Kaempferol antagonizes adipogenesis by repressing histone H3K4 methylation at PPARγ target genes

A narrative review on the mechanism of natural flavonoids in improving glucolipid metabolism disorders

Glucolipid metabolism disorder (GLMD) is a complex chronic disease characterized by glucose and lipid metabolism disorders with a complex and diverse etiology and rapidly increasing incidence. Many studies have identified the role of flavonoids in ameliorating GLMD, with mechanisms related to peroxisome proliferator-activated receptors, nuclear factor kappa-B, AMP-activated protein kinase, nuclear factor (erythroid-derived 2)-like 2, glucose transporter type 4, and phosphatidylinositol-3-kinase/protein kinase B pathway. However, a comprehensive summary of the flavonoid effects on GLMD is lacking. This study reviewed the roles and mechanisms of natural flavonoids with different structures in the treatment of GLMD reported globally in the past 5 years and provides a reference for developing flavonoids as drugs for treating GLMD.

Bioactive alkaloidal and phenolic phytochemicals as promising epidrugs for diabetes mellitus 2: A review of recent development

Type 2 diabetes (T2D) remains a major chronic metabolic disorder affecting hundreds of millions of the global population, mostly among adults, engendering high rates of morbidity and mortality. It is characterized by complex aetiologies including insulin deficiency and resistance, and hyperglycemia, and these significantly constitute therapeutic challenges. Several pathways have been implicated in its pathophysiology and treatment including the epigenetic regulatory mechanism, notably, deoxyribonucleic acid (DNA) methylation/demethylation, histone modification, non-coding ribonucleic acid (ncRNA) modulation and other relevant pathways. Many studies have recently documented the implications of phytochemicals on the aforementioned biomarkers in the pathogenesis and treatment of T2D. In this review, the cellular and molecular mechanisms of the epigenetic effects of some bioactive alkaloidal and phenolic phytochemicals as potential therapeutic alternatives for T2D have been overviewed from the recent literature (2019-2024). From the survey, the natural product-based compounds, C1-C32 were curated as potent epigenetic modulators for T2D. Their cellular and molecular mechanisms of anti-T2D activities with relevant epigenetic biomarkers were revealed. Although, more comprehensive experimental analyses are observably required for validating their activity and toxicological indices. Thus, perspectives and challenges were enumerated for such demanding future translational studies. The review reveals advances in scientific efforts towards reversing the global trend of T2D through epigenetic phytotherapeutics.

Anti-obesity Properties of Phytochemicals: Highlighting their Molecular Mechanisms against Obesity

Obesity is a complex, chronic and inflammatory disease that affects more than one-third of the world's population, leading to a higher incidence of diabetes, dyslipidemia, metabolic syndrome, cardiovascular diseases, and some types of cancer. Several phytochemicals are used as flavoring and aromatic compounds, also exerting many benefits for public health. This study aims to summarize and scrutinize the beneficial effects of the most important phytochemicals against obesity. Systematic research of the current international literature was carried out in the most accurate scientific databases, e.g., Pubmed, Scopus, Web of Science and Google Scholar, using a set of critical and representative keywords, such as phytochemicals, obesity, metabolism, metabolic syndrome, etc. Several studies unraveled the potential positive effects of phytochemicals such as berberine, carvacrol, curcumin, quercetin, resveratrol, thymol, etc., against obesity and metabolic disorders. Mechanisms of action include inhibition of adipocyte differentiation, browning of the white adipose tissue, inhibition of enzymes such as lipase and amylase, suppression of inflammation, improvement of the gut microbiota, and downregulation of obesity-inducing genes. In conclusion, multiple bioactive compounds-phytochemicals exert many beneficial effects against obesity. Future molecular and clinical studies must be performed to unravel the multiple molecular mechanisms and anti-obesity activities of these naturally occurring bioactive compounds.

Kaempferol: A Review of Current Evidence of Its Antiviral Potential

Kaempferol and its derivatives are flavonoids found in various plants, and a considerable number of these have been used in various medical applications worldwide. Kaempferol and its compounds have well-known antioxidant, anti-inflammatory and antimicrobial properties among other health benefits. However, the antiviral properties of kaempferol are notable, and there is a significant number of experimental studies on this topic. Kaempferol compounds were effective against DNA viruses such as hepatitis B virus, viruses of the alphaherpesvirinae family, African swine fever virus, and pseudorabies virus; they were also effective against RNA viruses, namely feline SARS coronavirus, dengue fever virus, Japanese encephalitis virus, influenza virus, enterovirus 71, poliovirus, respiratory syncytial virus, human immunodeficiency virus, calicivirus, and chikungunya virus. On the other hand, no effectiveness against murine norovirus and hepatitis A virus could be determined. The antiviral action mechanisms of kaempferol compounds are various, such as the inhibition of viral polymerases and of viral attachment and entry into host cells. Future research should be focused on further elucidating the antiviral properties of kaempferol compounds from different plants and assessing their potential use to complement the action of antiviral drugs.

Native-compound-Coupled Affinity Matrix (NCAM) in target identification and validation of bioactive compounds: Application, mechanism and outlooks

In drug discovery and development, the direct target identification of bioactive small molecules plays a significant role for understanding the mechanism of action, predicting the side effects, and rationally designing more potent compounds. However, due to the complicated regulatory processes in a cell together with thousands of biomacromolecules, target identification is always the major obstacle. New methods and technologies are continuously invented to tackle this problem. Nevertheless, the mainly used tools possess several disadvantages. High synthetic skills are typically required to laboriously synthesize a probe for protein enrichment. To detect the ligand-protein interaction by analyzing proteins' responses to proteolytic or thermal treatment, costly and precise instruments are always necessary. Therefore, convenient and practical techniques are urgently needed. Over the past decades, a strategy using native compounds without the requirement of chemical modification, also termed Native-compound-Coupled Affinity Matrix (NCAM), is developing continuously. Two practical tactics based on "label-free" compounds have been invented and used, that is Photo-cross-linked Small-molecule Affinity Matrix (PSAM) and Native-compound-Coupled CNBr-activated Beads (NCCB). Presently, we will elucidate the characteristics, coupling mechanism, advantages and disadvantages, and future prospect of NCAM in specific target identification and validation.

Epigenetic effects of herbal medicine

Epigenetic memory is essential for life that governs the predefined functional features of cells. Recent evidence has indicated that the epigenetic modification provides a potential link to gene expression changes that may be involved in the development of various chronic diseases, and targeting the epigenome becomes a plausible method for treating diseases. Traditional herbal medicine has gradually entered the vision of researchers due to its low toxicity and its effectiveness in treating diseases. As a matter of fact, researchers found that the possessed epigenetic modification capacity of herbal medicine had the ability to combat the progression of the disease, such as various types of cancer, diabetes, inflammation, amnesia, liver fibrosis, asthma, and hypertension-induced renal injury. Studies on the epigenetic effects of herbal medicine will provide valuable insights into the molecular mechanisms of human diseases, which may lead to new therapeutic approaches and diagnoses. Thus, this review summarized the impact of herbal medicine and its bioactive components on disease epigenome as examples of how utilization of epigenetic plasticity could be useful as the basis for the future development of targeted therapies in chronic diseases.

Mulberry extract ameliorates T2DM-related symptoms via AMPK pathway in STZ-HFD-induced C57BL/6J mice

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry (Morus alba L.) is not only a tasty food but also a beneficial medicinal substance that has been historically used to treat diabetes, as recorded in Tang Ben Cao. Recent research on animal models has shown that the ethyl acetate extract of Morus alba L. fruits (EMF) has hypoglycemic and hypolipidemic properties. However, there is a lack of documentation on the specific mechanisms through which EMF exerts its hypoglycemic effects.

OBJECTIVE OF THE STUDY

This study aimed to investigate the impact of EMF on L6 cells and C57/BL6J mice and to elucidate the potential mechanisms underlying its effects. The findings of this study can contribute to the existing evidence for the application of EMF as a therapeutic drug or dietary supplement in the management of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

The UPLC-Q-TOF-MS technique was utilized to gather MS data. Masslynx 4.1 software in conjunction with the SciFinder database and other relevant references were used to analyze and identify the chemical composition of EMF. A series of in vitro investigations including MTT assay, glucose uptake assay and Western blot analysis were performed using an L6 cell model stably expressing IRAP-mOrange after EMF treatment. In vivo investigations were performed on a STZ-HFD co-induced T2DM mouse model, which included assessments of body composition, biochemical tests, histopathological analysis, and Western blot analysis.

RESULTS

MTT results revealed that EMF had no toxic effects on the cells at various concentrations. When EMF was administered to L6 cells, there was an increase in glucose transporter type 4 (GLUT4) translocation activity and a significant dose-dependent enhancement of glucose uptake by L6 myotubes. EMF treatment led to a marked increase in P-AMPK levels and GLUT4 expression in the cells, but these effects were reversed by an AMPK inhibitor (Compound C). In diabetic mice with STZ-HFD-induced diabetes, EMF treatment improved oral glucose tolerance, hyperglycemia, and hyperinsulinemia. Furthermore, EMF supplementation significantly reduced insulin resistance (IR) in diabetic mice, as evaluated using a steady-state model of the insulin resistance index. Histopathological sections demonstrated that acute EMF treatment reduced hepatic steatosis, pancreatic damage, and adipocyte hypertrophy. Western blot analysis demonstrated that EMF treatment also reduced abnormally high PPARγ expression, elevated the level of p-AMPK and p-ACC, and augmented the abundance of GLUT4 in insulin-sensitive peripheral tissues.

SUMMARY

The results suggest that EMF may exert beneficial effects on T2DM through the AMPK/GLUT4 and AMPK/ACC pathways, as well as by regulating PPARγ expression.

Shikonin Binds and Represses PPARγ Activity by Releasing Coactivators and Modulating Histone Methylation Codes

Shikonin, a natural ingredient produced by Lithospermum erythrorhizon, has anti-inflammatory, anti-cancer, and anti-obesity effects. It also inhibits adipocyte differentiation; however, the underlying molecular and epigenetic mechanisms remain unclear. We performed RNA-sequencing of shikonin-treated 3T3-L1 cells. Gene ontology and gene set enrichment analysis showed that shikonin is significantly associated with genes related to adipogenesis, histone modification, and PPARγ. Shikonin treatment downregulated the mRNA expression of PPARγ-responsive genes and rosiglitazone-induced transcriptional activity of PPARγ. Microscale thermophoresis assays showed a KD value 1.4 ± 0.13 μM for binding between shikonin and PPARγ. Glutathione S-transferase pull-down assays exhibited that shikonin blocked the rosiglitazone-dependent association of PPARγ with its coactivator CBP. In addition, shikonin decreased the enrichment of the active histone code H3K4me3 and increased the repressive code H3K27me3 of PPARγ target promoters. Shikonin is a PPARγ antagonist that suppresses adipogenesis by regulating the enrichment of histone codes during adipogenesis. Therefore, it may be used to treat obesity-related disorders via epigenetic changes.

Targeting epigenetics in diabetic cardiomyopathy: Therapeutic potential of flavonoids

The pathophysiological mechanisms of diabetic cardiomyopathy have been extensively studied, but there is still a lack of effective prevention and treatment methods. The ability of flavonoids to protect the heart from diabetic cardiomyopathy has been extensively described. In recent years, epigenetics has received increasing attention from scholars in exploring the etiology and treatment of diabetes and its complications. DNA methylation, histone modifications and non-coding RNAs play key functions in the development, maintenance and progression of diabetic cardiomyopathy. Hence, prevention or reversal of the epigenetic alterations that have occurred during the development of diabetic cardiomyopathy may alleviate the personal and social burden of the disease. Flavonoids can be used as natural epigenetic modulators in alternative therapies for diabetic cardiomyopathy. In this review, we discuss the epigenetic effects of different flavonoid subtypes in diabetic cardiomyopathy and summarize the evidence from preclinical and clinical studies that already exist. However, limited research is available on the potential beneficial effects of flavonoids on the epigenetics of diabetic cardiomyopathy. In the future, clinical trials in which different flavonoids exert their antidiabetic and cardioprotective effects through various epigenetic mechanisms should be further explored.

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.