The Combination of Mulberry Extracts and Silk Amino Acids Alleviated High Fat Diet-Induced Nonalcoholic Hepatic Steatosis by Improving Hepatic Insulin Signaling and Normalizing Gut Microbiome Dysbiosis in Rats

Anthocyanins-gut microbiota-health axis: A review

Anthocyanins are a subclass of flavonoids responsible for color in some fruits and vegetables with potent antioxidative capacity. During digestion, a larger proportion of dietary anthocyanins remains unabsorbed and reach the large intestine where they interact with the gut microbiota. Anthocyanins can modulate gut microbial populations to improve diversity and the proportion of beneficial populations, leading to alterations in short chain fatty acid and bile acid production. Some anthocyanins can be degraded into colonic metabolites, such as phenolic acids, which accumulate in the body and regulate a range of biological activities. Here we provide an overview of the effects of dietary anthocyanin consumption on gut microbial interactions, metabolism, and composition. Progression of chronic diseases has been strongly associated with imbalances in gut microbial populations. We therefore focus on the role of the gut microbiota as the 'mediator' that facilitates the therapeutic potential of anthocyanins against various chronic diseases, including obesity, type II diabetes, cardiovascular disease, neurodegenerative disease, inflammatory bowel disease, cancer, fatty liver disease, chronic kidney disease and osteoarthritis.

Blueberry-Mulberry Extract Alleviates Cognitive Impairment, Regulates Gut Metabolites, and Inhibits Inflammation in Aged Mice

Cognitive impairment is associated with aging; however, the underlying mechanism remains unclear. Our previous study found that polyphenol-rich blueberry-mulberry extract (BME) had an antioxidant capability and effectively alleviated cognitive impairment in a mouse model of Alzheimer's disease. Thus, we hypothesized that BME would improve cognitive performance in naturally aging mice and assessed its effects on related signaling pathways. Eighteen-month-old C57BL/6J mice were gavaged with 300 mg/kg/d of BME for 6 weeks. Behavioral phenotypes, cytokine levels, tight junction protein levels, and the histopathology of the brain were assessed, and 16S ribosomal RNA sequencing and targeted metabolome analyses were used for gut microbiota and metabolite measurements. Our results showed that the cognitive performance of aged mice in the Morris water maze test was improved after BME treatment, neuronal loss was reduced, IL-6 and TNF-α levels in the brain and intestine were decreased, and the levels of intestinal tight junction proteins (ZO-1 and occludin) were increased. Further, 16S sequencing showed that BME significantly increased the relative abundance of Lactobacillus, Streptococcus, and Lactococcus and decreased the relative abundance of Blautia, Lachnoclostridium, and Roseburia in the gut. A targeted metabolomic analysis showed that BME significantly increased the levels of 21 metabolites, including α-linolenic acid, vanillic acid, and N-acetylserotonin. In conclusion, BME alters the gut microbiota and regulates gut metabolites in aged mice, which may contribute to the alleviation of cognitive impairment and to inflammation inhibition in both the brain and the gut. Our results provide a basis for future research on natural antioxidant intervention as a treatment strategy for aging-related cognitive impairment.

Protection against Osteoporosis by Fermented Mulberry Vinegar Supplementation via Inhibiting Osteoclastic Activity in Ovariectomized Rats and Osteoclastic Cells

Menopause increases the osteoporosis risk, to which phytoestrogen intake can be beneficial. This study hypothesized that mulberry vinegar had a preventive effect on osteoporosis by decreasing osteoclastic activity. The hypothesis was tested in ovariectomized (OVX) rats and RANKL-differentiated osteoclast cells. OVX rats were given 0(OVX-CON), 0.5(OVX-MVL), 1(OVX-MVM), and 2(OVX-MVH) fermented mulberry vinegar (MV) mL/kg body weight (BW) daily for 12 weeks. Sham-operated rats had no MV supplementation (Normal-CON). The osteoporosis-related biomarkers were measured, and Micro-CT determined the bone mass of the femur. RANKL-differentiated Raw 264.7 cells were treated with MV (0–100 μg/mL). The cell viability, osteoporosis-related mRNA expression, and protein contents were measured. MV contained Acetobacter pasteurianus (7.31 log CFU/mL), citric acid (106 mg/mL), lactic acid (19.2 mg/mL), acetic acid (15.0 mg/mL), and rutin (0.36 mg/mL). OVX-MVM elevated the serum 17β-estradiol concentration similar to the Normal-CON group, but it did not prevent the decrease in uterine weight. OVX-MVM prevented the increase in osteoclastic-related parameters, including cathepsin K(CtsK), receptor activator of NF-κB ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) in the circulation. OVX-MVH also lowered C-telopeptide of type Ⅰ collagen as much as the Normal-CON group (p < 0.05). By contrast, OVX-MVH increased the serum osteoprotegerin concentration, an inhibitor of osteoclasts, better than the Normal-CON group (p < 0.05). These changes were integrated to alter the bone mineral density (BMD) in Micro-CT analysis: OVX-MVM and OVX-MVH prevented BMD decrease after OVX as much as the Normal-CON. In RANKL-differentiated osteoclast cells, the MV treatment for 24 and 48 h decreased RANKL-induced differentiation in osteoclast cells dose-dependently up to 100 µg/mL. Its decrease was related to inhibiting the TRAP activity and reducing TRAP-positive multinucleated cells during the five-day administration of RANKL. MV treatments also decreased mRNA expression of osteoclast-related genes (TRAP, Ctsk, OSCAR, and NFATc1). MV suppressed the protein contents of NFATc1 and c-FOS-related osteoclast. In conclusion, MV intake (1 mg/kg bw) protected against BMD loss mainly by inhibiting the osteoclastic activity (RANKL/RANK/TRAP) in OVX rats. MV may develop as a functional food for anti-osteoporosis in menopausal women.

Research progress on intervention effect and mechanism of protocatechuic acid on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become a surge burden worldwide due to its high prevalence, with complicated deterioration symptoms such as liver fibrosis and cancer. No effective drugs are available for NALFD so far. The rapid growth of clinical demand has prompted the treatment of NAFLD to become a research hotspot. Protocatechuic acid (PCA) is a natural secondary metabolite commonly found in fruits, vegetables, grains, and herbal medicine. It is also the major internal metabolites of anthocyanins and other polyphenols. In the present manuscript, food sources, metabolic absorption, and efficacy of PCA were summarized while analyzing its role in improving NAFLD, as well as the mechanism involved. The results indicated that PCA could ameliorate NAFLD by regulating glucose and lipid metabolism, oxidative stress and inflammation, gut microbiota and metabolites. It was proposed for the first time that PCA might reduce NAFLD by enhancing the energy consumption of brown adipose tissue (BAT). However, the PCA administration mode and dose for NAFLD remain inconclusive. Fresh insights into the specific molecular mechanisms are required, while clinical trials are essential in the future. This review provides new targets and reasoning for the clinical application of PCA in the prevention and treatment of NAFLD.

Dietary anthocyanins as potential natural modulators for the prevention and treatment of non-alcoholic fatty liver disease: A comprehensive review

Nonalcoholic fatty liver disease (NAFLD) refers to a metabolic syndrome linked with type 2 diabetes mellitus, obesity, and cardiovascular diseases. It is characterized by the accumulation of triglycerides in the hepatocytes in the absence of alcohol consumption. The prevalence of NAFLD has abruptly increased worldwide, with no effective treatment yet available. Anthocyanins (ACNs) belong to the flavonoid subclass of polyphenols, are commonly present in various edible plants, and possess a broad array of health-promoting properties. ACNs have been shown to have strong potential to combat NAFLD. We critically assessed the literature regarding the pharmacological mechanisms and biopharmaceutical features of the action of ACNs on NAFLD in humans and animal models. We found that ACNs ameliorate NAFLD by improving lipid and glucose metabolism, increasing antioxidant and anti-inflammatory activities, and regulating gut microbiota dysbiosis. In conclusion, ACNs have potential to attenuate NAFLD. However, further mechanistic studies are required to confirm these beneficial impacts of ACNs on NAFLD.

Schizonepeta Tenuifolia with Alpinia Oxyphylla Alleviates Atopic Dermatitis and Improves the Gut Microbiome in Nc/Nga Mice

Atopic dermatitis (AD) is a chronic inflammatory skin disease that may be related to gut microbes. Schizonepeta Tenuifolia Briquet (STB) and Alpinia Oxyphylla Miquel (AOM) has traditionally been used for anti-inflammatory activity. We evaluated the effects of STB, AOM and STB+AOM extracts on 2,4-dinitro-1-chlorobenzene (DNCB)-induced AD skin lesions in Nc/Nga mice and action mechanism was explored. AD lesions were induced in the dorsal skin of Nc/Nga mice by topical application of 1% followed by 0.2% DNCB. After DNCB was applied, the mice had topical applications of either 30% water, 0.01% dexamethasone, 30% STB, 30% AOM, 15% STB + 15% AOM extracts in butylene glycol (BG). Each group was also fed corresponding high-fat diets with 1% dextrin (AD-Con and AD-Positive), 1% STB (AD-STB), 1% AOM (AD-AOM) and 0.5% STB + 0.5% (AD-MIX). Normal-control mice had no DNCB application. The study evaluated the skin AD severity, scratching behavior and weight changes of AD mice for 5 weeks. Compared with AD-Con, AD-STB, AD-AOM and AD-MIX alleviated the clinical AD symptoms (erythema, pruritus, edema, erosion and lichenification and scratching behaviors), normalized immune chemistry (serum IgE concentration, mast cells and eosinophil infiltration), improved skin hyperplasia and enhanced the gut microbiome. AD-STB, AD-AOM, AD-MIX and AD-positive treatments inhibited cutaneous mRNA expression of TNF-α, IL-4 and IL-13 and serum IgE concentrations. AD-MIX most effectively reduced clinical AD symptoms and proinflammatory cytokines. AD-Positive also reduced them but serum GOT and GPT concentrations were abnormally high. AD-STB and AD-MIX increased the alpha-diversity of fecal bacteria and reduced the serum acetate concentration, compared to the AD-Con. In conclusion, the mixture of STB and AOM is effective for treating AD symptoms locally and systemically without adverse effects and are potential interventions for atopic dermatitis.

Corosolic Acid Attenuates Hepatic Lipid Accumulation and Inflammatory Response via AMPK/SREBPs and NF-κB/MAPK Signaling Pathways

Corosolic acid (CA) is the main active component of Lagetstroemia speciosa and has been known to serve as several different pharmacological effects, such as antidiabetic, anti-oxidant, and anticancer effects. In this study, effects of CA on the hepatic lipid accumulation were examined using HepG2 cells and tyloxapol (TY)-induced hyperlipidemia ICR mice. CA significantly inhibited hepatic lipid accumulation via inhibition of SREBPs, and its target genes FAS, SCD1, and HMGCR transcription in HepG2 cells. These effects were mediated through activation of AMPK, and these effects were all abolished in the presence of compound C (CC, an AMPK inhibitor). In addition, CA clearly alleviated serum ALT, AST, TG, TC, low-density lipoprotein cholesterol (LDL-C), and increased high-density lipoprotein cholesterol (HDL-C) levels, and obviously attenuated TY-induced liver steatosis and inflammation. Moreover, CA significantly upregulated AMPK, ACC, LKB1 phosphorylation, and significantly inhibited lipin1, SREBPs, TNF-[Formula: see text], F4/80, caspase-1 expression, NF-[Formula: see text]B translocation, and MAPK activation in TY-induced hyperlipidemia mice. Our results suggest that CA is a potent antihyperlipidemia and antihepatic steatosis agent and the mechanism involved both lipogenesis and cholesterol synthesis and inflammation response inhibition via AMPK/SREBPs and NF-[Formula: see text]B/MAPK signaling pathways.

Mixture of blackberry leaf and fruit extracts alleviates non-alcoholic steatosis, enhances intestinal integrity, and increases Lactobacillus and Akkermansia in rats

We hypothesized that a mixture of blackberry fruit and leaf extracts may alleviate non-alcoholic fatty liver disease (NAFLD). Rats with diet-induced NAFLD were used to test the hypothesis and explore possible mechanisms. Male Sprague–Dawley rats were orally administered diets 51% of energy from fat and 450 mg dextrin/kg bw (NAFLD-control), 50% ethanol blackberry leaf extract (450 mg/kg bw; BL), 50% ethanol blackberry fruit extract (450 mg/kg bw; BF), the mixture of blackberry leaf and fruit extracts (2:1; 150 mg/kg bw; BLF), and milk thistle extracts (150 mg/kg bw; positive-control) for 12 weeks. Normal-control rats were fed low-fat diets with 450 mg dextrin/kg bw (20 En% fat diet) Body weight, visceral fat mass, liver triglycerides, serum cholesterol, triglyceride, non-esterified fatty acid, and insulin resistance were all elevated in rats in the NAFLD-control group compared to the normal-controls. Rats in the NAFLD-control group exhibited liver damage accompanied by increased oxidative stress and inflammation compared to the rats in the normal-control group. BL and BLF protected the NAFLD rats against the triglyceride and lipid peroxide accumulation, improved insulin sensitivity and dyslipidemia, and increased the antioxidant enzymes, SOD, and GSH-Px, to levels similar to the normal-control group. Further, BL and BLF ameliorated inflammation and hepatocyte damage compared to the NAFLD-controls, and they suppressed mRNA expressions of genes involved in triglyceride synthesis (FAS and SREBP-1c). BLF also modulated the gut microbiota by elevating Lactobacillus and Akkermansia in the feces from the cecum compared to the NAFLD-control group. The integrity of intestinal tissues was improved, and the number of goblet cells was elevated by BLF. In conclusion, BL and BLF prevented high-fat diet-induced liver damage by protecting against oxidation and inflammation-induced injury. BLF (human equivalent 1.3 g/day) might, therefore, be used as a therapeutic agent for NAFLD.

Impact statement

NAFLD is a diet-related metabolic disease with no good drug treatments. Therefore, dietary interventions are needed to alleviate NAFLD. This paper demonstrated that feeding a blackberry leaf and fruit mixture extract can alleviate diet-induced NAFLD in rats. Specifically, the blackberry extract, rich in flavonoids and anthocyanins decreased hepatic triglycerides and lipid peroxides, increased genes related to beta oxidation, decreased those involved fatty acid biosynthesis, alleviated oxidative stress, and suppressed pro-inflammatory cytokine release. The blackberry extract also alleviated gut dysbiosis that was associated with NAFLD by increasing the amount of Lactobacillus and Akkermansia in the feces. This research demonstrated that the extract of a common and inexpensive fruit can help alleviate NAFLD and associated intestinal dysbiosis at a dose equivalent to 1.3 g/day in humans. If this work can be duplicated in humans, it would provide a safe and inexpensive intervention to help alleviate NAFLD.