The Structural Characteristics of Green Tea Polyphenols on Lipopolysaccharide-Stimulated RAW Cells

Abstract

The inflammatory response of macrophages is involved in pathogenesis of lifestyle-related diseases. Green tea consumption reduces the incidence of lifestyle-related diseases. This study investigated the anti-inflammatory effect of polyphenols of green tea including gallic acid, (+)-catechin, (-)-catechin, (-)-epicatechin and (-) epigallocatechin-3-gallate (EGCG) in vitro. The macrophage cell line RAW264 cells were pre-treated with different concentrations of polyphenols (gallic acid, (+)-catechin, (-)-catechin, (-)-epicatechin and EGCG) for 4 h, and were stimulated with LPS for 45 min, 2 h and 24 h. After 24 h LPS challenge, cell lysates and supernatants were harvested. The protein concentration of whole cell lysate was used for determination of cell growth/viability by the BCA assay. The production of TNF-? and IL-6 was measured by ELISA. The total expression and phosphorylation of p38 MAPK was detected by Western blotting. Our results showed that the total protein content of cells was decreased after LPS challenge, while this effect was attenuated when cells were pre-treated with 10 ?M gallic acid and EGCG. Pre-treatment with 1 and 10 ?M EGCG and (-)-catechin significantly decreased the production of TNF-? and IL-6. Furthermore, pre-treatment with 10 ?M gallic acid significantly reduced the production of TNF-? and IL-6. Pre-treatment with 10 ?M (+)-catechin, (-)-catechin, (-) epicatechin, and EGCG enhanced the expression and phosphorylation of p38 MAPK after stimulation with LPS for 45 min and 2 h. By contrast, pre-treatment with gallic acid did not affect the production and phosphorylation of p38 MAPK. These results demonstrated that polyphenols with pyrogallol-type structures in green tea attenuate the activation of macrophages.

Sulforaphane Protects Cells against Lipopolysaccharide-Stimulated Inflammation in Murine Macrophages

“…Generally, the immune system lyses the bacteria and releases the lipid part of LPS into the circulation, which initiates endotoxic activity and triggers the release of pro-inflammatory mediators from macrophages [28,29]. Past experiments revealed that LPS-challenged macrophages excessively produced TNF-α and IL-6, along with other cytokines [30,31]. In order to suppress the activation of macrophages, adequate antioxidant supply is needed through the diet, which may further repair the damaged site [32].…”

Chronic Inflammation as an Immunological Abnormality and Effectiveness of Exercise

“…Also, the infiltration of macrophages and the production of inflammatory cytokines were shown to be suppressed by macrophage depletion [33]. We have, therefore, been studying the effects of exercise-induced anti-inflammatory effects to suppress the recruitment and activation of neutrophils and monocytes/macrophages as the sources of inflammatory mediators and ROS and in preventing exercise-induced tissue damage [5,9,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47].…”

“…We have reported that an eight-week KD may increase intramuscular oxidative stress [69,71]. As mentioned below, certain supplementation such as green tea extract or polyphenols may alleviate exercise-induced oxidative stress, and those antioxidants may then contribute to the promotion of muscle health and exercise capacity [34,35,37,39,45,72,73]. In any case, some combined and/or restricted applications should be considered and explored.…”

Exercise Reverses the Alterations in Gut Microbiota Upon Cold Exposure and Promotes Cold-Induced Weight Loss

“…In this regard, Veillonella atypical, the abundance of which increases in response to exercise, has been demonstrated to enhance running time performance via its metabolism of lactate (Scheiman et al, 2019), whereas Akkermansia muciniphila, which is reduced in abundance in response to cold exposure, is known to be associated with intestinal gene expression promoting tissue remodeling and suppression of apoptosis via a currently unknown pathway (Chevalier et al, 2015). Besides, other components such as lipopolysaccharide of diet-induced obesity-related gut bacteria may promote inflammation (Boulangé et al, 2016), However, the obesity-related inflammation is reversed by exercise (Kawanishi et al, 2012), ketogenic diet (Ma et al, 2018), or food components such as green tea polyphenols (Hung et al, 2018), which might be due to certain modulations by the gut microbiome. Microbiota depletion has been shown to promote the browning of white adipose tissue and to reduce obesity (Suárez-Zamorano et al, 2015).…”