Sargassum horneri extract containing polyphenol alleviates DNCB-induced atopic dermatitis in NC/Nga mice through restoring skin barrier function.

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by skin barrier dysfunction. Sargassum horneri (S. horneri) is a brown alga that has been widely used in traditional medicine of eastern Asian countries. Recent studies proved that a brown alga S. horneri has anti-inflammatory activity. In this study, we investigated the effect of S. horneri ethanol extract (SHE) against AD in 2,4-dinitrobenzene (DNCB) induced AD in NC/Nga mice. We observed that SHE treatment decreased the epidermal thickness and epidermal hyperplasia that had been worsened through DNCB application. Moreover, SHE significantly inhibited the proliferation of mast cells and decreased the expression of IL-13 on CD4⁺ cells prompted by elevated thymic stromal lymphopoietin (TSLP) expression in DNCB-induced AD in mice. We also demonstrated that SHE directly inhibited the expression of keratinocyte-produced TSLP known to exacerbate skin barrier impairment. Especially, the decrease of filaggrin, an integral component of proper skin barrier function through a function in aggregating keratin filaments, observed in DNCB-induced AD mice was significantly improved when treated with SHE. More importantly, we proved that SHE was able to decrease the serum levels of IgG1 and IgG2ₐ, two crucial factors of AD, indicating the protective effect of SHE. Taken together, our findings suggest that SHE may protect NC/Nga mice against DNCB-induced AD via promoting skin barrier function.

Anti-obesity effect of sulforaphane in broccoli leaf extract on 3T3-L1 adipocytes and ob/ob mice.

The present study evaluated the anti-obesity effect of sulforaphane (SFN) and glucoraphanin (GRN) in broccoli leaf extract (BLE) on 3T3-L1 adipocytes and ob/ob mice. Based on Oil Red O staining and triglyceride (TG) assay, SFN and BLE significantly reduced (P<.05) both lipid accumulation and TG content in the differentiated 3T3-L1 adipocytes. SFN and BLE increased 2-NBDG uptake by 3T3-L1 adipocytes in a dose-dependent manner. Western blot analysis confirmed that SFN and BLE increased the phosphorylation levels of both AMPK (Thr172) and ACC (Ser79), and reduced the expression of HMGCR in liver and white adipose tissues of ob/ob mice. Histological analysis revealed that SFN and BLE ameliorated hepatic steatosis, and reduced the size of adipocyte in ob/ob mice. Treatment with SFN and BLE significantly reduced (P<.05) TG content, low-density lipoprotein (LDL) cholesterol, total cholesterol (TC), and glucose in the serum of ob/ob mice. RNA sequencing analysis showed that up- or down-regulation of 32 genes related to lipid metabolism was restored to control level in both SFN and BLE-treated ob/ob mice groups. A protein-protein interaction (PPI) network was constructed via STRING analysis, and Srebf2, Pla2g2c, Elovl5, Plb1, Ctp1a, Lipin1, Fgfr1, and Plcg1 were located in the functional hubs of the PPI network of lipid metabolism. Overall results suggest that the SFN content in BLE exerts a potential anti-obesity effect by normalizing the expression of genes related to lipid metabolism, which are up- or down-regulated in ob/ob mice.

Polyphenol containing Sargassum horneri attenuated Th2 differentiation in splenocytes of ovalbumin-sensitised mice: involvement of the transcription factors GATA3/STAT5/NLRP3 in Th2 polarization.

CONTEXT: Sargassum horneri (Turner) C. Agardh (Sargassaceae) is a brown marine alga used in oriental medicine to treat allergic conditions. OBJECTIVE: This study clarifies the effect of polyphenol-containing S. horneri ethanol extract (SHE) on T-helper type-2 (Th2) polarisation. MATERIALS AND METHODS: All mice (BALB/c mice, n = 12) except in the healthy control group were first sensitised with an intraperitoneal injection of ovalbumin (OVA; 20 µg) and alum (2 mg) on Day 0 and Day 14. Similarly, phosphate-buffered saline (PBS) was injected according to the same schedule into the healthy control mice. After the final administration, splenocytes were obtained. OVA sensitised mice were challenged with OVA (100 µg/mL) in the absence or presence (62.5 and 125 µg/mL) of SHE while healthy control group remained untreated. RESULTS: SHE (0-1000 µg/mL) was not cytotoxic to splenocytes and demonstrated IC50 values of 3.27 and 3.92 mg/mL, respectively, at 24 and 48 h of incubation. SHE suppressed cell proliferation at concentrations ≥62.5 µg/mL. SHE treatment (125 µg/mL) subdued (by 1.8-fold) the population expansion of CD3+CD4+ helper T cells induced by OVA challenge. SHE attenuated the OVA-induced activation of respective transcription factors GATA3 and NLRP3. Simultaneously, highly elevated levels of cytokines interleukin (IL)-4 and IL-5 caused by OVA stimulation were removed completely and IL-13 suppressed by 1.5-fold. CONCLUSIONS: SHE exhibits Th2 immune suppression under OVA stimulation via GATA3- and NLRP3-dependent IL-4, IL-5, and IL-13 suppression. Therefore, SHE could be therapeutically useful for alleviating the symptoms of allergen-mediated immune diseases.