Proanthocyanidins, anthocyanins and cardiovascular diseases

The Diverse Efficacy of Food-Derived Proanthocyanidins for Middle-Aged and Elderly Women

Middle-aged and elderly women are affected by various symptoms and diseases induced by estrogen deficiency. Proanthocyanidins, widely present in many kinds of fruits and berries, have many beneficial effects, such as antioxidative, anti-inflammatory, and antimicrobial activities. We researched the effects of proanthocyanidins for middle-aged and elderly women, finding that it has been revealed in many clinical trials and cohort studies that proanthocyanidins contribute to the prevention of cardiovascular disease, hypertension, obesity, cancer, osteoporosis, and urinary tract infection, as well as the improvement of menopausal symptoms, renal function, and skin damage. Thus, proanthocyanidins can be considered one of the potent representatives of complementary alternative therapy.

Advances in Biosynthesis and Biological Functions of Proanthocyanidins in Horticultural Plants

Proanthocyanidins are colorless flavonoid polymers condensed from flavan-3-ol units. They are essential secondary plant metabolites that contribute to the nutritional value and sensory quality of many fruits and the related processed products. Mounting evidence has shown that the accumulation of proanthocyanidins is associated with the resistance of plants against a broad spectrum of abiotic and biotic stress conditions. The biosynthesis of proanthocyanidins has been examined extensively, allowing for identifying and characterizing the key regulators controlling the biosynthetic pathway in many plants. New findings revealed that these specific regulators were involved in the proanthocyanidins biosynthetic network in response to various environmental conditions. This paper reviews the current knowledge regarding the control of key regulators in the underlying proanthocyanidins biosynthetic and molecular mechanisms in response to environmental stress. Furthermore, it discusses the directions for future research on the metabolic engineering of proanthocyanidins production to improve food and fruit crop quality.

Flavonoids as Multi-Target Compounds: A Special Emphasis on their Potential as Chemo-adjuvants in Cancer Therapy

Flavonoids are low molecular weight, polyphenolic phytochemicals, obtained from secondary metabolism of various plant compounds. They have a spectrum of pharmacological efficacies, including potential anticancer efficacy. Natural flavonoids are present in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. Flavonoids can attenuate or inhibit the initiation, promotion and progression of cancer by modulating various enzymes and receptors in diverse pathways that involve cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis and metastasis. Furthermore, in vitro, flavonoids have been shown to reverse multidrug resistance when used as chemo-adjuvants. Flavonoids (both natural and synthetic analogues) interact with several oncogenic targets through dependent and independent mechanisms to mediate their anticancer efficacy in different types of cancer cells.

Important Flavonoids and Their Role as a Therapeutic Agent

Flavonoids are phytochemical compounds present in many plants, fruits, vegetables, and leaves, with potential applications in medicinal chemistry. Flavonoids possess a number of medicinal benefits, including anticancer, antioxidant, anti-inflammatory, and antiviral properties. They also have neuroprotective and cardio-protective effects. These biological activities depend upon the type of flavonoid, its (possible) mode of action, and its bioavailability. These cost-effective medicinal components have significant biological activities, and their effectiveness has been proved for a variety of diseases. The most recent work is focused on their isolation, synthesis of their analogs, and their effects on human health using a variety of techniques and animal models. Thousands of flavonoids have been successfully isolated, and this number increases steadily. We have therefore made an effort to summarize the isolated flavonoids with useful activities in order to gain a better understanding of their effects on human health.

The elephant grass (Cenchrus purpureus) genome provides insights into anthocyanidin accumulation and fast growth

Elephant grass (2n = 4x = 28; Cenchrus purpureus Schumach.), also known as Napier grass, is an important forage grass and potential energy crop in tropical and subtropical regions of Asia, Africa and America. However, no study has yet reported a genome assembly for elephant grass at the chromosome scale. Here, we report a high‐quality chromosome‐scale genome of elephant grass with a total size of 1.97 Gb and a 1.5% heterozygosity rate, obtained using short‐read sequencing, single‐molecule long‐read sequencing and Hi‐C chromosome conformation capture. Evolutionary analysis showed that subgenome A' of elephant grass and pearl millet may have originated from a common ancestor more than 3.22 million years ago (MYA). Further, allotetraploid formation occurred at approximately 6.61 MYA. Syntenic analyses within elephant grass and with other grass species indicated that elephant grass has experienced chromosomal rearrangements. We found that some key enzyme‐encoding gene families related to the biosynthesis of anthocyanidins and flavonoids were expanded and highly expressed in leaves, which probably drives the production of these major anthocyanidin compounds and explains why this elephant grass cultivar has a high anthocyanidin content. In addition, we found a high copy number and transcript levels of genes involved in C₄ photosynthesis and hormone signal transduction pathways that may contribute to the fast growth of elephant grass. The availability of elephant grass genome data advances our knowledge of the genetic evolution of elephant grass and will contribute to further biological research and breeding as well as for other polyploid plants in the genus Cenchrus.

Transcriptome and metabolome analyses reveal the regulation of peel coloration in green, red Chinese prickly ash (Zanthoxylum L.)

Peel colour is an important external economic characteristic of Chinese prickly ash cultivars (Zanthoxylum bungeanum Maxim.). To gain insight into their coloration mechanisms, we performed an integrated analysis of green and red peels using combined metabolomic and transcriptomic analyses. Pelargonin-O-hexoside-O-rhamnoside-O-hexoside, pelargonidin 3,5-diglucoside, peonidin O-hexoside, cyanidin O-syringic acid and peonidin 3-O-glucoside were found to be the key anthocyanins. Transcriptome data indicated that the anthocyanidin synthase genes and UDP-glucose flavonoid 3-O-glucosytransferase genes were significantly increased to promote the redness of the peels. In addition, we discussed the role of R₂R₃-MYB transcription factors in coloration, of which the c80935 and c226097 genes may be the key regulatory factors for anthocyanin biosynthesis. Generally, this is the first study to identify and reveal the main anthocyanins in Chinese prickly ash peels during different developmental periods. The results of this research lay the foundation for understanding the regulation of coloration in Chinese prickly ash peels.

Pine bark (Pinus spp.) extract for treating chronic disorders

BACKGROUND

Pine bark (Pinus spp.) extract is rich in bioflavonoids, predominantly proanthocyanidins, which are antioxidants. Commercially-available extract supplements are marketed for preventing or treating various chronic conditions associated with oxidative stress. This is an update of a previously published review.

OBJECTIVES

To assess the efficacy and safety of pine bark extract supplements for treating chronic disorders.

SEARCH METHODS

We searched three databases and three trial registries; latest search: 30 September 2019. We contacted the manufacturers of pine bark extracts to identify additional studies and hand-searched bibliographies of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating pine bark extract supplements in adults or children with any chronic disorder.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, extracted data and assessed risk of bias. Where possible, we pooled data in meta-analyses. We used GRADE to evaluate the certainty of evidence. Primary outcomes were participant- and investigator-reported clinical outcomes directly related to each disorder and all-cause mortality. We also assessed adverse events and biomarkers of oxidative stress.

MAIN RESULTS

This review included 27 RCTs (22 parallel and five cross-over designs; 1641 participants) evaluating pine bark extract supplements across 10 chronic disorders: asthma (two studies; 86 participants); attention deficit hyperactivity disorder (ADHD) (one study; 61 participants), cardiovascular disease (CVD) and risk factors (seven studies; 338 participants), chronic venous insufficiency (CVI) (two studies; 60 participants), diabetes mellitus (DM) (six studies; 339 participants), erectile dysfunction (three studies; 277 participants), female sexual dysfunction (one study; 83 participants), osteoarthritis (three studies; 293 participants), osteopenia (one study; 44 participants) and traumatic brain injury (one study; 60 participants). Two studies exclusively recruited children; the remainder recruited adults. Trials lasted between four weeks and six months. Placebo was the control in 24 studies. Overall risk of bias was low for four, high for one and unclear for 22 studies. In adults with asthma, we do not know whether pine bark extract increases change in forced expiratory volume in one second (FEV1) % predicted/forced vital capacity (FVC) (mean difference (MD) 7.70, 95% confidence interval (CI) 3.19 to 12.21; one study; 44 participants; very low-certainty evidence), increases change in FEV1 % predicted (MD 7.00, 95% CI 0.10 to 13.90; one study; 44 participants; very low-certainty evidence), improves asthma symptoms (risk ratio (RR) 1.85, 95% CI 1.32 to 2.58; one study; 60 participants; very low-certainty evidence) or increases the number of people able to stop using albuterol inhalers (RR 6.00, 95% CI 1.97 to 18.25; one study; 60 participants; very low-certainty evidence). In children with ADHD, we do not know whether pine bark extract decreases inattention and hyperactivity assessed by parent- and teacher-rating scales (narrative synthesis; one study; 57 participants; very low-certainty evidence) or increases the change in visual-motoric coordination and concentration (MD 3.37, 95% CI 2.41 to 4.33; one study; 57 participants; very low-certainty evidence). In participants with CVD, we do not know whether pine bark extract decreases diastolic blood pressure (MD -3.00 mm Hg, 95% CI -4.51 to -1.49; one study; 61 participants; very low-certainty evidence); increases HDL cholesterol (MD 0.05 mmol/L, 95% CI -0.01 to 0.11; one study; 61 participants; very low-certainty evidence) or decreases LDL cholesterol (MD -0.03 mmol/L, 95% CI -0.05 to 0.00; one study; 61 participants; very low-certainty evidence). In participants with CVI, we do not know whether pine bark extract decreases pain scores (MD -0.59, 95% CI -1.02 to -0.16; one study; 40 participants; very low-certainty evidence), increases the disappearance of pain (RR 25.0, 95% CI 1.58 to 395.48; one study; 40 participants; very low-certainty evidence) or increases physician-judged treatment efficacy (RR 4.75, 95% CI 1.97 to 11.48; 1 study; 40 participants; very low-certainty evidence). In type 2 DM, we do not know whether pine bark extract leads to a greater reduction in fasting blood glucose (MD 1.0 mmol/L, 95% CI 0.91 to 1.09; one study; 48 participants;very low-certainty evidence) or decreases HbA1c (MD -0.90 %, 95% CI -1.78 to -0.02; 1 study; 48 participants; very low-certainty evidence). In a mixed group of participants with type 1 and type 2 DM we do not know whether pine bark extract decreases HbA1c (MD -0.20 %, 95% CI -1.83 to 1.43; one study; 67 participants; very low-certainty evidence). In men with erectile dysfunction, we do not know whether pine bark extract supplements increase International Index of Erectile Function-5 scores (not pooled; two studies; 147 participants; very low-certainty evidence). In women with sexual dysfunction, we do not know whether pine bark extract increases satisfaction as measured by the Female Sexual Function Index (MD 5.10, 95% CI 3.49 to 6.71; one study; 75 participants; very low-certainty evidence) or leads to a greater reduction of pain scores (MD 4.30, 95% CI 2.69 to 5.91; one study; 75 participants; very low-certainty evidence). In adults with osteoarthritis of the knee, we do not know whether pine bark extract decreases composite Western Ontario and McMaster Universities Osteoarthritis Index scores (MD -730.00, 95% CI -1011.95 to -448.05; one study; 37 participants; very low-certainty evidence) or the use of non-steroidal anti-inflammatory medication (MD -18.30, 95% CI -25.14 to -11.46; one study; 35 participants; very low-certainty evidence). We do not know whether pine bark extract increases bone alkaline phosphatase in post-menopausal women with osteopenia (MD 1.16 ug/L, 95% CI -2.37 to 4.69; one study; 40 participants; very low-certainty evidence). In individuals with traumatic brain injury, we do not know whether pine bark extract decreases cognitive failure scores (MD -2.24, 95% CI -11.17 to 6.69; one study; 56 participants; very low-certainty evidence) or post-concussion symptoms (MD -0.76, 95% CI -5.39 to 3.87; one study; 56 participants; very low-certainty evidence). For most comparisons, studies did not report outcomes of hospital admissions or serious adverse events.

AUTHORS' CONCLUSIONS

Small sample sizes, limited numbers of RCTs per condition, variation in outcome measures, and poor reporting of the included RCTs mean no definitive conclusions regarding the efficacy or safety of pine bark extract supplements are possible.

Invertebrate responses to microplastic ingestion: Reviewing the role of the antioxidant system

Microplastic ingestion in invertebrates reduces somatic and reproductive growth. This could be caused by energy reserves being detracted from growth processes and redistributed to maintenance processes that preserve life. A potential sink for this diverted energy is the antioxidant system, which minimises oxidative damage and reinstates redox homeostasis following disturbances caused by exposure to pollution. Several microplastic studies have used genetic and molecular redox biomarkers to assess how microplastic ingestion affects the functioning of the antioxidant system. This systematic review synthesises the current understanding of redox biomarker responses in invertebrates that have ingested microplastics. We found that biomarker response information exists for only seven invertebrate taxa, and early life stages have received little scientific attention. The microplastics used by most studies were polystyrene (45% of studies), spherical (51% of studies), and were < 10 μm in diameter (31% of studies). We found multiple examples of microplastic ingestion posing an oxidative challenge to invertebrates, which required upregulation of antioxidant system components. However, the lack of systematic experiments prevented us from clearly identifying which characteristic of microplastics caused these responses. We identify several areas for consideration when investigating biomarker responses to microplastic ingestion and offer research priorities for future studies.

Anthocyanins, Vibrant Color Pigments, and Their Role in Skin Cancer Prevention

Until today, numerous studies evaluated the topic of anthocyanins and various types of cancer, regarding the anthocyanins' preventative and inhibitory effects, underlying molecular mechanisms, and such. However, there is no targeted review available regarding the anticarcinogenic effects of dietary anthocyanins on skin cancers. If diagnosed at the early stages, the survival rate of skin cancer is quite high. Nevertheless, the metastatic form has a short prognosis. In fact, the incidence of melanoma skin cancer, the type with high mortality, has increased exponentially over the last 30 years, causing the majority of skin cancer deaths. Malignant melanoma is considered a highly destructive type of skin cancer due to its particular capacity to grow and spread faster than any other type of cancers. Plants, in general, have been used in disease treatment for a long time, and medicinal plants are commonly a part of anticancer drugs on the market. Accordingly, this work primarily aims to emphasize the most recent improvements on the anticarcinogenic effects of anthocyanins from different plant sources, with an in-depth emphasis on melanoma skin cancer. We also briefly summarized the anthocyanin chemistry, their rich dietary sources in flowers, fruits, and vegetables, as well as their associated potential health benefits. Additionally, the importance of anthocyanins in topical applications such as their use in cosmetics is also given.

Preparation of Lipid-Soluble Bilberry Anthocyanins through Acylation with Cinnamic Acids and their Antioxidation Activities

To enable the use of anthocyanins in food with high oil content, bilberry anthocyanins were acylated with cinnamic acids to address their poor lipid solubility. Structural analyses based on Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ¹H nuclear magnetic resonance analyses indicated that cinnamic acids were efficiently grafted onto 6-OH of glucoside and galactoside and 5-OH of arabinose through an esterification reaction. The higher the dose of the acylating agent, the higher the acylation degree (AD) and the lower the total anthocyanidin content (TAC) of bilberry anthocyanins. An-Ci4 presented the highest AD value (6.61%), and An-Ci3 exhibited the lowest TAC value (50.16 mg/g). After acylating with lipophilic cinnamic acids, the lipid solubility of acylated bilberry anthocyanins significantly improved. The color of the native bilberry anthocyanin solution dissolved in ethyl acetate and dioxane was transparent. By contrast, the acylated anthocyanin solution dissolved in these solvents was unmistakably red. In terms of the antioxidant activity, acylated bilberry anthocyanins demonstrated inferior performance in 2,2-diphenyl-1-picrylhydrazyl (DPPH) clearance but a better inhibition ratio in β-carotene bleaching assay compared with native bilberry anthocyanins. As AD value increased, the DPPH clearance of acylated anthocyanins decreased and their inhibition ratio increased in β-carotene bleaching assay.

Effects of α-casein and β-casein on the stability, antioxidant activity and bioaccessibility of blueberry anthocyanins with an in vitro simulated digestion

Blueberry anthocyanins are well-known for their diverse biological functions. However, the instability during digestion results in their weak bioavailability. The current study aimed to investigate the alteration in the stability, antioxidant capacity and bioaccessibility of blueberry anthocyanins with the addition of α-casein and β-casein in a simulated digestion system using pH differential method, HPLC-MS analysis, peroxyl scavenging capacity (PSC) assay, cellular antioxidant activity (CAA) and penetration test. The results showed that both α-casein and β-casein could increase the stability of blueberry anthocyanins during intestinal digestion and protect their antioxidant capacity. Moreover, the addition of α-casein or β-casein would enhance the bioaccessibility of blueberry anthocyanins. In conclusion, our study highlights that the interaction between α-casein or β-casein with blueberry anthocyanins can protect the compounds against influences associated with the simulated digestion.

What is the best diet for cardiovascular wellness? A comparison of different nutritional models

Cardiovascular diseases (CVD) represent to date the leading cause of mortality in both genders in the developed countries. In this context, a strong need for CVD prevention is emerging through lifestyle modification and nutrition. In fact, several studies linked CVD with unhealthy nutrition, alcohol consumption, stress, and smoking, together with a low level of physical activity. Thus, the primary aim is to prevent and reduce CVD risk factors, such as impaired lipid and glycemic profiles, high blood pressure and obesity. Different types of diet have been, therefore, established to optimize the approach regarding this issue such as the Mediterranean diet, Dietary Approaches to Stop Hypertension diet (DASH), vegetarian diet, ketogenic diet, and Japanese diet. Depending on the diet type, recommendations generally emphasize subjects to increase vegetables, fruits, whole grains, and pulses consumption, but discourage or recommend eliminating red meat, sweets, and sugar-sweetened beverages, along with processed foods that are high in sugar, salt, fat, or low in dietary fiber. In particular, we evaluated and compared the peculiar aspects of these well-known dietary patterns and, thus, this review evaluates the critical factors that increase CVD risk and the potential application and benefits of nutritional protocols to ameliorate dietary and lifestyle patterns for CVD prevention.

Synergistic antioxidant effects of petunidin and lycopene in H9c2 cells submitted to hydrogen peroxide: Role of Akt/Nrf2 pathway

Phenolics and carotenoids coexist in fruits and vegetables and could possess interaction effects after consumption. The present study aims to elucidate the possible mechanisms of the antioxidant interactions between anthocyanins and carotenoids using petunidin and lycopene as examples in hydrogen peroxide (H₂ O₂ )-induced heart myofibroblast cell (H9c2) line model. The results revealed that petunidin and lycopene showed antioxidant effects and petunidin in a larger proportion mixed with lycopene, for example, petunidin: lycopene = 9:1 significantly protected against the loss of the cell viability (8.98 ± 1.03%) and intracellular antioxidant enzyme activities of superoxide dismutase (SOD, 27.07 ± 3.51%), catalase (CAT, 29.51 ± 6.12%), and glutathione peroxidase (GSH-Px, 20.33 ± 2.65%). Moreover, the messenger RNA (mRNA) and protein expressions of NAD(P)H quinone reductase (NQO1) and heme oxygenase (HO-1) of the nuclear factor erythrocyte 2-related factor 2 (Nrf2) signaling pathway were significantly induced in petunidin, lycopene, and synergistic combinations, suggesting that the antioxidant action was through activating the Nrf2 antioxidant response pathway. This was further validated by Nrf2 siRNA, and the results that petunidin significantly induced more of NQO1 expression and lycopene more of HO-1 suggested that the synergism may be a result of concerted actions by the two compounds on these two different target genes of the Nrf2 pathway. The two compounds also significantly increased the phosphorylation of Akt in synergistic combinations. Findings of the present study demonstrated that petunidin and lycopene exerted synergistic antioxidant effects when petunidin in a larger proportion in the combinations and contribute to the prevention of cellular redox homeostasis, which might provide a theoretical basis for phenolics and carotenoids playing beneficial effects on the cardiovascular risk. PRACTICAL APPLICATION: In this study, we revealed that the combined treatments of petunidin and lycopen inhibited H₂ O₂ -induced oxidative damage in myocardial cells. Moreover, the treatments contributed to the Nrf2 pathway and the restoration of cellular redox homeostasis might provide a theoretical basis for phenolics and carotenoids playing beneficial effects on the cardiovascular risk.

Insight of Polyphenol Oxidase Enzyme Inhibition and Total Polyphenol Recovery from Cocoa Beans

A full factorial design (ascorbic acid/l-cysteine inhibitors, temperature, and time as factors) study was conducted to enhance inhibition of polyphenol oxidase (PPO) activity without decreasing cocoa polyphenol concentrations. The data obtained were modelled through a new equation, represented by Γ, which correlates both high polyphenol content with reduced specific PPO activity. At optimized values (70 mM inhibitory solution at 96 °C for 6.4 min, Γ = 11.6), 93.3% PPO inhibition and total polyphenol of 94.9 mg GAE/g were obtained. In addition, microscopy images confirmed the cell morphological changes measured as the fractal dimension and explained the possible cell lysis and denaturation as a result of heat treatment and chemical inhibitors. Results also showed that PPO enzyme was most suitable (higher v_max/K_m ratio) for catechol, with a reduction in its affinity of 13.7-fold after the inhibition heat treatment. Overall, this work proposed a suitable and food-safe procedure for obtaining enriched polyphenol extract with low enzyme activity.

Epigenetics/epigenomics of triterpenoids in cancer prevention and in health

Triterpenoids are a powerful group of phytochemicals derived from plant foods and herbs. Many reports have shown that they possess chemopreventive and chemotherapeutic effects not only in cell lines and animal models but also in clinical trials. Because epigenetic changes could potentially occur in the early stages of carcinogenesis preceding genetic mutations, epigenetics are considered promising targets in early interventions against cancer using epigenetic bioactive substances. The biological properties of triterpenoids in cancer prevention and in health have multiple mechanisms, including antioxidant and anti-inflammatory activities, cell cycle regulation, as well as epigenetic/epigenomic regulation. In this review, we will discuss and summarize the latest advances in the study of the pharmacological effects of triterpenoids in cancer chemoprevention and in health, including the epigenetic machinery.

Açaí (Euterpe oleracea Mart.) and juçara (Euterpe edulis Mart.) juices improved HDL-c levels and antioxidant defense of healthy adults in a 4-week randomized cross-over study

OBJECTIVE

To evaluate the effects of moderate-term açaí and juçara juice intake on fasting glucose, lipid profile, and oxidative stress biomarkers in healthy subjects.

METHODS

A randomized cross-over study was performed with 30 healthy adults. The subjects were assigned to drink 200 mL/day of açaí or juçara juice for four weeks with a 4-week washout period. Before and after each nutritional intervention, blood samples were obtained to evaluate the outcomes: fasting glucose, total cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c), small, dense LDL-c (sd-LDL-c), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), uric acid, and activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx).

RESULTS

After four weeks, açaí and juçara juices increased the concentrations of HDL-c by 7.7% and 11.4%, respectively (P < 0.05). In addition, açaí juice intake promoted significant increases in TAC (66.7%), CAT (275.1%), GPx (15.3%), and a decrease in OSI (55.7%) compared to baseline (P < 0.05 for all). Juçara juice intake significantly increased CAT activity (~15.0%) in relation to baseline. No significant intergroup differences were observed for any outcomes (P > 0.05).

CONCLUSION

The results indicated a positive impact of regular consumption of açaí and juçara juices on the HDL-c levels, as well as on the antioxidant enzyme activities, which may contribute to cardiovascular health.

Characterization of Flavonoid Compounds in Common Swedish Berry Species

Berries are considered an ideal source of polyphenols, especially from the flavonoid group. In this study, we examined the flavonoid content in 16 varieties of Swedish lingonberry, raspberry, blueberry, and strawberry. Nineteen flavonoids were simultaneously quantified using external standards. An additional 29 flavonoids were tentatively identified using MS as no standards were available. Quantification was done using HPLC-UV after optimization of chromatographic and extraction procedures. The method showed high linearity within the range of 2-100 μg/mL (correlation co-efficient >0.999), intra- and inter-day precision of 1.7-7.3% and average recovery above 84% for all compounds. Blueberries and lingonberries were found to contain higher contents of flavonoids (1100 mg/100 g dry weight) than raspberries and strawberries (500 mg/100 g dry weight). Anthocyanins were the dominant flavonoids in all berries. The tentatively characterized compounds contribute 18%, 29%, 61%, and 67% of the total flavonoid content in strawberries, lingonberries, raspberries, and blueberries, respectively. Overall, Swedish berries were shown to be good sources of polyphenols.

Direct versus Sequential Analysis of Procyanidin- and Prodelphinidin-Based Condensed Tannins by the HCl-Butanol-Acetone-Iron Assay

In this study, we optimized the HCl-butanol-acetone-iron (HBAI) assay for the analysis of B-linked procyanidin (PC) and prodelphinidin (PD) condensed tannins (CTs) by direct analysis of whole tissue and sequential analysis of acetone-water extracts and insoluble residues prepared from forage, woody plant, food, and food byproduct samples. Yields of anthocyanidins (cyanidin and delphinidin) were optimized by heating ≤0.25 mg mL^-1 CT standards, 1 mg mL^-1 tissue, or 1-2 mg mL^-1 acetone-water fractioned tissue for 3 h at 70 °C in medium containing 5% concentrated HCl, 6.7% total water, 50% acetone, 42% n-butanol, and 0.15% ammonium iron(III) sulfate dodecahydrate. Accurate quantitation required CT standards of known purity sourced from the same tissue being analyzed. Both analysis methods provided comparable estimates of total CTs for most PD-rich samples, but only the sequential method gave good recovery and accurate estimates of CTs in most PC-rich samples.

Assessment of Antioxidants in Selected Plant Rootstocks

The service tree (Sorbus domestica) is a wild fruit tree with immense medicinal and industrial value. This study aimed at determining the four major groups of antioxidants (flavonoids, phenolic acids and aldehydes, catechin and procyanidin) in rootstocks of Crataegus laevigata (genotypes O-LE-14 and O-LE-21), Aronia melanocarpa (genotypes O-LE-14 and O-LE-21), Chaenomeles japonica (genotype O-LE-9) and Cydonia oblonga (BA 29) (genotypes O-LE-14 and O-LE-21). Hyperoside (Quercetin 3-D-galactoside) was the most abundant flavonoid compound, since its average content in the rootstocks of Crataegus laevigata (O-LE-21) was 180.68 ± 0.04 μg·g-1. Dihydrokaempherol was the least frequently found flavonoid compound, with an average concentration of 0.43 ± 0.01 μg·g-1 in all the rootstocks of plants considered in this study. Among the phenolic compounds, the most represented one was protocatechuic acid, with 955.92 ± 10.25 μg·g-1 in the rootstocks of Aronia melanocarpa (O-LE-14). On the other hand, the least represented p-Coumaric acid exhibited the average concentration of 0.34 ± 0.01 μg·g-1 in the plant rootstocks. Epicatechin was the most abundant catechin compound, with a content of 3196.37 ± 50.10 μg·g-1 in the rootstocks of Aronia melanocarpa (O-LE-14). The lowest represented catechin compound was epigallocatechin, with the average concentration of 0.95 ± 0.08 μg·g-1 in the screened plant rootstocks. From the procyanidin compounds, the most abundant one was procyanidin b2 in the rootstocks of Crataegus laevigata (O-LE-14), with a concentration of 5550.40 ± 99.56 μg·g-1. On the contrary, procyanidin a2, with an average concentration of 40.35 ± 1.61 μg·g-1, represented the least frequent procyanidin compound in all the plant rootstocks screened herein.

Anthocyanin Fruit encodes an R2R3-MYB transcription factor, SlAN2-like, activating the transcription of SlMYBATV to fine-tune anthocyanin content in tomato fruit

Anthocyanin fruit (Aft) and atroviolacea (atv) were characterized in wild tomato and can enhance anthocyanin content in tomato fruit. However, the gene underlying the Aft locus and the mechanism by which Aft and atv act remain largely unknown. In this study, the Aft locus was fine-mapped to an approximately 145-kb interval on chromosome 10, excluding SlAN2 (Solyc10g086250), SlANT1 (Solyc10g086260) and SlANT1-like (Solyc10g086270), which have previously been suggested as candidates. Thus, the R2R3-MYB transcription factor SlAN2-like (Solyc10g086290) was considered the best candidate gene for Aft. The CRISPR/Cas9-mediated SlAN2-like mutants show a much lower accumulation of anthocyanins associated with the downregulation of multiple anthocyanin-related genes compared to the wild-type tomato, indicating that SlAN2-like is responsible for the Aft phenotype. The repressive function of SlMYBATV also was confirmed through the CRISPR/Cas9 approach. A yeast-two-hybrid assay revealed that SlMYBATV interacts with the bHLH protein SlJAF13. Furthermore, yeast-one-hybrid and dual-luciferase transient expression assays showed that Aft directly binds to the SlMYBATV promoter and activates its expression. The results herein provide candidate genes to enhance anthocyanin content in tomato fruit. This research also provides insight into a mechanism involving the Aft-SlMYBATV pathway that fine-tunes anthocyanin accumulation in tomato fruit.

Rapid microwave-assisted Porter method for determination of proanthocyanidins

INTRODUCTION

Proanthocyanidins have been widely developed and utilised in food, medicine, health care products and cosmetics. Porter-high-performance liquid chromatography (HPLC) is a quantitative method often utilised in many fields. This method uses a water bath to reflux the proanthocyanidins, but the process is cumbersome, the reagent consumption is large, and multiple batches of simultaneous treatments cannot be evaluated.

OBJECTIVE

To establish a more convenient, rapid and high-batch processing method for determining the content of proanthocyanidins in functional food by HPLC.

METHODS

N-Butanol-hydrochloric acid and iron salt are used as the reaction medium in the Porter method. After investigating the optimal conditions, the hydrolysis of proanthocyanidins can be performed in a microwave reactor at a power of 640 W for 75 s in the Porter reaction system. The content of proanthocyanidins was determined by HPLC with external standards.

RESULTS

After the rapid pretreatment of samples, proanthocyanidins were determined by HPLC with a diode array detector at a detection wavelength of 525 nm with 0.53 μg/mL and 1.61 μg/mL limits of detection and quantification, respectively, for proanthocyanidin ions, and the linearity was 0.9999. Intra- and inter-day relative standard deviation values were between 1.5% and 3.1%, and the recovery was between 91.40% and 107.43% for the determination of different products, such as capsules, tablets and tea, which were similar to the values obtained with the conventional Porter method.

CONCLUSION

This method is a time-saving and low cost approach for quantitative analysis of various proanthocyanidin health products that offers the advantages of high-batch processing and environmental friendliness.

Novel flavan-3-ol-glutathione conjugates from the degradation of proanthocyanidins as highly bioactive antioxidants

Synthesis, preparation and antioxidant capacity evaluation of flavan-3-ol-glutathione conjugates.

Novel Catechin-Tiopronin Conjugates Derived from Grape Seed Proanthocyanidin Degradation: Process Optimization, High-Speed Counter-Current Chromatography Preparation, as Well as Antibacterial Activity

Tiopronin, as a novel thiol-containing nucleophile, was introduced for depolymerizing polymeric proanthocyanidins from grape seed into catechins and three new proanthocyanidin-tiopronin degradation products: (+)-catechin-4β-S-tiopronin methyl ester (CT), (-)-epicatechin-4β-S-tiopronin methyl ester (ECT), and (-)-epicatechin gallate-4β-S-tiopronin methyl ester (ECGT). A Box-Behnken design was employed to optimize degradation conditions based on single-factor experiments to obtain target products. Each of the new degradation compounds was isolated by the high-speed counter-current chromatography combined with semipreparative high performance liquid chromatography in large amounts, and then, their structures were identified by ¹H NMR, ¹³C NMR, 2D-NMR, as well as mass spectrometry analysis. The absolute configurations were further confirmed by comparison between the calculated electronic circular dichroism and experimental spectra. Further evaluation of antibacterial activities of these compounds showed that CT and ECT possessed more inhibiting capacity against Staphylococcus aureus and Escherichia coli than parent compound catechin and epicatechin. However, ECGT has no bacteriostatic capacity against these two bacteria.

Differential Regulation of Anthocyanins in Green and Purple Turnips Revealed by Combined De Novo Transcriptome and Metabolome Analysis

Purple turnip Brassica rapa ssp. rapa is highly appreciated by consumers but the metabolites and molecular mechanisms underlying the root skin pigmentation remain open to study. Herein, we analyzed the anthocyanin composition in purple turnip (PT) and green turnip (GT) at five developmental stages. A total of 21 anthocyanins were detected and classified into the six major anthocynanin aglycones. Distinctly, PT contains 20 times higher levels of anthocyanins than GT, which explain the difference in the root skin pigmentation. We further sequenced the transcriptomes and analyzed the differentially expressed genes between the two turnips. We found that PT essentially diverts dihydroflavonols to the biosynthesis of anthocyanins over flavonols biosynthesis by strongly down-regulating one flavonol synthase gene, while strikingly up-regulating dihydroflavonol 4-reductase (DFR), anthocyanidin synthase and UDP-glucose: flavonoid-3-O-glucosyltransferase genes as compared to GT. Moreover, a nonsense mutation identified in the coding sequence of the DFR gene may lead to a nonfunctional protein, adding another hurdle to the accumulation of anthocyanin in GT. We also uncovered several key members of MYB, bHLH and WRKY families as the putative main drivers of transcriptional changes between the two turnips. Overall, this study provides new tools for modifying anthocyanin content and improving turnip nutritional quality.

Antidiabetic and Antioxidative Potential of the Blue Congo Variety of Purple Potato Extract in Streptozotocin-Induced Diabetic Rats

This study was designed to evaluate the effects of purple potato extract of the Blue Congo variety (PP) on diabetes and its antioxidant activities after two-week administration tostreptozotocin (STZ)-induced diabetic rats. The activities of PP were evaluated at a dose of 165 mg/kg body weight (b.w.) by estimating biochemical changes in blood plasma and through a histopathological study of kidney, muscles, and liver tissue. We evaluated the effect of treatment with extract on glucose level, glycated hemoglobin, activities of enzymatic antioxidants (including superoxide dismutase, glutathione peroxidase, and catalase), and lipid peroxidation. Moreover, we determined advanced glycation end-products (AGEs), advanced oxidation protein products (AOPPs), and the level of oxidative modified proteins (OMPs) as markers of carbonyl-oxidative stress in rats with diabetes. Using high-performance liquid chromatography, we identified five anthocyanins and six phenolic acids in the extract from Blue Congo with the dominant acylated anthocyanin as petunidin-3-p-coumaroyl-rutinoside-5-glucoside. The administration of Blue Congo extract lowered blood glucose, improved glucose tolerance, and decreased the amount of glycated hemoglobin. Furthermore, PP demonstrated an antioxidative effect, suppressed malondialdehyde levels, and restored antioxidant enzyme activities in diabetic rats. After administration of PP, we also noticed inhibition of OMP, AGE, and AOPP formation in the rats' blood plasma.

Proanthocyanidins: A comprehensive review

Proanthocyanidins are condensed tannins with various pharmacological properties. These phytochemicals are considered as 'offense and defense molecules because of their human health benefits. The validation of their diverse health aspects, namely, antioxidant, anticancer, antidiabetic, neuroprotective, and antimicrobial has earned them repute in thermochemistry. Proanthocyanidins are oligo- or polymers of monomeric flavan-3-ols produced as an end product of flavonoid biosynthetic pathway. Agricultural wastes and food processing wastes contain immense amount of proanthocyanidins, exploitation of which can be a sustainable source of dietary supplements and functional ingredients. The current review article discusses recent developments in the health promoting properties of proanthocyanidins and the associated hurdles.

Proanthocyanidins of Natural Origin: Molecular Mechanisms and Implications for Lipid Disorder and Aging-Associated Diseases

Proanthocyanidins are phytonutrients formed by oligomerization or polymerization of subunits catechin, epicatechin, and their gallic acid esters. Proanthocyanidins are a component of many plants and thus form an integral part of the human diet. Oligomeric proanthocyanidins are currently marketed as medicinal products that target vascular disorders and chronic pathological conditions, many of which are age-associated. Proanthocyanidins are also characterized by their effects on energy homeostasis. Not dissimilar to their chemically synthesized counterparts, naturally extracted proanthocyanidins act via inhibition of lipases, stimulation of energy expenditure, or suppression of appetite. Here we review the current knowledge-base and highlight challenges and future impacts regarding involvement of proanthocyanidins in global lipid metabolism, with a focus on the molecular mechanisms and pathological conditions that progress with aging.

GC-(4→8)-GCG, A Proanthocyanidin Dimer from Camellia ptilophylla, Modulates Obesity and Adipose Tissue Inflammation in High-Fat Diet Induced Obese Mice

SCOPE

Excessive fat accumulation in adipose tissue leads to obesity and related chronic inflammation. This study aims to examine the effects of gallocatechin -(4→8)-gallocatechin-3-O-gallate (GC-(4→8)-GCG), a main proanthocyanidin dimer from Camellia ptilophylla (Cocoa tea), on adipocyte- and adipose-related inflammation in vivo and in vitro.

METHODS AND RESULTS

C57BL/6 mice are fed a high-fat diet (HFD) and GC-(4→8)-GCG (40 or 80 mg kg^-1 d^-1 ) for 8 weeks. The metabolic profiles, adipose tissue hypertrophy, macrophage infiltration, and inflammatory cytokine production are investigated. Additionally, 3T3-L1 preadipocytes are utilized to investigate the effect of GC-(4→8)-GCG on preadipocyte differentiation and the tumor necrosis factor (TNF)-α-stimulated inflammatory response in vitro. GC-(4→8)-GCG supplementation decreases HFD-induced epididymal white adipose tissue (eWAT) hypertrophy, suppresses proinflammatory cytokine production and macrophage infiltration in eWAT, and improves insulin sensitivity in HFD-induced obese mice. In vitro, GC-(4→8)-GCG shows a strong anti-adipogenic potential in 3T3-L1 preadipocyte by inhibiting the expression of key adipogenic transcription factors and decreasing the production of proinflammatory cytokines by inhibiting the activation of the nuclear factor (NF)-κB, Janus tyrosine kinase/signal transducer and activator of transcription (JAK/STAT3) and mitogen-activated protein kinase (MAPK) signaling pathways.

CONCLUSION

GC-(4→8)-GCG can modulate obesity and improve obesity-related insulin resistance by inhibiting preadipocyte differentiation and the related proinflammatory responses.

Effects of anthocyanin-rich purple corn (Zea mays L.) stover silage on nutrient utilization, rumen fermentation, plasma antioxidant capacity, and mammary gland gene expression in dairy goats1

Eight healthy multiparous Saanen dairy goats (41.50 ± 1.84 kg) were assigned to a double 4 × 4 Latin square design. The four treatment diets were: (i) negative control, rice straw (NC); (ii) first positive control, sticky corn stover silage (PC1); (iii) second positive control, PC1 with 1 g/d commercial purple corn pigment (PC2); and (iv) anthocyanin-rich purple corn stover silage (PSS; AR). DMI did not differ (P > 0.05) among the treatments. Goats receiving the NC tended (P < 0.05) to reduce nutrient apparent digestibility, nitrogen (N) absorption, N retention, and volatile fatty acid production relative to the other groups. The levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and superoxide dismutase (SOD) in plasma were greater (P < 0.05) in goats fed PC2 and AR compared with NC and PC1. The inclusion of PC2 and AR increased (P < 0.05) the abundance of nuclear factor (erythroid-derived 2)-like 2 (NFE2L2), but decreased (P < 0.05) the level of tumor necrosis factor in the mammary gland. Moreover, goats receiving AR tended to increase (P < 0.05) the levels of SOD2, GPX1, and GPX2 mRNA expression in the mammary gland. There were significant (P < 0.05) positive correlations between DPPH scavenging activity, total antioxidant capacity, SOD, catalase enzymes in plasma, and the abundance of NFE2L2 in the mammary gland. In addition, stronger (P < 0.05) positive correlations were noted between the expression of several inflammation related and antioxidant genes. Collectively, the results from the current study indicated that the consumption of anthocyanin-rich PSS by dairy goats had the potential to enhance antioxidant potential by improving antioxidant capacity in plasma and by modulating the abundance of several inflammation related and antioxidant genes in the mammary gland.

Cherry Anthocyanins Regulate NAFLD by Promoting Autophagy Pathway

Nonalcoholic fatty liver disease (NAFLD) is a common chronic disease that threatens human health, and present therapies remain limited due to the lack of effective drugs. Lipid metabolic disturbance and oxidative stress have strong links to the development of NAFLD, while autophagy was generally accepted as a key regulatory mechanism on these steps. Our previous studies indicated that cherry anthocyanins (CACN) protected against high fat diet-induced obesity and NALFD in C57BL/6 mice, while the underlying molecule mechanism is still unclear. Thus, in this study, we show that CACN protect against oleic acid- (OA-) induced oxidative stress and attenuate lipid droplet accumulation in NAFLD cell models. According to the results of a transmission electron microscope (TEM), western blot, immunofluorescence (IF), and adenovirus transfection (Ad-mCherry-GFP-LC3B), autophagy is in accordance with the lipid-lowering effect induced by CACN. Further studies illustrate that CACN may activate autophagy via mTOR pathways. In addition, an autophagy inhibitor, 3-methyladenine (3-MA), was applied and the result suggested that autophagy indeed participates in the lipid clearance process in OA-induced lipid accumulation. All these results indicate that the positive effects of CACN on OA-induced hepatic lipid accumulation are mediated via activating autophagy, showing a potential target for the therapeutic strategy of NAFLD.

Modeling of the Adsorption/Desorption Characteristics and Properties of Anthocyanins from Extruded Red Cabbage Juice by Macroporous Adsorbent Resin

The adsorption/desorption characteristics, modeling and properties of anthocyanins from extruded red cabbage juice by macroporous resins were investigated. The static adsorption and desorption capacities of red cabbage anthocyanins on five macroporous resins were measured and compared. The X-5 resin showed the best capacities and was selected for the adsorption kinetics, isotherms and elution studies. The pseudo-second-order kinetic model and Langmuir isotherm model were used to describe the adsorption process and mechanism. Dynamic adsorption and desorption tests were performed on a fixed-bed column, and the loading and eluent conditions were optimized. The purity of anthocyanins in freeze-dried purified powder by the resin adsorption process is 21.3 ± 0.9 wt % and shows better stability in the air than the unpurified one. Finally, the antioxidant activity and color properties including color density, color intensity, color tonality and degradation index of the purified powders were measured.

Cardiovascular mortality attributable to dietary risk factors in 51 countries in the WHO European Region from 1990 to 2016: a systematic analysis of the Global Burden of Disease Study

This study was performed to highlight the relationship between single dietary risk factors and cardiovascular diseases (CVDs) in the WHO European Region. We used the comparative risk assessment framework of the Global Burden of Disease Study to estimate CVD mortality attributable to diet; comprising eleven forms of CVDs, twelve food and nutrient groups and 27 risk-outcome pairs in four GBD regions including 51 countries by age and sex between 1990 and 2016. In 2016, dietary risks were associated with 2.1 million cardiovascular deaths (95% uncertainty interval (UI), 1.7-2.5 million) in the WHO European Region, accounting for 22.4% of all deaths and 49.2% of CVD deaths. In terms of single dietary risks, a diet low in whole grains accounted for approximately 429,000 deaths, followed by a diet low in nuts and seeds (341,000 deaths), a diet low in fruits (262,000 deaths), a diet high in sodium (251,000 deaths), and a diet low in omega-3 fatty acids (227,000 deaths). Thus, with an optimized, i.e. balanced diet, roughly one in every five premature deaths could be prevented. Although age-standardized death rates decreased over the last 26 years, the absolute number of diet-related cardiovascular deaths increased between 2010 and 2016 by 25,600 deaths in Western Europe and by 4300 deaths in Central Asia. In 2016, approximately 601,000 deaths (28.6% of all diet-related CVD deaths) occurred among adults younger than 70 years. Compared to other behavioural risk factors, a balanced diet is a potential key lever to avoid premature deaths.

Short communication: Purple corn (Zea mays L.) stover silage with abundant anthocyanins transferring anthocyanin composition to the milk and increasing antioxidant status of lactating dairy goats

The present study used 16 multiparous lactating Saanen dairy goats (body weight, 41.80 ± 2.92 kg; mean ± standard deviation) with healthy and symmetrical udders. Goats were divided into 2 blocks of 8 goats based on milk yield averaged from 75 d in milk in a randomized completed block design. The 2 study groups were the control (CSSS), in which goats were fed sticky corn stover silage, and the treatment (TPSS), in which goats were fed anthocyanin-rich purple corn (Zea mays L.) stover silage (PSS). The results indicated that the TPSS group led to an elevation in the content of milk lactose relative to the CSSS. The inclusion of anthocyanin-rich PSS had no effect on the level of 5 particular anthocyanins [i.e., cyanidin-3-glucoside, delphinidin, cyanidin, pelargonidin (Pel), as well as total anthocyanins in milk]. The pelargonidin-3-glucoside and malvidin were unable to be detected in both groups. However, the TPSS resulted in higher levels of peonidin (Peo) and malvidin-3-O-glucoside (M3G) compared with the control. Moreover, goats receiving TPSS exhibited a higher level of superoxide dismutase (SOD) in plasma and milk relative to the CSSS. Interestingly, some positive correlations were detected between the certain milk components [i.e., fat and total solids as well as fat and solids-not-fat (SNF); protein and SNF; and total solids and SNF]. In addition, the positive correlations were observed between individual anthocyanins (cyanidin-3-glucoside, delphinidin, Peo, M3G, cyanidin, and Pel) and total anthocyanins. Specifically, stronger positive correlations were noted between several antioxidant enzymes and anthocyanin composition in milk (total antioxidant capacity and Pel; SOD and Peo as well as SOD and M3G). Taken together, PSS with abundant anthocyanins can transfer anthocyanins to the milk and enhance the amount of antioxidants in lactating dairy goats.

Fermentation alters the bioaccessible phenolic compounds and increases the alpha-glucosidase inhibitory effects of aronia juice in a dairy matrix following in vitro digestion

The prevalence of diabetes reached 415 million worldwide in 2015. Polyphenol-rich food intake can benefit the glycemic control for individuals with diabetes. Fermentation may increase the bioavailability of polyphenols, which is generally low. Aronia (Aronia melanocarpa) is a polyphenol-rich berry that is native to North America. Proanthocyanins and anthocyanins are the major phenolic compounds in aronia. In this study, aronia kefir was made by fermenting cow's milk with added aronia juice. The changes in bioaccessible polyphenols of aronia kefir during digestion were assessed using an in vitro model. The impact of fermentation on the potential bioactivity of aronia polyphenols was evaluated. Results showed that the bioaccessible polyphenols in aronia kefir were elevated during digestion and the antioxidant capacity increased (IC50 of DPPH scavenging decreased from 24.07 mg kefir per mL to 8.97 mg kefir per mL). Digested aronia kefir had less bioaccessible anthocyanins (cyanidin-3-galactoside, cyanidin-3-arabinoside and cyanidin-3-xyloside) but similar antioxidant capacity and stronger inhibitory activity on α-glucosidase (IC50: 152.53 mg kefir per mL) compared to the non-fermented control (IC50: 484.93 mg kefir per mL). These results indicate that fermentation may produce metabolites with higher antioxidant capacity and better α-glucosidase inhibitory activity. Utilizing aronia kefir in the diet is a good strategy to help control blood glucose levels without abdominal side effects. Fermentation may be an effective method to increase the bioavailability of dietary polyphenols in food. More studies about the effects of fermentation on polyphenol-rich food are needed to optimize the potential health-promoting properties.

Changes of Anthocyanin Component Biosynthesis in 'Summer Black' Grape Berries after the Red Flesh Mutation Occurred

The coloring process of grape flesh is valuable for research and promotion of the high nutritional quality of anthocyanins. 'Summer Black' and it is new red flesh mutant were used to analyze the changes of anthocyanin biosynthesis during grape berry development. Eighteen kinds of anthocyanins were detected in mature berries of the two cultivars, but the content of most 3'- and 3',5'-substituted anthocyanins was higher in the skin of the mutant. Anthocyanin accumulation occurred simultaneously in the skin and flesh of the mutant, and their types and content were more abundant in the former. For the mutant, there were only CHS, OMT, MYBA3, and MYBPA1 at lower transcriptional level in the flesh during veraison when compared with these in the skin, which might be an important factor to limit the anthocyanin accumulation in the flesh. The occurrence of red flesh might be related the enhancement of anthocyanin biosynthesis in the whole berry.

Melatonin in Heart Failure: A Promising Therapeutic Strategy?

Heart failure is a multifactorial clinical syndrome characterized by the inability of the heart to pump sufficient blood to the body. Despite recent advances in medical management, poor outcomes in patients with heart failure remain very high. This highlights a need for novel paradigms for effective, preventive and curative strategies. Substantial evidence supports the importance of endogenous melatonin in cardiovascular health and the benefits of melatonin supplementation in various cardiac pathologies and cardiometabolic disorders. Melatonin plays a crucial role in major pathological processes associated with heart failure including ischemic injury, oxidative stress, apoptosis, and cardiac remodeling. In this review, available evidence for the role of melatonin in heart failure is discussed. Current challenges and possible limitations of using melatonin in heart failure are also addressed. While few clinical studies have investigated the role of melatonin in the context of heart failure, current findings from experimental studies support the potential use of melatonin as preventive and adjunctive curative therapy in heart failure.