Mulberry leaf reduces inflammation and insulin resistance in type 2 diabetic mice by TLRs and insulin Signalling pathway

Effects of dietary mulberry leaves on growth, production performance, gut microbiota, and immunological parameters in poultry and livestock: a systematic review and meta-analysis

OBJECTIVE

This study aimed to assess the effects of dietary mulberry leaves on the growth, production performance, gut microbiota, and immunological parameters of poultry and livestock.

METHODS

The PubMed, Embase, and Scopus databases were systematically analyzed to identify pertinent studies up to December 2022. The effects of mulberry leaf diet was assessed using the weighted mean difference, and the 95% confidence interval was calculated using a random-effects model.

RESULTS

In total, 18 studies that sampled 2,335 poultry and livestock were selected for analysis. Mulberry leaves improved the average daily gain and reduced the feed/meat ratio in finishing pigs, and the average daily gain and average daily feed intake in chicken. In production performance, mulberry leaves lowered the half carcass weight, slaughter rate, and loin eye area in pigs, and the slaughter rate in chickens. Regarding meat quality in pigs, mulberry leaves reduced the cooked meat percentage, shear force, crude protein, and crude ash, and increased the 24 h pH and water content. In chickens, it increased the drip loss, shear force, 45 min and 24 h pH, crude protein, and crude ash. Mulberry leaves also affect the abundances of gut microbiota, including Bacteroides, Prevotella, Megamonas, Escherichia-Shigella, Butyricicoccus, unclassified Ruminococcaceae, Bifidobacterium, Lactobacillus, and Escherichia coli in poultry and livestock. Mulberry leaves at different doses were associated with changes in antioxidant capacity in chickens, and immune organ indexes in pigs. With respect to egg quality, mulberry leaves at different doses improved the shell strength, yolk color, eggshell thickness, and eggshell weight. However, moderate doses diminished the egg yolk ratio and the egg yolk moisture content.

CONCLUSION

In general, dietary mulberry leaves improved the growth, production performance, and immunological parameters in poultry and livestock, although the effects varied at different doses.

Potential Role and Mechanism of Mulberry Extract in Immune Modulation: Focus on Chemical Compositions, Mechanistic Insights, and Extraction Techniques

Mulberry is a rapidly growing plant that thrives in diverse climatic, topographical, and soil types, spanning temperature and temperate countries. Mulberry plants are valued as functional foods for their abundant chemical composition, serving as a significant reservoir of bioactive compounds like proteins, polysaccharides, phenolics, and flavonoids. Moreover, these compounds displayed potent antioxidant activity by scavenging free radicals, inhibiting reactive oxygen species generation, and restoring elevated nitric oxide production induced by LPS stimulation through the downregulation of inducible NO synthase expression. Active components like oxyresveratrol found in Morus demonstrated anti-inflammatory effects by inhibiting leukocyte migration through the MEK/ERK signaling pathway. Gallic and chlorogenic acids in mulberry leaves (ML) powder-modulated TNF, IL-6, and IRS1 proteins, improving various inflammatory conditions by immune system modulation. As we delve deeper into understanding its anti-inflammatory potential and how it works therapeutically, it is crucial to refine the extraction process to enhance the effectiveness of its bioactive elements. Recent advancements in extraction techniques, such as solid-liquid extraction, pressurized liquid extraction, superficial fluid extraction, microwave-assisted extraction, and ultrasonic-assisted extraction, are being explored. Among the extraction methods tested, including Soxhlet extraction, maceration, and ultrasound-assisted extraction (UAE), UAE demonstrated superior efficiency in extracting bioactive compounds from mulberry leaves. Overall, this comprehensive review sheds light on the potential of mulberry as a natural immunomodulatory agent and provides insights into its mechanisms of action for future research and therapeutic applications.

Identification of HDAC9 and ARRDC4 as potential biomarkers and targets for treatment of type 2 diabetes

We aimed to identify the key potential insulin resistance (IR)-related genes and investigate their correlation with immune cell infiltration in type 2 diabetes (T2D). The GSE78721 dataset (68 diabetic patients and 62 controls) was downloaded from the Gene Expression Omnibus database and utilized for single-sample gene set enrichment analysis. IR-related genes were obtained from the Comparative Toxicology Genetics Database, and the final IR-differentially expressed genes (DEGs) were screened by intersecting with the DEGs obtained from the GSE78721 datasets. Functional enrichment analysis was performed, and the networks of the target gene with microRNA, transcription factor, and drug were constructed. Hub genes were identified based on a protein-protein interaction network. Least absolute shrinkage and selection operator regression and Random Forest and Boruta analysis were combined to screen diagnostic biomarkers in T2D, which were validated using the GSE76894 (19 diabetic patients and 84 controls) and GSE9006 (12 diabetic patients and 24 controls) datasets. Quantitative real-time polymerase chain reaction was performed to validate the biomarker expression in IR mice and control mice. In addition, infiltration of immune cells in T2D and their correlation with the identified markers were computed using CIBERSORT. We identified differential immune gene set regulatory T-cells in the GSE78721 dataset, and T2D samples were assigned into three clusters based on immune infiltration. A total of 2094 IR-DEGs were primarily enriched in response to endoplasmic reticulum stress. Importantly, HDAC9 and ARRDC4 were identified as markers of T2D and associated with different levels of immune cell infiltration. HDAC9 mRNA level were higher in the IR mice than in control mice, while ARRDC4 showed the opposite trend. In summary, we discovered potential vital biomarkers that contribute to immune cell infiltration associated with IR, which offers a new sight of immunotherapy for T2D.

Natural compounds efficacy in complicated diabetes: A new twist impacting ferroptosis

Ferroptosis, as a way of cell death, participates in the body's normal physiological and pathological regulation. Recent studies have shown that ferroptosis may damage glucose-stimulated islets β Insulin secretion and programmed cell death of T2DM target organs are involved in the pathogenesis of T2DM and its complications. Targeting suppression of ferroptosis with specific inhibitors may provide new therapeutic opportunities for previously untreated T2DM and its target organs. Current studies suggest that natural bioactive compounds, which are abundantly available in drugs, foods, and medicinal plants for the treatment of T2DM and its target organs, have recently received significant attention for their various biological activities and minimal toxicity, and that many natural compounds appear to have a significant role in the regulation of ferroptosis in T2DM and its target organs. Therefore, this review summarized the potential treatment strategies of natural compounds as ferroptosis inhibitors to treat T2DM and its complications, providing potential lead compounds and natural phytochemical molecular nuclei for future drug research and development to intervene in ferroptosis in T2DM.

Exercise ameliorates skeletal muscle insulin resistance by modulating GRK4-mediated D1R expression

Exercise has been recommended as a nonpharmaceutical therapy to treat insulin resistance (IR). Previous studies showed that dopamine D1-like receptor agonists, such as fenoldopam, could improve peripheral insulin sensitivity, while antipsychotics, which are dopamine receptor antagonists, increased susceptibility to Type 2 diabetes mellitus (T2DM). Meanwhile, exercise has been proved to stimulate dopamine receptors. However, whether the dopamine D1 receptor (D1R) is involved in exercise-mediated amelioration of IR remains unclear. We found that the D1-like receptor antagonist, SCH23390, reduced the effect of exercise on lowering blood glucose and insulin in insulin-resistant mice and inhibited the contraction-induced glucose uptake in C2C12 myotubes. Similarly, the opposite was true for the D1-like receptor agonist, fenoldopam. Furthermore, the expression of D1R was decreased in skeletal muscles from streptozotocin (STZ)- and high-fat intake-induced T2DM mice, accompanied by increased D1R phosphorylation, which was reversed by exercise. A screening study showed that G protein-coupled receptor kinase 4 (GRK4) may be the candidate kinase for the regulation of D1R function, because, in addition to the increased GRK4 expression in skeletal muscles of T2DM mice, GRK4 transgenic T2DM mice exhibited lower insulin sensitivity, accompanied by higher D1R phosphorylation than control mice, whereas the AAV9-shGRK4 mice were much more sensitive to insulin than AAV9-null mice. Mechanistically, the up-regulation of GRK4 expression caused by increased reactive oxygen species (ROS) in IR was ascribed to the enhanced expression of c-Myc, a transcriptional factor of GRK4. Taken together, the present study shows that exercise, via regulation of ROS/c-Myc/GRK4 pathway, ameliorates D1R dysfunction and improves insulin sensitivity.

Identifying potential therapeutic targets of mulberry leaf extract for the treatment of type 2 diabetes: a TMT-based quantitative proteomic analysis

BACKGROUND

Mulberry (Morus alba L.) leaf, as a medicinal and food homologous traditional Chinese medicine, has a clear therapeutic effect on type 2 diabetes mellitus (T2DM), yet its underlying mechanisms have not been totally clarified. The study aimed to explore the mechanism of mulberry leaf in the treatment of T2DM through tandem mass tag (TMT)-based quantitative proteomics analysis of skeletal muscle.

METHODS

The anti-diabetic activity of mulberry leaf extract (MLE) was evaluated by using streptozotocin-induced diabetic rats at a dose of 4.0 g crude drug /kg p.o. daily for 8 weeks. Fasting blood glucose, body weight, food and water intake were monitored at specific intervals, and oral glucose tolerance test and insulin tolerance test were conducted at the 7th and 8th week respectively. At the end of the experiment, levels of glycated hemoglobin A1c, insulin, free fat acid, leptin, adiponectin, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were assessed and the pathological changes of rat skeletal muscle were observed by HE staining. TMT-based quantitative proteomic analysis of skeletal muscle and bioinformatics analysis were performed and differentially expressed proteins (DEPs) were validated by western blot. The interactions between the components of MLE and DEPs were further assessed using molecular docking.

RESULTS

After 8 weeks of MLE intervention, the clinical indications of T2DM such as body weight, food and water intake of rats were improved to a certain extent, while insulin sensitivity was increased and glycemic control was improved. Serum lipid profiles were significantly reduced, and the skeletal muscle fiber gap and atrophy were alleviated. Proteomic analysis of skeletal muscle showed that MLE treatment reversed 19 DEPs in T2DM rats, regulated cholesterol metabolism, fat digestion and absorption, vitamin digestion and absorption and ferroptosis signaling pathways. Key differential proteins Apolipoprotein A-1 (ApoA1) and ApoA4 were successfully validated by western blot and exhibited strong binding activity to the MLE's ingredients.

CONCLUSIONS

This study first provided skeletal muscle proteomic changes in T2DM rats before and after MLE treatment, which may help us understand the molecular mechanisms, and provide a foundation for developing potential therapeutic targets of anti-T2DM of MLE.

Ferroptosis and Traditional Chinese Medicine for Type 2 Diabetes Mellitus

Ferroptosis, an emerging form of regulated programmed cell death, has garnered significant attention in the past decade. It is characterized by the accumulation of lipid peroxides and subsequent damage to cellular membranes, which is dependent on iron. Ferroptosis has been implicated in the pathogenesis of various diseases, including tumors and diabetes mellitus. Traditional Chinese medicine (TCM) has unique advantages in preventing and treating type 2 diabetes mellitus (T2DM) due to its anti-inflammatory, antioxidant, immunomodulatory, and intestinal flora-regulating functions. Recent studies have determined that TCM may exert therapeutic effects on T2DM and its complications by modulating the ferroptosis-related pathways. Therefore, a comprehensive and systematic understanding of the role of ferroptosis in the pathogenesis and TCM treatment of T2DM is of great significance for developing therapeutic drugs for T2DM and enriching the spectrum of effective T2DM treatment with TCM. In this review, we review the concept, mechanism, and regulatory pathways of ferroptosis and the ferroptosis mechanism of action involved in the development of T2DM. Also, we develop a search strategy, establish strict inclusion and exclusion criteria, and summarize and analyze the application of the ferroptosis mechanism in TCM studies related to T2DM and its complications. Finally, we discuss the shortcomings of current studies and propose a future research focus.

Clinical potential and mechanistic insights of mulberry (Morus alba L.) leaves in managing type 2 diabetes mellitus: Focusing on gut microbiota, inflammation, and metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Natural herbs are gradually gaining recognition for their efficacy and safety in preventing diabetes and improving quality of life. Morus alba L. is a plant widely grown in Asia and is a traditional Chinese herb with a long history of use. Furthermore, several parts of Morus alba L. have been found to have significant health benefits. In particular, mulberry (Morus alba L.) leaves (ML) have been shown in human and animal studies to be promising hypoglycemic agents that can reduce or prevent glucolipid metabolism disorders caused by imbalances in the gut microbiota, inflammation, and oxidative stress and have demonstrated significant improvements in glucose metabolism-related markers, effectively lowering blood glucose, and reducing hyperglycemia-induced target organ damage.

AIM OF THE STUDY

This review briefly summarizes the methods for obtaining ML's bioactive components, elaborates on the clinical potential of the relevant components in managing type 2 diabetes mellitus (T2DM), and focuses on the therapeutic mechanisms of gut microbiota, inflammation, oxidative stress, and metabolism, to provide more inspiration and directions for future research in the field of traditional natural plants for the management of T2DM and its complications.

MATERIALS AND METHODS

Research on ML and its bioactive components was mainly performed using electronic databases, including PubMed, Google Scholar, and ScienceNet, to ensure the review's quality. In addition, master's and doctoral theses and ancient documents were consulted.

RESULTS

In clinical studies, we found that ML could effectively reduce blood glucose, glycated hemoglobin, and homeostasis model assessment of insulin resistance in T2DM patients. Furthermore, many in vitro and in vivo experiments have found that ML is involved in various pathways that regulate glucolipid metabolism and resist diabetes while alleviating liver and kidney damage.

CONCLUSIONS

As a potential natural anti-diabetic phytomedicine, an in-depth study of ML can provide new ideas and valuable references for applying traditional Chinese medicine to treat T2DM. While continuously exploring its clinical efficacy and therapeutic mechanism, the extraction method should be optimized to improve the efficacy of the bioactive components. in addition, further research on the dose-response relationship of drugs to determine the effective dose range is required.

Isolated compounds from Dracaena angustifolia Roxb and acarbose synergistically/additively inhibit α-glucosidase and α-amylase: an in vitro study

Background

As a traditional herbal medicine, Dracaena angustifolia Roxb has been used as an anti-inflammatory agent by the Li people in Hainan, China. In preliminary phytochemical studies conducted in our lab, its fractions were found to inhibit α-glucosidase in vitro, indicating a potential for alleviating glucose dysregulation.

Methods

Through in vitro enzymatic assays, the abilities of the separated components to affect α-glucosidase and α-amylase were evaluated. By establishing concentration gradients and generating Lineweaver–Burk plots, the corresponding inhibition modes together with kinetic parameters were assessed. Following the evaluation of the outcomes of their combination with acarbose, computational docking and molecular dynamic simulations were carried out to analyse the interaction mechanisms and perform virtual screening against human enzymes.

Results

Compared with acarbose, 7 compounds, including flavonoid derivatives, amides and aromatic derivatives, with higher α-glucosidase inhibitory efficiencies were confirmed. It was found that those competitive/mixed candidates and acarbose interacted synergistically or additively on α-glucosidase. Moreover, 3 of them were able to inhibit α-amylase in mixed mode, and additive effects were observed in combination with acarbose. Through in silico docking, it was found that the active site residues as well as adjacent residues were involved in α-glucosidase and α-amylase binding, which were mainly achieved through hydrogen bonding. Among those dual-function flavonoids, Compound 9 was predicted to be a considerable inhibitor of human enzymes, as the formation of ligand–enzyme complexes was mediated by the residues responsible for substrate recognition and catalysis, the stabilities of which were reiterated by molecular dynamics simulations.

Conclusion

Despite their mild effects on α-amylase, considerable α-glucosidase inhibitory efficiencies and potential synergy with acarbose were exhibited by these natural candidates. Furthermore, a stable ligand, human α-glucosidase, was predicted by the performed simulations, which provided useful information for the application of Dracaena angustifolia Roxb in diabetes treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03649-3.

The anti-obesity effect of mulberry leaf (Mori Folium) extracts was increased by bioconversion with Pectinex

Mulberry leaf (Mori Folium) extract (MLE) is known to have anti-obesity effects. In this study, the enhanced effects of MLE after bioconversion treatment using Pectinex (BMLE) on obesity were explored, and the underlying mechanisms were investigated using the active components, neochlorogenic acid (5-CQA) and cryptochlorogenic acid (4-CQA), whose amounts were increased by bioconversion of MLE. Both MLE and BMLE inhibited lipid accumulation in 3T3-L1 adipocytes without cytotoxicity and suppressed the expression of CCAAT/enhancer-binding protein alpha (C/EBPα). In addition, MLE and BMLE decreased high-fat diet-induced adipose tissue mass expansion. Notably, BMLE significantly increased antiadipogenic and anti-obesity effects compared to MLE in vitro and in vivo. The active ingredients increased by bioconversion, 5-CQA and 4-CQA, inhibited the protein levels of C/EBPα and the mRNA levels of stearoyl-CoA desaturase 1 (Scd1). These findings provide new insights into the therapeutic possibility of using bioconversion of MLE, by which upregulation of 5-CQA and 4-CQA potently inhibits adipogenesis.

Mulberry plant as a source of functional food with therapeutic and nutritional applications: A review

Medicinal plants from the family Moraceae have diverse applications in agriculture, cosmetics, food, and the pharmaceutical industry. Their extensive spectrum of pharmacological activity for treating numerous inflammatory illnesses, cancer, cardiovascular diseases, and gastrointestinal problems reflects their biological and therapeutic value. This article summarizes the molecular mechanisms related to the biological implications of mulberry extracts, fractions, and isolated bioactive compounds from different parts in various health-related ailments. Additionally, the food industry and animal nutrition applications are summarized. Phytochemicals such as steroids, saponins, alkaloids, glycosides, polysaccharides, and phenolic compounds including terpenoids, flavonoids, anthocyanins, and tannins are found in this medicinal plant. The aqueous, ethanolic, and methanolic extracts, as well as bioactive compounds, have anti-oxidative, hypoglycemic, nephroprotective, antimicrobial, neuroprotective, anti-mutagenic, hepatoprotective, anthelmintic, immune-modulatory, cardioprotective, and skin protecting activities. Mulberry supplementation in food products improves the stability of phenolics, sensory properties, antioxidant activity, and antimicrobial properties. Mulberry leaves in animal feed increase the nutrient digestibility, growth parameters, antimicrobial, and antioxidant properties. PRACTICAL APPLICATIONS: This review summarized the in vivo and in vitro biological activities of the mulberry and isolated constituents in various health conditions. In addition, the food uses such as antioxidant potential, antimicrobial, and physicochemical properties were discussed. Furthermore, in vivo studies revealed mulberry as a significant protein source and its flavonoids as potential animal foliage.

Novel active compounds and the anti-diabetic mechanism of mulberry leaves

Mulberry (Morus alba L.) leaves have long been considered beneficial in traditional Chinese medicine to treat infectious and internal diseases. Recently studies have discovered that the mulberry leaf’s total flavonoids (MLF) display excellent hypoglycemia properties. However, the active ingredients and their molecular mechanisms are still uncharacterized. In this study, we explored the hypoglycemic effects of MLF and mulberry leaf polysaccharides (MLP) on ob/ob mice, an animal model of type 2 diabetes mellitus (T2DM), compared with Ramulus Mori (Sangzhi) alkaloid (RMA). Network pharmacology was employed to identify the potential available targets and active compounds of MLF and RMA against hyperglycemia. Molecular docking, an insulin-resistant cell model and qPCR were employed to verify the antidiabetic activity of the critical compounds and the gene expression profiles of the top molecular targets. Here, the results showed that MLF and MLP improved glucose uptake in insulin-resistant hepatocytes. MLF, MLP and RMA alleviated insulin resistance and glucose intolerance in ob/ob mice. Unlike MLF and MLP, RMA administration did not influence the accumulation of intrahepatic lipids. Network pharmacology analysis revealed that morusin, kuwanon C and morusyunnansin L are the main active compounds of MLF and that they amend insulin resistance and glycemia via the PI3K- Akt signaling pathway, lipid and atherosclerosis pathways, and the AGE-RAGE signaling pathway. Moreover, 1-deoxynojirimycin (DNJ), fagomine (FA), and N-methyl-1-deoxynojirimycin are the primary active ingredients of RMA and target carbohydrate metabolism and regulate alpha-glucosidase activity to produce a potent anti-diabetic effect. The molecular docking results indicated that morusin, kuwanon C and morusyunnansin L are the critical bioactive compounds of MLF. They had high affinities with the key targets adenosine A1 receptor (ADORA1), AKT serine/threonine kinase 1 (AKT1), peroxisome proliferator-activated receptor gamma (PPARγ), and glycogen synthase kinase 3 beta (GSK3β), which play crucial roles in the MLF-mediated glucose-lowering effect. Additionally, morusin plays a role in amending insulin resistance of hepatocytes by repressing the expression of the ADORA1 and PPARG genes. Our results shed light on the mechanism behind the glucose-lowering effects of MLF, suggesting that morusin, kuwanon C, and morusyunnansin L might be promising drug leads for the management of T2DM.

Herbal tea, a novel adjuvant therapy for treating type 2 diabetes mellitus: A review

Type 2 diabetes mellitus (T2DM) is a metabolic, endocrine disease characterized by persistent hyperglycemia. Several studies have shown that herbal tea improves glucose metabolism disorders in patients with T2DM. This study summarizes the published randomized controlled trials (RCTs) on herbal tea as a adjuvant therapy for treating T2DM and found that herbal teas have potential add-on effects in lowering blood glucose levels. In addition, we discussed the polyphenol contents in common herbal teas and their possible adverse effects. To better guide the application of herbal teas, we further summarized the hypoglycemic mechanisms of common herbal teas, which mainly involve: 1) improving insulin resistance, 2) protecting islet β-cells, 3) anti-inflammation and anti-oxidation, 4) inhibition of glucose absorption, and 5) suppression of gluconeogenesis. In conclusion, herbal tea, as a novel adjuvant therapy for treating T2DM, has the potential for further in-depth research and product development.

Molecular mechanism of ferroptosis and its role in the occurrence and treatment of diabetes

Ferroptosis is an iron-dependent programmed cell death, which is different from apoptosis, necrosis, and autophagy. Specifically, under the action of divalent iron or ester oxygenase, unsaturated fatty acids that are highly expressed on the cell membrane are catalyzed to produce lipid peroxidation, which induces cell death. In addition, the expression of the antioxidant system [glutathione (GSH) and glutathione peroxidase 4 (GPX4)] is decreased. Ferroptosis plays an important role in the development of diabetes mellitus and its complications. In this article, we review the molecular mechanism of ferroptosis in the development of diabetes mellitus and its complications. We also summarize the emerging questions in this particular area of research, some of which remain unanswered. Overall, this is a comprehensive review focusing on ferroptosis-mediated diabetes and providing novel insights in the treatment of diabetes from the perspective of ferroptosis.

Therapeutic mechanisms of mulberry leaves in type 2 diabetes based on metabolomics

Background: Type 2 diabetes (T2D) is considered as one of the most significant metabolic syndromes worldwide, and the long-term use of the drugs already on the market for T2D often gives rise to some side effects. The mulberry leaf (ML), Morus alba L., has advantages in terms of its comprehensive therapeutic efficacy, which are characterized as multicomponent, multitarget, multipathway, and matching with the complex pathological mechanisms of diabetes.

Methods: T2D rats were established by a high-fat diet combined with an intraperitoneal injection of streptozotocin; an evaluation of the hypoglycemic effects of the ML in combination with fasting blood glucose and other indicators, in addition to the utilization of metabolomics technology, was performed to analysis the metabolite changes in serum of rats.

Results: MLs significantly reduced the fasting blood glucose of T2D rats, while improving the symptoms of polyphagia and polyuria. ML treatment altered the levels of various metabolites in the serum of T2D rats, which are involved in multiple metabolic pathways (amino acid metabolism, carbohydrate metabolism, and lipid metabolism), played a role in antioxidative stress and anti-inflammation, modulated immune and gluconeogenesis processes, and improved obesity as well as insulin resistance (IR).

Conclusion: The ML contains a variety of chemical components, and metabolomic results have shown that MLs regulate multiple metabolic pathways to exert hypoglycemic effects, suggesting that MLs may have great promise in the development of new hypoglycemic drugs.

Mulberry Leaf Extract Improves Metabolic Syndrome by Alleviating Lipid Accumulation In Vitro and In Vivo

Metabolic syndrome (MS) is a metabolic disease with multiple complications. Mulberry leaf extract (MLE) is rich in flavonoids and has great potential in alleviating glucose and lipid metabolism disorders. This study evaluated the effect and mechanism of MLE on the alleviation of MS. The components of the MLE were analyzed, and then the regulation of lipid metabolism by MLE in vitro and in vivo was determined. In a hepatocyte model of oleic acid-induced lipid accumulation, it was found that MLE alleviated lipid accumulation and decreased the expression of genes involved in lipogenesis. Furthermore, MLE improved obesity, insulin resistance, plasma lipid profile, and liver function in MS mice after a 15-week intervention. MLE decreased the expression of SREBP1, ACC, and FAS through the AMPK signaling pathway to inhibit lipid synthesis and increase the level of CPT1A to promote lipid decomposition to achieve its hypolipidemic effect. Meanwhile, MLE was also shown to affect the composition of the gut microbiota and the production of short-chain fatty acids, which contributed to the alleviation of lipid accumulation. Our results suggest that MLE can improve MS by improving lipid metabolism through multiple mechanisms and can be developed into dietary supplements for the improvement of MS.

Mulberry Leaf Flavonoids Inhibit Liver Inflammation in Type 2 Diabetes Rats by Regulating TLR4/MyD88/NF-κB Signaling Pathway

The incidence of liver-related complications in type 2 diabetes mellitus (T2DM) is rapidly increasing, which affects the physical and mental health of T2DM patients. Mulberry leaf flavonoids (MLF) were confirmed to have certain effects on lowering blood glucose and anti-inflammation. In this study, the high-fat diet (HFD) + STZ method was used to establish T2DM rat model and the MLF was administered by gavage for eight weeks. During the experiment, body weight and blood glucose level were measured at different time points. The pathological changes of rat liver were observed by H&E staining. The serum glucolipid metabolic indicators of serum, fasting insulin (FINS), and inflammatory factors levels were detected by ELISA. The expression levels of toll-like receptor 4 (TLR4), TNF receptor-associated factor 6 (TRAF6), myeloid differentiation factor 88 (MyD88), inhibitor of NF-κB alpha (IκΒα), p-IκΒα, and nuclear factor kappa-B (NF-κB)/p65 protein in liver tissue were measured by Western Blot. After 8 weeks' MLF treatment, the blood glucose of rats showed a downward trend; glycolipid metabolism level and insulin resistance were improved, which suggested that MLF could improve the disorder of glucose and lipid metabolism. The pathological damage and inflammation of the liver in T2DM rats were significantly improved, the levels of related serum inflammatory factors were reduced, and the expression of liver tissue-related proteins was downregulated. Our results indicated that MLF could reduce blood glucose and inhibit the development of liver inflammation. The mechanisms may be associated with the activation of TLR4/MyD88/NF-κB signal pathway to reduce the levels of inflammatory factors in serum.

Ferroptosis as a Novel Therapeutic Target for Diabetes and Its Complications

The global diabetes epidemic and its complications are increasing, thereby posing a major threat to public health. A comprehensive understanding of diabetes mellitus (DM) and its complications is necessary for the development of effective treatments. Ferroptosis is a newly identified form of programmed cell death caused by the production of reactive oxygen species and an imbalance in iron homeostasis. Increasing evidence suggests that ferroptosis plays a pivotal role in the pathogenesis of diabetes and diabetes-related complications. In this review, we summarize the potential impact and regulatory mechanisms of ferroptosis on diabetes and its complications, as well as inhibitors of ferroptosis in diabetes and diabetic complications. Therefore, understanding the regulatory mechanisms of ferroptosis and developing drugs or agents that target ferroptosis may provide new treatment strategies for patients with diabetes.

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.

Effects of mulberry leaf silage on antioxidant and immunomodulatory activity and rumen bacterial community of lambs

Background

Rumen is a natural fermentation system and the microorganisms inside can effectively utilize plant bioresource and interact with host metabolism. Here, analysis of rumen microbiome, together with animal performance and serum metabolism in a lamb model were performed to identify the potential use of mulberry leaf silage (MS) to replace alfalfa silage (AS) as a new functional feed resource and to mining the novel specific mulberry leaf associated rumen bacteria interact with host metabolism.

Results

The lambs fed with MS diet showed improved antioxidant capacity and immune function compared to those fed AS diet. The MS diet significantly altered rumen microbiota α- and β-diversity and taxonomic composition. Microbial analysis revealed that Bifidobacterium, Lactobacillus and Schwartzia were enhanced, and Ruminococcaceae UCG-010 and Lachnospiraceae_XPB1014_group were down-regulated in the rumen of MS group. A strong association was also found between these rumen microbial taxa and host antioxidant and immunomodulatory capacity.

Conclusion

These findings indicated that mulberry leaf silage can be a high-quality feed source or bioactive pharmaceutical that is responsible for ruminant’s health benefits. The modified rumen microbial community by mulberry leaf silage were associated with the enhanced antioxidant capacity and immunomodulatory of lambs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02311-1.

Anti-Obesity Effects of Morus alba L. and Aronia melanocarpa in a High-Fat Diet-Induced Obese C57BL/6J Mouse Model

The present study investigated the synergic effect of extracts of Morus alba (MA) and Aronia melanocarpa (Michx.) (AR) against high-fat diet induced obesity. Four-week-old male C57BL/6J mice were randomly divided into five groups that were fed for 14 weeks with a normal diet (ND), high-fat diet (HD), HD with M. alba 400 mg/kg body weight (MA), HD with A. melanocarpa 400 mg/kg body weight (AR), or HD with a mixture (1:1, v/v) of M. alba and A. melanocarpa (400 mg/kg) (MA + AR). Treatment with MA, AR, and MA + AR for 14 weeks reduced high fat diet-induced weight gain and improved serum lipid levels, and histological analysis revealed that MA and AR treatment markedly decreased lipid accumulation in the liver and adipocyte size in epididymal fat. Furthermore, micro-CT images showed MA + AR significantly reduced abdominal fat volume. Expression levels of genes involved in lipid anabolism, such as SREBP-1c, PPAR-γ, CEBPα, FAS, and CD36 were decreased by MA + AR treatment whereas PPAR-α, ACOX1, and CPT-1a levels were increased by MA + AR treatment. Protein expression of p-AMPK and p-ACC were increased in the MA + AR group, indicating that MA + AR ameliorated obesity by upregulating AMPK signaling. Together, our findings indicate that MA and AR exert a synergistic effect against diet-induced obesity and are promising agents for managing obesity.

Exosomes from mesenchymal stem cells expressing microribonucleic acid-125b inhibit the progression of diabetic nephropathy via the tumour necrosis factor receptor-associated factor 6/Akt axis

Diabetic nephropathy (DN) seriously threatens the health of patients with diabetes. Moreover, it has been reported that mesenchymal stem cell (MSC)-derived exosomal miRNAs can modulate the progression of multiple diseases, including DN. It has been suggested that miR-125b is involved in DN. However, the biological functions of exosomal miRNAs, especially miR-125b, in DN are still unclear. To establish a DN model in vitro, we used a model of human embryonic kidney epithelial cells (HKCs) injury induced by high glucose (HG). Then, miR-125b was delivered to the model cells in vitro via MSC-derived exosomes (MSC-Exos), and the effect of exosomal miR-125b on HKCs apoptosis was evaluated by flow cytometry. qRT-PCR or western blotting was performed to measure miR-125b or tumour necrosis factor receptor-associated factor 6 (TRAF6) expression in HKC. The effect of MSC-Exos on HKCs apoptosis after miR-125b knockdown was determined by flow cytometry. Moreover, dual-luciferase reporter assays were used to determine the targeting relationship between miR-125b and TRAF6 in HKCs. Our data revealed that MSC-Exos increased HG-induced autophagy in HKCs and reversed HKCs apoptosis. Moreover, our study found that miR-125b was enriched in MSC-Exos and directly targeted TRAF6 in HKCs. In addition, exosomally transferred miR-125b inhibited the apoptosis of HG-treated HKCs by mediating Akt signalling. In summary, MSC-derived exosomal miR-125b induced autophagy and inhibited apoptosis in HG-treated HKCs via the downregulation of TRAF6. Therefore, our study provided a new idea for DN treatment.

Mulberry leaf activates brown adipose tissue and induces browning of inguinal white adipose tissue in type 2 diabetic rats through regulating AMP-activated protein kinase signalling pathway

The current epidemic of type 2 diabetes mellitus (T2DM) significantly affects human health worldwide. Activation of brown adipocytes and browning of white adipocytes are considered as a promising molecular target for T2DM treatment. Mulberry leaf, a traditional Chinese medicine, has been demonstrated to have multi-biological activities, including anti-diabetic and anti-inflammatory effects. Our experimental results showed that mulberry leaf significantly alleviated the disorder of glucose and lipid metabolism in T2DM rats. In addition, mulberry leaf induced browning of inguinal white adipose tissue (IWAT) by enhancing the expressions of brown-mark genes as well as beige-specific genes, including uncoupling protein-1 (UCP1), peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), peroxisome proliferator-activated receptor alpha (PPARα), PRD1-BF-1-RIZ1 homologous domain containing protein 16 (PRDM16), cell death inducing DFFA-like effector A (Cidea), CD137 and transmembrane protein 26 (TMEM26). Mulberry leaf also activated brown adipose tissue (BAT) by increasing the expressions of brown-mark genes including UCP1, PGC-1α, PPARα, PRDM16 and Cidea. Moreover, mulberry leaf enhanced the expression of nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) genes that are responsible for mitochondrial biogenesis in IWAT and BAT. Importantly, mulberry leaf also increased the expression of UCP1 and carnitine palmitoyl transferase 1 (CPT-1) proteins in both IWAT and BAT via a mechanism involving AMP-activated protein kinase (AMPK) and PGC-1α pathway. In conclusion, our findings identify the role of mulberry leaf in inducing adipose browning, indicating that mulberry leaf may be used as a candidate browning agent for the treatment of T2DM.

Systematic Evaluation of the Mechanisms of Mulberry Leaf (Morus alba Linne) Acting on Diabetes Based on Network Pharmacology and Molecular Docking

BACKGROUND

Diabetes mellitus is one of the most common endocrine metabolic disorder- related diseases. The application of herbal medicine to control glucose levels and improve insulin action might be a useful approach in the treatment of diabetes. Mulberry leaves (ML) have been reported to exert important activities of anti-diabetic.

OBJECTIVE

In this work, we aimed to explore the multi-targets and multi-pathways regulatory molecular mechanism of Mulberry leaves (ML, Morus alba Linne) acting on diabetes.

METHODS

Identification of active compounds of Mulberry leaves using Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was carried out. Bioactive components were screened by FAF-Drugs4 website (Free ADME-Tox Filtering Tool). The targets of bioactive components were predicted from SwissTargetPrediction website, and the diabetes related targets were screened from GeneCards database. The common targets of ML and diabetes were used for Gene Ontology (GO) and pathway enrichment analysis. The visualization networks were constructed by Cytoscape 3.7.1 software. The biological networks were constructed to analyze the mechanisms as follows: (1) compound-target network; (2) common target-compound network; (3) common targets protein interaction network; (4) compound-diabetes protein-protein interactions (ppi) network; (5) target-pathway network; and (6) compound-target-pathway network. At last, the prediction results of network pharmacology were verified by molecular docking method.

RESULTS

17 active components were obtained by TCMSP database and FAF-Drugs4 website. 51 potential targets (11 common targets and 40 associated indirect targets) were obtained and used to build the PPI network by the String database. Furthermore, the potential targets were used for GO and pathway enrichment analysis. Eight key active compounds (quercetin, Iristectorigenin A, 4- Prenylresveratrol, Moracin H, Moracin C, Isoramanone, Moracin E and Moracin D) and 8 key targets (AKT1, IGF1R, EIF2AK3, PPARG, AGTR1, PPARA, PTPN1 and PIK3R1) were obtained to play major roles in Mulberry leaf acting on diabetes. And the signal pathways involved in the mechanisms mainly include AMPK signaling pathway, PI3K-Akt signaling pathway, mTOR signaling pathway, insulin signaling pathway and insulin resistance. The molecular docking results show that the 8 key active compounds have good affinity with the key target of AKT1, and the 5 key targets (IGF1R, EIF2AK3, PPARG, PPARA and PTPN1) have better affinity than AKT1 with the key compound of quercetin.

CONCLUSION

Based on network pharmacology and molecular docking, this study provided an important systematic and visualized basis for further understanding of the synergy mechanism of ML acting on diabetes.

Potential probiotics Lactobacillus casei K11 combined with plant extracts reduce markers of type 2 diabetes mellitus in mice

AIMS

Probiotics and plant extracts have been used to prevent the development of type 2 diabetes mellitus (T2DM). The study aimed to explore the effect of the interaction between potential probiotics and bitter gourd extract (BGE) or mulberry leaf extract (MLE) on T2DM.

METHODS AND RESULTS

Potential probiotics were tested for their gastrointestinal tract viability and growth situation combined with BGE and MLE in vitro. The diabetes model was constructed in C57BL/6 mice, and the potential effect and mechanism of regulating blood glucose were verified. Hematoxylin-eosin staining (HE), gas chromatography (GC), ELISA, and RT-PCR were also used for analysis. The results showed that Lactobacillus casei K11 had outstanding gastrointestinal tract viability and growth situation with plant extracts. Administration of L. casei K11 combined with BGE and MLE significantly reduced blood glucose levels and ameliorated insulin resistance in diabetic mice than the administration of Lactobacillus paracasei J5 combined with BGE and MLE. Moreover, in L. casei K11 combined with BGE and MLE groups, lipid metabolism, oxidative stress, and proinflammatory cytokine levels were regulated. Furthermore, the results indicated that L. casei K11 combined with BGE and MLE improved free fatty acid receptor 2 (FFAR2) upregulation, glucagon-like peptide-1 (GLP-1) secretion, and short-chain fatty acid (SCFA) levels.

CONCLUSIONS

These findings showed that L. casei K11 combined with BGE and MLE modified the SCFA-FFAR2-GLP-1 pathway to improve T2DM.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study identified a new modality for evaluating interactions between potential probiotics and plant extracts. Our findings revealed that L. casei K11 combined with BGE and MLE significantly promoted the SCFA-FFAR2-GLP-1 pathway to inhibit T2DM.

Plant Extracts for Type 2 Diabetes: From Traditional Medicine to Modern Drug Discovery

Type 2 diabetes mellitus (T2DM) is one of the largest public health problems worldwide. Insulin resistance-related metabolic dysfunction and chronic hyperglycemia result in devastating complications and poor prognosis. Even though there are many conventional drugs such as metformin (MET), Thiazolidinediones (TZDs), sulfonylureas (SUF), dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon like peptide 1 (GLP-1) and sodium-glucose cotransporter-2 (SGLT-2) inhibitors, side effects still exist. As numerous plant extracts with antidiabetic effects have been widely reported, they have the potential to be a great therapeutic agent for type 2 diabetes with less side effects. In this study, sixty-five recent studies regarding plant extracts that alleviate type 2 diabetes were reviewed. Plant extracts regulated blood glucose through the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway. The anti-inflammatory and antioxidant properties of plant extracts suppressed c-Jun amino terminal kinase (JNK) and nuclear factor kappa B (NF-κB) pathways, which induce insulin resistance. Lipogenesis and fatty acid oxidation, which are also associated with insulin resistance, are regulated by AMP-activated protein kinase (AMPK) activation. This review focuses on discovering plant extracts that alleviate type 2 diabetes and exploring its therapeutic mechanisms.

Inhibition of proliferation and migration and induction of apoptosis in glioma cells by silencing TLR4 expression levels via RNA interference

The objective of the present study was to investigate the expression levels of toll-like receptor 4 (TLR4) in glioma cells and the mechanisms underlying its regulatory effects on proliferation, migration and apoptosis of glioma cells. A total of three TLR4 silencing short hairpin (sh)RNA plasmids were established, and Lipofectamine^® was used to the transfect the human glioma cell line U-87MG. Transfection efficiency was measured via flow cytometry. The interference plasmid exhibiting the largest silencing effect on TLR4 was screened for subsequent experiments using puromycin. Reverse transcription-quantitative PCR and western blot analysis were used to detect the TLR4 gene and protein expression levels, respectively, in stably transfected cells. Flow cytometry measured cell cycle and apoptosis and a wound healing assay was employed to assess the migration ability of transfected cells. The proliferation of transfected cells was detected using Cell Counting Kit-8 assay. TLR4-sh2 exhibited the highest transfection efficiency. Following transfection of U-87MG cells with TLR4-sh2 and negative control (NC) plasmids for 48 h and screening by puromycin, stable transfected cells were named U-87MG-Sh and U-87MG-NC cells respectively. The TLR4 gene and protein expression levels in the U-87MG-Sh cells were significantly lower than in U-87MG and U-87MG-NC cells. The apoptosis rate and the percentage of G_0/1 cells were significantly higher, whereas the cell proliferation rate was notably lower, in U-87MG-Sh cells than in the U-87MG-NC and U-87MG cells. The proliferation rate and the cell migration ability of U-87MG-Sh cells were significantly lower than those of U-87MG-NC and U-87MG cells. TLR4 is associated with the proliferation of glioma cells. Inhibition of TLR4 expression levels significantly inhibited proliferation of glioma cells and induced apoptosis. The present study provided insights into the mechanisms associated with the development, progression and invasion ability of glioma cells.

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.

The Protective Effects of Cryptochlorogenic Acid on β-Cells Function in Diabetes in vivo and vitro via Inhibition of Ferroptosis

PURPOSE

Mulberry leaf extract has exerted better antidiabetic activities, while the effects of major active components in mulberry leaf extract are still unclear. Cryptochlorogenic acid (CCA) as the major active component in mulberry leaf extracts was investigated herein.

MATERIALS AND METHODS

Rats were treated with 50mg/kg streptozotocin for the establishment of diabetic model in vivo, and cells were treated with 33.3 mM glucose for the establishment of cell model in vitro. HE staining assay was performed for observation of pancreatic pathology and aldehyde fuchsin staining assay for examining islet cell numbers. The iron content was detected via Perls staining assay with iron assay kit (ab83366). The malondialdehyde (MDA), glutathione (GSH) and oxidized glutathione (GSSG) were detected by corresponding kits. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed for assessment of gene level and Western blot for measurement of protein expression level. The cell survival was detected via CCK-8 assay.

RESULTS

The blood glucose level, iron content, accumulation of lipid peroxides and islet injury in diabetic model were all improved by CCA via a concentration-dependent manner. CCA functions via inhibition of ferroptosis by activation of cystine/glutamate transporter system (XC^-)/glutathione peroxidase 4(GPX4)/Nrf2 and inhibition of nuclear receptor coactivator 4 (NCOA4) in diabetes.

CONCLUSION

CCA exerted excellent antidiabetic effects via inhibition of ferroptosis, so it may be a promising agent for diabetes therapy, providing a new avenue for diabetes treatment.