In this study, the response surface method (RSM) was used to optimize the deproteinization process of polysaccharides from Vitis vinifera L. SuoSuo (VTP). The antioxidant capacities of polysaccharides before and after deproteinization were evaluated. The structure of deproteinized VTP (DVTP), which has relatively strong antioxidant activity, was characterized, and the protective effect of DVTP on H₂O₂-induced HT22 cell damage was evaluated. The results of the RSM experiment revealed that the ideal parameters for deproteinization included a chloroform/n-butanol ratio (v/v) of 4.6:1, a polysaccharide/Sevage reagent (v/v) ratio of 2:1, a shaking time of 25 min, and five rounds of deproteinization. Preliminary characterization revealed that the DVTP was an acidic heteropolysaccharide composed of seven monosaccharides, among which the molar ratio of galacturonic acid was 40.65. FT-IR and the determination of uronic acid content revealed that DVTP contained abundant uronic acid and that the content was greater than that of VTP. In vitro, the antioxidant activity assay revealed that the hydroxyl radical scavenging capacity and total antioxidant capacity of DVTP were greater than those of VTP. In the range of 0.6~0.8 mg/mL, the DPPH scavenging capacities of VTP and DVTP were greater than that of vitamin C. In addition, cell viability was measured via a CCK-8 assay, which revealed that DVTP had a strong defense effect on H₂O₂-induced damage to HT22 cells. These findings suggest that DVTP has high antioxidant activity and could be used as a natural antioxidant in functional foods and medicines.

Claudins (CLDNs), pivotal components of tight junctions (TJs), are integral to epithelial barrier function, cell polarity, and paracellular permeability as well as in tumor initiation and development. Among the histological subtypes of lung cancer, lung adenocarcinoma (LUAD) predominates and is frequently diagnosed at an advanced stage, contributing to its dismal 5-year survival rate and posing a significant threat to patient survival. In this work, the expression, prognosis and diagnostic of CLDNs in pan-cancer were analyzed using bioinformatics. In particular, the relationship between claudin12 (CLDN12) and the expression, prognosis and clinical stage in LUAD was paid attention to, and the diagnostic efficiency of CLDN12 was evaluated by receiver operator characteristic curve. The PPI network was constructed using STRING database, followed by Cytoscape-assisted hub gene identification. Functional enrichment analyses (GO and KEGG) were conducted to elucidate potential signaling pathways linked to CLDN12. These results showed that CLDNs were differentially expressed in pan-cancer, and were valuable for the prognosis and diagnosis of tumors. Specifically, CLDN12 was significantly upregulated in LUAD, correlating with advanced tumor stage, lymph nodes metastasis, and poor survival outcomes. In vitro functional assays revealed that CLDN12 knockdown suppressed LUAD cell proliferation, migration, and invasion while promoting cell apoptosis. In summary, CLDN12 may serve as a promising biomarker for LUAD detection and a potential therapeutic target.