The edible tree peony (Paeonia suffruticosa Andrews) flowers are rich in bioactive components with potential health benefits, but the skin-health-promoting effects of their protein hydrolysates remain understudied. The present research sought to evaluate the antioxidant, anti-wrinkle, moisturizing, and whitening properties of tree peony flower protein hydrolysate (TPFP). TPFP was prepared via enzymatic hydrolysis and ultrafiltration, and its peptide sequences were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), revealing 54 unique small-molecule peptides with an average amino acid length of 8.2 residues and a molecular weight of 914.51 Da. In vitro safety evaluation using CCK-8 assay showed TPFP (20–100 μM) did not induce substantial cytotoxic effects in either HaCaT keratinocytes or B16F10 melanoma cell lines. Functional assays demonstrated that TPFP dose-dependently inhibited UVB-induced reactive oxygen species (ROS) overproduction and restored superoxide dismutase (SOD) and catalase (CAT) activities in HaCaT cells, exerting antioxidant effects. Additionally, TPFP protected pro-collagen I from UVB-induced loss, suppressed the expression of matrix metalloproteinase 1 (MMP-1), and restored hyaluronic acid (HA) content, showing anti-wrinkle and moisturizing potentials. In α-MSH-stimulated B16F10 cells, TPFP suppressed melanin synthesis by downregulating the protein expression of tyrosinase (TYR), tyrosinase-related protein 1 (TRP-1), and TRP-2, achieving a whitening effect. These findings indicate that TPFP possesses comprehensive skin-health-promoting activities with good biocompatibility, highlighting its potential as a natural functional ingredient in cosmetics and functional foods.

Pectic polysaccharides from tea residues represent a promising class of prebiotic dietary fibers. This study aimed to optimize the extraction of Oolong tea (Camellia sinensis ‘Foshou’) polysaccharides (FCTP), elucidate the structural alterations induced by ultrasonic degradation, and evaluate the consequent in vitro utilization using Lactobacillus salivarius BXP5. Enzyme-assisted extraction significantly improved the yield of FCTP to 11.10%, compared to 6.74% via conventional hot-water extraction. Ultrasonic treatment (120–240 W, 20–45 min) reduced the molecular weight (Mw) from 1079.9 kDa to 690.7–824.4 kDa, increased the uronic acid content, disrupted the triple-helix conformation, and transformed the polysaccharide into a looser and more water-accessible structure. Structural characterization by FTIR, methylation, and NMR further indicated that uFCTP remained an acidic pectic polysaccharide enriched in homogalacturonan (HG)-like domains. In vitro fermentation demonstrated that ultrasonically degraded FCTP (uFCTP) more effectively promoted BXP5 proliferation than native FCTP. Non-targeted metabolomics and proteomics revealed that uFCTP exerted more pronounced regulatory effects on nucleotide metabolism, carbon metabolism, and ribosomal biogenesis. Correlation analysis identified key metabolites (e.g., gallic acid, xanthosine monophosphate) tightly associated with differentially expressed proteins involved in carbohydrate utilization and cellular growth. These findings indicate that ultrasonic degradation is an effective physical modification strategy to improve utilization by L. salivarius BXP5 of tea-derived pectic polysaccharides by tailoring their molecular architecture for improved probiotic fermentation and metabolic cross-talk.