The inhibitory effect of polyphenol extracts (Seapolynol(™), SPN) of the marine brown algae Ecklonia cava and dieckol, a major component of SPN, on hyperlipidemia was investigated in ICR mice fed a high-fat diet (HFD) for five weeks. For analysis of the anti-hyperlipidemic effects of SPN and dieckol, these two agents were given orally on a daily basis to HFD-fed mice for four weeks, starting one week after the beginning of HFD feeding. Groups administered with SPN as well as dieckol showed lower body weight gains than the HFD only group. Administration of SPN and dieckol also resulted in a significant reduction of the level of total cholesterol (TCHO), triglyceride (TG), and low-density lipoprotein (LDL) cholesterol in the serum of HFD-fed mice. In Oil Red O staining using 3T3-L1 preadipocytes, it was shown that both SPN and dieckol markedly inhibited lipid accumulation of 3T3-L1 cells. Furthermore, SPN and dieckol (50 μg/mL) significantly inhibited 3-hydroxyl-methyl glutaryl coenzyme A (HMGCoA) reductase activity in vitro. Taken together, these results suggest that polyphenols of Ecklonia cava (SPN) and dieckol reduce body weight gain and fat accumulation in HFD-induced obese mice, and that their hypolipidemic effect is related to the inhibition of adipogenesis of adipocytes and HMGCoA reductase activity.

The liver-brain axis is an emerging concept linking liver dysfunction and brain disease. Hepatic metabolic abnormalities induce systemic oxidative stress and endothelial dysfunction, which contribute to central nervous system (CNS) inflammation and neurodegeneration. Redox regulation plays a key role in the liver-brain axis, with NADPH oxidase (NOX) and nitric oxide synthase (NOS) being involved in the generation of various reactive oxygen species (ROS) and reactive nitrogen species (RNS), respectively, thereby inducing oxidative stress and disrupting the NADPH/NADP balance. Dysregulation of NOX-NOS cross-signaling not only amplifies oxidative stress, but also disrupts endothelial homeostasis and exacerbates neuroinflammation, leading to progressive neurodegeneration. For instance, reactive carbonyl species such as methylglyoxal (MGO) and acrolein can upregulate NOX isoforms and stimulate NLRP (NOD like receptor protein) inflammasomes activation, illustrating disease-relevant links between hepatic redox imbalance and CNS pathology. Mechanistically, superoxide (O₂•^-) generated by NOX readily reacts with nitric oxide (•NO) derived from NOS to form peroxynitrite (ONOO^-), a highly reactive oxidant that exacerbates vascular and neuronal injury. Despite extensive research on NOX and NOS, their interactive contributions to redox imbalance and the progression of neurodegenerative diseases remain poorly understood. In this review, we introduce the NOX-NOS axis as a key regulator of the liver-brain axis, and highlight the roles of NOX and NOS in linking hepatic metabolic dysfunction to central nervous system pathology through intermediary metabolites in the exacerbation of neuroinflammation and oxidative stress. We also explore therapeutic strategies targeting NOX-NOS interactions, including selective NOX inhibitors, NOS modulators, and redox homeostasis regulators, providing new insights into redox regulation and the management of metabolic neurodegenerative diseases.

Korean red ginseng has been shown to possess a variety of biological activities. However, little is known about antiviral activity of ginsenosides of Korean red ginseng. Here, we investigated the protective effect by oral administration of various ginsenosides on the lethal infection of haemagglutinating virus of Japan (HVJ) in mice. In a lethal infection model in which almost all mice infected with HVJ died within 15 days, the mice were administered orally (per os) with 1 mg/mouse of dammarane-type (ginsenoside-Rb1, -Rb2, -Rd, -Re, and -Rg2) or oleanolic acid-type (ginsenoside-Ro) ginsenosides 3, 2, and 1 d before virus infection. Ginsenoside-Rb2 showed the highest protective activity, although other dammarane-type and oleanolic acid-type ginsenosides also induced a significant protection against HVJ. However, neither the consecutive administration with a lower dosage (300 μg/mouse) nor the single administration of ginsenoside-Rb2 (1 mg/mouse) was active. In comparison of the protective activity between ginsenoside-Rb2 and its two hydrolytic products [20(S)- and 20(R)-ginsenoside-Rg3], 20(S)-ginsenoside-Rg3, but not 20(R)-ginsenoside-Rg3, elicited a partial protection against HVJ. The protective effect of ginsenoside-Rb2 and 20(S)-ginsenoside-Rg3 on HVJ infection was confirmed by the reduction of virus titers in the lungs of HVJ-infected mice. These results suggest that ginsenoside-Rb2 is the most effective among ginsenosides from red ginseng to prevent the lethal infection of HVJ, so that this ginsenoside is a promising candidate as a mucosal immunoadjuvant to enhance antiviral activity.

The ginseng berry contains a variety of biologically active compounds and has a higher ginsenoside content than its roots. This study focused on the hepatoprotective activity of ginseng berry extract prepared by enzyme treatment (EGB) compared to the non-enzyme-treated ginseng berry extract (GB) and quality control of EGB. The feeding effect of EGB on alcohol-induced liver damage (AILD) was investigated by measuring the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) compared with those of EtOH-fed mice. Furthermore, cytokine levels in the culture supernatants of EGB- or GB-treated RAW 264.7 cells were determined by enzyme-linked immunosorbent assay. The developed method was applied to the simultaneous quantification of four major ginsenosides in EGB using UPLC-QTOF/MS. Treatment with EGB at a dose of 0.5 or 1 mg/mouse significantly suppressed the AST and ALT levels in mice with AILD. Enzyme-treated ginseng berry was also found to suppress the production of inflammatory mediators like nitric oxide (NO), tumor-necrosis factor-α (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, showing higher activity than that of GB. The amount of ginsenoside Re, F5, F3, and Rd in the EGB obtained using UPLC-QTOF/MS was 45.9, 3.3, 4.0, and 6.2 mg/g, respectively. These results suggest that EGB has a potential effect on AILD, and its hepatoprotective effect provides beneficial insights into developing new candidates for the prevention and cure of AILD. Also, this study demonstrated the utility of UPLC-QTOF/MS-based major compounds for quality control (QC) of EGB.