Anti-obesity potential of Porelis, a standardized extract of purple tea (Camellia sinensis), via modulation of obesity-related inflammation in RAW264.7 macrophages and anti-adipogenesis in 3T3-L1 cells

Abstract

Purpose: To assess the effect of Porelis, a standardized extract of purple tea (Camellia sinensis) on inflammation in RAW 264.7 cells, anti-adipogenesis and lipid accumulation in 3T3-L1 cells. Methods: Viability of RAW 264.7 and 3T3L1 cells was determined by MTT assay. Lipopolysaccharide (LPS) was used to induce inflammation in RAW264.7 cells. Nitric oxide (NO) generation and levels of anti-inflammatory cytokines (TNF-α and IL-6) were determined using Gries reagent and ELISA, respectively. In addition, Oil-O red staining was carried out to assess the differentiation of 3T3L cells. Furthermore, Western blotting was used to quantify the protein expressions of PPAR- γ, C/EBP and SREBP-1 while RT-PCR was used to determine leptin and FAS mRNA expression. Results: Porelis comprised 3 – 5 % of 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-β-D-glucose (GHG). Its use significantly inhibited the generation of NO, IL-6 and TNF-α in LPS-stimulated RAW 264.7 cells (p < 0.0001). Interestingly, there was a significantly inhibited adipocyte differentiation, fat accumulation and protein expression of PPARγ and CEBPα in a dose-dependent manner (p < 0.0001). The mRNA levels of leptin and FAS were significantly (p < 0.0001) upregulated in differentiated adipocytes compared to preadipocytes. Furthermore, treatment with Porelis significantly inhibited mRNA expression levels of leptin and FAS. Conclusion: Porelis may exert anti-inflammatory activity by inhibiting inflammatory responses in RAW264.7 macrophages as well as anti‑obesity activity by blocking fat accumulation via inhibition of adipogenesis in 3T3L adipocytes. This study shows that Porelis could be a promising dietary supplement for prevention of inflammation and obesity.