Efficacy of black rice extract on obesity in obese postmenopausal women: a 12-week randomized, double-blind, placebo-controlled preliminary clinical trial

Composition and Biological Activity of Colored Rice-A Comprehensive Review

Colored rice (black, purple, red and brown) has been consumed in China for nearly 4000 years. Recent research has focused on exploring its nutritional and metabolomic profiles and associated health benefits. Due to the improvement in detection and quantification techniques for health-promoting compounds and their activities, the number of studies has increased significantly. In this regard, a timely and updated review of research on nutritional composition, phytochemistry, and metabolite content and composition can significantly enhance consumer awareness. Here, we present a detailed and up-to-date understanding and comparison of the nutritional and phytochemical (metabolite) composition of colored rice. While earlier literature reviews focus on either single type of colored rice or briefly present nutritional comparison or bioactivities, here we present more detailed nutrient profile comparison (carbohydrates, fats, proteins, amino acids, minerals, and vitamins), together with the most recent comparative data on phytochemicals/metabolites (flavonoids, anthocyanins, fatty acids, amino acids and derivatives, phenolic acids, organic acids, alkaloids, and others). We discuss how metabolomics has broadened the scope of research by providing an increasing number of detected compounds. Moreover, directions on the improvement in colored rice nutritional quality through breeding are also presented. Finally, we present the health-beneficial activities (antioxidant, anti-inflammatory, antimicrobial, hypoglycemic, neuroprotective, anti-aging, and antitumor activities) of different colored rice varieties, together with examples of the clinical trials, and discuss which bioactive substances are correlated with such activities.

Critical Review on Anti-Obesity Effects of Anthocyanins Through PI3K/Akt Signaling Pathways

Obesity is a global health crisis and is one of the major reasons for the rising prevalence of metabolic disorders such as type 2 diabetes, cardiovascular diseases, and certain cancers. There has been growing interest in the search for natural molecules with potential anti-obesity effects; among the phytochemicals of interest are anthocyanins, which are flavonoid pigments present in many fruits and vegetables. Anthocyanins influence obesity via several signaling pathways. The PI3K/Akt signaling pathway plays a major role with a focus on downstream targets such as GLUT4, FOXO, GSK3β, and mTOR, which play a central role in the regulation of glucose metabolism, lipid storage, and adipogenesis. The influence of critical factors such as oxidative stress and inflammation also affect the pathophysiology of obesity. However, the studies reviewed have certain limitations, including variations in experimental models, bioavailability challenges, and a lack of extensive clinical validation. While anthocyanin shows tremendous potential, challenges such as poor bioavailability, stability, and regulatory matters must be overcome for successful functional food inclusion of anthocyanins. The future of anthocyanin-derived functional foods lies in their ability to overcome hurdles. Therefore, this review highlights the molecular mechanisms of obesity through the PI3K/Akt signaling pathways and explores how anthocyanins can modulate these signaling pathways to address obesity and related metabolic disorders. It also addresses some ways to solve the challenges, like bioavailability and stability, while emphasizing future possibilities for anthocyanin-based functional foods in obesity management.

Amelioration of aging-induced muscular decline by black soybean (Rhynchosia nulubilis) and black rice (Oryza sativa L.) extracts

Aging leads to a decline in the mass and function of skeletal muscles, a condition known as sarcopenia. It was previously reported that aging-related alterations in protein degradation, chronic inflammation, and deterioration of mitochondrial metabolism affect the acceleration of muscle atrophy in the elderly. However, the detailed mechanism or substantial causes for age-related muscle loss are still lacking, yet exercise or an increment in dietary protein intake are suggested as effective approaches to mitigate muscle atrophy. This study aims to investigate the regulatory effect of black soybean (Rhynchosia nulubilis) and black rice (Oryza sativa L.) mixture extract (BBME), which are rich in protein and bioactive compounds, in 12-month-old aged mice and L6 myotubes. BBME was orally administered at 300 and 600 mg/kg/day (low and high doses) for 12 weeks, and its effects on systemic glucose homeostasis and skeletal muscle metabolism were evaluated. Consequently, BBME at a high dose marginally ameliorated muscle loss and significantly improved glucose metabolism. BBME also reduced cellular senescence markers and enhanced mitochondrial biogenesis in aged skeletal muscles. Additionally, BBME exerted insulin-like activity by promoting glucose metabolism in L6 myotubes. These findings suggest the potential of BBME as a functional food ingredient in alleviating aging-induced muscle loss by modulating mitochondrial activity and glucose metabolism.

Effect of dietary anthocyanins on the risk factors related to metabolic syndrome: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis aims to systematically investigate whether dietary anthocyanin supplementation can reduce metabolic syndrome (MetS)-related risk factors: abdominal obesity, dyslipidemia (low high-density lipoprotein cholesterol (HDL-C) and hypertriglyceridemia), hypertension, and hyperglycemia by conducting a meta-analysis of randomized controlled trials (RCTs).

METHODS

A systematic search of 5 electronic databases (PubMed, Web of Science, Scopus, Cochrane Library, and Embase) was conducted from inception until April 25, 2024. A total of 1213 studies were identified, of which randomized controlled trials involving subjects with MetS-related factors, comparing dietary anthocyanin supplementation with placebo, and reporting results on anthropometric, physiological, and metabolic markers relevant to this study were selected. Depending on the heterogeneity of the included studies, a fixed-effect model was applied for low heterogeneity (I2 < 50%), whereas a random-effects model was employed when substantial heterogeneity was present (I2 ≥ 50%). The weighted mean difference (WMD) and 95% confidence intervals (CI) were calculated.

RESULTS

This meta-analysis included 29 randomized controlled trials with 2006 participants. The results showed that dietary anthocyanins significantly improved various lipid and glycemic markers: HDL-C: increased by 0.05 mmol/L (95% CI: 0.01 to 0.10, p = 0.026), LDL-C: decreased by 0.18 mmol/L (95% CI: -0.28 to -0.08, p = 0.000), Triglycerides (TGs): reduced by 0.11 mmol/L (95% CI: -0.20 to -0.02, p = 0.021), Total cholesterol (TC): lowered by 0.34 mmol/L (95% CI: -0.49 to -0.18, p = 0.000), Fasting blood glucose (FBG): reduced by 0.29 mmol/L (95% CI: -0.46 to -0.12, p = 0.001), Glycated hemoglobin (HbA1c): decreased by 0.43% (95% CI: -0.74 to -0.13, p = 0.005). Weight: (WMD: -0.12 kg, 95% CI: -0.45 to 0.21, p = 0.473), Body mass index (BMI): (WMD: -0.12 kg/m2, 95% CI: -0.26 to 0.03, p = 0.12), Overall WC: (WMD: 0.18 cm, 95% CI: -0.51 to 0.87, p = 0.613), Systolic blood pressure (SBP): (WMD: -0.12 mmHg, 95% CI: -1.06 to 0.82, p = 0.801), Diastolic blood pressure (DBP): (WMD: 0.61 mmHg, 95% CI: -0.03 to 1.25, p = 0.061), Insulin levels: (WMD: -0.02 mU/L, 95% CI: -0.44 to 0.40, p = 0.932), HOMA-IR: (WMD: -0.11, 95% CI: -0.51 to 0.28, p = 0.573). Additionally, a 100 mg/day dosage of anthocyanins significantly reduced: Waist circumference (WC): by 0.55 cm (95% CI: -1.09 to -0.01, p = 0.047). Subgroup analyses based on intervention duration, anthocyanin dosage, health status, formulation, dosage frequency, physical activity levels, and baseline levels of corresponding markers revealed varying significances, particularly in relation to blood pressure.

CONCLUSION

Dietary anthocyanins effectively improve low HDL cholesterol, hypertriglyceridemia, and hyperglycemia, making them a promising adjunct for managing MetS. However, it is important to note that dietary anthocyanin interventions may raise systolic blood pressure (SBP) and diastolic blood pressure (DBP) depending on intervention dose, duration, participant health status, and formulation. Clinicians should fully consider these effects when recommending anthocyanin supplementation. Further long-term, well-designed, large-scale clinical trials are needed to draw definitive conclusions.

Role of sirtuins in obesity and osteoporosis: molecular mechanisms and therapeutic targets

The prevalence of obesity and osteoporosis (OP) represents a significant public health concern on a global scale. A substantial body of evidence indicates that there is a complex relationship between obesity and OP, with a correlation between the occurrence of OP and obesity. In recent years, sirtuins have emerged as a prominent area of interest in the fields of aging and endocrine metabolism. Among the various research avenues exploring the potential of sirtuins, the effects of these proteins on obesity and OP have garnered significant attention from numerous researchers. Sirtuins regulate energy balance and lipid balance, which in turn inhibit the process of adipogenesis. Additionally, sirtuins regulate the balance between osteogenic and osteoblastic activity, which protects against the development of OP. However, no study has yet provided a comprehensive discussion of the relationship between the three: sirtuins, obesity, and OP. This paper will therefore describe the relationship between sirtuins and obesity, the relationship between sirtuins and OP, and a discussion focusing on the possibility of treating OP caused by obesity by targeting sirtuins. This will be based on the common influences on the occurrence of obesity and OP (such as mesenchymal stem cells, gut microbiota, and insulin). Finally, the potential of SIRT1, an important member of sirtuins, in polyphenolic natural products for the treatment of obesity and OP will be presented. This will contribute to a better understanding of the interactions between sirtuins and obesity and bone, which will facilitate the development of new therapeutic strategies for obesity and OP in the future.

Effect of Pigmented Rice Consumption on Cardiometabolic Risk Factors: A Systematic Review of Randomized Controlled Trials

PURPOSE OF REVIEW

Dietary patterns that include polyphenols may help manage cardiometabolic risk factors. Pigmented rice contains phenolic acids and flavonoids that contribute to its antioxidant properties. This review examined the effect of polyphenol-containing pigmented rice on antioxidant status, lipid profile, glucose/insulin, blood pressure, and weight among adults. Four electronic databases including PubMed, ProQuest, EBSCOhost, and Google Scholar were systematically searched for relevant articles published in English since 2000, using PRISMA guidelines (PROSPERO registration: CRD42022358132). Two-staged screening resulted in the inclusion of seventeen (seven acute, ten chronic) randomized controlled trials. A random effects model was conducted on cardiometabolic outcomes reported in at least three studies.

RECENT FINDINGS

Acute intake increased plasma antioxidant activity and lowered postprandial glucose and insulin levels. Chronic consumption was associated with reductions in fasting glucose (WMD: -1.60 mg/dL; 95% CI:-3.05,-0.14, p = 0.03, k = 5, n = 349), weight (WMD: -0.23 kg, 95% CI: -0.44, -0.02, p = 0.03, k = 3, n = 182), and diastolic blood pressure (WMD: -1.39 mmHg, 95% CI: -2.21, -0.56, p = 0.001, k = 3, n = 185). No effect on total cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, body mass index, and systolic blood pressure was found. The consumption of pigmented rice may improve cardiometabolic risk factors. However, the small number of studies and differences in study design, including participants' health status, form of rice utilized, and duration of intervention, support the need for more high-quality trials to further investigate these findings.

Anthocyanins' effects on diabetes mellitus and islet transplantation

The incidence of diabetes mellitus is dramatically increasing every year, causing a huge global burden. Moreover, existing anti-diabetic drugs inevitably bring adverse reactions, and the application of islet transplantation is often limited by the damage caused by oxidative stress after transplantation. Thus, new approaches are needed to combat the growing burden of diabetes mellitus. Anthocyanins are of great nutritional interest and have been documented that have beneficial effects on chronic diseases, including diabetes mellitus. Here, we describe the health effects of anthocyanins on diabetes mellitus and islet transplantation. Epidemiological studies demonstrated that moderate intake of anthocyanins leading to a reduction in risk of diabetes mellitus. Numerous experiments both animal and clinical studies also showed positive effects of anthocyanins on prevention and treatment of diabetes and diabetic complications. These effects of anthocyanins may be related to mechanisms of improving glucose and lipid metabolism and insulin resistance, antioxidant, and anti-inflammatory activities. In addition, damage and function of pancreatic islets after transplantation are also improved by anthocyanins. These findings suggest that daily intake of anthocyanins may not only improve nutritional metabolism in healthy individuals to prevent from diabetes, but also as a supplementary treatment of diabetes mellitus and islet transplantation. Thus, more evidence is needed to better understand the potential health benefits of anthocyanins.

Effects of anthocyanin supplementation on blood lipid levels: a systematic review and meta-analysis

Introduction

Dyslipidemia is a major cardiovascular disease risk factor associated with increased mortality. The intake of plant food-derived bioactive compounds is associated with beneficial cardiovascular effects, including decreased blood lipid levels and cardiovascular risk. We aimed to evaluate the effects of anthocyanin intake on blood lipid levels by analyzing relevant randomized controlled trials.

Methods

We searched the PubMed and Embase databases using the "Patient/Population, Intervention, Comparison, and Outcomes" format to determine whether anthocyanin supplementation intervention affected blood lipid levels compared with placebo supplementation in human participants.

Results

A total of 41 studies with 2,788 participants were included in the meta-analysis. Anthocyanin supplementation significantly reduced triglyceride [standardized mean difference (SMD) = -0.10; 95% confidence interval [CI], -0.18, -0.01) and low-density lipoprotein-cholesterol (SMD = -0.16; 95% CI -0.26, -0.07) levels and increased high-density lipoprotein-cholesterol levels (SMD = 0.42; 95% CI 0.20, 0.65).

Discussion

Anthocyanin supplementation significantly improved blood lipid component levels in the included studies. Larger, well-designed clinical trials are needed to further investigate the effects of anthocyanin intake on blood lipid levels and the safety of anthocyanin supplementation for treating dyslipidemia.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021257087, identifier: CRD42021257087.

Pharmacological studies of the genus rice (Oryza L.): a literature review

Rice (Oryza L.) is an essential food for more than 50 percent of the world's population and is the world's second-largest grain crop. Pigmented rice comes in various colors, such as black, red, brown, and green. Anthocyanins, like cyanidin-3-O-glucoside and peonidin-3-O-glucoside, are the primary color pigments in colored rice, whereas proanthocyanidins and flavan-3-ol oligosaccharides, with catechins as the central synthesis unit, are found in brown rice. This review article's aim is to give information and a summary of rice activities, research methods, also mechanisms of action (Oryza L.). Intake of pigmented rice was already associated with a number of health benefits, including antioxidant activity, anticancer, antitumor, antidiabetic activity, and a reduced risk of cardiovascular disease. Rice contains several bioactive compounds, such as γ-oryzanol, phenolic acid, anthocyanins, proanthocyanidins, flavonoids, carotenoids, and phytosterols, which have been widely studied and shown to have several pharmacological activities. The use of current herbal compounds is rapidly increasing, including the practice of pharmacological disease prevention and treatment. Herbal remedies have entered the international market as a result of research into plant biopharmaceuticals and nutraceuticals. Through a variety of pharmacological activities, it is clear that Oryza L. is a popular herb. As a result, additional research on Oryza L. can be conducted to investigate more recent and comprehensive pharmacological effectiveness, to provide information and an overview of Rice (Oryza L.) activities, research methods, and mechanisms of action. Several natural substances are characterized by low water solubility, low stability, and sensitivity to light and oxygen, and the potential for poor absorption of the active substances requires modification of the formulation. To improve the effectiveness of pharmacologically active substances originating from natural ingredients, drug delivery systems that use lipid-based formulations can be considered innovations.

Resistant starch from black rice, Oryza sativa L. var. ameliorates renal inflammation, fibrosis and injury in insulin resistant rats

It has recently been reported that black rice (BR) extract has anti-obesity, anti-diabetic, and anti-osteoporosis effects. It has been shown to reduce obese-related kidney dysfunction in animal models. This study aimed to investigate the effect of resistant starch from BR (RS) on renal inflammation, oxidative stress, and apoptosis in obese insulin resistant rats. Male Wistar rats were divided into six groups: normal diet (ND), ND treated with 150 mg of RS (NDRS150), high-fat (HF) diet, HF treated with 100 and 150 mg of RS (HFRS100), (HFRS150), and HF treated with metformin as a positive control. Insulin resistance was shown in the HF rats by glucose intolerance, increased insulin, total area under the curve of glucose and homeostasis model assessment of insulin resistance and dyslipidemia. The resulting metabolic disturbance in the HF rats caused renal inflammation, fibrosis and apoptosis progressing to kidney injury and dysfunction. Prebiotic RS including anthocyanin from BR at doses of 100 and 150 mg ameliorated insulin resistance, dyslipidemia and liver injury. Treatment with RS reduced TGF-β fibrotic and apoptotic pathways by inhibition of NF-κB and inflammatory cytokines which potentially restore kidney damage and dysfunction. In conclusion, prebiotic RS from BR ameliorated obesity induced renal injury and dysfunction by attenuating inflammatory, fibrotic, and apoptotic pathways in insulin resistant rats induced by HF.

Anthocyanins in Chronic Diseases: The Power of Purple

Anthocyanins are mainly purple-coloured phenolic compounds of plant origin that as secondary metabolites are important in plant survival. Understanding their health benefits in humans requires sourcing these unstable compounds in sufficient quantities at a reasonable cost, which has led to improved methods of extraction. Dark-coloured fruits, cereals and vegetables are current sources of these compounds. The range of potential sustainable sources is much larger and includes non-commercialised native plants from around the world and agri-waste containing anthocyanins. In the last 5 years, there have been significant advances in developing the therapeutic potential of anthocyanins in chronic human diseases. Anthocyanins exert their beneficial effects through improvements in gut microbiota, oxidative stress and inflammation, and modulation of neuropeptides such as insulin-like growth factor-1. Their health benefits in humans include reduced cognitive decline; protection of organs such as the liver, as well as the cardiovascular system, gastrointestinal tract and kidneys; improvements in bone health and obesity; and regulation of glucose and lipid metabolism. This review summarises some of the sources of anthocyanins and their mechanisms and benefits in the treatment of chronic human diseases.