Perilla Seed Hulls Polyphenol Extract: Molecular Characterization and Suppression of LPS-Induced Inflammation in RAW 264.7 Cells via NF-κB Signaling Pathway.

As a dual-purpose medicinal and edible resource, Perilla seeds are rich in bioactive compounds. There are very few studies on the by-product of perilla seed hells. Moreover, there is a lack of systematic research on the chemical composition and biological activity of perilla seed hell polyphenols. We employed ultrasound-assisted extraction (60% ethanol, 410 W power, 30 min, liquid-solid ratio 30:1 mL/g) to obtain polyphenols from PSH, yielding perilla seed hulls polyphenol crude extraction (PSH-C), and further verified the presence of polyphenolic compounds using Fourier transform infrared spectroscopy (FT-IR). Subsequently, PSH-C was further separated and purified using HPD600 macroporous resin to obtain a purified perilla seed hulls polyphenol extract (PSH-P). The polyphenolic composition of PSH-P was characterized by UPLC-MS/MS, and the major polyphenols were quantitatively analyzed using authentic standards. Antioxidant assays demonstrated that PSH-P could effectively scavenge free radicals. PSH-P significantly inhibited nitric oxide (NO) production, suppressed the production of inflammatory factors, and downregulated the transcription of iNOS and COX-2. PSH-P likely exerts anti-inflammatory effects by suppressing LPS-induced nuclear translocation of NF-κB (p65) and inhibiting the expression of P-p65 and P-IκBα, thereby blocking NF-κB signaling pathway activation. PSH-P likely exerts its anti-inflammatory effects by blocking NF-κB pathway activation through suppression of LPS-induced nuclear translocation of p65 and inhibition of P-p65 and P-IκBα expression.