Antioxidant polyphenolic extract from Rosa cymosa Tratt alleviates the inflammatory response in RAW264.7 macrophages via regulating NF-κB pathway and cell autophagy.

ETHNOPHARMACOLOGICAL RELEVANCE

Rosa cymosa Tratt is a traditional Chinese medicine with long history of medicinal use. The fruit of R. cymosa, which named as 'Xiao Jin Ying Zi, has been documented has the function of treatment of contusions, injuries, and wind-phlegm cough.

AIMS OF THE STUDY

The objective of this study was to isolate the biological polyphenolic extracts from R. cymosa fruit, identify its main components, and evaluate its antioxidant and anti-inflammatory effects in vitro.

METHODS

The polyphenolic extract from R. cymosa fruit (PRCF) was obtained using an optimized orthogonal extraction method and purified by D140 macroporous resin column. The components were characterized by UV and IR spectroscopy. The composition of PRCF was analyzed using the UPLC-QTRAP-MS system. The antioxidant activities of PRCF were systematically evaluated through the inhibition rates of various radicals, iron ion reduction power, and total reducing power. Furthermore, the anti-inflammatory activity of PRCF was assessed using a lipopolysaccharide-stimulated macrophage model. The expression of anti-inflammatory cytokines was evaluated at both the transcriptional and translational levels. Additionally, protein expressions within the NF-κB and autophagy pathways were analyzed. Furthermore, the nuclear translocation of P65 protein and lysosomal levels in macrophages were assessed to elucidate the potential anti-inflammatory effects of PRCF.

RESULTS

The PRCF primarily comprises phenolic acids and flavonoid components, including protocatechuic acid, gentisic acid, and procyanidin B2. UV and IR spectra indicated characteristic absorptions of aromatic rings, hydroxyl groups, and carboxyl groups. The PRCF showed excellent scavenging activity against ABTS and DPPH radicals, as well as significant total reducing power. Furthermore, PRCF inhibited the secretion of NO, TNFα and IL-6 in LPS-induced macrophages, mRNA and protein expression of iNOS and COX2, as well as the phosphorylation and nuclear translocation level of P65 proteins. Additionally, PRCF significantly decreased the expression of P62 proteins and increased conversion of LC3-I to LC3-II protein and the lysosomal expression in LPS-induced inflammatory macrophages.

CONCLUSIONS

The purified polyphenolic-rich extract PRCF demonstrated strong antioxidant activity by scavenging multiple free radicals. Additionally, the extract suppressed inflammatory responses in activated macrophages by modulating autophagy levels and regulating protein expression in the NF-κB pathway.