Hypoglycemic bioactivity of anthocyanins: A review on proposed targets and potential signaling pathways

Acylated anthocyanins from Dendrobium officinale Kimura & Migo: Structural characteristics, antioxidant and hypoglycemic activities

Dendrobium officinale Kimura & Migo (D. officinale) has been widely used as Chinese medicine and functional food. In present study, the structural characteristics of anthocyanins in D. officinale were investigated by ultra-performance liquid chromatography with diode array detector (UPLC-DAD) and ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS/MS). Totally, 14 anthocyanins were detected and identified, and 13 of them were first reported in D. officinale. Results showed that the vast majority of anthocyanins had multi-glycosylated cyanidin core, with variable acylation pattern mainly comprising phenolic acids. The composition and content of anthocyanins in D. officinale stems with different cultivation modes and years have been compared. The anthocyanins showed potent antioxidant activity in terms of radicals scavenging capacity and reducing power, as well as superior α-amylase and α-glucosidase inhibitory activity. The results provided a complete profile of anthocyanins in D. officinale and laid a foundation for further utilizing them as functional foods.

Non-aggregated and water soluble non-peripherally octa substituted Co(II) and Cu(II) phthalocyanines: Synthesis and α-glucosidase inhibitory effects

Type 2 diabetes (T2DM) is a progressive metabolic disease associated with high blood sugar levels that affects 537 million people worldwide. This study aim is to investigate the potential for use in the treatment of T2DM by examining the in vitro glucosidase inhibitory effects of novel synthesized metallophthalocyanines. For this reason, we have synthesized cobalt(II), copper(II) phthalocyanines (3PY-ON-CoQ, 3PY-ON-CuQ) that are both water-soluble and do not aggregate in water. These compounds were characterized by using various spectroscopic methods. The α-glucosidase inhibitory properties of 3PY-ON-CoQ and 3PY-ON-CuQ were carried out using the spectrophotometric method. Then, Lineweaver-Burk and Dixon plots were examined to determine the inhibitory type and constant (Ki). The IC50 values of 3PY-ON-CoQ and 3PY-ON-CuQ were 6.85 ± 1.25 μM and 55.09 ± 2.64 μM, respectively. Both compounds displayed mixed inhibitory effects on α-glucosidase according to Lineweaver-Burk plots. The Ki values of 3PY-ON-CoQ and 3PY-ON-CuQ were calculated as 6.30 ± 1.55 μM and 54.25 ± 1.20 μM, respectively. The results of this work may lead to the discovery of new compounds for the treatment of T2DM.

Anthocyanins and Type 2 Diabetes: An Update of Human Study and Clinical Trial

Anthocyanins are phenolic compounds occurring in fruits and vegetables. Evidence from pre-clinical studies indicates their role in glucose level regulation, gut microbiota improvement, and inflammation reduction under diabetic conditions. Therefore, incorporating these research advancements into clinical practice would significantly improve the prevention and management of type 2 diabetes. This narrative review provides a concise overview of 18 findings from recent clinical research published over the last 5 years that investigate the therapeutic effects of dietary anthocyanins on diabetes. Anthocyanin supplementation has been shown to have a regulatory effect on fasting blood glucose levels, glycated hemoglobin, and other diabetes-related indicators. Furthermore, increased anthocyanin dosages had more favorable implications for diabetes treatment. This review provides evidence that an anthocyanin-rich diet can improve diabetes outcomes, especially in at-risk groups. Future research should focus on optimal intervention duration, consider multiple clinical biomarkers, and analyze anthocyanin effects among well-controlled versus poorly controlled groups of patients with diabetes.

Physiologic effects of the maqui berry (Aristotelia chilensis): a focus on metabolic homeostasis

The prevalence and socioeconomic impact of metabolic diseases is rapidly growing. The limited availability of effective and affordable treatments has fuelled interest in the therapeutic potential of natural compounds as they occur in selected food sources. These compounds might help to better manage the current problems of treatment availability, affordability, and adverse effects that, in combination, limit treatment duration and efficacy at present. Specifically, berries garnered interest given a strong epidemiological link between their consumption and improved metabolic functions, making the analysis of their phytochemical composition and the identification and characterization of biologically active ingredients an emerging area of research. In this regard, the present review focuses on the South American maqui berry Aristotelia chilensis, which has been extensively used by the indigenous Mapuche population for generations to treat a variety of disease conditions. An overview of the maqui plant composition precedes a review of pre-clinical and clinical studies that investigated the effects of maqui berries and their major components on metabolic homeostasis. The final part of the review highlights possible technologies to conserve maqui berry structural and functional integrity during passage through the small intestine, ultimately aiming to augment their systemic and luminal bioavailability and biological effects. The integration of the various aspects discussed herein can assist in the development of effective maqui-based therapies to benefit the growing population of metabolically compromised patients.

Effects of Anthocyanins on Components of Metabolic Syndrome-A Review

Metabolic syndrome (MetS) is a significant health problem. The co-occurrence of obesity, carbohydrate metabolism disorders, hypertension and atherogenic dyslipidaemia is estimated to affect 20-30% of adults worldwide. Researchers are seeking solutions to prevent and treat the conditions related to MetS. Preventive medicine, which focuses on modifiable cardiovascular risk factors, including diet, plays a special role. A diet rich in fruits and vegetables has documented health benefits, mainly due to the polyphenolic compounds it contains. Anthocyanins represent a major group of polyphenols; they exhibit anti-atherosclerotic, antihypertensive, antithrombotic, anti-inflammatory and anticancer activities, as well as beneficial effects on endothelial function and oxidative stress. This review presents recent reports on the mechanisms involved in the protective effects of anthocyanins on the body, especially among people with MetS. It includes epidemiological data, in vivo and in vitro preclinical studies and clinical observational studies. Anthocyanins are effective, widely available compounds that can be used in both the prevention and treatment of MetS and its complications. Increased consumption of anthocyanin-rich foods may contribute to the maintenance of normal body weight and modulation of the lipid profile in adults. However, further investigation is needed to confirm the beneficial effects of anthocyanins on serum glucose levels, improvement in insulin sensitivity and reduction in systolic and diastolic blood pressure.

The Effects of Cranberry Consumption on Glycemic and Lipid Profiles in Humans: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This study aims to update the evidence and clarify whether cranberry possesses lipid-lowering and hypoglycemic properties in humans. PubMed, Web of Science, and Scopus were searched to identify relevant articles published up to December 2023. In total, 3145 publications were reviewed and 16 of them were included for qualitative synthesis and meta-analysis. Stata 15.0 and Review Manager 5.4 were applied for statistical analyses. The results revealed a significant decrease in the total cholesterol to high-density lipoprotein cholesterol ratio (TC/HDL-C) (MD = -0.24; 95% CI: -0.45, -0.04; peffect = 0.02) and homeostasis model assessment of insulin resistance (HOMA-IR) (MD = -0.59; 95% CI: -1.05, -0.14; peffect = 0.01) with cranberry consumption. However, it did not influence total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), fasting blood glucose (FBG), glycated hemoglobin (HbA1c), and fasting insulin. In subgroup analysis, cranberry consumption in dried form (capsules, powder, and tablets) was found to significantly decrease the fasting insulin level (three studies, one hundred sixty-five participants, MD = -2.16; 95% CI: -4.24, -0.07; peffect = 0.04), while intervention duration, health conditions, and dosage of polyphenols and anthocyanins had no impact on blood lipid and glycemic parameters. In summary, cranberry might have potential benefits in regulating lipid and glucose profiles.

Colon-targeted delivery of polyphenols: construction principles, targeting mechanisms and evaluation methods

Polyphenols have received considerable attention for their promotive effects on colonic health. However, polyphenols are mostly sensitive to harsh gastrointestinal environments, thus, must be protected. It is necessary to design and develop a colon-targeted delivery system to improve the stability, colon-targeting and bioavailability of polyphenols. This paper mainly introduces research on colon-targeted controlled release of polyphenols. The physiological features affecting the dissolution, release and absorption of polyphenol-loaded delivery systems in the colon are first discussed. Simultaneously, the types of colon-targeted carriers with different release mechanisms are described, and colon-targeting assessment models that have been studied so far and their advantages and limitations are summarized. Based on the current research on polyphenols colon-targeting, outlook and reflections are proposed, with the goal of inspiring strategic development of new colon-targeted therapeutics to ensure that the polyphenols reach the colon with complete bioactivity.

Flavonoids improve type 2 diabetes mellitus and its complications: a review

The prevalence of type 2 diabetes mellitus (T2DM) is increasing every year. Medications are currently the most common therapy for T2DM. However, these medications have certain adverse effects. In order to find safe and effective ways to improve this disease, researchers have discovered that some natural products can decrease blood sugar. Flavonoids are one of the most essential low molecular weight phenolic chemicals in the plant world, which widely exist in plant roots, stems, leaves, flowers, and fruits. They possess a variety of biological activities, including organ protection, hypoglycemic, lipid-lowering, anti-oxidative and anti-inflammatory effects. Some natural flavonoids ameliorate T2DM and its complications through anti-oxidation, anti-inflammatory action, glucose and lipid metabolism regulation, insulin resistance management, etc. Hence, this review aims at demonstrating the potential benefits of flavonoids in T2DM and its complications. This laid the foundation for the development of novel hypoglycemic medications from flavonoids.

Biochemical Evaluation of Some Fruit Characteristics of Blueberry Progenies Obtained from 'Simultan × Duke'

The popularity of Vaccinium corymbosum blueberry cv. has increased over time because its fruits are highly valued for their taste, aroma, and multiple ways of use. A field trial with two genotypes and their hybrids was organized during 2021-2022 at the Research Institute for Fruit Growing Pitesti-Maracineni, Romania. This paper proposes a comparative analysis of the quality of berries in 17 hybrids of the 'Simultan' and 'Duke' cultivars, selected by the size and the soluble solid content, in agreement with the objectives of the blueberry breeding program. The genotype influence on berry weight, total soluble solids, pH, vitamin C, total polyphenols, total flavonoids, total anthocyanins, lycopene, β-carotene, and antioxidant activity was determined considering the climatic factors. The results showed that fruit weight varied between 1.22 and 2.47 g, total soluble solids reached a maximum of 19.22 °Brix, and the pH oscillated between 3.14 and 3.89. Vitamin C content varied from 9.52 to 18.69 mg in 100 g fresh weight, with an average of 14.35 mg/100 g. Total polyphenol, flavonoid, and anthocyanin contents averaged 709.92 mg gallic acid equivalent in 100 g fresh weight, 165.48 mg catechin equivalent in 100 g fresh weight, and 81.88 mg cyanidin-3-O-glucoside equivalent in 100 g fresh weight, respectively. Results show that the strategy of growers to produce blueberries with a large diameter, visually attractive for traders and consumers, is not sufficient for repeat sales. Our study proves that large fruits do not have the highest content of bioactive compounds. Smaller berries had higher polyphenol, lycopene, and β-carotene contents. It is recommended that the selection of the hybrid in the breeding program also takes into account the content of bioactive compounds.

Stabilization of Anthocyanins from Coffee (Coffea arabica L.) Husks and In Vivo Evaluation of Their Antioxidant Activity

Coffee (Coffea arabica L.) is one of the most popular and widely consumed products throughout the world, mainly due to its taste, aroma, caffeine content, and natural antioxidants. Among those antioxidants, anthocyanins are one of the most important natural pigments, which can be found in coffee husks. It is widely known that anthocyanins have multiple health benefits partially linked to their antioxidant properties. However, anthocyanins have low stability and are sensitive to all types of changes. In order to prevent its degradation, anthocyanins can be stabilized with nanoparticles. Thus, the main objective of this study was to evaluate the stability of the anthocyanins extracted from coffee husks, using three different extracting agents (ethanol, methanol, and water) and stabilizing them through conjugation with zinc oxide nanoparticles. The anthocyanins extracts were mainly composed of cyanidin-3-rutinoside (97%) and the total phenolic compounds of the fresh extracts were 458.97 ± 11.32 (methanol), 373.53 ± 12.74 (ethanol), and 369.85 ± 15.93 (water) mg GAE/g. On the other hand, the total phenolic compounds of the nanoparticle-anthocyanin conjugates underwent no significant changes after stabilization as the major loss was less than 3%. Furthermore, the percentage of anthocyanins' degradation was less than 5% after 12 weeks of storage. On top of that, fresh anthocyanin extracts and anthocyanin-nanoparticle conjugates exhibited a strong protective effect against oxidative stress and increased the survival rate of Caenorhabditis elegans.

GSK-J4, a Specific Histone Lysine Demethylase 6A Inhibitor, Ameliorates Lipotoxicity to Cardiomyocytes via Preserving H3K27 Methylation and Reducing Ferroptosis

Changes in modern lifestyle provoke a series of metabolic stresses such as hyperlipidemia. Excessive free fatty acids induce cardiomyocyte metabolic reprogramming and rearrangement of the lipid content of cardiomyocyte and promote oxidative stress. As a newly defined lipid peroxidation-related cell death pathway, the role of ferroptosis in metabolic stress-induced cardiomyocyte injury is poorly revealed. Our work indicates that GSK-J4, a histone lysine demethylase 6A/6B dual inhibitor, can alleviate palmitic acid (PA)-induced hypersensitivity to ferroptosis by suppressing H3K27 demethylation. Mechanistically, PA stimulation reduces the H3K27me3 level and hence promotes the expression of ACSL4, a key lipid modulator of ferroptosis. GSK-J4 pretreatment significantly preserves the H3K27me3 level and reduces the ACSL4 level. GSK-J4 also reduces reactive oxygen species to alleviate oxidative stress, which further decreases lipid peroxidation. Taken together, our data suggest that cardiomyocyte undergoes epigenetic reprogramming under metabolic challenges, rearranging lipid content, and sensitizing to ferroptosis. GSK-J4 can be a potential drug for treating hyperlipidemia-induced cardiomyocyte injury by targeting epigenetic modulations.