Germinated Thai Black Rice Extract Protects Experimental Diabetic Rats from Oxidative Stress and Other Diabetes-Related Consequences

Effects of germinated brown rice and germinated black rice on people with type 2 diabetes mellitus combined with dyslipidaemia

Objective: This study aimed to observe the effects of germinated brown rice and germinated black rice on blood lipid levels, blood glucose levels and lipid metabolism-related enzymes in T2DM patients with dyslipidaemia and to study their effects on the gut microbiome and short-chain fatty acids. Methods: According to the inclusion and exclusion criteria, 68 subjects were randomly divided into a germinated brown rice group, a germinated black rice group and a white rice group. At the end of the intervention, relevant anthropometric indices, blood biochemistry, and levels of adipokines and lipid metabolism-related enzymes were measured. Faecal samples were collected for 16S rDNA high-throughput sequencing and for an analysis of short-chain fatty acids. Results: After 3 months of intervention with germinated brown rice, germinated black rice or white rice, 21 people in each group completed the intervention as required. At the end of the intervention, the levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in the germinated brown rice group and germinated black rice group were significantly lower than those in the white rice group. The levels of adiponectin (ADPN) and lecithin cholesterol acyltransferase (LCAT) in the germinated brown rice group were significantly higher than those in the white rice group (P < 0.05). At the genus level, interventions with germinated brown rice and germinated black rice significantly increased the relative abundance of Megamonas, Muribaculaceae and Alloprevotella and significantly decreased the relative abundance of Veillonella (P < 0.05). After 3 months of intervention, a significant decrease in waist circumference was observed within the germinated brown rice group compared to that at baseline (P < 0.05). Conclusions: Compared with the consumption of white rice, the consumption of germinated brown rice and germinated black rice can effectively regulate the glucose and lipid metabolism of this population. In addition, interventions involving the use of germinated brown rice and germinated black rice may further improve intestinal diversity and abundance, increase the relative abundance of Megamonas and decrease the relative abundance of Veillonella.

Postprandial glycemic and lipidemic effects of black rice anthocyanin extract fortification in foods of varying macronutrient compositions and matrices

Anthocyanin (ACN) fortification of commonly consumed foods is significant as a dietary strategy against the development of metabolic complications by delivering ACNs at high doses. However, its bioactivity and translated metabolic effects in the presence of varying food matrices and macro-constituents is particularly unclear. This end-to-end study investigates the metabolic effects of black rice ACN extract (BRAE) fortification-from in-vitro enzyme inhibitory activities and digestibility, to downstream in vivo impacts on GI, postprandial glycemia and lipidemia. The in vivo effects were investigated in two separate crossover randomised controlled trials (RCT) of 24 healthy participants each-the first RCT determined the postprandial blood glucose, insulin, and ACN bioavailability to a starch-rich single food over 2 h, while the second RCT determined the postprandial blood glucose, insulin, lipid panel, and lipoprotein particles and subfractions to a starch- and fat-rich composite meal over 4 h. In-vitro findings confirmed the inhibitory activities of major black rice ACNs on carbohydrases (p = 0.0004), lipases (p = 0.0002), and starch digestibility (p < 0.0001). in vivo, a 27-point mean GI reduction of wheat bread was observed with BRAE fortification, despite a non-significant attenuation in postprandial glycemia. Conversely, there were no differences in postprandial glycemia when fortified bread was consumed as a composite meal, but acute lipid profiles were altered: (1) improved plasma HDL-c, ([0.0140 mmol/L, 95% CI: (0.00639, 0.0216)], p = 0.0028), Apo-A1 ([0.0296 mmol/L, 95% CI: (0.00757, 0.0515)], p = 0.0203), and Apo-B ([0.00880 mmol/L, 95% CI: (0.00243, 0.0152)], p = 0.0185), (2) modified LDL and HDL subfractions (p < 0.05), and (3) remodelled lipid distributions in HDL and LDL particles. This end-to-end study indicates the potential of ACN fortification in GI reduction and modulating postprandial lipoprotein profiles to starch- and fat-rich composite meals.

Riceberry Rice Germination and UVB Radiation Enhance Protocatechuic Acid and Vanillic Acid to Reduce Cellular Oxidative Stress and Suppress B16F10 Melanogenesis Relating to F-Actin Rearrangement

Ultraviolet type B (UVB) radiation plays an important role in hyperpigmentation disorder, which induces cellular oxidative stress and causes abnormal melanin production and secretion. The stress condition plays an essential role in actin polymerization relating to F-actin rearrangement and forms dendrite to send melanin pigment to the uppermost layer of the skin. Phenolic compounds are secondary metabolites that mainly synthesize under stress conditions to protect plants from harmful environments and have been reported as effective agents in anti-oxidant and anti-melanogenesis. However, the influence of phenolic compounds on F-actin rearrangement-associated dendrite formation has not been studied so far. Hence, this study aimed to investigate the enhancing phytophenolic targets in riceberry rice (Oryza sativa L.) germination and UVB radiation (RR-GR) to suppress melanogenesis relating to F-rearrangement. As a result, the RR-GR had the potential to enhance phenolic acids such as protocatechuic and vanillic acid, which have been proven to possess anti-oxidant activity and anti-tyrosinase properties. Riceberry rice's modification showed the potential to reduce cellular oxidative stress and suppress B16F10 melanogenesis relating to F-actin rearrangement that is associated with dendrite formation.

Comparative analysis of bioactive-phytochemical characteristics, antioxidants activities, and anti-inflammatory properties of selected black rice germ and bran (Oryza sativa L.) varieties

Black rice has numerous health benefits and one of the well-known functional foods throughout the world. To encourage the increasing trend of the consumer interest in health-promoting functional foods, special varieties of rice have been developed offering greater nutrient values and exhibiting biological activities that are beneficial to the consumer. In this study, we aimed to evaluate the associations of the phytochemical contents, antioxidants, and anti-inflammatory properties among eight selected black rice germ and bran extracts (BR extracts) from 4 non-glutinous and 4 glutinous rice varieties. Accordingly, glutinous BR extracts possessed higher degree of Cyanidin-3-O-glucoside (C3G), Peonidin-3-O-glucoside (P3G) contents, antioxidant and anti-inflammatory properties than the non-glutinous BR extracts. Pearson's correlation indicated that the amount of C3G in the BR extracts had a strong positive association with the antioxidant properties (DPPH; r = 0.846, ABTS; r = 0.923, and FRAP; r = 0.958, p < 0.01). While P3G exhibited a strong positive association with the anti-inflammatory properties (r value = 0.717 and 0.797 for IL-6 and TNF-α inhibition, respectively, p < 0.05). Lastly, the principal component analysis (PCA) categorized the black rice varieties into three groups: Group A with high C3G content and superior antioxidant properties, Groups B with a high amount of P3G and potent anti-inflammatory properties, and Group C with a lower amount of phytochemical contents and less potent bioactivities. Overall, the outcomes of this study could provide vital information to food industries in selecting the variety of black rice for the functional food based on the anthocyanin contents that could benefit to consumers for new normal healthy lifestyle.

Photochemistry, Functional Properties, Food Applications, and Health Prospective of Black Rice

This review investigates black rice’s photochemistry, functional properties, food applications, and health prospects. There are different varieties of black rice available in the world. The origins of this product can be traced back to Asian countries. This rice is also known as prohibited rice, emperor’s rice, and royal’s rice. Black rice is composed of different nutrients including fiber, protein, carbohydrates, potassium, and vitamin B complex. It contains an antioxidant called anthocyanin and tocopherols. Antioxidants are found mostly in foods that are black or dark purple. Due to its nutritious density, high fiber level, and high antioxidant content, black rice is a good alternative to white and brown rice. Utilizing black rice in various foods can enhance the nutritional value of food and be transformed into functional food items. Many noncommunicable diseases (NCDs) can be prevented by eating black rice daily, including cancer cells, atherosclerosis, hypertension, diabetes, osteoporosis, asthma, digestive health, and stroke risk. This review aim was to discuss the role of nutritional and functional properties of black rice in the formation of functional food against different noncommunicable diseases.

Effect and mechanism of peanut skin proanthocyanidins on gliadin-induced Caco-2 celiac disease model cells

Proanthocyanidins have been shown to inhibit the signaling pathways related to oxidative stress and inflammation, also improved cell membrane integrity. The effect of peanut skin proanthocyanidins (PSPc) on CD remains unknown. In this paper, the effect and mechanism of PSPc on glial protein-induced Caco-2 cytotoxicity were studied. The results showed that PSPc may inhibit oxidative stress in DPG-induced CD model in vitro by regulating SIRT1/NRF2 pathway. By regulating SIRT1 and IκB signaling pathways, inhibit the phosphorylation of NF-κB and the deacetylation of NF-κB, inhibit inflammatory response, reduce release of inflammatory cytokines (IL-1β, IL-6, TNF-α), the cell survival rate was and the expression of TGM2 were improved, avoiding the damage of cell monolayer model. This experiment proved the prominent effect of PSPc on CD intervention. Studying the mechanism of PSPc in the treatment of CD injury will contribute to explore new therapies for CD which will be of great significance to supplement or replace gluten-free diets.

Black bean husk and black rice anthocyanin extracts modulated gut microbiota and serum metabolites for improvement in type 2 diabetic rats

Black rice and black bean have not yet been fully investigated as healthy foods for their therapeutic effects on type 2 diabetes mellitus (T2DM). In this study, we aimed to evaluate the antidiabetic effects of black rice, black bean husk anthocyanin extracts, and their combination on glycolipid metabolism, gut microbiota, and serum metabolites in T2DM rats. Black bean husk and black rice anthocyanin extracts were administered to T2DM rats by gavage for 4 weeks. The results showed that black rice and black bean husk anthocyanin extracts significantly improved blood glucose, insulin resistance, serum oxidative stress state, lipid metabolism and inflammatory cytokines levels in rats, and alleviated liver damage. Black rice and black bean husk anthocyanin extracts increased the abundance of short-chain fatty acid (SCFA) producing bacteria Akkermansia spp., Phascolarctobacterium spp., Bacteroides spp., and Coprococcus spp., changed the gut microbiota structure; activated AMPK, PI3K, and AKT; inhibited HMGCR, G6pase and PEPCK expression; and inhibited hepatic gluconeogenesis. Moreover, by adjusting the levels of urea, deoxycytidine, L-citrulline, pseudouridine, and other serum metabolites in T2DM rats, the arginine biosynthesis and pyrimidine metabolism pathways were downregulated. The above results indicated that black rice and black bean husk anthocyanin extracts had a significant impact on the development of T2DM.

The Effects of GABA-Rich Adzuki Beans on Glycolipid Metabolism, as Well as Intestinal Flora, in Type 2 Diabetic Mice

Objectives

In this study, the effects of γ-aminobutyric acid (GABA)-rich sprouted adzuki beans on the glycolipid metabolism and gastrointestinal health were investigated in mice with type 2 diabetes mellitus (T2DM).

Methods

Mice with T2DM were subjected to dietary intervention with different doses of GABA-rich sprouted adzuki beans for 6 consecutive weeks, during which growth indicators, glycolipid metabolism, and the composition and diversity of the gut microbiota changes were observed.

Results

A high dietary intake of GABA-rich sprouted adzuki beans had a preventive effect against weight gain, significantly reduced serum levels of FBG, TG, and TC. Additionally, high dietary intake of GABA-rich sprouted adzuki beans increased the abundances of Firmicutes, Bacteroidetes, Verrucomicrobia, and Akkermansia, leading to a shift in the structure of the gut microbiota toward the dominance of probiotics with regulatory effects on glycolipid metabolism.

Conclusions

GABA-rich sprouted adzuki beans can effectively control the bodyweight of mice with T2DM, maintain a balanced blood glucose level, improve glycolipid metabolism and the changes in the microbiota may mediate the anti-diabetic effect of sprouted adzuki beans.

Synergistic Effects of Combined Anthocyanin and Metformin Treatment for Hyperglycemia In Vitro and In Vivo

The mechanism underlying the hypoglycemic effect of the simultaneous use of metformin and anthocyanin-rich foods is not yet clear. Hence, the effects and possible mechanisms of action of these substances, alone and in combination, were evaluated in insulin-resistant HepG2 cells and a diabetic mouse model. The results indicated that anthocyanin and metformin had a significant synergistic effect on glucose consumption (CI < 0.9) compared with metformin alone in HepG2 cells. In the mouse model, combined treatment (50 and 100 mg/kg metformin + anthocyanin groups) demonstrated synergistic restorative effects on the blood glucose level, insulin resistance, and organ damage in the liver, pancreas, and ileum. Additionally, combined metformin and anthocyanin treatment suppressed protein tyrosine phosphatase 1B expression and regulated the PI3K/AKT/GSK3β pathway. Combined treatment also altered the gut microbial composition and structure by increasing the relative abundance of beneficial bacteria and the short-chain fatty acid content. These results suggest that the use of anthocyanins can enhance the efficacy of metformin treatment for hyperglycemia and provide a reference for further clinical research regarding nutrition and supplementary treatment.

Revealing the Hypoglycemic Effects and Mechanism of GABA-Rich Germinated Adzuki Beans on T2DM Mice by Untargeted Serum Metabolomics

Type 2 diabetes mellitus (T2DM) is one of the most common metabolic diseases, and exploring strategies to prevent and treat diabetes has become extremely important. In recent decades the search for new therapeutic strategies for T2DM involving dietary interventions has attracted public attention. We established a diabetic mouse model by feeding mice a high-fat diet combined with injection of low-dose streptozotocin, intending to elucidate the effects and possible mechanisms of different dosages of γ-aminobutyric acid (GABA)-rich germinated adzuki beans on the treatment of diabetes in mice. The mice were treated for 6 weeks either with increasing doses of GABA-enriched germinated adzuki beans, with non-germinated adzuki beans, with GABA, or with the positive control drug metformin. Then, the blood glucose levels and blood lipid biochemical indicators of all the mice were measured. At the same time, serum differential metabolite interactions were explored by UPLC-Q/TOF-MS-based serum metabolomic analysis. The results showed that body weight and fasting blood glucose levels were significantly reduced (P < 0.05). We also report improved levels of total cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, urea, and serum creatinine. We observed a significant improvement in the homeostasis model assessment of the beta cell function and insulin resistance (HOMA-β and HOMA-IR) scores (P < 0.05) in the group of mice treated with the highest dose of GABA-enriched germinated adzuki beans. In addition, the metabolic profiles of the serum were analyzed, and 31 differential metabolites including amino acids and lipids were obtained. According to the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, this was found to be correlated with nine significantly enriched metabolic pathways involving the up-regulation of levels of L-serine, SM (d18:1/22:1(13Z)), L-histidine, creatine, and 3-indoleacetic acid. Our data suggest that the hypoglycemic effect of GABA-enriched germinated adzuki beans on diabetic mice may be related to improving tryptophan metabolism, glycerol phospholipid metabolism, sphingosline metabolism, and the glycine, serine, and threonine metabolic pathways. This study provides a reference for the application of GABA-enriched germinated foods in type 2 diabetes and could provide a cue for searching biomarkers to be adopted for T2DM diagnosis.

Alpha glucosidase inhibitory properties of a few bioactive compounds isolated from black rice bran: combined in vitro and in silico evidence supporting the antidiabetic effect of black rice

Alpha glucosidase inhibitors reduce post prandial hyperglycemia and are the drugs of choice for the treatment of type 2 diabetes. As synthetic α-glucosidase inhibitors often produce undesirable side effects, less toxic inhibitors from natural sources are in high demand.

The nutritional profile and human health benefit of pigmented rice and the impact of post-harvest processes and product development on the nutritional components: A review

Pigmented rice has attracted considerable attention due to its nutritional value, which is in large conferred by its abundant content of phenolic compounds, considerable micronutrient concentrations, as well as its higher resistant starch and thereby slower digestibility properties. A wide range of phenolic compounds identified in pigmented rice exhibit biological activities such as antioxidant activity, anti-inflammatory, anticancer, and antidiabetic properties. Post-harvest processes significantly reduce the levels of these phytochemicals, but recent developments in processing methods have allowed greater retention of their contents. Pigmented rice has also been converted to different products for food preservation and to derive functional foods. Profiling a large set of pigmented rice cultivars will thus not only provide new insights into the phytochemical diversity of rice and the genes underlying the vast array of secondary metabolites present in this species but also provide information concerning their nutritional benefits, which will be instrumental in breeding healthier rice. The present review mainly focuses on the nutritional composition of pigmented rice and how it can impact human health alongside the effects of post-harvest processes and product development methods to retain the ambient level of phytochemicals in the final processed form in which it is consumed.

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

OBJECTIVES

Postmenopausal obesity is a paramount health concern among older women. Black rice is a well-known pigmented rice variety with a higher anthocyanin content. Both in vitro and in vivo studies have demonstrated the effects of black rice on obesity. The present study aimed to investigate the effects of black rice extract (BRE) on obesity among obese postmenopausal women from Korea.

METHODS

This was a 12-week, randomized, double-blind, placebo-controlled preliminary clinical trial. The participants were postmenopausal women who had stopped menstruating for more than a year. Specifically, 105 participants were randomly assigned to the BRE (1 g/d) or placebo (maltodextrin, 1 g/d) group.

RESULTS

Eighty-eight participants completed the study, 47 in the intervention group and 41 in the placebo group. At the study endpoint, dual-energy x-ray absorptiometry assessment showed that the BRE group had a significantly lower trunk fat (P = 0.04), total fat (P = 0.04), and total body fat percentage (P = 0.04) than did the placebo group. The body fat percentage (P = 0.04) was lower in the BRE group with marginal significance, and there were no significant differences in anthropometric measures such as weight, body mass index, waist circumference, or waist-to-hip ratio estimated by bioelectrical impedance analysis.

CONCLUSION

BRE supplementation for 12 weeks seems to be effective in reducing fat accumulation in postmenopausal women.

Oral Administration of Germinated, Pigmented, Giant Embryo Rice (Oryza sativa L. cv. Keunnunjami) Extract Improves the Lipid and Glucose Metabolisms in High-Fat Diet-Fed Mice

Obesity is a significant risk factor for chronic diseases. The effect of ethanol extract from germinated Keunnunjami, blackish-purple rice with a giant embryo, compare to ordinary brown rice, on the body weight and lipid and glucose metabolism in high-fat diet-fed mice was analyzed. Mice were fed with a high-fat diet-fed for 3 weeks and then orally administered with either distilled water (HF) or extract (0.25%, w/w) from brown, germinated brown, Keunnunjami, and germinated Keunnunjami rice for 4 weeks. Control mice were fed with a normal diet and orally administered with distilled water. The HF group showed markedly higher body weight and triglyceride, cholesterol, fatty acid, glucose, and insulin levels than the control group. However, the oral administration of rice extracts ameliorated this high-fat diet-induced obesity, hyperlipidemia, and hypoglycemia through the modulation of adipokine production, lipogenic and glucose-regulating enzyme activities, and mRNA expression of genes associated with lipid and glucose metabolism. The germinated Keunnunjami extract exhibited greater hypolipidemic, hypoglycemic, and body weight-lowering effects than the other rice extracts. The results demonstrated that germination could further enhance the physiological properties of rice and that germinated Keunnunjami extract has a strong therapeutic potential against high-fat diet-induced obesity, hyperlipidemia, and hyperglycemia.

Postprandial Glucose Levels Are Better Associated with the Risk Factors for Diabetes Compared to Fasting Glucose and Glycosylated Hemoglobin (HbA1c) Levels in Elderly Prediabetics: Beneficial Effects of Polyherbal Supplements-A Randomized, Double-Blind, Placebo Controlled Trial

Backgrounds

Prediabetes is a condition in which a person's blood glucose levels are higher than normal physiological levels but lower compared to patients with diabetes. Up to 70% of individuals with prediabetes will eventually develop diabetes. To date, there have been no pharmaceutical drugs to treat diabetes. It is believed that early diagnosis and nonpharmacological intervention for prediabetes are critical for effective prevention of diabetes. Most individuals with prediabetes remain undiagnosed even after being evaluated using the standard tests for fasting glucose (FG) and HbA1c. We investigated if postprandial glucose levels (2h-PG) were associated with pre/diabetes and if polyherbal supplements could be beneficial for individuals with prediabetes.

Materials and Methods

100 elderly individuals with impaired 2h-PG or fasting glucose levels were recruited to receive either a 12-week supplement of GlucoVita (an antioxidative polyherbal formulation) (n=50) or placebo (n=50).

Results

No baseline differences were observed for FG, HbA1c, or 2h-PG. Individuals who received a twelve-week administration of GlucoVita supplements had significantly reduced 2h-PG (8.15±1.67 versus 7.35±2.06 mmol/l, P<0.05) levels compared to individuals in the placebo group. In addition, HbA1c levels were lower in individuals who received GlucoVita (5.81±0.49 %) compared to the individuals in the placebo group (6.00±0.51%) (P=0.08) after 12-weeks. Stratified analysis, based on impaired fasting glucose (IFG), 2h-PG, metabolic symptom, and age, demonstrated that, after the 12-week intervention, HbA1c levels were significantly lower in the GlucoVita administered group compared to the placebo group (IFG subgroup; 5.85±0.46%, n= 27 versus 6.14±0.50, n=33, P<0.05) and the metabolic symptom-free subgroup (5.73±0.45%, n=23 versus 6.04±0.52%, n=24, P<0.05). GlucoVita also reduced FG in individuals with normal 2h-PG (6.37±0.27 versus 6.08±0.38 mmol/l, P<0.05). Baseline 2h-PG levels, but not HbA1c or FG levels, were significantly correlated with body weight, waist circumference, and BMI (r=0.25, P<0.05; r=0.31, P<0.01; r=0.22, P<0.05, respectively).

Conclusion

2h-PG levels were better associated with body weight, waist circumference, and BMI risk factors compared to FG and HbA1c levels in elderly individuals with prediabetes. Polyherbal formulation GlucoVita supplements improved 2h-PG and HbA1c levels only in elderly individuals who were overweight but were symptom-free and under 65 years of age. Due to the small cohort size of this pilot study, future studies are required to validate our findings.

Recent advances on bioactivities of black rice

PURPOSE OF REVIEW

Black rice has been consumed for centuries in Asian countries such as China, Korea or Japan. Nowadays, extracts and derivatives are considered as beneficial functional foods because of their high content in several bioactive molecules such as anthocyanins, other phenolics and terpenoids. The purpose of this review is to summarize and discuss recent developments on black rice bioactivities.

RECENT FINDINGS

Some sterols and triterpenoids with potential anticancer properties already tested in vitro and in vivo have been isolated and identified from bran extracts of black rice. Protection against osteoporosis has been suggested for the first time for black rice extracts. Because of its antioxidant and anti-inflammatory properties, black rice also protects liver and kidney from injuries. One clinical study reported the interest of black rice in case of alcohol withdrawal.

SUMMARY

Several advances have been recently achieved on the understanding of the potential biological effects of black rice and its derivatives. They further confirm that black rice should be considered as a promising source of health-promoting functional foods targeting a large set of noninfectious diseases. However, more clinical studies are needed to support the findings highlighted in this review.