Xanthigen attenuates high-fat diet-induced obesity through down-regulation of PPARγ and activation of the AMPK pathway

Roles of Marine Macroalgae or Seaweeds and Their Bioactive Compounds in Combating Overweight, Obesity and Diabetes: A Comprehensive Review

Obesity and diabetes are matters of serious concern in the health sector due to their rapid increase in prevalence over the last three decades. Obesity is a severe metabolic problem that results in energy imbalance that is persistent over a long period of time, and it is characterized by insulin resistance, suggesting a strong association with type 2 diabetes (T2D). The available therapies for these diseases have side effects and some still need to be approved by the Food and Drug Administration (FDA), and they are expensive for underdeveloped countries. Hence, the need for natural anti-obesity and anti-diabetic drugs has increased in recent years due to their lower costs and having virtually no or negligible side effects. This review thoroughly examined the anti-obesity and anti-diabetic effects of various marine macroalgae or seaweeds and their bioactive compounds in different experimental settings. According to the findings of this review, seaweeds and their bioactive compounds have been shown to have strong potential to alleviate obesity and diabetes in both in vitro and in vivo or animal-model studies. However, the number of clinical trials in this regard is limited. Hence, further studies investigating the effects of marine algal extracts and their bioactive compounds in clinical settings are required for developing anti-obesity and anti-diabetic medicines with better efficacy but lower or no side effects.

Therapeutic Potential of Seaweed-Derived Bioactive Compounds for Cardiovascular Disease Treatment

Cardiovascular diseases are closely related to hypertension, type 2 diabetes mellitus, obesity, and hyperlipidemia. Many studies have reported that an unhealthy diet and sedentary lifestyle are critical factors that enhance these diseases. Recently, many bioactive compounds isolated from marine seaweeds have been studied for their benefits in improving human health. In particular, several unique bioactive metabolites such as polyphenols, polysaccharides, peptides, carotene, and sterol are the most effective components responsible for these activities. This review summarizes the current in vitro, in vivo, and clinical studies related to the protective effects of bioactive compounds isolated from seaweeds against cardiovascular disorders, including anti-diabetic, anti-hypertensive, anti-hyperlipidemia, and anti-obesity effects. Therefore, this present review summarizes these concepts and provides a basis for further in-depth research.

Gymnaster Koraiensis Extract Alleviated Metabolic Syndrome Symptoms and Stimulated UCP1-Independent Energy Consumption via AMPK Activation in White Adipose Tissue

SCOPE

Metabolic syndrome and obesity are rising worldwide concerns that are accompanied by adverse health consequences. Here, it is hypothesized that the ethanol extract from Gymnaster koraiensis (GK), an edible Korean plant known for its anti-cancer and hepatoprotective properties, could attenuate metabolic syndrome-related symptoms in high-fat dietary-induced obese (DIO) mice.

METHODS AND RESULTS

Administration of 100 mg kg^-1 GK extract to DIO mice effectively reduces body and white adipose tissue (WAT) weight. It also reduces cardiovascular disease risk and improves insulin resistance by lowering the fasting blood glucose levels and mitigating oxidative stress and inflammation. Moreover, supplementation with GK causes elevated energy expenditure in WAT by increasing the mitochondrial oxidative capacity and lipid catabolism through upregulated adenosine monophosphate-activated protein kinase (AMPK) signaling. Orlistat is used as a positive control drug due to its widespread use in previous studies. It is found that GK extract causes weight loss, similar to Orlistat, and it additionally shows unique functions, such as upregulation of energy consumption in WAT.

CONCLUSION

GK extract treatment prominently reduces obesity and its associated metabolic complications, such as hyperlipidemia, hyperglycemia, and insulin resistance. Hence, It can be used as a promising multi-target functional food that can improve metabolic syndrome-related symptoms.

Lactate-Fortified Puerariae Radix Fermented by Bifidobacterium breve Improved Diet-Induced Metabolic Dysregulation via Alteration of Gut Microbial Communities

BACKGROUND

Puerariae Radix (PR), the dried root of Pueraria lobata, is reported to possess therapeutic efficacies against various diseases including obesity, diabetes, and hypertension. Fermentation-driven bioactivation of herbal medicines can result in improved therapeutic potencies and efficacies.

METHODS

C57BL/6J mice were fed a high-fat diet and fructose in water with PR (400 mg/kg) or PR fermented by Bifidobacterium breve (400 mg/kg) for 10 weeks. Histological staining, qPCR, Western blot, and 16s rRNA sequencing were used to determine the protective effects of PR and fermented PR (fPR) against metabolic dysfunction.

RESULTS

Treatment with both PR and fPR for 10 weeks resulted in a reduction in body weight gain with a more significant reduction in the latter group. Lactate, important for energy metabolism and homeostasis, was increased during fermentation. Both PR and fPR caused significant down-regulation of the intestinal expression of the MCP-1, IL-6, and TNF-α genes. However, for the IL-6 and TNF-α gene expressions, the inhibitory effect of fPR was more pronounced (p < 0.01) than that of PR (p < 0.05). Oral glucose tolerance test results showed that both PR and fPR treatments improved glucose homeostasis. In addition, there was a significant reduction in the expression of hepatic gene PPARγ, a key regulator of lipid and glucose metabolism, following fPR but not PR treatment. Activation of hepatic AMPK phosphorylation was significantly enhanced by both PR and fPR treatment. In addition, both PR and fPR reduced adipocyte size in highly significant manners (p < 0.001). Treatment by fPR but not PR significantly reduced the expression of PPARγ and low-density lipoproteins in adipose tissue.

CONCLUSION

Treatment with fPR appears to be more potent than that of PR in improving the pathways related to glucose and lipid metabolism in high-fat diet (HFD)+fructose-fed animals. The results revealed that the process of fermentation of PR enhanced lactate and facilitated the enrichment of certain microbial communities that contribute to anti-obesity and anti-inflammatory activities.

PACAP ameliorates hepatic metabolism and inflammation through up-regulating FAIM in obesity

Obesity is considered a chronic inflammatory disease, the inflammatory factors, such as interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) and small inducible cytokine A5 (RANTES), are elevated in obese individuals. Pituitary adenylate cyclase-activating polypeptide (PACAP) suppresses anti-inflammatory cytokines and ameliorates glucose and lipid metabolism. Our previous study showed that Fas apoptosis inhibitory molecule (FAIM) is a new mediator of Akt2 signalling, increases the insulin signalling pathway and lipid metabolism. In this study, we found that PACAP promoted the expression of FAIM protein in a human hepatocyte cell line (L02). Overexpression of FAIM with lentivirus suppressed the expression of the inflammatory factor interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) and tumour necrosis factor alpha (TNF-α). Following treatment of obese mice with FAIM or PACAP for 2 weeks, inflammation was alleviated and the bodyweight and blood glucose levels were decreased. Overexpression of FAIM down-regulated the expression of adipogenesis proteins, including SREBP1, SCD1, FAS, SREBP2 and HMGCR, and up-regulated glycogen synthesis proteins, including Akt2 (Ser474) phosphorylation, GLUT2 and GSK-3β, in the liver of obese mice. However, down-regulation of FAIM with shRNA promotes obesity. Altogether, our data identified that FAIM mediates the function of PACAP in anti-inflammation, glucose regulation and lipid metabolism in obese liver.

Does pomegranate consumption affect weight and body composition? A systematic review and meta-analysis of randomized controlled clinical trials

Pomegranate is rich in tannins, polyphenols, flavonoids, and several other types of antioxidant compounds whose role in weight loss has been shown in previous studies. However, the results have been mixed regarding the effects of pomegranate consumption on weight loss. Electronic databases such as PubMed, Scopus, ISI Web of Science, and Google Scholar were systematically searched up to May 2018 for controlled clinical trials assessing the effect of pomegranate consumption on weight loss. A random effects model was used to calculate the weighted mean difference (WMD) and 95% confidence interval (CI) as the difference between the mean for the intervention and control groups. Thirteen randomized controlled trials (including 513 participants) were included in the present meta-analysis. Compared with the control groups, there was no significant reduction in bodyweight, body mass index, waist circumference, and body fat percentage after pomegranate consumption (WMD = -0.23 kg, 95% CI: -0.94, 0.47, P = 0.515; WMD = -0.12 kg/m² , 95% CI: -0.29, 0.03, P = 0.132; WMD = -0.08 cm, 95% CI: -0.33, 0.17, P = 0.534; WMD = -0.05, 95% CI: -1.66, 1.55, P = 0.947, respectively). According to the results of the present systematic review and meta-analysis, there was no significant effect of pomegranate consumption on weight and body composition indices.

n-Butanol Extract of Lotus Seeds Exerts Antiobesity Effects in 3T3-L1 Preadipocytes and High-Fat Diet-Fed Mice via Activating Adenosine Monophosphate-Activated Protein Kinase

In this study, the antiobesity effects of n-butanol extract of lotus seeds (LBE) were evaluated in cultured 3T3-L1 preadipocytes and in high-fat diet (HFD)-fed mice. LBE decreased lipid contents in mature 3T3-L1 cells without obvious cytotoxicity. Meanwhile, LBE supplementation also led to weight loss and improved plasma lipid profiles in HFD-fed mice. Furthermore, LBE could activate AMP-activated protein kinase (AMPK) accompanied by down-regulation of lipogenesis related genes (PPARγ, aP2, LPL, C/EBPα, FAS, SREBP-1c) and up-regulation of lipolysis genes (adiponectin and PPARα) in vitro and in vivo. Collectively, our data demonstrated LBE possesses antiadipogenic and antilipogenic activities which are, at least partially, mediated by the activation of AMPK signaling pathways.

Toxicological assessment of Xanthigen® nutraceutical extract combination: Mutagenicity, genotoxicity and oral toxicity

Xanthigen® is a nutraceutical combination for weight management capable of increasing energy expenditure via uncoupling protein 1 (UCP-1) in white adipose tissue. It consists of brown seaweed Undaria pinnatifida extract, rich in the carotenoid fucoxanthin (FX) and pomegranate seed oil (PSO), rich in punicic acid. Xanthigen was screened to determine its genotoxicity and 90-days repeated oral toxicity. Genotoxicity was assessed with the Ames test (TA89, TA100, TA1535, TA1537, WP2), chromosomal aberration assay (Chinese hamster ovary cells) and mammalian micronucleus test (in mice). Xanthigen did not exhibit genotoxicity in any tested strain. Sub-chronic toxicity was evaluated with daily oral administration of 250, 500 and 1000 mg/kg/day doses of Xanthigen® to Sprague-Dawley rats over 90 days. No deaths and no deleterious effects were observed during the 90-day treatment, indicating an absence of sub-chronic toxicity and a no observed adverse effect level greater than 1000 mg/kg/day. A statistically significant decrease in bodyweight and food intake in Xanthigen® treated groups was attributed to the weight loss property of Xanthigen®. Overall, Xanthigen® shows no significant mutagenic or toxic effects.

Overview on the Antihypertensive and Anti-Obesity Effects of Secondary Metabolites from Seaweeds

Hypertension and obesity are two significant factors that contribute to the onset and exacerbation of a cascade of mechanisms including activation of the sympathetic and renin-angiotensin systems, oxidative stress, release of inflammatory mediators, increase of adipogenesis and thus promotion of systemic dysfunction that leads to clinical manifestations of cardiovascular diseases. Seaweeds, in addition to their use as food, are now unanimously acknowledged as an invaluable source of new natural products that may hold noteworthy leads for future drug discovery and development, including in the prevention and/or treatment of the cardiovascular risk factors. Several compounds including peptides, phlorotannins, polysaccharides, carotenoids, and sterols, isolated from brown, red and green macroalgae exhibit significant anti-hypertensive and anti-obesity properties. This review will provide a comprehensive overview of the recent advances on bioactive pure compounds isolated from different seaweed sources focusing on their potential use as drugs to treat or prevent hypertension and obesity. On the other hand, although it is obvious that macroalgae represent promising sources of antihypertensive and anti-obesity compounds, it is also clear that further efforts are required to fully understand their cellular mechanisms of action, to establish structure-inhibition relationships and mainly to evaluate them in pre-clinical and clinical trials.

Anti-Obesity Effect of 6,8-Diprenylgenistein, an Isoflavonoid of Cudrania tricuspidata Fruits in High-Fat Diet-Induced Obese Mice

Obesity, which is characterized by excessive fat accumulation, is associated with several pathological disorders, including metabolic diseases. In this study, the anti-obesity effect of 6,8-diprenylgenistein (DPG), a major isoflavonoid of Cudrania tricuspidata fruits was investigated using high fat-diet (HFD)-induced obese mice at the doses of 10 and 30 mg/kg for six week. The body weight of the DPG-treated groups was significantly lower compared to the HFD-treated group. In addition, fat accumulation in epididymal adipose tissue and liver was dramatically decreased in the HFD + DPG groups. The food efficiency ratios of the HFD + DPG groups were also lower compared to the HFD group with the same food intake. Metabolic parameters that had increased in the HFD group were decreased in the HFD + DPG groups. Further studies demonstrate that DPG efficiently reduces lipogenic genes by regulation of transcription factors, such as peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), and hormones, such as leptin and adiponection. DPG also regulates acetyl-CoA carboxylase (ACC) and hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) by AMP-activated protein kinase (AMPK) activation. Taken together, DPG is beneficial for the regulation of obesity, especially resulting from high fat intake.

Health Benefits of Punicic Acid: A Review

Punicic acid (PA) is a polyunsaturated fatty acid (18:3 n-5), which is classified as a conjugated linolenic acid. PA is also referred as a "super CLnA" whose effect is even more potent than that of an ordinary CLnA. It is found mainly in the seeds of pomegranate fruit (Punica granatum) and Trichoxanthes kirilowii and some other minor sources. It possesses a wide array of biological properties including antidiabetic, antiobesity, antiproliferative, and anticarcinogenic activity against various forms of cancer. In spite of this, PA has not been explored as a nutraceutical or as an ingredient of food products which can be aimed at specific consumer target groups. This review details the various health-beneficial properties of PA and explores the possibilities of its utilization as an active ingredient in various food products.