Mulberry leaf and its effects against obesity: A systematic review of phytochemistry, molecular mechanisms and applications

BACKGROUND

Obesity and hyperlipidemia can induce a variety of diseases, and have become major health problems worldwide. How to effectively prevent and control obesity has become one of the hot-spots of contemporary research. Mulberry leaf is the dried leaf of Morus alba L., which is approved by the Ministry of Health as a "homology of medicine and food", rich in diverse active constituents and with a variety of health effects including anti-obesity and anti-hyperlipidemia activities.

PURPOSE

The review attempts to summarize and provide the molecular basis, mechanism, safety and products for further exploration and application of mulberry leaf on the treatment on the control of weight gain and obesity.

METHODS

This review is conducted by using ScienceDirect, PubMed, CNKI and Web of Science databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Based on the research progress of domestic and foreign scholars, the effective phytochemicals, molecular mechanisms and product applications of mulberry leaf in the prevention and treatment of obesity and related metabolic diseases were summarized.

CONCLUSION

Mulberry leaf has excellent medicinal and health care value in obesity treatment. However, its pharmacodynamic substance basis and molecular mechanisms need to be further studied.

Flavonoids, gut microbiota, and host lipid metabolism

Flavonoids are widely distributed in nature and have a variety of beneficial biological effects, including antioxidant, anti-inflammatory, and anti-obesity effects. All of these are related to gut microbiota, and flavonoids also serve as a bridge between the host and gut microbiota. Flavonoids are commonly used to modify the composition of the gut microbiota by promoting or inhibiting specific microbial species within the gut, as well as modifying their metabolites. In turn, the gut microbiota extensively metabolizes flavonoids. Hence, this reciprocal relationship between flavonoids and the gut microbiota may play a crucial role in maintaining the balance and functionality of the metabolism system. In this review, we mainly highlighted the biological effects of antioxidant, anti-inflammatory and antiobesity, and discussed the interaction between flavonoids, gut microbiota and lipid metabolism, and elaborated the potential mechanisms on host lipid metabolism.

Unveiling the Potential of Natural Compounds: A Comprehensive Review on Adipose Thermogenesis Modulation

The process of adipocyte browning has recently emerged as a novel therapeutic target for combating obesity and obesity-related diseases. Non-shivering thermogenesis is the process of biological heat production in mammals and is primarily mediated via brown adipose tissue (BAT). The recruitment and activation of BAT can be induced through chemical drugs and nutrients, with subsequent beneficial health effects through the utilization of carbohydrates and fats to generate heat to maintain body temperature. However, since potent drugs may show adverse side effects, nutritional or natural substances could be safe and effective as potential adipocyte browning agents. This review aims to provide an extensive overview of the natural food compounds that have been shown to activate brown adipocytes in humans, animals, and in cultured cells. In addition, some key genetic and molecular targets and the mechanisms of action of these natural compounds reported to have therapeutic potential to combat obesity are discussed.

Flavonoids from mulberry leaves inhibit fat production and improve fatty acid distribution in adipose tissue in finishing pigs

This study evaluated the effects of flavonoids from mulberry leaves (FML) on plasma biochemical indices, serum activities of lipid metabolism-related enzymes, fat morphology, fatty acid composition, and lipid metabolism in different adipose tissues of finishing pigs. We used 120 Chinese hybrid barrows of Berkshire and Bama mini-pigs with an average initial body weight of 45.11 ± 4.23 kg. The pigs were randomly assigned to five treatment groups and fed a control diet based on corn, soybean meal, and wheat bran or a control diet supplemented with 0.02%, 0.04%, 0.08%, or 0.16% FML. Each experimental group had six replicates (pens), with four pigs per pen. After a 7-d adaptation period, the feeding trial was conducted for 58 d. Blood and adipose tissue samples were collected from 30 pigs (one pig per pen) at the end of the test. The results showed that FML supplementation significantly decreased the feed intake to body gain ratio, the plasma concentrations of total cholesterol and free fatty acids, and the serum activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (linear or quadratic effects, P < 0.05), and decreased the plasma triglyceride concentration (quadratic, P = 0.07). Increasing FML supplementation increased the average daily gain and serum activities of lipoprotein lipase (linear and quadratic effects, P < 0.05) and adipose triglyceride lipase (linear, P < 0.05). Dietary FML supplementation decreased the adipocyte area in the dorsal subcutaneous adipose (DSA) tissue of finishing pigs (linear, P = 0.05) and increased the adipocyte area in the visceral adipose tissue (quadratic, P < 0.01). Increasing FML supplementation decreased the C20:1 content in DSA, abdominal subcutaneous adipose, and visceral adipose tissues of finishing pigs (P < 0.05) and increased the C18:3n3 and n-3 PUFA contents (P < 0.05). The lipid metabolism genes were regulated by the PPARγ-LXRα-ABCA1 signaling pathway, and their expressions differed in different adipose tissues. These findings suggest that FML improved growth performance, regulated lipid metabolism, inhibited fat production, and improved fatty acid distribution in the adipose tissue of finishing pigs, thereby improving pig fat's nutritional quality and health value.

Anti-obesity effects of mulberry leaf extracts on female high-fat diet-induced obesity: Modulation of white adipose tissue, gut microbiota, and metabolic markers

Mulberry leaves (MLs) are reported to have beneficial effects in modulating obesity in male models. However, the impact of different types of mulberry leaf extracts (MLEs) on female models, specifically their influence on adipocytes, gut microbiota, and related metabolic markers, remains poorly understood. In this study, we observed a strong correlation between the total phenolic content (TPC), antioxidant and adipocyte modulation effects of water extracted MLEs. HB-W (water-extracted baiyuwang) and HY-W (water-extracted Yueshen) demonstrated remarkable inhibition effects on adipocytes in 3 T3-L1 adipocytes model. Moreover, MLEs effectively reduced the levels of triglycerides (TG), non-esterified fatty acids (NEFA), and total cholesterol (T-CHO) in adipocytes in vitro. In vivo experiments conducted on female mice with high fat diet (HFD)-induced obesity revealed the anti-obesity effects of HB-W and HY-W, leading to a significant decrease in weight gain rates and notable influence on the ratios of adipose tissue, particularly white adipose tissue (WAT). Gene expression analysis demonstrated the up-regulation of WAT-related genes (Pla2g2a and Plac8) by HB-W, while HY-W supplementation showed beneficial effects on the regulation of blood sugar-related genes. Furthermore, both HB-W and HY-W exhibited modulatory effects on obesity-related gut microbiota (Firmicutes-to-Bacteroidetes ratio) and short chain fatty acid (SCFA) contents. Importantly, they also mitigated abnormalities in liver function and uncoupling protein 1 (UPC1) expression. Overall, our findings underscore the anti-obesity effects of MLEs in female rats with high-fat diet-induced obesity.

Unraveling Obesity: Transgenerational Inheritance, Treatment Side Effects, Flavonoids, Mechanisms, Microbiota, Redox Balance, and Bioavailability-A Narrative Review

Obesity is known as a transgenerational vicious cycle and has become a global burden due to its unavoidable complications. Modern approaches to obesity management often involve the use of pharmaceutical drugs and surgeries that have been associated with negative side effects. In contrast, natural antioxidants, such as flavonoids, have emerged as a promising alternative due to their potential health benefits and minimal side effects. Thus, this narrative review explores the potential protective role of flavonoids as a natural antioxidant in managing obesity. To identify recent in vivo studies on the efficiency of flavonoids in managing obesity, a comprehensive search was conducted on Wiley Online Library, Scopus, Nature, and ScienceDirect. The search was limited to the past 10 years; from the search, we identified 31 articles to be further reviewed. Based on the reviewed articles, we concluded that flavonoids offer novel therapeutic strategies for preventing obesity and its associated co-morbidities. This is because the appropriate dosage of flavonoid compounds is able to reduce adipose tissue mass, the formation of intracellular free radicals, enhance endogenous antioxidant defences, modulate the redox balance, and reduce inflammatory signalling pathways. Thus, this review provides an insight into the domain of a natural product therapeutic approach for managing obesity and recapitulates the transgenerational inheritance of obesity, the current available treatments to manage obesity and its side effects, flavonoids and their sources, the molecular mechanism involved, the modulation of gut microbiota in obesity, redox balance, and the bioavailability of flavonoids. In toto, although flavonoids show promising positive outcome in managing obesity, a more comprehensive understanding of the molecular mechanisms responsible for the advantageous impacts of flavonoids-achieved through translation to clinical trials-would provide a novel approach to inculcating flavonoids in managing obesity in the future as this review is limited to animal studies.

Bifidobacterium lactis TY-S01 protects against alcoholic liver injury in mice by regulating intestinal barrier function and gut microbiota

Alcohol-induced liver injury poses a significant threat to human health. Probiotics have been proven to prevent and treat alcohol-induced liver injury. In this study, the preventive effect of Bifidobacterium lactis TY-S01 on alcohol-induced liver injury in mice was investigated. TY-S01 pretreatment effectively protected mice against alcohol-induced liver injury by preserving the levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, triglyceride and high-density lipoprotein-cholesterol in serum and maintaining the levels of the inflammatory cytokines tumor necrosis factor-α, interleukin-6 and interleukin-1β in liver tissue. Additionally, TY-S01 could maintain the endotoxin levels in serum, maintain the mRNA expression levels of zonula occluden-1, occludin, claudin-1 and claudin-3 in the gut, and prevent gut microbiota dysbiosis in mice with alcoholic liver injury. Spearman's correlation analysis revealed that there was a clear correlation among serum indicators, inflammatory cytokines and gut microbiota. In conclusion, TY-S01 attenuates alcohol-induced liver injury by protecting the integrity of the intestinal barrier and maintaining the balance of the gut microbiota.

Browning of Adipocytes: A Potential Therapeutic Approach to Obesity

The increasing prevalence of overweight and obesity suggests that current strategies based on diet, exercise, and pharmacological knowledge are not sufficient to tackle this epidemic. Obesity results from a high caloric intake and energy storage, the latter by white adipose tissue (WAT), and when neither are counterbalanced by an equally high energy expenditure. As a matter of fact, current research is focused on developing new strategies to increase energy expenditure. Against this background, brown adipose tissue (BAT), whose importance has recently been re-evaluated via the use of modern positron emission techniques (PET), is receiving a great deal of attention from research institutions worldwide, as its main function is to dissipate energy in the form of heat via a process called thermogenesis. A substantial reduction in BAT occurs during normal growth in humans and hence it is not easily exploitable. In recent years, scientific research has made great strides and investigated strategies that focus on expanding BAT and activating the existing BAT. The present review summarizes current knowledge about the various molecules that can be used to promote white-to-brown adipose tissue conversion and energy expenditure in order to assess the potential role of thermogenic nutraceuticals. This includes tools that could represent, in the future, a valid weapon against the obesity epidemic.

Evidence of Flavonoids on Disease Prevention

A growing body of evidence highlights the properties of flavonoids in natural foods for disease prevention. Due to their antioxidative, anti-inflammatory, and anti-carcinogenic activities, flavonoids have been revealed to benefit skeletal muscle, liver, pancreas, adipocytes, and neural cells. In this review, we introduced the basic classification, natural sources, and biochemical properties of flavonoids, then summarize the experimental results and underlying molecular mechanisms concerning the effects of flavonoid consumption on obesity, cancers, and neurogenerative diseases that greatly threaten public health. Especially, the dosage and duration of flavonoids intervening in these diseases are discussed, which might guide healthy dietary habits for people of different physical status.

Effect and Correlation of Rosa roxburghii Tratt Fruit Vinegar on Obesity, Dyslipidemia and Intestinal Microbiota Disorder in High-Fat Diet Mice

To investigate the effect of Rosa roxburghii Tratt fruit vinegar (RFV) on the intervention of obesity and hyperlipidemia and its potential mechanism, a high-fat diet (HFD)-induced obesity model in mice was established and gavaged with RFV, saline and xuezhikang for 30 consecutive days, respectively. The results showed that RFV supplementation significantly reduced fat accumulation, and improved dyslipidemia and liver inflammation in HFD mice. RFV intervention for 30 days significantly improved the diversity of gut microbiota and altered the structure of gut microbiota in HFD mice. Compared with the model group (MC), the ratio of Firmicutes to Bacteroidetes at least decreased by 15.75% after RFV treatment, and increased the relative abundance of beneficial bacteria (Proteobacteria, Bacteroidetes, Lactobacillaceae, Bacteroides, Akkermansia,) and decreased the relative abundance of harmful bacteria (Ruminococcaceae, Erysipelotrichaceae, Ruminococcaceae _UCG-013, Lachnospiraceae, Allobaculum, Actinobacteria). Spearman’s correlation analysis revealed that Erysipelotrichaceae, Allobaculum, Lachnospiraceae, Ruminococcaceae, Ruminococcaceae_UCG-013, uncultured_bacterium_f_Lachnospiraceae and Desulfobacterota were positively correlated (p < 0.05) with the body weight of mice, while Proteobacteria was negatively correlated (p < 0.05) with the body weight of mice. The two main bacteria that could promote dyslipidemia in obese mice were Actinobacteria and Firmicutes, while those that played a mitigating role were mainly Bacteroidetes. It is concluded that RFV plays an important role in the intervention of obesity and related complications in HFD mice by regulating their gut microbiota.

Quercetin improves high-fat diet-induced obesity by modulating gut microbiota and metabolites in C57BL/6J mice

High-fat diet-induced obesity is characterized by low-grade inflammation, which has been linked to gut microbiota dysbiosis. We hypothesized that quercetin supplementation would alter gut microbiota and reduce inflammation in obese mice. Male C57BL/6J mice, 4 weeks of age, were divided into 3 groups, including a low-fat diet group, a high-fat diet (HFD) group, and a high-fat diet plus quercetin (HFD+Q) group. The mice in HFD+Q group were given 50 mg per kg BW quercetin by gavage for 20 weeks. The body weight, fat accumulation, gut barrier function, glucose tolerance, and adipose tissue inflammation were determined in mice. 16 s rRNA amplicon sequence and non-targeted metabolomics analysis were used to explore the alteration of gut microbiota and metabolites. We found that quercetin significantly alleviated HFD-induced obesity, improved glucose tolerance, recovered gut barrier function, and reduced adipose tissue inflammation. Moreover, quercetin ameliorated HFD-induced gut microbiota disorder by regulating the abundance of gut microbiota, such as Adlercreutzia, Allobaculum, Coprococcus_1, Lactococcus, and Akkermansia. Quercetin influenced the production of metabolites that were linked to alterations in obesity-related inflammation and oxidative stress, such as Glycerophospho-N-palmitoyl ethanolamine, sanguisorbic acid dilactone, O-Phospho-L-serine, and P-benzoquinone. Our results demonstrate that the anti-obesity effects of quercetin may be mediated through regulation in gut microbiota and metabolites.

Protective Effect of Flavonoids from Mulberry Leaf on AAPH-Induced Oxidative Damage in Sheep Erythrocytes

To evaluate the antioxidant activity of flavonoids extracted from Chinese herb mulberry leaves (ML), flavonoids from mulberry leaves (FML) were extracted and purified by using ultrasonic-assisted enzymatic extraction and D101 macroporous resin. Using LC-MS/MS-Liquid Chromatography with tandem mass spectrometry analysis, hesperidin, rutoside, hyperoside, cyanidin-3-o-glucoside, myricitrin, cyanidin, and quercetin were identified, and NMR and UV were consistent with the verification of IR flavonoid characteristics. The antioxidant activity of FML has also been evaluated as well as the protective effect on 2,2 0-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress. The results showed that FML exhibited powerful antioxidant activity. Moreover, FML showed dose-dependent protection against AAPH-induced sheep erythrocytes’ oxidative hemolysis. In the enzymatic antioxidant system, pretreatment with high FML maintained the balance of SOD, CAT, and GSH-Px; in the non-enzymatic antioxidant system, the content of MDA can be effectively reduced after FML treatment. This study provides a research basis for the development of natural products from mulberry leaves.

Combined analysis of differentially expressed lncRNAs and miRNAs in liver tissues of high-fat fed rabbits by transcriptome sequencing

High-fat diet could lead to a series of metabolic diseases, including obesity, and its mechanism is not clear. In this study, the rabbit individuals were fed with high-fat diet, the liver tissues were collected, high-throughput sequencing technology was used to reveal the expression of lncRNA and miRNA difference, and the molecular regulation mechanism of lncRNA-miRNA. A total of 24,615 DE lncRNAs and 52 DE miRNAs were identified, including 15 novel discovered DE miRNAs (5 upregulated and 10 downregulated). Furthermore, five miRNAs and three mRNAs were verified by qRT-PCR, and the results showed that the expression of the DE miRNAs and DE lncRNAs in the two groups was consistent with our sequencing results. GO and KEGG analyzed 7,57,139 target genes respectively, enriching the pathways related to lipid metabolism, including mucin O-glycan biosynthesis pathway, insulin resistance and glucagon signaling pathway. Moreover, 65 targeting relationships were obtained. Among them, LOC103348122/miR-450a-5p, LOC103350359/miR-450a-3p and LOC103350429/miR-148a-5p were proposed the first time. Significantly, LOC103348122/miR-450a-5p and LOC103350429/miR-148a-5p were related to lipid metabolism in the liver. This study is of great significance to the CeRNA regulatory network related to lipid metabolism in the liver of rabbits, and provides a basis for understanding hepatic steatosis in rabbits.

Mulberry leaf polyphenols alleviated high-fat diet-induced obesity in mice

Mulberry leaf is an important medicinal food plant, which is rich in polyphenol compounds. Mulberry leaf polyphenols (MLP) possess significant lipid-lowering and antioxidant effects, and healthcare functions. In this study, the polyphenol content of mulberry leaf ethanol extract was measured using HPLC. The analysis of mulberry leaf extract resulted in the identification of 14 compounds, of which Chlorogenic acid and Quercitrin were the highest. A high-fat diet (HFD)-induced obese mouse model was developed and treated with MLP for 12 weeks to explore their effect on lipid metabolism in HFD-induced obese mice. The results showed that the MLP could inhibit the weight gain and fat cell volume increase in the HFD-induced obese mice in a dose-dependent manner. Further analysis revealed that the MLP decelerated the fatty acid composition in the adipose tissues of HFD-induced obese mice, and significantly increased the polyunsaturated-to-saturated fatty acid (PUFA/SFA) ratio. The real-time quantitative PCR (RT-qPCR) results indicated that the MLP significantly inhibited the down regulation of uncoupling protein (UCP) 1 (UCP1), UCP3, and PR domain zinc finger protein 16 (PRDM16) caused by the HFD. These beneficial effects of MLP on HFD-induced obese mice might be attributed to their ability to change the fatty acid composition of adipose tissue and increase the expression of thermogenesis genes. Overall, the study results suggested that the MLP could serve as potential lipid-lowering and weight-loss functional food and healthcare products.

1-Deoxynojirimycin attenuates septic cardiomyopathy by regulating oxidative stress, apoptosis, and inflammation via the JAK2/STAT6 signaling pathway

Cardiac dysfunction caused by sepsis is the predominant reason for death in patients with sepsis. However, the effective drugs for its prevention and the molecular mechanisms remain elusive. 1-Deoxynojirimycin (DNJ), a natural iminopyranose, exhibits various biological properties, such as hypoglycemic, antitumor, antiviral, and anti-inflammatory activities. However, whether DNJ can mediate biological activity resistance in sepsis-induced myocardial injury and the underlying mechanisms are unclear. Janus kinase and signal transducer and activator of transcription (JAK/STAT) signaling is an important pathway for the signal transduction of several key cytokines in the pathogenesis of sepsis, which can transcribe and modulate the host immune response. This study was conducted to confirm whether DNJ mediates oxidative stress, apoptosis, and inflammation in cardiomyocytes, thereby alleviating myocardial injury in sepsis via the JAK2/STAT6 signaling pathway. Septic cardiomyopathy was induced in mice using lipopolysaccharide (LPS), and they were then treated with DNJ. The results showed that DNJ markedly improved sepsis-induced cardiac dysfunction, attenuated reactive oxygen species generation, reduced cardiomyocyte apoptosis, and mitigated inflammation. Mechanistically, increased JAK2/STAT6 phosphorylation was observed in the mouse sepsis models, which decreased significantly after DNJ oral treatment. To further confirm whether DNJ mediates the JAK2/STAT6 pathway, the selective inhibitor fedratinib was used to block the JAK2 signaling pathway in vitro, which enhanced the protective effects of DNJ against the sepsis-induced cardiac damage. Collectively, these findings suggest that DNJ attenuates sepsis-induced myocardial injury by decreasing myocardial oxidative damage, apoptosis, and inflammation via the regulation of the JAK2/STAT6 signaling pathway.

Sargassum fusiforme fucoidan ameliorates diet-induced obesity through enhancing thermogenesis of adipose tissues and modulating gut microbiota

Obesity has become a global epidemic. Sargassum fusiforme fucoidan (Fuc) is a group of water-soluble heteropolysaccharides that exhibits a wide range of medicinal functions. It consists of l-fucose and sulfate groups, with l-fucose as the main monosaccharide. This study investigated the therapeutic effects of Fuc on diet-induced obesity (DIO) in C57BL/6J female mice. Fuc significantly alleviated obesity in mice induced by high-fat high-fructose (HFHF) feeding, inhibiting body weight gain, reducing fat accumulation, and improving hepatic steatosis. In addition, Fuc significantly improved glucose tolerance and insulin sensitivity by enhancing the phosphorylation level of AKT (at Ser473) in the adipose tissues. Mechanistically, although Fuc did not decrease the energy intake in DIO mice, it significantly increased the energy expenditure by up-regulating the expression of uncoupling protein 1 (UCP1) in the adipose tissues. Notably, Fuc also improved the obesity-driven dysbiosis of gut microbiota and decreased the relative abundance of the obesity-related intestinal bacteria. However, Fuc was unable to alleviate DIO-induced metabolic disorders in pseudo-sterile mice. Our findings suggested that Fuc might remodel gut microbiota and exert its weight loss and hypolipidemic effects by increasing the energy expenditure, thus providing a novel perspective for treating obesity and related complications.

Bifidobacterium lactis TY-S01 Prevents Loperamide-Induced Constipation by Modulating Gut Microbiota and Its Metabolites in Mice

Probiotics have received widespread attention as a healthy ingredient. The preventive effect of Bifidobacterium lactis TY-S01 on loperamide-induced constipation in mice was investigated in this study. TY-S01 accelerated the peristalsis of intestine, maintained the humidity of faeces, and prevented the destruction of gut barrier. TY-S01 also maintained the 5-HT, MTL and SP at normal levels in constipated mice. Simultaneously, TY-S01 up-regulated the mRNA expressions of 5-HT4R, SERT, and MUC-2, while down-regulated the mRNA expressions of pro-inflammatory genes remarkably. The levels of short-chain fatty acids in the feces of constipated mice were also increased because of the intervention with TY-S01. Moreover, TY-S01 prevented gut microbiological dysbiosis in constipated mice. Spearman’s correlation analysis revealed that there was an obvious association between metabolic biomarkers and gut microbiota. In summary, TY-S01 regulated gut microbiota and the production of intestinal metabolites to prevent loperamide-induced constipation.

Medicinal Plants and Their Impact on the Gut Microbiome in Mental Health: A Systematic Review

Background: Various neurocognitive and mental health-related conditions have been associated with the gut microbiome, implicating a microbiome–gut–brain axis (MGBA). The aim of this systematic review was to identify, categorize, and review clinical evidence supporting medicinal plants for the treatment of mental disorders and studies on their interactions with the gut microbiota. Methods: This review included medicinal plants for which clinical studies on depression, sleeping disorders, anxiety, or cognitive dysfunction as well as scientific evidence of interaction with the gut microbiome were available. The studies were reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Results: Eighty-five studies met the inclusion criteria and covered thirty mental health-related medicinal plants with data on interaction with the gut microbiome. Conclusion: Only a few studies have been specifically designed to assess how herbal preparations affect MGBA-related targets or pathways. However, many studies provide hints of a possible interaction with the MGBA, such as an increased abundance of health-beneficial microorganisms, anti-inflammatory effects, or MGBA-related pathway effects by gut microbial metabolites. Data for Panax ginseng, Schisandra chinensis, and Salvia rosmarinus indicate that the interaction of their constituents with the gut microbiota could mediate mental health benefits. Studies specifically assessing the effects on MGBA-related pathways are still required for most medicinal plants.

Targeting Gut Microbiota and Host Metabolism with Dendrobium officinale Dietary Fiber to Prevent Obesity and Improve Glucose Homeostasis in Diet-Induced Obese Mice

SCOPE

Obesity is becoming a major public health problem due to excess dietary fat intake. Dendrobium officinale (D. officinale) is a medicine food homology plant and exerts multiple health-promoting effects. However, its antiobesity effects and the potential mechanisms remain unclear.

METHODS AND RESULTS

High-fat diet (HFD)-fed mice are administered D. officinale dietary fiber (DODF) daily by gavage for 11 weeks. The results show that treatment with DODF alleviates obesity, liver steatosis, inflammation, and oxidant stress in HFD-induced obese mice. Improved glucose homeostasis in obese mice after DODF treatment is achieved by enhancing insulin pathway and hepatic glycogen synthesis. DODF restructures the gut microbiota in obese mice by decreasing the relative abundance of Bilophila and increasing the relative abundances of Akkermansia, Bifidobacterium, and Muribaculum. Also, DODF reshapes the metabolic phenotype of obese mice as indicated by up-regulating energy metabolism, increasing acetate and taurine, and reducing serum low density/very low density lipoproteins (LDL/VLDL). These beneficial effects are partly transferred by FMT, implying the gut microbiota as a target for the protective effect of DODF on obesity-related symptoms.

CONCLUSION

The results suggest that DODF can be used as a novel prebiotics to maintain the gut microbial homeostasis and improve metabolic health, preventing obesity and related metabolic syndrome.

Pleurotus Ostreatus Ameliorates Obesity by Modulating the Gut Microbiota in Obese Mice Induced by High-Fat Diet

Pleurotus ostreatus (PO), a common edible mushroom, contains rich nutritional components with medicinal properties. To explore the effect of PO on ameliorating obesity and modulating the gut microbiota, we administered the mice with a low-fat diet or high-fat diet containing different dosages of PO (mass fraction: 0%, 2.5%, 5% and 10%). The body weight, adipose tissue weight, GTT, ITT, blood lipids, serum biomarkers of liver/kidney function, the gut microbiota and function were measured and analyzed after 6 weeks of PO treatment. The results showed PO prevented obesity, maintained glucose homeostasis and beneficially modulated gut microbiota. PO modified the composition and functions of gut microbiota in obese mice and make them similar to those in lean mice, which contributed to weight loss. PO significantly increased the relative abundance of Oscillospira, Lactobacillus group and Bifidobacterium, while decreased the relative abundance of Bacteroides and Roseburia. The prediction of gut microbiota function showed PO upregulated lipid metabolism, carbohydrate metabolism, bile acid biosynthesis, while it downregulated adipocytokine signaling pathway and steroid hormone biosynthesis. Correlation analysis further suggested the potential relationship among obesity, gut microbiota and the function of gut microbiota. In conclusion, all the results indicated that PO ameliorated obesity at least partly by modulating the gut microbiota.

Lipid metabolism disorders and lipid mediator changes of mice in response to long-term exposure to high-fat and high sucrose diets and ameliorative effects of mulberry leaves

Mulberry leaves exhibit anti-lipogenic and lipid-lowering effects. However, the lipid biomarkers and underlying mechanisms for the improvement of the action of mulberry leaves on obesity and lipid metabolism disorders have not been sufficiently investigated yet. Herein, biochemical analysis combined with metabolomics targeting serum lipid mediators (oxylipins) were used to explore the efficacy and underlying mechanisms of mulberry leaf water extract (MLWE) in high-fat and high-sucrose diet (HFHSD)-fed mice. Our results showed that MLWE supplementation not only decreased body weight gain, serum total triglycerides, low-density lipoprotein cholesterol, alanine transaminase and aspartate transaminase levels, but also increased the serum level of high-density lipoprotein cholesterol. In addition, MLWE supplementation also ameliorated hepatic steatosis and lipid accumulation. These beneficial effects were associated with down-regulating genes involved in oxidative stress, inflammation, and lipogenesis such as acetyl-CoA carboxylase and fatty acid synthase, and up-regulating genes related to lipolysis that encoded peroxisome proliferator-activated receptor α, adiponectin (ADPN), adiponectin receptor (AdipoR) 1, AdipoR2, adenosine monophosphate-activated protein kinase (AMPK) and hormone-sensitive lipase. Moreover, a total of 54 serum lipid mediators were differentially changed in HFHSD-fed mice, among which 11 lipid mediators from n-3 polyunsaturated fatty acids (PUFAs) were apparently reversed by MLWE. These findings indicated that the ADPN/AMPK pathway, anti-inflammation, anti-oxidation, and n-3 PUFA metabolism played important roles in anti-obesity and improvement of lipid metabolism disorders modulated by MLWE supplementation.

Aged green tea reduces high-fat diet-induced fat accumulation and inflammation via activating the AMP-activated protein kinase signaling pathway

Background

Obesity is a global public health concern and increases the risk of metabolic syndrome and other diseases. The anti-obesity effects of various plant-derived bioactive compounds, such as tea extracts, are well-established. The mechanisms underlying the anti-obesity activity of Jinxuan green tea (JXGT) from different storage years are still unclear.

Objective

The aim of this study was to evaluate the effects of JXGTs from three different years on the high fat diet (HFD)-fed mouse model.

Design

The mice were divided into six groups, the control group received normal diet and the obese model group received HFD. We analyzed the effects of JXGTs from 2005, 2008, and 2016 on HFD-fed obese mice over a period of 7 weeks.

Results

The JXGTs reduced the body weight of the obese mice, and also alleviated fat accumulation and hepatic steatosis. Mechanistically, JXGTs increased the phosphorylation of AMP-activated protein kinase (p-AMPK)/AMP-activated protein kinase (AMPK) ratio, up-regulated carnitine acyl transferase 1A (CPT-1A), and down-regulated fatty acid synthase (FAS), Glycogen synthase kinase-3beta (GSK-3β), Peroxisome proliferator-activated receptor-gamma co-activator-1alpha (PGC-1α), Interleukin 6 (IL-6), and Tumour necrosis factor alpha (TNFα). Thus, JXGTs can alleviate HFD-induced obesity by inhibiting lipid biosynthesis and inflammation, thereby promoting fatty acid oxidation via the AMPK pathway.

Discussion

The anti-obesity effect of three aged JXGTs were similar. However, JXGT2016 exhibited a more potent activation of AMPK, and JXGT2005 and JXGT2008 exhibited a more potent inhibiting glycogen synthase and inflammation effect. Furthermore, the polyphenol (–)-epicatechin (EC) showed the strongest positive correlation with the anti-obesity effect of JXGT.

Conclusions

These findings demonstrate that JXGT treatment has a potential protection on HFD-induced obesity mice via activating the AMPK/CPT-1A and down-regulating FAS/GSK-3β/PGC-1α and IL-6/TNFα. Our study results also revealed that different storage time would not affect the anti-obesity and anti-inflammation effect of JXGT.

Graphical abstract

Efficacy and Sustainability of Diabetes-Specific Meal Replacement on Obese and Overweight Type-2 Diabetes Mellitus Patients: Study Approaches for a Randomised Controlled Trial and Impact of COVID-19 on Trial Progress

Meal replacement (MR) is widely used in weight and diabetes management programs due to its ease of compliance and handling. However, little is known about its impact on outcomes other than glycaemic control and weight loss. Furthermore, not many studies evaluate its cost-effectiveness and sustainability. This study aimed to evaluate the efficacy of a diabetes-specific MR for the weight reduction and glycaemic controls of overweight and obese T2DM patients, as compared to routine dietary consultation. Other health outcomes, the cost effectiveness, and the sustainability of the MR will also be evaluated. Materials and Methods: This randomised controlled clinical trial will involve 156 participants who have been randomised equally into the intervention and control groups. As a baseline, both groups will receive diet consultation. Additionally, the intervention group will receive an MR to replace one meal for 5 days a week. The duration of intervention will be 12 weeks, with 36 weeks of follow-up to monitor the sustainability of the MR. The primary endpoints are weight and Hemoglobin A1c (HbA1c) reduction, while the secondary endpoints are anthropometry, biochemical measurements, satiety, hormone changes, quality of life, and cost-effectiveness. The impact of the COVID-19 pandemic on study design is also discussed in this paper. This study has obtained human ethics approval from RECUKM (JEP-2019-566) and is registered at the Thai Clinical Trials Registry (TCTR ID: TCTR20210921004).

High Hydrostatic Pressure Extract of Mulberry Leaf Attenuated Obesity-Induced Inflammation in Rats

Low-grade inflammation might be a link between obesity and obesity-associated metabolic dysfunction, including diabetes, hepatic steatosis, and other health complications. This study investigated whether the supplementation of high hydrostatic pressure extract of mulberry (Morus alba L.) leaves (HML) to obese rats could counteract obesity-related inflammation. Three-week-old male Sprague-Dawley rats were separated into three groups as follows: (a) a normal diet, (b) 45% high-fat (HF) diet, and HF diet containing 0.4% HML (c) or 0.8% HML (d) (IACUC No. 17-033). After 14 weeks of HML supplementation, adipose tissue mass, mRNA expression of adipogenic genes, such as aP2, peroxisome proliferator-activated receptor γ (PPARγ), and sterol regulatory element binding protein 1c (SREBP1c), and macrophage recruitment were significantly decreased in HF-fed obese rats. Serum concentrations of nitric oxide and mRNA levels of arginase1 (Arg1), CD11c, and inducible nitric oxide synthase (iNOS) involved in adipose tissue macrophage M1 polarization were also significantly reduced by HML. Moreover, HML alleviated the serum and hepatic lipid profiles and reduced hepatic lipogenic gene expression of acetyl-CoA carboxylase (ACC), cluster of differentiation 36 (CD36), CPT1, fatty acid synthase (FAS), stearoyl-CoA desaturase (SCD1), and SREBP1c, and inflammation-associated genes, including IL1β, interleukin 6 (IL6), and tumor necrosis factor α (TNFα). Serum IL6 and TNFα levels were remarkedly suppressed in the 0.8% HML group. These results suggested that the favorable effect of HML on obesity-associated inflammation might be related in part to the decrease in adipose tissue and hepatic fat deposition and inflammation.

Phytochemistry, bioactivities and future prospects of mulberry leaves: A review

Mulberry leaves (MLs) have been used traditionally to raise silkworms and as herbs and herbal drinks. In vitro and in vivo studies as well as some clinical trials provide some evidence of health benefits, mostly for ML extracts. ML extracts showed antioxidant, hypoglycemic, anticholesterol (affecting lipid metabolism), antiobesity, anti-inflammatory, anticancer activities, and so on. These might be linked to strong antioxidant activities, inhibition of α-glucosidase and α-amylase, reduction of foam cell formation, inhibition of fat formation, decrease of NF-κB activity, and the promotion or induction of apoptosis. Phenolic constituents, especially flavonoids, phenolic acids and alkaloids, are likely to contribute to the reported effects. The phytochemistry and pharmacology of MLs confer the traditional and current uses as medicine, food, fodder, and cosmetics. This paper reviews the economic value, chemical composition and pharmacology of MLs to provide a reference for the development and utilization of MLs.

Physicochemical Properties and Elimination of the Activity of Anti-Nutritional Serine Protease Inhibitors from Mulberry Leaves

Mulberry leaf is an excellent protein resource that can be used as feed additive for livestock and poultry. Nevertheless, the use of mulberry leaves in animal diets is limited by its protease inhibitors, tannic acid and other anti-nutritional factors. This study systematically analyzed the type and activity of serine protease inhibitors (SPIs) from the leaves of 34 mulberry varieties, aiming to reveal the physicochemical properties and inactivation mechanism of SPIs. The types and activities of trypsin inhibitors (TIs) and chymotrypsin inhibitors (CIs) exhibited polymorphisms among different mulberry varieties. The highest number of types of inhibitors was detected in Jinshi, with six TIs (TI-1~TI-6) and six CIs (CI-1~CI-6). TIs and CIs exhibited strong thermal and acid–base stability. High-temperature and high-pressure treatment could reduce the activities of TIs and CIs to a certain extent. β-mercaptoethanol treatment could completely abolish TIs and CIs, suggesting that the disulfide bridges were critical for their inhibitory activities. The Maillard reaction could effectively eliminate the inhibitory activities of TI-1~TI-4 and CI-1~CI-4. This study reveals the physicochemical properties and inactivation mechanisms of the anti-nutritional SPIs from mulberry leaves, which is helpful to exploit mulberry-leaf food with low-activity SPIs, promote the development and utilization of mulberry-leaf resources in animal feed and provide reference for mulberry breeding with different functions.

Serum metabolite profiling yields insights into health promoting effect of A. muciniphila in human volunteers with a metabolic syndrome

Reduction of A. muciniphila relative abundance in the gut microbiota is a widely accepted signature associated with obesity-related metabolic disorders. Using untargeted metabolomics profiling of fasting plasma, our study aimed at identifying metabolic signatures associated with beneficial properties of alive and pasteurized A. muciniphila when administrated to a cohort of insulin-resistant individuals with metabolic syndrome. Our data highlighted either shared or specific alterations in the metabolome according to the form of A. muciniphila administered with respect to a control group. Common responses encompassed modulation of amino acid metabolism, characterized by reduced levels of arginine and alanine, alongside several intermediates of tyrosine, phenylalanine, tryptophan, and glutathione metabolism. The global increase in levels of acylcarnitines together with specific modulation of acetoacetate also suggested induction of ketogenesis through enhanced β-oxidation. Moreover, our data pinpointed some metabolites of interest considering their emergence as substantial compounds pertaining to health and diseases in the more recent literature.

Morus alba L. water extract changes gut microbiota and fecal metabolome in mice induced by high-fat and high-sucrose diet plus low-dose streptozotocin

Gut microbiota plays a key role in the pathophysiology of type 2 diabetes mellitus (T2D). Mulberry leaf has a hypoglycemic effect, but the potential mechanism is not fully understood. This study aimed to explore the influences and potential mechanisms of mulberry leaf water extract (MLWE) intervention on mice with T2D induced through a high-fat and high-sucrose diet combined with streptozotocin by the combination of fecal metabolomics and gut microbiota analysis. Results showed that MLWE could decrease fasting blood glucose and body weight while ameliorating lipid profiles, insulin resistance, liver inflammation, and the accumulation of lipid droplets in T2D mice. MLWE could reverse the abundances of the phyla Actinobacteria and Bacteroidetes and the ratio of Firmicutes/Bacteroidetes, and increase the abundances of the phyla Cyanobacteria and Epsilonbacteraeota in the feces of T2D mice. The abundances of genera Alloprevotella, Parabacteroides, Muribaculaceae, and Romboutsia in the feces of T2D mice could be reversed, while Oscillatoriales_cyanobacterium and Gastranaerophilales could be reinforced by MLWE supplementation. The levels of nine metabolites in the feces of T2D mice were improved, among which glycine, Phe-Pro, urocanic acid, phylloquinone, and lactate were correlated with Romboutsia and Gastranaerophilales. Taken together, we conclude that MLWE can effectively alleviate T2D by mediating the host-microbial metabolic axis.

Mulberry (Morus alba L.) leaf polysaccharide ameliorates insulin resistance- and adipose deposition-associated gut microbiota and lipid metabolites in high-fat diet-induced obese mice

Dietary supplements are currently being used to ameliorate metabolic alterations via maintaining gut microflora balance. Mulberry leaf is known as medicine homologous food for its glucose- and lipid-modulating properties. However, the effects of mulberry leaf polysaccharide (MP) on metabolic dysbiosis and gut microbiota are still poorly understood. After extraction and characterization, the beneficial effects of water-soluble MP were evaluated in high-fat diet-induced obese mice. MP treatment could reduce adipose tissue, improve insulin resistance, and alleviate the pathological lesions in colon. Investigation of the underlying mechanism showed that MP modulated gut microbial community by 16S rRNA analysis and reversed the elevation of lipid indexes by plasma lipidomics analysis. Correlation analysis indicated that the abundance of seven key bacterial species and six lipids were closely associated with the metabolic traits, respectively. Overall, MP could ameliorate metabolic disorders, and modify the gut microbiota and lipids. This would greatly facilitate the utilization of MP as a functional food.

Network pharmacology approach to evaluate the therapeutic effects of mulberry leaf components for obesity

Obesity is a chronic condition that has become a serious public health challenge globally due to the association with a high incidence of complications. Mulberry leaf is one of the most commonly used medicinal and herbal medicines that has been reported to ameliorate obesity and hyperlipidemia. However, the mechanism remains unclear. In the present study, a network pharmacology approach was used to explore the potential mechanism underlying the effects of mulberry leaf extract on obesity. First, the potential targets of mulberry leaf and obesity were predicted using SwissTargetPrediction, Online Mendelian Inheritance in Man, GeneCards and Comparative Toxicogenomics Database databases, which were then used to construct the protein-protein interaction networks. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyzes were performed using R version 3.6.3. Finally, results of this network analysis were verified by using the mulberry leaf extract to treat high-fat diet-induced obese mice. In total, 24 target genes associated with obesity that could potentially be affected by mulberry leaf treatment were predicted by network pharmacology, using which top seven related pathways were determined by KEGG enrichment analysis. Triglyceride (TG) and total cholesterol (TC) levels in mice serum were detected using TG and TC assay kits. Hepatic fat accumulation was detected by H&E staining whereas liver lipid droplets were detected by Oil red O staining in mice tissues. The expression of IL-1β, NF-κB inhibitor α, inducible nitric oxide synthase, AMP-activated protein kinase (AMPK), sterol regulatory element-binding proteins and fatty acid synthase in the visceral white adipose tissues of mice was analyzed by western blotting. The expression of TNF-α, peroxisome proliferator activated receptor (PPAR)D, PPARG, fatty acid amide hydrolase (FAAH) and hydroxysteroid 11-β dehydrogenase 1 (HSD11B1) in the visceral white adipose tissues of mice was detected by reverse transcription-quantitative PCR. Mulberry leaf extract was found to reduce fat accumulation and hepatic lipid droplet formation. Mulberry leaf also alleviated inflammation and lipogenesis whilst promoting lipid catabolism and fatty acid oxidation by promoting the AMPK signaling pathway. The possible anti-obesity effects of mulberry leaf on the mice may be due to the downregulation of TNF-α, PPARD and PPARG and the upregulation of FAAH and HSD11B1. These results were consistent with the GO enrichment analysis and suggested that mulberry leaf may regulate lipid metabolism and catabolism, fatty acid metabolism and biosynthesis and the inflammatory response to reduce obesity.

Mulberry leaf (Morus alba L.): A review of its potential influences in mechanisms of action on metabolic diseases

The leaves of Morus alba L. (called Sangye in Chinese, ML), which belong to the genus Morus., are highly valuable edible plants in nutrients and nutraceuticals. In Asian countries including China, Japan and Korea, ML are widely used as functional foods including beverages, noodles and herbal tea because of its biological and nutritional value. Meanwhile, ML-derived products in the form of powders, extracts and capsules are widely consumed as dietary supplements for controlling blood glucose and sugar. Clinical studies showed that ML play an important role in the treatment of metabolic diseases including the diabetes, dyslipidemia, obesity, atherosclerosis and hypertension. People broadly use ML due to their nutritiousness, deliciousness, safety, and abundant active benefits. However, the systematic pharmacological mechanisms of ML on metabolic diseases have not been fully revealed. Therefore, in order to fully utilize and scale relevant products about ML, this review summarizes the up-to-date information about the ML and its constituents effecting on metabolic disease.

Polysaccharides from mulberry (Morus alba L.) leaf prevents obesity by inhibiting pancreatic lipase in high-fat diet induced mice

Pancreatic lipase (PL) is a key enzyme related to the prevention and treatment of obesity. The aim of the study was to evaluate the inhibitory effects of mulberry leaf polysaccharides (MLP) on PL and possible interaction mechanism, inhibition on lipid accumulation in vitro and in vivo. The results revealed that MLP had obvious inhibitory effects on PL (P < 0.05). The interaction of MLP-PL complexes was in a spontaneous way driven by enthalpy, and hydrogen bonds were the main factors in the binding. MLP could significantly inhibit the development of lipid accumulation in HepG2 cells (P < 0.05). Furthermore, consumption of high-fat diet containing MLP showed protective effects on liver and adipose tissue damages in mice, and inhibited the lipid absorption in digestive tract. MLP also significantly reduced the increased expression level of pancreatic digestive enzymes (P < 0.05). The study indicated that the anti-obesity effect of MLP might be caused by inhibition of lipid absorption via reducing PL activity.

Food phenolics stimulate adipocyte browning via regulating gut microecology

Fat browning has piqued the interest of researchers as a potential target for treating obesity and related metabolic disorders. Recruitment of brown adipocytes leads to enhanced energy dissipation and reduced adiposity, thus facilitating the maintenance of metabolic homeostasis. Evidence is increasing to support the crucial roles of polyphenols and gut microecology in turning fat "brown". However, it is not clear whether the intestinal microecology is involved in polyphenol-mediated regulation of adipose browning, so this concept is worthy of exploration. In this review, we summarize the current knowledge, mostly from studies with murine models, supporting the concept that the effects of food phenolics on brown fat activation and white fat browning can be attributed to their regulatory actions on gut microecology, including microbial community profile, gut metabolites, and gut-derived hormones. Furthermore, the potential underlying pathways involved are also discussed. Basically, understanding gut microecology paves the way to determine the underlying roles and mechanisms of food phenolics in adipose browning.

A combined network pharmacology and molecular biology approach to investigate the active ingredients and potential mechanisms of mulberry (Morus alba L.) leaf on obesity

BACKGROUND

As one of traditional Chinese medicine, mulberry leaf is abundant in diverse active ingredients and widely used for the treatment of metabolic disease and its complications. However, there are a few of reports on its application in the prevention and treatment of obesity. And the molecular mechanism on the anti-obesity of mulberry leaf are unknown till now.

PURPOSE

The present study aimed to evaluate the potential ingredients and targets of mulberry leaf and uncover the anti-obesity mechanisms by using the network pharmacology tactics and verify its effect by biological experiments.

STUDY DESIGN

Active ingredients and key targets of mulberry leaf, genes related to obesity were screened through public database. Based on the results of network pharmacology, the flavonoids-enriched fraction of mulberry leaf (MLF) was extracted and composition of this fraction was identified. After that, HepG2 cells model of lipid accumulation was established for verifying the effect of MLF and related mechanisms.

RESULTS

A total of 37 active ingredients in mulberry leaf, 192 predicted biological targets and 8813 obesity-related targets were determined, of which 180 overlapping targets might have obvious curative effects on obesity. The networks showed that mulberry leaf might play a role through key targets, such as AKT, MAPK and IL-6, and regulated PI3K-Akt signaling pathway. Based on HPLC-ESI-QQQ-MS analysis, 13 constituents of MLF were identified, including 9 flavonoids. Furthermore, HepG2 cells model of lipid accumulation was established. The results indicated that MLF treatment could down-regulate the secretion of inflammatory cytokines, as well as clearly inhibited lipid droplets formation and alleviated TC, TG, HDL-C and LDL-C levels. Positive effect was observed on hypolipidemic efficacy due to the regulation of PI3K/Akt/Bcl-xl pathway, as indicated by the amelioration of PI3K, Akt and Bcl-xl gene and protein expression.

CONCLUSION

This study firstly systematically disclose the multi-ingredients, multi-targets mechanisms of mulberry leaf on obesity by using network pharmacology approach, and validate in HepG2 cells that the protective effect of MLF against obesity involved both inflammation response and lipid metabolism involving PI3K/Akt/Bcl-xl signaling pathway. It provides indications for further mechanistic research of mulberry leaf and also for the development as a potential candidate for the therapy for obese patients.

Plant Extracts in Obesity: A Role of Gut Microbiota

Obesity has become one of the most serious chronic diseases threatening human health. Its occurrence and development are closely associated with gut microbiota since the disorders of gut microbiota can promote endotoxin production and induce inflammatory response. Recently, numerous plant extracts have been proven to mitigate lipid dysmetabolism and obesity syndrome by regulating the abundance and composition of gut microbiota. In this review, we summarize the potential roles of different plant extracts including mulberry leaf extract, policosanol, cortex moutan, green tea, honokiol, and capsaicin in regulating obesity via gut microbiota. Based on the current findings, plant extracts may be promising agents for the prevention and treatment of obesity and its related metabolic diseases, and the mechanisms might be associated with gut microbiota.

Polyphenols and their anti-obesity role mediated by the gut microbiota: a comprehensive review

Obesity is a global public health problem that results in chronic pathologies such as diabetes, cardiovascular diseases, and cancer. The treatment approach based on energy restriction and promotion of physical activity is ineffective in the long term. Due to the high prevalence of this pathology, complementary treatments such as brown adipose tissue activation (BAT) and white adipose tissue browning (WAT) have been proposed. Dietary polyphenols are plant secondary metabolites that can stimulate browning and thermogenesis of adipose tissue. They have also been shown to prevent body weight gain, and decrease systemic inflammation produced by high-fat diets. Ingested dietary polyphenols that reach the colon are metabolized by the gut microbiota (GM), regulating its composition and generating a great array of metabolites. GM is involved in the production of short chain fatty acids and secondary bile salts that regulate energetic metabolism. The alteration in the composition of GM observed in metabolic diseases such as obesity and type 2 diabetes can be attenuated by polyphenols. Recent studies support the hypothesis that GM would mediate WAT browning and BAT thermogenesis activation induced by polyphenol administration. Together, these results indicate that GM in the presence of polyphenols plays a fundamental role in the control of obesity possible through BAT activation.

High hydrostatic pressure extract of mulberry leaves ameliorates hypercholesterolemia via modulating hepatic microRNA-33 expression and AMPK activity in high cholesterol diet fed rats

Background

Mulberry leaf (Morus alba L.) contains multiple bioactive ingredients and has been used in the treatment of obesity, diabetes, inflammation, and atherosclerosis. High hydrostatic pressure (HHP) processing has been developed for the extraction of bioactive compounds from plants. However, the hypocholesterolemic effect of the HHP extract from mulberry leaves and its underlying mechanism have never been investigated.

Objective

The specific aim of the present study was to investigate the hypocholesterolemic property of a novel extract obtained from mulberry leaves under HHP in rats.

Design

Sprague–Dawley rats were divided into four groups and fed either a normal diet (NOR), a high cholesterol diet containing 1% cholesterol and 0.5% cholic acid (HC), an HC diet containing 0.5% mulberry leaf extract (ML), or a 1% mulberry leaf extract (MH) for 4 weeks.

Results

High hydrostatic pressure extract of mulberry leaves significantly reduced the HC-increased serum levels of triglyceride (TG), cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), and hepatic contents of TG and TC. The HHP extraction from mulberry leaves also increased the HC-decreased fecal TC and bile acid levels without changing body weight, food intake, liver weight, and serum activities of alanine transaminase (ALT) and aspartate transaminase (AST) (P < 0.05). The mulberry leaf extract significantly enhanced the expression of hepatic genes such as cholesterol 7 alpha-hydroxylase (CYP7A1), liver X receptor alpha (LXRα), and ATP-binding cassette transporters, ABCG5/ABCG8, involved in hepatic bile acid synthesis and cholesterol efflux (P < 0.05). In addition, the HHP extraction of mulberry leaves significantly suppressed hepatic microRNA(miR)-33 expression and increased adenosine monophosphate-activated protein kinase (AMPK) activity.

Conclusion

These results suggest that the HHP extract of mulberry leaves lowers serum cholesterol levels by partially increasing hepatic bile acid synthesis and fecal cholesterol excretion through the modulation of miR-33 expression and AMPK activation in the liver.

Safety assessment of desaminotyrosine: Acute, subchronic oral toxicity, and its effects on intestinal microbiota in rats

In this work, the acute and subchronic toxicities of desaminotyrosine (DAT) by oral administration in SD rats and its effects on the intestinal microflora were investigated. The acute toxicity test showed that DAT is a low-toxic substance with a LD50 of 3129 mg/kg. The subchronic toxicity test showed that DAT has no toxicity at a low dose (125 mg/kg/day). However, DAT exhibited obvious toxicities to food intake, liver, kidney, and lung at higher dose (250 mg/kg/day and 500 mg/kg/day). DAT inhibited the food intake of rats in a dose-dependent manner. Serum biochemical analysis showed that DAT can increase the serum glucose level of rats. Fecal microbiota analysis showed that DAT treatment can significantly change the intestinal microflora of rats, the dose of 125 mg/kg/day has the most significant effect on the diversity of intestinal microbiota. In daily application, the side effects caused by DAT might be gastrointestinal irritation, weight loss, liver or kidney injury, and blood sugar elevation. Based on our study, the no-observed-adverse-effect level (NOAEL) of DAT is 125 mg/kg BW/day for rats.

Qingke β-glucan synergizes with a β-glucan-utilizing Lactobacillus strain to relieve capsaicin-induced gastrointestinal injury in mice

Capsaicin (CAP) is the main pungent component in capsicum fruits. Eating too much CAP leads to gastrointestinal injury. Previously, Qingke β-glucan combined with β-glucan-utilizing Lactobacillus plantarum S58 (LP.S58) ameliorated high fat-diet-induced obesity, but their effects on CAP-induced gastrointestinal injury have not been investigated. Our results showed that Qingke β-glucan reduced the CAP-induced gastrointestinal injury in Kunming mice. The serum levels of inflammatory cytokines and gastrointestinal hormones, and the localized inflammation and the expression of EGF, EGFR, VEGF, and ZO-1 in the gastrointestinal tissues in CAP-treated mice were partly restored by Qingke β-glucan. The CAP-induced increase in the abundances of proinflammatory intestinal bacteria was also reduced by Qingke β-glucan. More importantly, we found that these beneficial effects of Qingke β-glucan were markedly enhanced by β-glucan-utilizing LP.S58 supplementation. Our study indicated that Qingke β-glucan coupled with β-glucan-utilizing LP.S58 relieved CAP-induced gastrointestinal injury.

Amelioration of high-fat diet-induced obesity and its associated complications by a myricetin derivative-rich fraction from Syzygium malaccense in C57BL/6J mice

Obesity is a driving factor in the onset of metabolic disorders. This study aims to investigate the effects of the myricetin derivative-rich fraction (MD) from Syzygium malaccense leaf extract on high-fat diet (HFD)-induced obesity and its associated complications and its influence on uncoupling protein-1 (UCP-1) and gut microbiota in C57BL/6J mice. Mice were randomly assigned into four groups (n = 6) and given a normal diet (ND) or high-fat diet (HFD) for 10 weeks to induce obesity. The HFD groups (continued with HFD) were administered 50 mg kg-1 MD (treatment), 50 mg kg-1 metformin (positive control) and normal saline (HFD and ND controls) daily for four weeks via oral gavage. The ten-week HFD-feeding resulted in hyperglycemia and elevated urinary oxidative indices. The subsequent MD administration caused significant weight reduction without appetite suppression and amelioration of insulin resistance, steatosis and dyslipidemia. Besides, MD significantly reduced lipid hydroperoxides and protein carbonyls in tissue homogenates and urine and elevated Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and reduced glutathione (GSH) and thus, alleviated oxidative stress. The weight reduction was correlated with downregulation of inflammatory markers and the increased UCP-1 level, suggesting weight loss plausibly through thermogenesis. The Akkermansia genus (reflects improved metabolic status) in the HFD50 group was more abundant than that in the HFD group while the non-enzymatic antioxidant markers were strongly associated with UCP-1. In conclusion, MD ameliorates obesity and its related complications possibly via the upregulation of UCP-1 and increased abundance of Akkermansia genus and is promising as a therapeutic agent in the treatment of obesity and its associated metabolic disorders.

Skin and Gut Microbiome in Psoriasis: Gaining Insight Into the Pathophysiology of It and Finding Novel Therapeutic Strategies

Psoriasis affects the health of myriad populations around the world. The pathogenesis is multifactorial, and the exact driving factor remains unclear. This condition arises from the interaction between hyperproliferative keratinocytes and infiltrating immune cells, with poor prognosis and high recurrence. Better clinical treatments remain to be explored. There is much evidence that alterations in the skin and intestinal microbiome play an important role in the pathogenesis of psoriasis, and restoration of the microbiome is a promising preventive and therapeutic strategy for psoriasis. Herein, we have reviewed recent studies on the psoriasis-related microbiome in an attempt to confidently identify the “core” microbiome of psoriasis patients, understand the role of microbiome in the pathogenesis of psoriasis, and explore new therapeutic strategies for psoriasis through microbial intervention.

The Great Healing Potential Hidden in Plant Preparations of Antioxidant Properties: A Return to Nature?

The application of chemicals in industry and agriculture has contributed to environmental pollution and exposure of living organisms to harmful factors. The development of new pharmaceutical agents enabled successful therapy of various diseases, but their administration may be connected with side effects. Oxidative stress has been found to be involved into etiology of numerous diseases as well as harmful action of drugs and chemicals. For some time, plant origin substances have been studied as potential protective agents alleviating toxicity of various substances and symptoms of diseases. The aim of the current review was to present the diversity of the research performed during the last five years on animal models. The outcomes showed a huge protective potential inherent in plant preparations, including alleviating prooxidative processes, strengthening antioxidant defence, ameliorating immune parameters, and reversing histopathological changes. In many cases, plant origin substances were proved to be comparable or even better than standard drugs. Such findings let us suggest that in the future the plant preparations could make adjuvants or a replacement for pharmaceutical agents. However, the detailed research regarding dose and way of administration as well as the per se effects needs to be performed. In many studies, the last issue was not studied, and in some cases, the deleterious effects have been observed.

Mulberry Leaf Flavonoids Improve Milk Production, Antioxidant, and Metabolic Status of Water Buffaloes

This study was aimed to evaluate the effect of mulberry leaf flavonoids (MLF) on oxidative stress, metabolic hormones, and milk production in Murrah buffaloes. Forty multiparous Murrah buffaloes (4 ± 1 lactations) with similar body weight (average 600 ± 50 Kg) and stage of lactation (90 ± 20 d) were randomly selected for this trial. Four treatment groups (10 buffaloes per group) with different doses of MLF included; control (0 g/d), MLF15 (15 g/d), MLF30 (30 g/d), and MLF45 (45 g/d). Buffaloes were fed with total mix ration consisting of grass (Pennisetum purpureum schum), brewery's grain and concentrate mixture for 5 weeks. Meteorological data including ambient temperature and relative humidity were recorded using the online dust monitoring system to calculate temperature-humidity index (THI). After 1 week of the adaptation, milk yield was recorded daily while physiological parameters (respiratory rate, rectal, and body surface temperature), and milk composition were measured weekly. At the end of the trial, blood samples were collected to analyze serum metabolic hormones including estradiol (E2), growth hormone (GH), prolactin (PRL), Tri-iodothyronine (T3), and Thyroxine (T4). Moreover, serum heat shock proteins (HSP), antioxidants enzymes including malondialdehyde (MDA), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and blood biochemical indices were also analyzed. Results revealed a decrease (P = 0.012) in serum MDA level while increasing (P < 0.01) the HSP and serum GHS-Px contents in supplemented buffaloes. Treatment showed a linear and quadratic decrease (p = 0.001) in the serum T-AOC while reducing CAT contents linearly (p = 0.012) as compared to the control. However, no effect of treatment on serum SOD content was observed. Treatment resulted a linear increase (p = 0.001) in serum GH and PRL hormones while increasing serum E2 levels linearly (P < 0.001) and quadratically (P = 0.025). Treatment increased (p = 0.038) the daily milk yield as compared to the control. However, increase (P < 0.05) in serum T3 and T4 contents, fat corrected milk (4%) and milk protein (%) was observed only in MLF45. Moreover, we observed no change in serum biochemical indices except insulin which linearly increased (p = 0.002) in MLF45. Our findings indicated that MLF at 45 g per day is an appropriate level to enhance milk performance and alleviate heat stress in buffaloes.

Select Polyphenol-Rich Berry Consumption to Defer or Deter Diabetes and Diabetes-Related Complications

Berries are considered "promising functional fruits" due to their distinct and ubiquitous therapeutic contents of anthocyanins, proanthocyanidins, phenolic acids, flavonoids, flavanols, alkaloids, polysaccharides, hydroxycinnamic, ellagic acid derivatives, and organic acids. These polyphenols are part of berries and the human diet, and evidence suggests that their intake is associated with a reduced risk or the reversal of metabolic pathophysiologies related to diabetes, obesity, oxidative stress, inflammation, and hypertension. This work reviewed and summarized both clinical and non-clinical findings that the consumption of berries, berry extracts, purified compounds, juices, jams, jellies, and other berry byproducts aided in the prevention and or otherwise management of type 2 diabetes mellitus (T2DM) and related complications. The integration of berries and berries-derived byproducts into high-carbohydrate (HCD) and high-fat (HFD) diets, also reversed/reduced the HCD/HFD-induced alterations in glucose metabolism-related pathways, and markers of oxidative stress, inflammation, and lipid oxidation in healthy/obese/diabetic subjects. The berry polyphenols also modulate the intestinal microflora ecology by opposing the diabetic and obesity rendered symbolic reduction of Bacteroidetes/Firmicutes ratio, intestinal mucosal barrier dysfunction-restoring bacteria, short-chain fatty acids, and organic acid producing microflora. All studies proposed a number of potential mechanisms of action of respective berry bioactive compounds, although further mechanistic and molecular studies are warranted. The metabolic profiling of each berry is also included to provide up-to-date information regarding the potential anti-oxidative/antidiabetic constituents of each berry.

Comparative Study of the Antioxidant and Anti-Inflammatory Effects of Leaf Extracts from Four Different Morus alba Genotypes in High Fat Diet-Induced Obesity in Mice

Increased levels of reactive oxygen species (ROS) and a low-grade chronic inflammation in multiple organs have been demonstrated in obesity. Morus alba leaves extracts (MAEs) have been used in traditional medicine as anti-inflammatory agents. In this work, the bioactive compounds of different genotypes of M. alba L. (Filipina, Valenciana Temprana, Kokuso, and Italia) were analyzed not only by reverse phase high performance liquid chromatography–electrospray ionization-time of flight-mass spectrometry (RP-HPLC-ESI-TOF-MS) and hydrophilic interaction chromatography–electrospray ionization-time of flight-mass spectrometry (HILIC-ESI-TOF-MS), but also screened for in vitro and in vivo antioxidant activity by means of DPPH• radical scavenging assay and Caenorhabditis elegans model. These MAEs were administered daily in a model of diet-induced obesity in mice. Filipina and Italia genotypes significantly reduced weight gain, the glycemic levels in high fat diet, as well as, levels of LDL-cholesterol and triglycerides. Filipina and Italia MAEs also reduced the expression of proinflammatory mediators such as Tnf-α, Il-1β, Il-6 and increased the levels of adiponectin and AMPK, which exert anti-inflammatory effects. Moreover, Italia genotype ameliorated the intestinal barrier function. In conclusion, Filipina and Italia methanolic extracts show the highest antioxidant and anti-inflammatory effect, due to the presence of compounds such as protocatechuic acid or quercetin-3-glucoside, and they could be developed as a complementary treatment for obesity and metabolic disorders.

Flavonoids from Mulberry Leaves Alleviate Lipid Dysmetabolism in High Fat Diet-Fed Mice: Involvement of Gut Microbiota

Here, we investigated the roles and mechanisms of flavonoids from mulberry leaves (FML) on lipid metabolism in high fat diet (HFD)-fed mice. ICR mice were fed either a control diet (Con) or HFD with or without FML (240 mg/kg/day) by oral gavage for six weeks. FML administration improved lipid accumulation, alleviated liver steatosis and the whitening of brown adipose tissue, and improved gut microbiota composition in HFD-fed mice. Microbiota transplantation from FML-treated mice alleviated HFD-induced lipid metabolic disorders. Moreover, FML administration restored the production of acetic acid in HFD-fed mice. Correlation analysis identified a significant correlation between the relative abundances of Bacteroidetes and the production of acetic acid, and between the production of acetic acid and the weight of selected adipose tissues. Overall, our results demonstrated that in HFD-fed mice, the lipid metabolism improvement induced by FML administration might be mediated by gut microbiota, especially Bacteroidetes-triggered acetic acid production.

Consumption of Biscuits with a Beverage of Mulberry or Barley Leaves in the Afternoon Prevents Dinner-Induced High, but Not Low, Increases in Blood Glucose among Young Adults

We examined the impact of consuming biscuits with a beverage of powdered mulberry or barley leaves in the afternoon on postprandial glucose levels at dinnertime among young adults. A total of 18 young adults participated in a partially double-blinded, randomized crossover trial over 2 weeks, consuming either: (1) no biscuits; (2) a biscuit; (3) a biscuit with a beverage of powdered mulberry leaves; or (4) a biscuit with a beverage of powdered barley leaves, as an afternoon snack followed by a standardized test dinner. Glucose levels were recorded after each meal. Results showed intake of biscuits with a beverage of mulberry and barley leaves significantly reduced postprandial rises in glucose after their immediate consumption and dinner, though there was no direct relationship between the glucose levels at the two meals. Compared to those with low glucose levels, participants with high glucose levels at dinner showed a stronger second meal effect, that was attributed to the mulberry or barley leaves, and were also more likely to have lean body weights and prefer evenings. Our findings indicate that eating snacks alongside mulberry or barley leaves is an effective way to suppress postprandial glucose levels in young adults with high glucose levels who prefer evenings.

Dietary supplementation of Morus nigra L. leaves decrease fat mass partially through elevating leptin-stimulated lipolysis in pig model

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry leaves are the dry leaves of Morus nigra L. trees, which are widely cultivated in central and southern China. Mulberry has a long history of medicinal use, such as anti-stress, lowering blood glucose and anti-obesity.

AIM OF THE STUDY

Explore the effects of mulberry leaves on fat deposition as well as the underlying mechanisms.

MATERIALS AND METHODS

Total of 48 fattening pigs weighing about 70 kg were randomly allotted to normal diet or die supplemented with 5% (w/w) mulberry leave powder. Changes of fat mass, indicated by backfat thickness was measured with Piggyback tester, blood triglyceride and cholesterol were tested using commercial biochemical kits, serum hormones were estimated by ELISA, and leptin-related signaling activity were assessed using western-blot.

RESULTS

Supplementation with Mulberry leaf feed (MF) significantly reduced serum triglyceride and free cholesterol concentrations and increased the ratio of high-density lipoprotein cholesterol (HDL-c) to low-density lipoprotein cholesterol (LDL-c), while serum glucose and free fatty acids remained unchanged. Dietary MF resulted in a significant reduction in the size of adipocytes and backfat thickness (P < 0.05). Accordingly, hormone-sensitive lipase (HSL) in backfat was significantly up-regulated and fatty acid synthase (FAS) was down-regulated by MF supplementation (both P < 0.05). Furthermore, MF supplementation significantly elevated circulating leptin and adiponectin without influencing serum insulin and glucocorticoid. Moreover, significantly higher leptin receptor (Leptin-R) and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) were detected in MF-supplemented pigs, suggesting an enhanced leptin signaling induced by MF in the subcutaneous fat.

CONCLUSIONS

Mulberry leaves have obvious anti-obesity effects, providing a theoretical basis for the development of mulberry leaves as a drug against obesity.