Fat-lowering effects of isorhamnetin are via NHR-49-dependent pathway in Caenorhabditis elegans

Curcumin enhances the anti-obesogenic activity of orlistat through SKN-1/NRF2-dependent regulation of nutrient metabolism in Caenorhabditis elegans

BACKGROUND

Metabolic dysregulation, a defining feature of obesity, disrupts essential signalling pathways involved in nutrient sensing and mitochondria homeostasis. The nuclear factor erythroid 2-related factor 2 (NRF-2) serves as a pivotal regulator of the cellular stress response, and recent studies have implicated it in the pathogenesis of obesity, diabetes, and metabolic syndrome. Curcumin, a polyphenolic compound derived from turmeric, has been identified as a potent activator of NRF-2. Evidence suggests curcumin impacts obesity and metabolic disorders by modulating gut microbiota composition, increasing energy expenditure, and regulating lipid metabolism. Orlistat, an anti-obesity drug, inhibits fat absorption in the gastrointestinal tract, but its side effects limits its broader use.

OBJECTIVES

The present study aims to investigate the potential synergetic effect of a hybrid combination between orlistat and curcumin. Additionally, we provide a detailed understanding of the molecular mechanisms through which this combination mitigates glucose-induced lipid accumulation in Caenorhabditis elegans, with a focus on the role of the skinhead 1 (SKN-1) transcription factor, an orthologue of NRF2.

METHODS

We assessed the lipid accumulation and the changes in skn-1 transcriptional activity in C. elegans using confocal GFP-based detection, alongside mRNA expression analysis of genes from lipid metabolism and oxidative stress response in wild-type, QV225 and LD1 strains. Furthermore, we evaluated locomotion, chemotaxis and mitochondrial dynamics to enhance our understanding of the proposed molecular-based model.

RESULTS

Our findings reveal that the orlistat/curcumin combination exerts an anti-obesogenic effect through SKN-1/NRF2-dependent regulation of conserved genes involved in carbohydrate and lipid metabolism in C. elegans. Moreover, the combination stimulates mitochondrial potential, further contributing to the observed synergistic effects.

CONCLUSION

The hybrid combination of orlistat and curcumin demonstrates significant anti-obesity activity by regulating nutrient-sensing pathways through SKN-1/NRF-2 modulation. This approach may allow for the reduction of orlistat dosage, thereby minimizing its adverse effects while maintaining its therapeutic efficacy.

Natural Remedies and Health; A Review of Bee Pollen and Bee Bread Impact on Combating Diabetes and Obesity

PURPOSE OF THE REVIEW

Diabetes and obesity are complicated multifactorial conditions that have been highlighted as a significant global burden for both health care and national budgets and their complications are considered a substantial public health concern. This review focuses on the potential anti-diabetic and anti-obesity properties of bee pollen (BP) and bee bread (BB), two bee products with a long history of use in traditional medicine and supplemental nutrition.

RECENT FINDINGS

Recent studies, encompassing cellular models, experimental models, and clinical trials, have shed light on the therapeutic potential of these bee products. BP and BB are rich in phytochemical constituents like flavonoids and phenolic acids, which are believed to confer their anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, and anti-obesity properties. These bee products have shown promising results in the treatment of diabetes and obesity, underscoring their potential as natural therapeutic tools. BP and BB possess properties that aid in decreasing blood glucose levels and body weight. BP and BB have been found to enhance insulin sensitivity, alleviate oxidative stress, regulate appetite, adjust levels of hormones linked to obesity, while bolstering anti-oxidant defense systems. BP and BB nutritional qualities and health benefits make them promising candidates for further research towards diabetes and obesity treatment strategies.

Isorhamnetin alleviates cisplatin-induced acute kidney injury via enhancing fatty acid oxidation

Cisplatin is an effective chemotherapy drug widely used in the treatment of various solid tumors. However, the clinical usage of cisplatin is limited by its nephrotoxicity. Isorhamnetin, a natural flavanol compound, displays remarkable pharmacological effects, including anti-inflammatory and anti-oxidation. In this study, we aimed to investigate the potential of isorhamnetin in alleviating acute kidney injury induced by cisplatin. In vitro study showed that isorhamnetin significantly suppressed the cytotoxic effects of cisplatin on human tubular epithelial cells. Furthermore, isorhamnetin exerted significantly inhibitory effects on cisplatin-induced apoptosis and inflammatory response. In acute kidney injury mice induced by a single intraperitoneal injection with 20 mg/kg cisplatin, oral administration of isorhamnetin two days before or 2 h after cisplatin injection effectively ameliorated renal function and renal tubule injury. Transcriptomics RNA-seq analysis of the mice kidney tissues suggested that isorhamnetin treatment may protect against cisplatin-induced nephrotoxicity via PGC-1α mediated fatty acid oxidation. Isorhamnetin achieved significant enhancements in the lipid clearance, ATP level, as well as the expression of PGC-1α and its downstream target genes PPARα and CPT1A, which were otherwise impaired by cisplatin. In addition, the protection effects of isorhamnetin against cisplatin-induced nephrotoxicity were abolished by a PGC-1α inhibitor, SR-18292. In conclusion, our findings indicate that isorhamnetin could protect against cisplatin-induced acute kidney injury by inducing PGC-1α-dependent reprogramming of fatty acid oxidation, which highlights the clinical potential of isorhamnetin as a therapeutic approach for the management of cisplatin-induced nephrotoxicity.

Antiobesity and Hypolipidemic Potential of Nitraria retusa Extract in Overweight/Obese Women: A Randomized, Double-Blind, Placebo-Controlled Pilot Study

This study aimed to assess the efficacy of Nitraria retusa extract (NRE) in reducing weight, body mass index (BMI), body fat composition (BF), and anthropometric parameters among overweight/obese women, comparing the results with those of a placebo group. Overweight/obese individuals participated in a 12-week, double-blind, randomized, placebo-controlled trial. Body weight, BMI, body composition, and anthropometric parameters were assessed. Additionally, lipid profile and safety evaluation parameters were evaluated. Compared to the placebo group, the NRE group exhibited a mean weight loss difference of 2.27 kg (p < 0.001) at the trial's conclusion. Interestingly, the most significant weight reduction, amounting to 3.34 kg ± 0.93, was observed in younger participants with a BMI > 30.0. Similarly, BMI and BF% significantly decreased in the NRE group, contrary to the placebo group (p = 0.008 and p = 0.005, respectively). The percentage of body water (BW) (p = 0.006) as well as the ratio of LBM/BF (p = 0.039) showed a significant increase after the NRE intervention compared to the placebo. After age adjustment, all variables, except LBM/BF, retained statistical significance. Additionally, all anthropometric parameters were significantly reduced only in the NRE group. Most importantly, a significant reduction in Triglyceride (TG) levels in the NRE group was revealed, in contrast to the placebo group (p = 0.011), and the significance was still observed after age adjustment (p = 0.016). No side effects or adverse changes in kidney and liver function tests were observed in both groups. In conclusion, NRE demonstrated potent antiobesity effects, suggesting that NRE supplementation may represent an effective alternative for treating obesity compared to antiobesity synthetic drugs.

Comparison of Lipid Composition between Quasipaa spinosa Oil and Rana catesbeiana Oil and Its Effect on Lipid Accumulation in Caenorhabditis elegans

Frog oil has been recognized for its nutritional and medicinal value. However, there is limited research on the role of frog oil in preventing obesity. In this study, we aimed to investigate the lipid composition of Quasipaa spinosa oil (QSO) and Rana catesbeiana oil (RCO) using lipidomics analysis. We compared the lipid accumulation effects of these two kinds of frog oils and soybean oil (SO) in Caenorhabditis elegans (C. elegans). Additionally, we determined the gene expression related to lipid metabolism and used the nhr-49 mutant (RB1716) and sir-2.1 mutant (VC199) for validation experiments. The results showed that the lipid composition of QSO and RCO was significantly different (p < 0.05), and QSO was rich in more polyunsaturated fatty acids (PUFAs). After feeding C. elegans, the lipid accumulation of the QSO group was the lowest among the three dietary oil groups. In addition, compared with RCO and SO, QSO significantly inhibited the production of malondialdehyde (MDA) and increased the activity of superoxide dismutase (SOD). The effects of three kinds of dietary oils on the fatty acid composition of C. elegans were significantly different. Compared with SO and RCO, QSO significantly up-regulated (p < 0.05) the expression of sir-2.1 and ech-1 genes. The results showed that QSO might reduce lipid accumulation through the SIRT1 and nuclear hormone signaling pathways. Such a situation was verified experimentally by the nhr-49 mutant (RB1716) and sir-2.1 mutant (VC199). This study proposed a new functional oil, laying the groundwork for developing functional foods from Quasipaa spinosa.

Nuclear hormone receptor NHR-49 is an essential regulator of stress resilience and healthy aging in Caenorhabditis elegans

The genome of Caenorhabditis elegans encodes 284 nuclear hormone receptor, which perform diverse functions in development and physiology. One of the best characterized of these is NHR-49, related in sequence and function to mammalian hepatocyte nuclear factor 4α and peroxisome proliferator-activated receptor α. Initially identified as regulator of lipid metabolism, including fatty acid catabolism and desaturation, additional important roles for NHR-49 have since emerged. It is an essential contributor to longevity in several genetic and environmental contexts, and also plays vital roles in the resistance to several stresses and innate immune response to infection with various bacterial pathogens. Here, we review how NHR-49 is integrated into pertinent signaling circuits and how it achieves its diverse functions. We also highlight areas for future investigation including identification of regulatory inputs that drive NHR-49 activity and identification of tissue-specific gene regulatory outputs. We anticipate that future work on this protein will provide information that could be useful for developing strategies to age-associated declines in health and age-related human diseases.

Effects of epigallocatechin gallate, caffeine, and their combination on fat accumulation in high-glucose diet-fed Caenorhabditis elegans

Epigallocatechin gallate (EGCG) and caffeine are inevitable to be ingested together in the process of drinking green tea. This study used Caenorhabditis elegans as an organism model to examine whether the binding of EGCG and caffeine could influence the fat-reduction effect. The results revealed that EGCG significantly reduced the Nile Red fluorescence intensity and the triglyceride/protein ratio of the C. elegans obesity model by 14.7% and 16.5%, respectively, while the effect of caffeine was not significant. Moreover, the degree of reduction in fluorescence intensity and triglyceride/protein ratio by EGCG + caffeine was comparable to that of EGCG. In the exploration of underlying mechanism, we found that EGCG and EGCG + caffeine treatments had no influence on food intake and energy expenditure of C. elegans. Their fat-reduction effects were dependent on the regulation of lipogenesis, as shown by the decreased expression of the sbp-1, fat-7, and daf-16 genes.

Flowers of Allium cepa L. as Nutraceuticals: Phenolic Composition and Anti-Obesity and Antioxidant Effects in Caenorhabditis elegans

Allium cepa L., commonly known as onion, is one of the most-consumed vegetables. The benefits of the intake of its bulb are well studied and are related to its high polyphenol content. The flowers of onions are also edible; however, there are no studies about their biological properties. Our aim was to determine the polyphenolic profile and assess the antioxidant and anti-obesity capacity of an ethanolic extract from fresh flowers of A. cepa. The phenolic constituents were identified through LC-DAD-ESI/MSn. For the anti-obesity potential, the inhibitory activity against digestive enzymes was measured. Several in vitro assays were carried out to determine the antioxidant capacity. A Caenorhabditis elegans model was used to evaluate the effect of the extract on stress resistance and fat accumulation. For the first time, kaempferol and isorhamnetin glucosides were identified in the flowers. The extract reduced fat accumulation in the nematode and had a high lipase and α- glucosidase inhibitory activity. Regarding the antioxidant activity, the extract increased the survival rate of C. elegans exposed to lethal oxidative stress. Moreover, the activities of superoxide dismutase and catalase were enhanced by the extract. Our results demonstrate, for the first time, the antioxidant and anti-obesity activity of onion flowers and their potential use as functional foods and nutraceuticals.

Anti-Obesity Effects of Isorhamnetin and Isorhamnetin Conjugates

Isorhamnetin is a plant-derived secondary metabolite which belongs to the family of flavonoids. This review summarises the main outcomes described in the literature to date, regarding the effects of isorhamnetin on obesity from in vitro and in vivo studies. The studies carried out in pre-adipocytes show that isorhamnetin is able to reduce adipogenesis at 10 μM or higher doses and that these effects are mediated by Pparγ and by Wnt signalling pathway. Very few studies addressed in rodents are available so far. It seems that treatment periods longer than two weeks are needed by isorhamnetin and its glycosides to be effective as anti-obesity agents. Nevertheless, improvements in glycaemic control can be observed even in short treatments. Regarding the underlying mechanisms of action, although some contradictory results have been found, reductions in de novo lipogenesis and fatty acid uptake could be proposed. Further research is needed to increase the scientific evidence referring to this topic; studies in animal models are essential, as well as randomised clinical trials to determine whether the positive results observed in animals could also be found in humans, in order to determine if isorhamnetin and its glycosides can represent a real tool against obesity.

Pediococcus acidilactici CECT9879 (pA1c) Counteracts the Effect of a High-Glucose Exposure in C. elegans by Affecting the Insulin Signaling Pathway (IIS)

The increasing prevalence of metabolic syndrome-related diseases, including type-2 diabetes and obesity, makes it urgent to develop new alternative therapies, such as probiotics. In this study, we have used Caenorhabditis elegans under a high-glucose condition as a model to examine the potential probiotic activities of Pediococcusacidilactici CECT9879 (pA1c). The supplementation with pA1c reduced C. elegans fat accumulation in a nematode growth medium (NGM) and in a high-glucose (10 mM) NGM medium. Moreover, treatment with pA1c counteracted the effect of the high glucose by reducing reactive oxygen species by 20%, retarding the aging process and extending the nematode median survival (>2 days in comparison with untreated control worms). Gene expression analyses demonstrated that the probiotic metabolic syndrome-alleviating activities were mediated by modulation of the insulin/IGF-1 signaling pathway (IIS) through the reversion of the glucose-nuclear-localization of daf-16 and the overexpression of ins-6 and daf-16 mediators, increased expression of fatty acid (FA) peroxisomal β-oxidation genes, and downregulation of FA biosynthesis key genes. Taken together, our data suggest that pA1c could be considered a potential probiotic strain for the prevention of the metabolic syndrome-related disturbances and highlight the use of C. elegans as an appropriate in vivo model for the study of the mechanisms underlying these diseases.

Effects of Isorhamnetin on Diabetes and Its Associated Complications: A Review of In Vitro and In Vivo Studies and a Post Hoc Transcriptome Analysis of Involved Molecular Pathways

Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is characterized by high levels of glycemia and insulinemia due to impaired insulin secretion and insulin sensitivity of the cells, known as insulin resistance. T2DM causes multiple and severe complications such as nephropathy, neuropathy, and retinopathy causing cell oxidative damages in different internal tissues, particularly the pancreas, heart, adipose tissue, liver, and kidneys. Plant extracts and their bioactive phytochemicals are gaining interest as new therapeutic and preventive alternatives for T2DM and its associated complications. In this regard, isorhamnetin, a plant flavonoid, has long been studied for its potential anti-diabetic effects. This review describes its impact on reducing diabetes-related disorders by decreasing glucose levels, ameliorating the oxidative status, alleviating inflammation, and modulating lipid metabolism and adipocyte differentiation by regulating involved signaling pathways reported in the in vitro and in vivo studies. Additionally, we include a post hoc whole-genome transcriptome analysis of biological activities of isorhamnetin using a stem cell-based tool.

Differentiated 4,4-dimethylsterols from vegetable oils reduce fat deposition depending on the NHR-49/SCD pathway in Caenorhabditis elegans

Consumption of 4-desmethylsterols has been claimed to have many beneficial effects, but the benefits of 4,4-dimethylsterols are less appreciated. We utilized a nematode model, Caenorhabditis elegans (C. elegans), to explore the anti-obesity effects of different classes of 4,4-dimethylsterols purified from rice bran oil (RST) and shea nut butter (SST). Both SST and RST significantly reduced fat deposition in C. elegans with smaller sizes and numbers of lipid droplets. But the food intake was not significantly affected. Metabolomics analysis indicated a significantly altered pathway after treatment with 4,4-dimethylsterols. Finally, it was found that 4,4-dimethylsterols targeted stearoyl-CoA desaturases (SCD) and nuclear hormone receptor-49 (NHR-49), resulting in a reduced desaturation index as proved by a lower ratio of oleic acid (C18:1n-9) to stearic acid (C18:0). Overall, 4,4-dimethylsterols can inhibit fat deposition via regulating the NHR-49/SCD pathway in C. elegans.

Kahweol Reduces Food Intake of Caenorhabditis elegans

The coffee diterpene kahweol may contribute to the anti-obesity effects of coffee but its physiological effects have yet to be elucidated. Caenorhabditis elegans is used as an animal model in obesity research because its lipid metabolism is conserved in humans. The goal was to investigate kahweol's effects on lipid metabolism in C. elegans. Kahweol at 120 μM reduced fat accumulation by 17% compared to the control, which was associated with a reduced food intake. Kahweol did not reduce fat in eat-2 mutants, which have a disrupted pharynx contraction rate, suggesting that the fat-lowering effects of kahweol were dependent on food intake. Lipid metabolism-related gene homologues of tubby protein (tub-1), enoyl-CoA hydratase (ech-1.1), adipose triglyceride lipase (atgl-1), insulin/insulin-like growth receptor (daf-2), and forkhead box O transcription factor (daf-16) were also associated with changes in food intake by kahweol. Therefore, kahweol's fat-lowering effects are due to a reduction of food intake in C. elegans.

Butein inhibits lipogenesis in Caenorhabditis elegans

Butein, a flavonoid found in annatto seeds and lacquer trees, may be used for many health benefits, including the prevention of obesity. However, its anti-obesity effects are not completely understood; in particular, the effects of butein on the regulation of lipid metabolism have not been explained. Thus, the goal of the current study was to determine the effects of butein on lipid metabolism in Caenorhabditis elegans, which is a multi-organ nematode used as an animal model in obesity research. Butein at 70 μM reduced triglyceride content by 27% compared to the control without altering food intake and energy expenditure. The reduced triglyceride content by butein was associated with the downregulation of sbp-1, fasn-1, and fat-7, the lipogenesis-related homologs of sterol regulatory element-binding proteins, fatty acid synthase and stearoyl-CoA desaturase, respectively. Furthermore, fat-7 and skn-1, a homolog of nuclear respiratory factors, were identified as genetic requirements for butein's effects on triglyceride content in C. elegans. The effects of butein on sbp-1 and fasn-1 were dependent on skn-1, but the downregulation of fat-7 was independent of skn-1. These results suggest that the inhibitory effects of butein on lipogenesis are via SKN-1- and FAT-7-dependent pathways in C. elegans.