The development and progression of alcoholic fatty liver disease (AFLD) is influenced by the intestinal microbiota. Astaxanthin, a type of oxygenated carotenoid with strong antioxidant and anti-inflammatory properties, has been proven to relieve liver injury. However, the relationship between the gut microbiota regulation effect of astaxanthin and AFLD improvement remains unclear. The effects of astaxanthin on the AFLD phenotype, overall structure, and composition of gut microbiota were assessed in ethanol-fed C57BL/6J mice. The results showed that astaxanthin treatment significantly relieves inflammation and decreases excessive lipid accumulation and serum markers of liver injury. Furthermore, astaxanthin was shown to significantly decrease species from the phyla Bacteroidetes and Proteobacteria and the genera Butyricimonas, Bilophila, and Parabacteroides, as well as increase species from Verrucomicrobia and Akkermansia compared with the Et (ethanol)group. Thirteen phylotypes related to inflammation as well as correlated with metabolic parameters were significantly altered by ethanol, and then notably reversed by astaxanthin. Additionally, astaxanthin altered 18 and 128 KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways involved in lipid metabolism and xenobiotic biodegradation and metabolism at levels 2 and 3, respectively. These findings suggest that Aakkermansia may be a potential target for the astaxanthin-induced alleviation of AFLD and may be a potential treatment for bacterial disorders induced by AFLD.

Ginsenosides Rg1 is one of the major pharmacologically active saponins in ginseng, which as an antioxidant reduces oxidative damage in the liver and can also be used to prevent cardiovascular diseases and diabetes. However, there is no research targeting the effect of lipid metabolism in high-fat diet (HFD)-induced mice. In this study, we evaluated the anti-obesity effects of Rg1 in 3T3-L1 adipocyte cells and HFD-induced obese C57BL/6J mice. Administration of Rg1 to HFD-induced obese mice significantly decreased body weight, total cholesterol, and total triglyceride levels. In addition to effects in 3T3-L1 cells, Rg1 reduced the accumulation of lipid droplets in a dose-dependent manner. Furthermore, Rg1 exhibits an anti-adipogenic effect via regulation of the expression of the transcriptional factors and lipid metabolism-related genes in vivo and in vitro. We observed that Rg1 administration significantly increased the phosphorylation level of AMP-activated protein kinase (AMPK) in both epididymal white adipose tissue and 3T3-L1 cells. These results indicated that Rg1 works both in an anti-adipogenic and anti-obesity manner through inducing AMPK activation, inhibiting lipogenesis, and decreasing intracellular lipid content, adipocyte size, and adipose weight.

Zeaxanthin (ZEA), a type of oxygenated carotenoid with strong antioxidant activity, has previously been found to exhibit an anti-lipogenesis effect. In the present study, we investigated the effect of ZEA on brown-like adipocyte formation and mitochondrial biogenesis in 3T3-L1 adipocytes. Brown adipocyte-specific markers, mitochondrial biogenesis and oxidative stress, and the involvement of AMP-activated protein kinase (AMPK) α1 were assessed. ZEA treated adipocytes demonstrated a brown-like pattern, with upregulated expression of uncoupling protein 1 (UCP1) and other brown adipocyte markers. In addition, ZEA intervention induced a dramatic increase in mitochondrial DNA (mtDNA) content and in the mRNA levels of genes associated with mitochondrial biogenesis. Furthermore, ZEA attenuated mitochondrial oxidative damage caused by lipid peroxidation in adipocytes, significantly improved the mitochondrial membrane potential (MMP), and scavenged intracellular reactive oxygen species (ROS) and mitochondrial superoxide. Finally, we concluded that AMPKα1 mediated the ZEA-caused inhibition of lipid accumulation and promotion of brown and beige adipocyte-biomarker expression, as the positive effects of ZEA were diminished by Prkaa1 (AMPKα1) knockdown. These findings demonstrated that ZEA promoted the expression of brown and beige adipogenesis markers and mitochondrial biogenesis, which involved AMPKα1 activation, thus contributing to the anti-obesity effects of ZEA.

Zeaxanthin, a type of carotenoid, has been proven to exhibit anti-lipogenesis effect; however, the detailed mechanism of this effect is less known. Herein, we evaluated the effects of zeaxanthin on the inhibition of adipogenesis in 3T3-L1 adipocytes and obesity in high-fat diet fed C57BL/6J mice. Zeaxanthin significantly decreased the intracellular lipid content in a dose-dependent manner (5–15 μM) in adipocytes without causing cytotoxicity. In high-fat-diet-induced obese mice, oral administration of 20 mg kg⁻¹ zeaxanthin attenuated the progression of obesity and improved dyslipidemia. It exhibits an anti-adipogenic effect via down-regulating the transcriptional factors and adipocyte-specific genes involved in adipogenesis, both in vitro and in vivo. Furthermore, zeaxanthin treatment reversed the MDI (0.5 mM 3-isobutyl-1-methylxanthine, 1.0 μM dexamethasone, and 1.0 μg mL⁻¹ insulin) and HFD (high-fat diet)-induced inhibition of AMPK phosphorylation in adipocytes and epididymal adipose tissues, respectively, thereby modulating the energy metabolism. These results indicated that zeaxanthin plays anti-adipogenic and anti-obesity roles by inducing AMPK activation, inhibiting lipogenesis, and decreasing intracellular lipid content, adipocyte size, and adipose weight.

Ginsenoside Rg2 is one of the specific ginsenosides in red ginseng, and has been reported to exhibit protective effects against neurotoxicity and memory impairment, and also inhibition of hepatic glucose production. However, the effect of Rg2 on the prevention of obesity has not been investigated. In this study, we evaluated the anti-obesity and anti-adipogenic effects of Rg2 in high-fat diet-induced obese mice (HFD mice) and 3T3-L1 preadipocytes. Oral administration of Rg2 (10 mg kg⁻¹) to HFD mice significantly decreased body weight gain, total triglycerides, and free fatty acid levels. In 3T3-L1 preadipocytes, Rg2 (80 μM) inhibited adipocyte differentiation and reduced the accumulation of intracellular lipids. Quantitative PCR and western blot analysis revealed that Rg2 decreased the expression levels of adipogenic transcription factors (PPARγ, C/EBPα, and SREBP1-c), and then regulated target genes such as acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). Rg2 significantly promoted AMP-activated protein kinase (AMPK) both in vivo and in vitro, which is known to suppress adipogenesis. It was also found that pretreating with compound C, a typical inhibitor of AMPK, attenuated the inhibitory effect of Rg2 on AMPK phosphorylation. These findings suggested that Rg2-induced activation of AMPK leads to a decrease in the expression of adipogenic transcription factors, and suppression of adipogenesis in vivo and in vitro. Hence, Rg2 has the potential for the development of healthy foods and the prevention of obesity.