合物的研究。