Nonalcoholic fatty liver disease (NAFLD), which promotes serious health problems, is related to the increase in the nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome and pyroptosis by a high-fat diet (HFD). Whether dieckol (DK), a component of Ecklonia cava extracts (ECE), attenuated NAFLD in an HFD-induced NAFLD animal model was evaluated. The expression of high mobility group box 1/Toll-like receptor 4/nuclear factor-κB, which initiated the NLRP3 inflammasome, was increased in the liver of HFD-fed animals and significantly decreased with ECE or DK administration. The expression of NLRP3/ASC/caspase-1, which are components of the NLRP3 inflammasome, and the number of pyroptotic cells were increased by HFD and decreased with ECE or DK administration. The accumulation of triglycerides and free fatty acids in the liver was increased by HFD and decreased with ECE or DK administration. The histological NAFLD score was increased by HFD and decreased with ECE or DK administration. The expression of lipogenic genes (FASN, SREBP-2, PPARγ, and FABP4) increased and that of lipolytic genes (PPARα, CPT1A, ATGL, and HSL) was decreased by HFD and attenuated with ECE or DK administration. In conclusion, ECE or DK attenuated NAFLD by decreasing the NLRP3 inflammasome and pyroptosis.

Blood circulation disorders, such as hyperlipidemia and arteriosclerosis, are not easily cured by dietary supplements, but they can be mitigated. Although Ecklonia cava extract (ECE), as dietary supplements, are associated with improving the conditions, there are not many studies verifying the same. In this study, the beneficial effect of ECE and leaf of Ginkgo biloba extract (GBE), which is a well-known dietary supplement, were first confirmed in a diet induced-obese model. Afterwards, 4 phlorotannins were isolated from ECE, and their inhibitory effects on vascular cell dysfunction were validated. Pyrogallol-phloroglucinol-6,6-bieckol (PPB) was selected to be orally administered in two mice models: the diet induced obese model and diet induced hypertension model. After four weeks of administration, the blood pressure of all mice was measured, after which they were subsequently sacrificed. PPB was found to significantly improve blood circulation, including a reduction of adhesion molecule expression, endothelial cell (EC) death, excessive vascular smooth muscle cell (VSMC) proliferation and migration, blood pressure, and lipoprotein and cholesterol levels. Based on the excellent efficacy in diet-induced mouse models of obese and hypertension, our results demonstrate that PPB is a valuable active compound from among the phlorotannins that were isolated and it has the potential to be used in functional foods for improving the blood circulation.

It is well known that perivascular fat tissue (PVAT) dysfunction can induce endothelial cell (EC) dysfunction, an event which is related with various cardiovascular diseases. In this study, we evaluated whether Ecklonia cava extract (ECE) and pyrogallol-phloroglucinol-6,6-bieckol (PPB), one component of ECE, could attenuate EC dysfunction by modulating diet-induced PVAT dysfunction mediated by inflammation and ER stress. A high fat diet (HFD) led to an increase in the number and size of white adipocytes in PVAT; PPB and ECE attenuated those increases. Additionally, ECE and PPB attenuated: (i) an increase in the number of M1 macrophages and the expression level of monocyte chemoattractant protein-1 (MCP-1), both of which are related to increases in macrophage infiltration and induction of inflammation in PVAT, and (ii) the expression of pro-inflammatory cytokines (e.g., tumor necrosis factor-α (TNF-α) and interleukin (IL)-6, chemerin) in PVAT which led to vasoconstriction. Furthermore, ECE and PPB: (i) enhanced the expression of adiponectin and IL-10 which had anti-inflammatory and vasodilator effects, (ii) decreased HFD-induced endoplasmic reticulum (ER) stress and (iii) attenuated the ER stress mediated reduction in sirtuin type 1 (Sirt1) and peroxisome proliferator-activated receptor γ (PPARγ) expression. Protective effects against decreased Sirt1 and PPARγ expression led to the restoration of uncoupling protein -1 (UCP-1) expression and the browning process in PVAT. PPB or ECE attenuated endothelial dysfunction by enhancing the pAMPK-PI3K-peNOS pathway and reducing the expression of endothelin-1 (ET-1). In conclusion, PPB and ECE attenuated PVAT dysfunction and subsequent endothelial dysfunction by: (i) decreasing inflammation and ER stress, and (ii) modulating brown adipocyte function.

Obesity induces inflammation both in the adipose tissue and the brain. Activated macrophage infiltration, polarization of macrophages to a more inflammatory type (M1), and increased levels of pro-inflammatory cytokines are related to brain inflammation, which induces leptin resistance in the brain. Pyrogallol-phloroglucinol-6,6-bieckol (PPB), a compound from Ecklonia cava, has anti-inflammatory effects. In this study, we evaluated the effects of PPB effect M1 polarization and inflammation and its ability to restore the effects of leptin, such as a decrease in appetite and body weight. We administered PPB to diet-induced obesity (DIO) and leptin-deficient (ob/ob) mice, evaluated macrophage activation, polarization, and changes of inflammatory cytokine level in adipose tissue and brain, and determined the effect of PPB on leptin resistance or leptin sensitivity in the brain. The levels of activated macrophage marker, M1/M2, and pro-inflammatory cytokines were increased in the adipose tissue and brain of DIO and ob/ob mice than control. TLR4 expression, endoplasmic reticulum (ER) stress, and NF-κB expression in the brain of DIO and ob/ob mice were also increased; this increase was related to the upregulation of SOCS3 and decreased phosphorylated STAT3, which decreased leptin sensitivity in the brain. PPB decreased inflammation in the brain, restored leptin sensitivity, and decreased food intake and weight gain in both DIO and ob/ob mice.

Hyperlipidemia induces vascular smooth muscle cell (VSMC) proliferation and phenotype switching from contractile to synthetic. This process is involved in arterial remodeling via the chemokine ligand 5 (CCL5)/chemokine receptor 5 (CCR5) pathway. Arterial remodeling is related to atherosclerosis or intimal hyperplasia. The purpose of this study was to evaluate whether pyrogallol-phloroglucinol-6,6-bieckol (PPB) from E. cava reduces VSMC proliferation and phenotype switching via the CCL5/CCR5 pathway. The CCL5/CCR5 expression, VSMC proliferation and phenotypic alterations were evaluated using a cell model of VSMC exposed in hyperlipidemia, and an animal model of mice fed a high-fat-diet (HFD). The expression of CCL5/CCR5 increased in both the cell and animal models of hyperlipidemia. Treatment with PPB decreased CCL5/CCR5 expression in both models. The expression of contractile markers of VSMCs, including alpha-smooth muscle actin (α-SMA), smooth muscle myosin heavy chain (SM-MHC), and smooth muscle protein 22 alpha (SM22α), were decreased by hyperlipidemia and restored after treatment with PPB. The silencing of CCR5 attenuated the effects of PPB treatment. VSMC proliferation and the intima-media thickness of the aortas, increased with HFD and decreased after treatment with PPB. The VSMC proliferation ratio and messenger ribonucleic acid (mRNA) expression of cell cycle regulatory factors increased in the in vitro model and were restored after treatment with PPB. PPB treatment reduced VSMC proliferation and phenotype switching induced by hyperlipidemia through inhibition of the CCL5/CCR5 pathway.

Hypertension induces renal fibrosis or tubular interstitial fibrosis, which eventually results in end-stage renal disease. Epithelial-to-mesenchymal transition (EMT) is one of the underlying mechanisms of renal fibrosis. Though previous studies showed that Ecklonia cava extracts (ECE) and dieckol (DK) had inhibitory action on angiotensin (Ang) I-converting enzyme, which converts Ang I to Ang II. It is known that Ang II is involved in renal fibrosis; however, it was not evaluated whether ECE or DK attenuated hypertensive nephropathy by decreasing EMT. In this study, the effect of ECE and DK on decreasing Ang II and its down signal pathway of angiotensin type 1 receptor (AT1R)/TGFβ/SMAD, which is related with the EMT and restoring renal function in spontaneously hypertensive rats (SHRs), was investigated. Either ECE or DK significantly decreased the serum level of Ang II in the SHRs. Moreover, the renal expression of AT1R/TGFβ/SMAD was decreased by the administration of either ECE or DK. The mesenchymal cell markers in the kidney of SHRs was significantly decreased by ECE or DK. The fibrotic tissue of the kidney of SHRs was also significantly decreased by ECE or DK. The ratio of urine albumin/creatinine of SHRs was significantly decreased by ECE or DK. Overall, the results of this study indicate that ECE and DK decreased the serum levels of Ang II and expression of AT1R/TGFβ/SMAD, and then decreased the EMT and renal fibrosis in SHRs. Furthermore, the decrease in EMT and renal fibrosis could lead to the restoration of renal function. It seems that ECE or DK could be beneficial for decreasing hypertensive nephropathy by decreasing EMT and renal fibrosis.