Preventive Effects of Green Tea Extract against Obesity Development in Zebrafish.

Various natural products (NPs) have been used to treat obesity and related diseases. However, the best way to fight obesity is preventive, with accurate body weight management through exercise, diet, or bioactive NPs to avoid obesity development. We demonstrated that green tea extract (GTE) is an anti-obesity NP using a zebrafish obesity model. Based on a hypothesis that GTE can prevent obesity, the objective of this study was to assess GTE's ability to attenuate obesity development. Juvenile zebrafish were pretreated with GTE for seven days before obesity induction via a high-fat diet; adult zebrafish were pretreated with GTE for two weeks before obesity induction by overfeeding. As a preventive intervention, GTE significantly decreased visceral adipose tissue accumulation in juveniles and ameliorated visceral adiposity and plasma triglyceride levels in adult zebrafish obesity models. RNA sequencing analysis was performed using liver tissues from adult obese zebrafish, with or without GTE administration, to investigate the underlying molecular mechanism. Transcriptome analysis revealed that preventive GTE treatment affects several pathways associated with anti-obesity regulation, including activation of STAT and downregulation of CEBP signaling pathways. In conclusion, GTE could be used as a preventive agent against obesity.

Anti-Obesity Natural Products Tested in Juvenile Zebrafish Obesogenic Tests and Mouse 3T3-L1 Adipogenesis Assays.

(1) Background: The obesity epidemic has been drastically progressing in both children and adults worldwide. Pharmacotherapy is considered necessary for its treatment. However, many anti-obesity drugs have been withdrawn from the market due to their adverse effects. Instead, natural products (NPs) have been studied as a source for drug discovery for obesity, with the goal of limiting the adverse effects. Zebrafish are ideal model animals for in vivo testing of anti-obesity NPs, and disease models of several types of obesity have been developed. However, the evidence for zebrafish as an anti-obesity drug screening model are still limited. (2) Methods: We performed anti-adipogenic testing using the juvenile zebrafish obesogenic test (ZOT) and mouse 3T3-L1 preadipocytes using the focused NP library containing 38 NPs and compared their results. (3) Results: Seven and eleven NPs reduced lipid accumulation in zebrafish visceral fat tissues and mouse adipocytes, respectively. Of these, five NPs suppressed lipid accumulation in both zebrafish and 3T3-L1 adipocytes. We confirmed that these five NPs (globin-digested peptides, green tea extract, red pepper extract, nobiletin, and Moringa leaf powder) exerted anti-obesity effects in diet-induced obese adult zebrafish. (4) Conclusions: ZOT using juvenile fish can be a high-throughput alternative to ZOT using adult zebrafish and can be applied for in vivo screening to discover novel therapeutics for visceral obesity and potentially also other disorders.

RNA-seq Based Transcriptome Analysis of the Anti-Obesity Effect of Green Tea Extract Using Zebrafish Obesity Models.

Green tea is a popular beverage that is rich in polyphenolic compounds such as catechins. Its major content, (-)-epigallocatechin-3-gallate, has been shown to have beneficial effects on several diseases including cancer, metabolic syndrome, cardiovascular diseases, and neurodegenerative diseases. The aim of this study was to assess the anti-obesity effects and the underlying molecular mechanisms of green tea extract (GTE) using zebrafish larva and adult obesity models. We administered 100 µg/mL GTE to zebrafish larvae and performed a short-term obesogenic test. GTE significantly decreased the visceral adipose tissue volume induced by a high-fat diet. Oral administration (250 µg/g body weight/day) of GTE to adult diet-induced obese zebrafish also significantly reduced their visceral adipose tissue volume, with a reduction of plasma triglyceride and total cholesterol levels. To investigate the molecular mechanism underlying the GTE effects, we conducted RNA sequencing using liver tissues of adult zebrafish and found that GTE may ameliorate the obese phenotypes via the activation of Wnt/ß-catenin and adenosine monophosphate-activated protein kinase (AMPK) pathway signaling. In addition, the comparative transcriptome analysis revealed that zebrafish and mammals may share a common molecular response to GTE. Our findings suggest that daily consumption of green tea may be beneficial for the prevention and treatment of obesity.

Zebrafish obesogenic test identifies anti-adipogenic fraction in Moringa oreifera leaf extracts.

The zebrafish obesogenic test (ZOT) is a powerful tool for identifying anti-adipogenic compounds for in vivo screening. In our previous study, we found that Moringa oleifera (MO) leaf powder suppressed the accumulation of visceral adipose tissue (VAT) in ZOT. MO demonstrates a wide range of pharmacological effects; however, little is known about its functional constituents. To identify the anti-adipogenic components of MO leaves, we prepared extracts using different extraction methods and tested the obtained extracts and fractions using ZOT. We found that the dichloromethane extract and its hexane:EtOAc = 8:2 fraction reduced VAT accumulation in young zebrafish fed a high-fat diet. We also performed gene expression analysis in the zebrafish VAT and found that CCAAT/enhancer-binding protein beta and CCAAT/enhancer-binding protein delta (associated with early stages of adipogenesis) gene expression was downregulated after fraction 2 administration. We identified a new MO fraction that suppressed VAT accumulation by inhibiting early adipogenesis using the ZOT. Phenotype-driven zebrafish screening is a reasonable strategy for identifying bioactive components in natural products.

Globin Digest Improves Visceral Adiposity Through UCP1 Upregulation in Diet-Induced Obese Zebrafish and Mice.

Globin digest (GD), a bioactive oligopeptide derived from porcine hemoglobin proteins, has been demonstrated to have beneficial effects on improving postprandial hyperlipidemia, hyperglycemia, and liver injury. We previously reported the lipid-lowering effects of GD using a zebrafish obesogenic test. Here, we sought to evaluate the effect of GD on visceral adiposity and the underlying molecular mechanisms using zebrafish and mouse obesity models. GD ameliorated dyslipidemia and suppressed the accumulation of visceral adipose tissue (VAT) in adult obese zebrafish. Transcriptomic analysis by RNA sequencing of GD-treated adult zebrafish revealed that GD upregulated UCP1-related pathways. Further, we performed mouse experiments and found that GD intake (2 mg/g body weight/day) was associated with lowered plasma triglyceride and total cholesterol levels, decreased VAT accumulation, and improved adipocyte hypertrophy with the upregulation of Ucp1 expression in white adipose tissue at both the mRNA and protein levels. Taken together, these results indicate that GD improves visceral adiposity by upregulating UCP1 expression, providing a novel perspective on combating obesity.

Characteristic Analysis of Trigonelline Contained in Raphanus sativus Cv. Sakurajima Daikon and Results from the First Trial Examining Its Vasodilator Properties in Humans.

Vascular disease poses a major public health problem worldwide. Trigonelline isolated from Raphanus sativus cv. Sakurajima Daikon (Sakurajima radish) induces nitric oxide production from vascular endothelial cells and enhances vascular function. Here, we investigated the characteristics of trigonelline and its effects on endothelial function after consumption of Sakurajima radish by humans. Our results show that Sakurajima radish contains approximately 60 times more trigonelline than other radishes and squashes. Additionally, no significant differences were observed between varieties of Sakurajima radish, suggesting that any type of Sakurajima radish can be ingested for trigonelline supplementation. The effects of cooking and processing Sakurajima radish were also evaluated, as were the effects of freezing, and changes in osmotic pressure and pH. A first-in-human trial using Sakurajima radish showed that ingestion of 170 g/day of Sakurajima radish for ten days increased blood trigonelline concentrations and significantly improved flow-mediated dilation, which is a measure of vascular endothelial function. Overall, our findings suggest that the trigonelline contained in Sakurajima radish may contribute to improved human vascular endothelial function. Hence, Sakurajima radish may enhance vascular endothelial function as a functional food.

Chemical and physical properties, safety and application of partially hydrolized guar gum as dietary fiber.

The ideal water-soluble dietary fiber for the fiber-enrichment of foods must be very low in viscosity, tasteless, odorless, and should produce clear solutions in beverages. Partially hydrolyzed guar gum (PHGG) produced from guar gum by enzymatic process has the same chemical structure with intact guar gum but less than one-tenth the original molecular length of guar gum, which make available to be used as film former, foam stabilizer and swelling agent. The viscosity of PHGG is about 10 mPa.s in 5% aqueous solution, whereas 1% solution of guar gum shows range from 2,000 to 3,000 mPa.s. In addition, PHGG is greatly stable against low pH, heat, acid and digestive enzyme. For these reasons, PHGG seems to be one of the most beneficial dietary fiber materials. It also showed that interesting physiological functions still fully exert the nutritional function of a dietary fiber. PHGG has, therefore, been used primarily for a nutritional purpose and became fully integrated food material without altering the rheology, taste, texture and color of final products. PHGG named as Benefiber(R) in USA has self-affirmation on GRAS status of standard grade PHGG. PHGG named as Sunfiber(R) is now being used in various beverages, food products and medicinal foods as a safe, natural and functional dietary fiber in all over the world.

Amla (Emblica officinalis Gaertn.) attenuates age-related renal dysfunction by oxidative stress.

To investigate the effects of amla on renal dysfunction involved in oxidative stress during the aging process, we employed young (2 months old) and aged (13 months old) male rats and administered SunAmla (Taiyo Kagaku Co., Ltd., Japan) or an ethyl acetate (EtOAc) extract of amla, a polyphenol-rich fraction, at a dose of 40 or 10 mg/kg body weight/day for 100 days. The administration of SunAmla or EtOAc extract of amla reduced the elevated levels of serum creatinine and urea nitrogen in the aged rats. In addition, the tail arterial blood pressure was markedly elevated in aged control rats as compared with young rats, while the systolic blood pressure was significantly decreased by the administration of SunAmla or EtOAc extract of amla. Furthermore, the oral administration of SunAmla or EtOAc extract of amla significantly reduced thiobarbituric acid-reactive substance levels of serum, renal homogenate, and mitochondria in aged rats, suggesting that amla would ameliorate oxidative stress under aging. The increases of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expression in the aorta of aging rats were also significantly suppressed by SunAmla extract or EtOAc extract of amla, respectively. Moreover, the elevated expression level of bax, a proapoptotic protein, was significantly decreased after oral administration of SunAmla or EtOAc extract of amla. However, the level of bcl-2, an antiapoptotic protein, did not show any difference among the groups. The expressions of renal nuclear factor-kappaB (NF-kappaB), inhibitory kappaB in cytoplasm, iNOS, and COX-2 protein levels were also increased with aging. However, SunAmla or EtOAc extract of amla reduced the iNOS and COX-2 expression levels by inhibiting NF-kappaB activation in the aged rats. These results indicate that amla would be a very useful antioxidant for the prevention of age-related renal disease.

The nontoxic mushroom Auricularia auricula contains a polysaccharide with anticoagulant activity mediated by antithrombin.

An acidic polysaccharide with anticoagulant activity was isolated from the edible mushroom Auricularia auricula using water, alkali or acid extracts. The alkali extract showed the highest anticoagulant activity and was thereby further purified using gel filtration chromatography. Specific anticoagulant activity of the purified polysaccharide was 2 IU/mg and its average mass was approximately 160 kDa. The polysaccharide from this species of mushroom contains mainly mannose, glucose, glucuronic acid and xylose but no sulfate esters. Its anticoagulant activity was due to catalysis of thrombin inhibition by antithrombin but not by heparin cofactor II. Inhibition of Factor Xa by antithrombin was not catalyzed by the polysaccharide. The glucuronic acid residues were essential for the anticoagulant action of the mushroom polysaccharide since the activity disappeared after reduction of its carboxyl groups. In ex vivo tests using rats orally fed with the polysaccharide, we observed an inhibitory effect on platelet aggregation as observed with aspirin, a well-known antiplatelet agent. The polysaccharides from these mushrooms may constitute a new source of compounds with action on coagulation, platelet aggregation and, perhaps, on thrombosis.

Hydrolyzed guar gum decreases postprandial blood glucose and glucose absorption in the rat small intestine.

We hypothesized that infusing partially hydrolyzed guar gum (PHGG) into the duodenum would reduce increases in postprandial plasma glucose by decreasing the rate of glucose diffusion from the small intestine luminal digesta of the rat. The postprandial plasma glucose and apparent glucose disappearance from the small intestine were measured after infusing artificial digesta containing 0 (control), 3.0, or 6.0 g/L PHGG into the duodenum via a cannula under anesthesia in experiments 1 and 2. The diffusion of glucose in the artificial digesta was estimated using dialysis tubing, filled with the same artificial digesta, soaked in a buffer in experiment 3. In experiment 1, the plasma glucose concentration was lower in the digesta containing 3.0 and 6.0 g/L PHGG than in the control digesta at 120 minutes (P < .05). The plasma insulin concentration was lower for the digesta containing 6.0 g/L PHGG than for the control digesta at 60 minutes (P < .05) and lower for the digesta containing 6.0 g/L PHGG than for that containing 3.0 g/L PHGG at 120 minutes (P < .05).The area under the curve of plasma glucose and insulin (experiment 1), apparent disappearance of glucose in the lumen of the small intestine (experiment 2), and net disappearance of glucose in the dialysis tube depended negatively on the viscosity of the artificial digesta (P < .05, .05, .001, and .05), which was increased by adding PHGG. Therefore, PHGG can decrease the postprandial blood glucose by lowering the rate of absorption from the small intestine in the rat by reducing the diffusion of glucose in the lumen.