Antioxidant and anti-inflammatory properties of Xianju wheat paste: A traditional condiment with functional food potential.

The antioxidant and anti-inflammatory properties of Xianju wheat paste (XJWP), a traditional condiment originating from Hubei Province, China, were evaluated for the first time. XJWP is an essential appetizer and condiment for local residents. It is also utilized for its anti-inflammatory properties in treating minor wounds in daily life, which suggests that it possesses bioactive properties, notably anti-inflammatory effects. In this study, five extracts of XJWP were obtained using different polar solvents, and all of them exhibited antioxidant activity through DPPH, •OH, ABTS free radical scavenging tests and ferric reducing antioxidant power. Subsequently, a lipopolysaccharide-induced RAW264.7 cell model was established to evaluate their anti-inflammatory effects. All of the XJWP extracts significantly inhibited NO secretion in the cells (p < 0.05), and ethyl acetate extract (XJ-EA) exhibited the most potent effect characterized by an EC value of 61.92 μg/mL. At a concentration of 40 μg/mL, XJ-EA suppressed the overproduction of TNF-α, IL-6, and IL-1β to normal levels. The in vivo anti-inflammatory activity of XJ-EA was evaluated using a mouse model of ear edema induced by xylene exposure. The result revealed that high-dose XJ-EA reduced the ear edema rate in mice by 56 %, mitigated oxidative damage, inhibited the activity of COX-2 and iNOS, decreased the levels of prostaglandin E2 and NO, and achieved significant anti-inflammatory effects (p < 0.05). Qualitative analysis identified 21 potential anti-inflammatory components in XJ-EA, and molecular docking studies showed favorable interactions with iNOS and COX-2. These findings provide a theoretical foundation for the development of XJWP as a functional condiment, and even as a natural antioxidant and anti-inflammatory drug resource to improve public health and increase the economic value of this product.