The effects of naringenin and naringin on the glucose uptake and AMPK phosphorylation in high glucose treated HepG2 cells

From waste to wonder: exploring the hypoglycemic and anti-oxidant properties of corn processing by-products

Introduction: The industrial processing of corn (Zeamays L.) generates by-products such as corn silk, straw peels, and straw core, which contribute to adverse environmental impacts. Our study aimed to investigate sustainable approaches for mitigating these effects by evaluating the hypoglycemic potential and mechanisms of ethyl acetate fractions derived from these corn derivatives. Methods: We employed glucose consumption assays, high glucose stress tests, UPLC-QE-Orbitrap-MS analysis, molecular docking, and simulations to assess their components and efficacy. Antioxidant capacities were evaluated using DPPH, FRAP, ABTS, and •OH scavenging assays. Results: Notably, the ethyl acetate fraction extracted from straw peels (SPE) exhibited a high concentration of flavonoids and phenolic compounds along with pronounced hypoglycemic activity and antioxidant capacity. SPE significantly enhanced glucose consumption in insulin-resistant HepG2 cells while protecting HUVECs against damage caused by high glucose levels. Molecular docking analyses confirmed the interaction between active compounds and α-glucosidase as well as α-amylase, while molecular dynamic simulations indicated stability at their binding sites. Discussion: In conclusion, the hypoglycemic and antioxidative properties observed in corn by-products such as straw peels, corn silk, and straw core can be attributed to the inhibition of α-glucosidase and α-amylase activities, coupled with their rich phenolic and flavonoid content. These findings highlight the potential of these by-products for applications in healthcare management and their sustainable utilization, demonstrating significant value in the use of agricultural residues.

Hypoglycemic and hypolipidemic effects of Lippia origanoides Kunth in diabetic rats

Diabetes mellitus is a metabolic disorder commonly associated with atherosclerosis. Plants with therapeutic potential, such as Lippia origanoides Kunth, emerge as effective alternatives for treating these diseases. Therefore, this work aims to analyze the antihyperglycemic and antidyslipidemic potential of the hydroalcoholic extract of Lippia origanoides Kunth (ELo) in alloxan-diabetic rats. Animals were treated orally: normal control, hyperglycemic control, positive control glibenclamide (5 mg/kg), and groups treated with ELo (75, 150, and 250 mg/kg). Preclinical evaluation of ELo showed hypoglycemic, hypolipidemic, hepatic, and renal protective effects. At all doses, ELo significantly reduced hyperglycemia, triglycerides, total cholesterol, low-density lipoprotein, atherogenic index, atherogenic coefficient, and cardiovascular risk index (p < .05). Elo at different doses promoted an increase in insulin release compared to untreated animals (p < .05) and showed α-glucosidase inhibitory activity (p < .05). Also, ELo (250 mg/kg group) showed maximum reduction of hyperglycemia, alanine transaminase, aspartate aminotransferase, malonaldehyde, and urea compared to the hyperglycemic and glibenclamide groups, and creatinine only compared to the hyperglycemic groups (p < .05). The promising action of ELo in the context of diabetes may be related to the synergistic action of flavonoid compounds identified in liquid chromatography, whose pharmacological capabilities have already been documented in previous studies. The mechanisms may be the stimulation of insulin release; the inhibitory activity of α-glucosidase; improving general clinical conditions; and the antioxidant effects of the extract. These findings pave the way for the future development of an herbal presentation of L. origanoides Kunth as a hypoglycemic and cardiovascular protector with a lipid-lowering effect.

Naringenin enhances the efficacy of ferroptosis inducers by attenuating aerobic glycolysis by activating the AMPK-PGC1α signalling axis in liver cancer

Liver cancer is a heterogeneous disease characterized by poor responses to standard therapies and therefore unfavourable clinical outcomes. Understanding the characteristics of liver cancer and developing novel therapeutic strategies are imperative. Ferroptosis, a type of programmed cell death induced by lipid peroxidation, has emerged as a potential target for treatment. Naringenin, a natural compound that modulates lipid metabolism by targeting AMPK, shows promise in enhancing the efficacy of ferroptosis inducers. In this study, we utilized liver cancer cell lines and xenograft mice to explore the synergistic effects of naringenin in combination with ferroptosis inducers, examining both phenotypic outcomes and molecular mechanisms. Our study results indicate that the use of naringenin at non-toxic doses to hepatocytes can significantly enhance the anticancer effects of ferroptosis inducers (erastin, RSL3, and sorafenib). The combination index method confirmed a synergistic effect between naringenin and ferroptosis inducers. In comparison to naringenin or ferroptosis inducers alone, the combined therapy caused more robust lipid peroxidation and hence more severe ferroptotic damage to cancer cells. The inhibition of aerobic glycolysis mediated by the AMPK-PGC1α signalling axis is the key to naringenin's effect on reducing ferroptosis resistance in liver cancer, and the synergistic cytotoxic effect of naringenin and ferroptosis inducers on cancer cells was reversed after pretreatment with an AMPK inhibitor or a PGC1α inhibitor. Taken together, these findings suggest that naringenin could boost cancer cell sensitivity to ferroptosis inducers, which has potential clinical translational value.

Clinical applications and mechanism insights of natural flavonoids against type 2 diabetes mellitus

Diabetes is a complex disease that affects a large percentage of the world's population, and it is associated with several risk factors. Self-management poses a significant challenge, but natural sources have shown great potential in providing effective glucose reducing solutions. Flavonoids, a class of bioactive substances found in different natural sources including medicinal plants, have emerged as promising candidates in this regard. Indeed, several flavonoids, including apigenin, arbutin, catechins, and cyanidin, have demonstrated remarkable anti-diabetic properties. The clinical effectiveness of these flavonoids is linked to their potential to decrease blood glucose concentration and increase insulin concentration. Thus, the regulation of certain metabolic pathways such as glycolysis and neoglycogenesis has also been demonstrated. In vitro and in vivo investigations revealed different mechanisms of action related to flavonoid compounds at subcellular, cellular, and molecular levels. The main actions reside in the activation of glycolytic signaling pathways and the inhibition of signaling that promotes glucose synthesis and storage. In this review, we highlight the clinical efficiency of natural flavonoids as well as the molecular mechanisms underlying this effectiveness.

Oxidative stress signaling in the pathogenesis of diabetic cardiomyopathy and the potential therapeutic role of antioxidant naringenin

Diabetes mellitus (DM) is one of the most prevalent metabolic disorders that poses a global threat to human health. It can lead to complications in multiple organs and tissues, owing to its wide-ranging impact on the human body. Diabetic cardiomyopathy (DCM) is a specific cardiac manifestation of DM, which is characterized by heart failure in the absence of coronary heart disease, hypertension and valvular heart disease. Given that oxidative stress is a key factor in the pathogenesis of DCM, intervening to mitigate oxidative stress may serve as a therapeutic strategy for managing DCM. Naringenin is a natural product with anti-oxidative stress properties that can suppress oxidative damage by regulating various oxidative stress signaling pathways. In this review, we address the relationship between oxidative stress and its primary signaling pathways implicated in DCM, and explores the therapeutic potential of naringenin in DCM.

Antiadipogenic Effect of Citrus Flavonoids: Evidence from RNA Sequencing Analysis and Activation of AMPK in 3T3-L1 Adipocytes

Citrus fruits are rich in dietary flavonoids and have many health benefits, but their antiadipogenic mechanism of action and their impact on lipid metabolism remain unclear. In this study, we investigated the effect of citrus flavonoids, namely, hesperidin (HES), narirutin (NAR), nobiletin (NOB), sinensetin (SIN), and tangeretin (TAN), on preventing fat cell development by gene expression in 3T3-L1 adipocytes. Among the citrus flavonoids tested, HES and NAR significantly reduced fat storage and triglyceride levels and increased glucose uptake in 3T3-L1 adipocytes. Additionally, HES and NAR treatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) while reducing the protein expression of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). Furthermore, in silico docking revealed that flavonoids activate AMPK. RNA sequencing analysis demonstrated that citrus flavonoids normalized the expression of 40 genes, which were either upregulated by more than 2-fold or downregulated by less than 0.6-fold including Acadv1, Acly, Akr1d1, Awat1, Cyp27a1, Decr1, Dhrs4, Elovl3, Fasn, G6pc, Gba, Hmgcs1, Mogat2, Lrp5, Sptlc3, and Snca to levels comparable to the control group. Altogether, HES and NAR among five citrus flavonoids showed antiadipogenic effects by regulating the expression of specific lipid metabolism genes partially restored to control levels in 3T3-L1 cells.

Effect of Citrus bergamia extract on lipid profile: A combined in vitro and human study

With the aim of characterising the hypo-lipidemic function of the Brumex™ ingredient obtained from the whole fruit of Citrus bergamia, a combined pre-clinical and clinical study was conducted. In the HepG2 experimental model, we first demonstrated that Brumex™ does not trigger any significant alteration in cell viability over the tested concentration range of 1-2000 μg/mL (4 and 24 h). By stimulating the phosphorylation of AMP-activated protein kinase (AMPK) at threonine 172, Brumex™ significantly reduces both cholesterol and triglyceride (TG) intracellular content of HepG2 cells and impairs the expression levels of lipid synthesis-related genes (namely, SREBF1c, SREBF2, ACACA, SCD1, HMGCR and FASN). In vitro data have been validated in a dedicated double-blind, placebo-controlled, randomised clinical trial performed in 50 healthy moderately hyper-cholesterolemic subjects, undergoing supplementation with either Brumex™ (400 mg) or placebo for 12 weeks. Clinical and blood laboratory data were evaluated at the baseline and at the end of the trial. Brumex™ positively impacted on both plasma lipid pattern and liver enzymes compared with the placebo, mainly in terms of significant reduction of total cholesterol (TC), TG, low-density lipoprotein-cholesterol (LDL-C), non-high-density lipoprotein-cholesterol (non-HDL-C), apolipoprotein B100 (ApoB), fasting plasma glucose (FPG), glutamic-oxaloacetic transaminase (GOT), glutamate pyruvate transaminase (GPT) and gamma-glutamyl-transferase (gGT).

Biological Activities and Solubilization Methodologies of Naringin

Naringin (NG), a natural flavanone glycoside, possesses a multitude of pharmacological properties, encompassing anti-inflammatory, sedative, antioxidant, anticancer, anti-osteoporosis, and lipid-lowering functions, and serves as a facilitator for the absorption of other drugs. Despite these powerful qualities, NG's limited solubility and bioavailability primarily undermine its therapeutic potential. Consequently, innovative solubilization methodologies have received considerable attention, propelling a surge of scholarly investigation in this arena. Among the most promising solutions is the enhancement of NG's solubility and physiological activity without compromising its inherent active structure, therefore enabling the formulation of non-toxic and benign human body preparations. This article delivers a comprehensive overview of NG and its physiological activities, particularly emphasizing the impacts of structural modification, solid dispersions (SDs), inclusion compound, polymeric micelle, liposomes, and nanoparticles on NG solubilization. By synthesizing current research, this research elucidates the bioavailability of NG, broadens its clinical applicability, and paves the way for further exploration and expansion of its application spectrum.

The protective roles of citrus flavonoids, naringenin, and naringin on endothelial cell dysfunction in diseases

The endothelial cells (ECs) make up the inner lining of blood vessels, acting as a barrier separating the blood and the tissues in several organs. ECs maintain endothelium integrity by controlling the constriction and relaxation of the vasculature, blood fluidity, adhesion, and migration. These actions of ECs are efficiently coordinated via an intricate signaling network connecting receptors, and a wide range of cellular macromolecules. ECs are naturally quiescent i.e.; they are not stimulated and do not proliferate. Upon infection or disease, ECs become activated, and this alteration is pivotal in the pathogenesis of a spectrum of human neurological, cardiovascular, diabetic, cancerous, and viral diseases. Considering the central position that ECs play in disease pathogenesis, therapeutic options have been targeted at improving ECs integrity, assembly, functioning, and health. The dietary intake of flavonoids present in citrus fruits has been associated with a reduced risk of endothelium dysfunction. Naringenin (NGN) and Naringin (NAR), major flavonoids in grapefruit, tomatoes, and oranges possess anti-inflammatory, antioxidant properties, and cell survival potentials, which improve the health of the vascular endothelium. In this review, we provide a comprehensive summary and present the advances in understanding of the mechanisms through which NGN and NAR modulate the biomarkers of vascular dysfunction and protect the endothelium against unresolved inflammation, oxidative stress, atherosclerosis, and angiogenesis. We also provide perspectives and suggest further studies that will help assess the efficacy of citrus flavonoids in the therapeutics of human vascular diseases.

The Emerging Importance of Cirsimaritin in Type 2 Diabetes Treatment

Cirsimaritin is a dimethoxy flavon that has different biological activities such as antiproliferative, antimicrobial, and antioxidant activities. This study aims to investigate the anti-diabetic effects of cirsimaritin in a high-fat diet and streptozotocin-(HFD/STZ)-induced rat model of type 2 diabetes mellitus (T2D). Rats were fed HFD, followed by a single low dose of STZ (40 mg/kg). HFD/STZ diabetic rats were treated orally with cirsimaritin (50 mg/kg) or metformin (200 mg/kg) for 10 days before terminating the experiment and collecting plasma, soleus muscle, adipose tissue, and liver for further downstream analysis. Cirsimaritin reduced the elevated levels of serum glucose in diabetic rats compared to the vehicle control group (p < 0.001). Cirsimaritin abrogated the increase in serum insulin in the treated diabetic group compared to the vehicle control rats (p < 0.01). The homeostasis model assessment of insulin resistance (HOMA-IR) was decreased in the diabetic rats treated with cirsimaritin compared to the vehicle controls. The skeletal muscle and adipose tissue protein contents of GLUT4 (p < 0.01 and p < 0.05, respectively) and pAMPK-α1 (p < 0.05) were upregulated following treatment with cirsimaritin. Cirsimaritin was able to upregulate GLUT2 and AMPK protein expression in the liver (p < 0.01, <0.05, respectively). LDL, triglyceride, and cholesterol were reduced in diabetic rats treated with cirsimaritin compared to the vehicle controls (p < 0.001). Cirsimaritin reduced MDA, and IL-6 levels (p < 0.001), increased GSH levels (p < 0.001), and reduced GSSG levels (p < 0.001) in diabetic rats compared to the vehicle control. Cirsimaritin could represent a promising therapeutic agent to treat T2D.

Puerarin Suppresses Glycolysis and Increases Cisplatin Chemosensitivity in Oral Squamous Cell Carcinoma via FBXW7/mTOR Signaling

This study aimed to observe the effects of puerarin on glycolysis and cisplatin sensitivity in oral squamous cell carcinoma (oSCC) cells and to explore the underlying mechanisms. CAL27 cells over- or under-expressing FBXW7 were treated with cisplatin or puerarin, and the levels of proteins involved in glycolysis as well as the activity of the respective enzymes were assessed. Glucose uptake and lactate production were also evaluated, and the IC50 value of cisplatin in CAL27 cells was determined. FBXW7 overexpression significantly downregulated HK2, PKM2, and LDH; suppressed the activity of the corresponding enzymes hexokinase, pyruvate kinase, and lactate dehydrogenase; as well as reduced glucose uptake and lactate production. FBXW7 overexpression was also associated with decreased mTOR phosphorylation and increased cisplatin sensitivity. These effects were partially antagonized by lactate or the mTOR agonist MHY1485. Puerarin suppressed glycolysis by reducing glucose uptake and lactate production, while it promoted cisplatin sensitivity and activated the FBXW7/mTOR signal pathway in a concentration-dependent manner. These effects were antagonized by FBXW7 downregulation or treatment with MHY1485. Our results suggest that FBXW7 improves cisplatin chemosensitivity and suppresses glycolysis in oSCC cells, indicating its promising potential as a target for puerarin to regulate the cisplatin sensitivity of oSCC cells.