To investigate the transformation rule of flavonoids in Abelmoschus esculentus (L.)Moench seeds induced by roasting and its impact on antioxidant activity, elucidate the underlying material basis and mechanism of action.

The antioxidant activity of Abelmoschus esculentus (L.) Moench seeds before and after roasting was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, expressed as the half-maximal inhibitory concentration (IC₅₀). The total flavonoid content was determined by ultraviolet-visible spectrophotometry. The content changes of 3 kinds of key flavonoid compounds—quercetin-3-O-gentiobioside,isoquercitrin and quercetin—were quantitatively analyzed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Compared with unroasted samples, roasted Abelmoschus esculentus(L.) Moench seeds exhibited significant component transformation and enhanced activity: The DPPH radical scavenging capacity was substantially increased, with the IC₅₀ value significantly decreased, indicating approximately 9-fold higher activity than the raw product (P<0.01). The total flavonoid average content was significantly increased by 346.3% (P<0.01). Component analysis revealed that the content of quercetin-3-O-gentiobioside and isoquercitrin decreased by 39.1% (P<0.01) and 48.9% (P<0.01), respectively, while the quercetin content significantly increased by 60.0% (P<0.01).

Roasting can induce the cleavage of glycosidic bonds in quercetin glycosides (quercetin-3-O-gentiobioside and isoquercitrin) in Abelmoschus esculentus(L.) Moench seeds, directing their conversion into the aglycone form—quercetin. This structural transformation leads to the exposure of free hydroxyl groups with stronger free radical scavenging capacity, which is the primary material basis and key mechanism for the significant enhancement of the antioxidant activity in Abelmoschus esculentus (L.)Moench seeds. This discovery provides a theoretical foundation for the deep processing and development of functional products from Abelmoschus esculentus (L.) Moench seeds.