Crude Ecklonia cava Flake Extracts Attenuate Inflammation through the Regulation of TLR4 Signaling Pathway in LPS-Induced RAW264.7 Cells

Antioxidant effects of seaweeds and their active compounds on animal health and production - A Review

Natural antioxidants applied as feed additives can improve not only animals’ health and overall performance but also increase their resistance to environmental stress such as heat stress, bad housing conditions, diseases, etc. Marine organisms, for example seaweeds – red, brown, and green macroalgae contain a plethora of biologically active substances, including phenolic compounds, polysaccharides, pigments, vitamins, micro- and macroelements, and proteins known for their antioxidant activity, which can help in the maintenance of appropriate redox status in animals and show pleiotropic effects for enhancing good health, and productivity. The dysregulated production of free radicals is a marked characteristic of several clinical conditions, and antioxidant machinery plays a pivotal role in scavenging the excessive free radicals, thereby preventing and treating infections in animals. Supplementation of seaweeds to animal diet can boost antioxidant activity, immunity, and the gut environment. Dietary supplementation of seaweeds can also enhance meat quality due to the deposition of marine-derived antioxidant components in muscles. The use of natural antioxidants in the meat industry is a practical approach to minimize or prevent lipid oxidation. However, overconsumption of seaweeds, especially brown macroalgae, should be avoided because of their high iodine content. An important point to consider when including seaweeds in animal feed is their variable composition which depends on the species, habitat, location, harvest time, growing conditions such as nutrient concentration in water, light intensity, temperature, etc. This review highlights the beneficial applications of seaweeds and their extracted compounds, which have antioxidant properties as feed additives and impact animal health and production.

The Anti-Inflammatory Properties of Rhododendron molle Leaf Extract in LPS-Induced RAW264.7

Rhododendron molle G.Don is a well-known traditional medicine which has been used to treat rheumatic inflammation. In this study, an inflammatory model of lipopolysaccharide (LPS)-stimulated RAW264.7 cells was established to analyze the anti-inflammatory effect and potential mechanism of the methanol extract of R. molle leaves (RLE). The production of NO and the expression of tumor necrosis factor by LPS were detected by Griess reaction and enzyme linked immunosorbent assay (ELISA). The mRNA expression of TNF-α, IL-1β, IL-6, COX-2 and iNOS was measured by qRT-PCR assay. Griess and qRT-PCR showed that the RLE could significantly concentration-dependently inhibit NO production and the expression of many pro-inflammatory cytokines and inflammatory-related enzymes. Scanning electron microscope (SEM) analysis indicated that RLE could inhibit LPS-stimulated RAW264.7 macrophages activation. The protein level of TNF-α and IL-1β were decreased over 50 % at 100 μg/ml of RLE, as detected by ELISA. These results indicated that RLE had strong anti-inflammatory and immunomodulatory activity.

Neutrophil extracellular traps induced by cigarette smoke contribute to airway inflammation in mice

Neutrophil extracellular traps (NETs) were initially identified as an important antimicrobial barrier to capture and kill microorganisms. Emerging evidence suggests that NETs play a crucial role in chronic airway inflammation induced by cigarette smoke (CS). However, how NETs form and the mechanisms by which NETs function in CS-related airway diseases are still unclear. To explore NET formation and its potential role in CS-related airway diseases, we first established a CS-induced subacute airway inflammation model in mice and verified NET formation in the airways. Moreover, NETs degradation by aerosolized DNase I treatment significantly inhibited the airway inflammation induced by CS in mice. More importantly, by in vitro experiments, we found that cigarette smoke extract (CSE) induces NET formation in an NADPH oxidase-dependent manner, and that macrophages and human bronchial epithelial cells (HBEs) are important targets for the NETs-induced secretion of inflammatory cytokines. Therefore, NETs may represent a critical link among neutrophils, macrophages and HBEs under chronic inflammation conditions induced by CS.

The Potential Application of Ecklonia cava Extract in Scalp Protection

The scalp is exposed to environmental hazards including airborne pollutants, which exert adverse effects on skin health. Therefore, compounds for defending skin from pollutants have attracted interest in the cosmeceutical community. We investigated whether Ecklonia cava exhibited prophylactic effects against urban pollutants by measuring cell viability and cell cycle distribution in human follicle dermal papilla cells (HFDPC). The effect of E. cava on pollutant-induced damage to skin barrier was determined by measuring filaggrin and MMP-1 expression in both keratinocytes and in a skin explant model. In a clinical trial, the effect of E. cava on scalp skin of patients with scalp scale was observed by evaluating hydration and redness after 4 weeks of daily treatment with a shampoo containing E. cava extract. E. cava extract recovered the loss of cell viability and abnormal cell cycle distribution induced by urban pollutants in HFDPCs. It also attenuated pollutant-induced damage to skin barrier by decreasing MMP-1 and increasing filaggrin expression in keratinocytes and the epidermis of skin explants. Moreover, E. cava showed soothing effects on human scalp by increasing hydration and decreasing redness in a clinical trial. Collectively, E. cava extract may be a good candidate for therapeutic applications designed to repair or protect hair scalp.

The Phlorotannin-Rich Fraction of Ecklonia cava Extract Attenuated the Expressions of the Markers Related with Inflammation and Leptin Resistance in Adipose Tissue

Obesity is associated with systemic chronic inflammation, and it induces central leptin resistance which blocks the appetite-suppressing effect of leptin and leptin resistance in adipocytes. In the present study, we evaluated the effects of Ecklonia cava extract (ECE), which contained rich phlorotannins, on inflammation and leptin resistance in the adipose tissue of a diet-induced obese model. Effects of ECE on fat deposition, inflammation, M1/M2 macrophage, and T-cell infiltrations were investigated, and leptin resistance and SOCS3 were also measured in adipose tissue. Furthermore, ECE attenuated the expression of inflammation-related receptors such as TLR4 and RAGE and leptin resistance by reducing SOCS3 expression, increasing expression of leptin receptor in adipose tissue, and increasing lipolysis. ECE showed antiadiposity and anti-inflammatory effects, attenuated leptin resistance, and increased lipolysis in the diet-induced obese model. This study shows that ECE is a suitable dietary supplement candidate for the prevention or treatment of obesity or obesity-associated diseases, especially inflammation-related diseases.

Therapeutic Effect of Ecklonia cava Extract in Letrozole-Induced Polycystic Ovary Syndrome Rats

Polycystic ovary syndrome (PCOS) is an endocrinal disorder that afflicts mainly women of childbearing age. The symptoms of PCOS are irregular menstrual cycles, weight gain, subfertility and infertility. However, because the etiology is unclear, management and treatment methods for PCOS are not well established. Recently, natural substances have been used for PCOS therapy. Ecklonia cava (E. cava) is a well-known natural substance that attenuates the effects of inflammation, allergies, and cancer. In this study, we investigated the effects of E. cava extract in rats with PCOS. When rats with letrozole-induced PCOS were exposed to the E. cava extract, the regular estrus cycle was restored, similar to that in placebo rats. Hormone levels, including the levels of testosterone, estrogen, luteinizing hormone (LH), follicle stimulating hormone (FSH), and anti-Müllerian hormone (AMH), were restored to their normal states. Histological analysis revealed that the polycystic ovary symptoms were significantly decreased in the E. cava-treated rats and were comparable to those of normal ovaries. At the transcriptional and translational levels, Ar, and Esr2 levels were markedly increased in the E. cava-treated rats with PCOS compared with the rats with letrozole-induced PCOS. These results suggest that the E. cava extract inhibits the symptoms of PCOS by restoring imbalanced hormonal levels and irregular ovarian cycles in letrozole-induced female rats.

Anti-inflammatory activities and potential mechanisms of phenolic acids isolated from Salvia miltiorrhiza f. alba roots in THP-1 macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

The roots of Salvia miltiorrhiza f. alba (Lamiaceae) (RSMA) are used as the Danshen, a traditional Chinese medicine, to treat the vascular diseases at local clinics, especially for the remedy of thromboangiitis obliterans (TAO) more than 100 years. Phenolic acids are one of the major effective constituents of RSMA, and some studies have linked phenolic acids with anti-inflammatory functions.

AIM OF THE STUDY

The purpose of this research was to isolate phenolic acids from RSMA and investigate their anti-inflammatory effects and potential mechanisms.

MATERIALS AND METHODS

Nine already known compounds were obtained from RSMA. Their structures were elucidated through the spectroscopic analysis and comparing the reported data. The anti-inflammatory effects and potential mechanisms were investigated in LPS-stimulated THP-1 cells, using salvianolic acid B (SalB) as the positive control. The enzyme-linked immunosorbent assays (ELISA) were used to determine the secretory protein levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). And quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze the mRNA levels of these inflammatory cytokines. The expression of TLR4, p65, p-p65, IκBα, and p-IκBα were measured using western blot.

RESULTS

All these compounds, except for rosmarinic acid (5) and isosalvianolic acid (6) for IL-6 protein levels, rosmarinic acid-o-β-D-glucopyranoside (3) for IL-6 mRNA, and rosmarinic acid-o-β-D-glucopyranoside (3), rosmarinic acid (5) and isosalvianolic acid (6) for TNF-α mRNA levels, remarkably inhibited the production of TNF-α, IL-1β, and IL-6 at the concentration of 5 and 25 μM in the mRNA and protein levels. Lithospermic acid (7) showed the strongest inhibitory effect among them and was similar to that of SalB. In particular, lithospermic acid (7) and SalB markedly downregulated the expressions of TLR4, p-p65, and p-IκBα induced by LPS in THP-1 macrophages.

CONCLUSIONS

All the phenolic acids displayed anti-inflammatory properties and the potential mechanisms involved the TLR4/NF-κB signal pathway. Results of this study indicate that phenolic acids may be effective constituents of RSMA to treat vascular diseases associated with inflammation.