Nuciferine Inhibited the Differentiation and Lipid Accumulation of 3T3-L1 Preadipocytes by Regulating the Expression of Lipogenic Genes and Adipokines

Preparation, pharmacokinetics and anti-obesity effects on dogs of nuciferine liposomes

BACKGROUND

Nuciferine (NUC), a natural compound extracted from lotus leaves, has been proven to have anti-obesity effects. However, the development and application of NUC as an anti-obesity drug in dogs are hindered due to its poor water solubility and low bioavailability.

OBJECTIVE

To promote the development of NUC-related products for anti-obesity in dogs, this study prepared NUC into a liposome formulation and evaluated its characteristics, pharmacokinetics in dogs, and anti-obesity effects on high-fat diet dogs.

METHODS

NUC liposomes were prepared by the ethanol injection method, using NUC, egg lecithin, and β-sitosterol as raw materials. The characteristics and release rate in vitro of liposomes were evaluated by particle size analyser and dialysis method, respectively. The pharmacokinetics in dogs after oral administration of NUC-liposomes was carried out by the high-performance liquid chromatography (HPLC) method. Moreover, we investigated the anti-obesity effect of NUC-liposomes on obese dogs fed with a high-fat diet.

RESULTS

NUC-liposome was successfully prepared, with an EE of (79.31 ± 1.06)%, a particle size of (81.25 ± 3.14) nm, a zeta potential of (-18.75 ± 0.23) mV, and a PDI of 0.175 ± 0.031. The cumulative release rate in vitro of NUC from NUC-liposomes was slower than that of NUC. The T1/2 and relative bioavailability of NUC-liposomes in dogs increased, and CL reduced compared with NUC. In addition, the preventive effect of NUC-liposomes on obesity in high-fat diet dogs is stronger than that of NUC.

CONCLUSIONS

The liposome formulation of NUC was conducive to improve its relative bioavailability and anti-obesity effect in dogs.

Bitter yet beneficial: The dual role of dietary alkaloids in managing diabetes and enhancing cognitive function

With the rising prevalence of diabetes and its association with cognitive impairment, interest in the use of dietary alkaloids and other natural products has grown significantly. Understanding how these compounds manage diabetic cognitive dysfunction (DCD) is crucial. This comprehensive review explores the etiology of DCD and the effects of alkaloids in foods and dietary supplements that have been investigated as DCD therapies. Data on how dietary alkaloids like berberine, trigonelline, caffeine, capsaicin, 1-deoxynojirimycin, nuciferine, neferine, aegeline, tetramethylpyrazine, piperine, and others regulate cognition in diabetic disorders were collected from PubMed, Research Gate, Web of Science, Science Direct, and other relevant databases. Dietary alkaloids could improve memory in behavioral models and modulate the mechanisms underlying the cognitive benefits of these compounds, including their effects on glucose metabolism, gut microbiota, vasculopathy, neuroinflammation, and oxidative stress. Evidence suggests that dietary alkaloids hold promise for improving cognition in diabetic patients and could open exciting avenues for future research in diabetes management.

Nuciferine prevents obesity by activating brown adipose tissue

Increasing evidence suggests that brown adipose tissue (BAT) plays an important role in obesity and related diseases. Increasing the amount or activity of BAT could prevent obesity. Therefore, a safe and effective method of activating BAT is urgently required. Here, we evaluated the potential effects of lotus leaf extract (LLE) on BAT function. We found that LLE substantially increased UCP1 mRNA and protein levels as well as thermogenic protein expression in primary brown adipocytes. Additionally, LLE treatment reduced diet-induced obesity and improved glucose homeostasis owing to BAT activation and increased energy expenditure. We found that nuciferine, an active ingredient of LLE, could dose-dependently activate BAT in vitro and in vivo, alleviate diet-induced obesity, and improve glucose homeostasis by increasing energy expenditure. Mechanistically, we found that nuciferine induced PPARG coactivator 1 alpha (PGC1-α) expression, which is a key gene involved in mitochondrial biogenesis promoter activity, by directly binding to RXRA. Furthermore, RXRA knockdown abolished expression of the nuciferine-induced mitochondrial and thermogenesis-related gene in primary brown adipocytes. In summary, we found that LLE and nuciferine have a notable effect on BAT activation and highlight the potential applications of the main component of LLE in preventing obesity and treating metabolic disorders.

Molecular docking Study of Nuciferine as a Tyrosinase Inhibitor and Its Therapeutic Potential for Hyperpigmentation

Melanin is synthesized by tyrosinase to protect the skin from ultraviolet light. However, overproduction and accumulation of melanin can result in hyperpigmentation and skin melanoma. Tyrosinase inhibitors are commonly used in the treatment of hyperpigmentation. Natural tyrosinase inhibitors are often favored over synthetic ones due to the potential side effects of the latter, which can include skin irritation, allergies, and other adverse reactions. Nuciferine, an alkaloid derived from Nelumbo nucifera, exhibits potent antioxidant and anti-proliferative properties. This study focused on the in silico screening of nuciferine for anti-tyrosinase activity, using kojic acid, ascorbic acid, and resorcinol as standards. The tyrosinase protein target was selected through homology modeling. The residues of the substrate binding pocket and active site pockets were identified for the purposes of grid box optimization and docking. Nuciferine demonstrated a binding energy of -7.0 kcal/mol and a Ki of 5 µM, both of which were comparatively higher than the corresponding values of kojic acid, which showed -5.3 kcal/mol and 122 µM respectively. Therefore, nuciferine is a potent natural tyrosinase inhibitor and shows promising potential for application in the treatment of hyperpigmentation and skin melanoma.

Non-Cardiotoxic Tetradecanoic Acid-2,4-Dinitrophenol Ester Nanomicelles in Microneedles Exert Potent Anti-Obesity Effect by Regulating Adipocyte Browning and Lipogenesis

Sustained oral uncoupler 2,4-dinitrophenol (DNP) administration exerts prominent anti-obesity effects, but the adipose tissue off-target disadvantage leads to systemic adverse effects. A novel non-cardiotoxicity DNP delivery method using a biocompatible microneedles patch containing the amphiphilic tetradecanoic acid-DNP ester (TADNP) is described, which is synthesized via esterification on the phenolic hydroxyl of DNP. The TADNP is self-assembled as nanomicelles, which enhance the endocytosis rate of DNP by adipocytes and its permeation in isolated adipose tissues. The microenvironment of adipose tissues promotes the massive release of DNP and plasma and simulated gastrointestinal fluids. The microneedles-delivered TADNP nanomicelles (MN-TADNP) effectively deliver DNP in treated adipose tissues and reduce DNP content in off-target organs. Both oral and MN patch-delivered TADNP micelles effectively exert anti-obesity effects in a mouse model of high-fat diet-induced obesity; and noteworthily, MN-TADNP exhibit more satisfactory biosafety than oral administration. Here, a smart MN patch loaded with tetradecanoic acid-modified DNP is reported, which enhances its accumulation in adipose tissues and exerts an anti-obesity effect without causing any systemic toxicity.

Inhibition of lipid droplet accumulation by Solanum nigrum by suppressing adipogenesis and inducing lipolysis, thermogenesis and autophagy in 3T3‑L1 cells

It has been reported that Solanum nigrum exhibits anti-obesity effects in animal models induced by a high-fat diet. However, research on how Solanum nigrum exerts its anti-obesity effects is currently limited. Thus, the present study focused on identifying the mechanism of action associated with the anti-obesity activity of Solanum nigrum aerial part (SNAP), which significantly inhibited the accumulation of lipid droplets in differentiating 3T3-L1 cells. Intracellular lipid accumulation in 3T3-L1 cells was analyzed by Oil-Red O staining and glycerol content was analyzed using an ELISA kit. In addition, changes in protein expression within 3T3-L1 cells were analyzed using western blot analysis. It decreased the expression level of adipogenic proteins such as CCAAT/enhancer-binding protein α, Peroxisome proliferator-activated receptor γ, fatty acid binding protein 4, and adiponectin. In addition, SNAP increased the expression levels of lipolytic proteins, such as adipose triglyceride lipase and hormone-sensitive lipase, while decreasing perilipin-1. The treatment of fully differentiated 3T3-L1 cells increased the free glycerol levels. SNAP treatment resulted in increased AMP-activated protein kinase phosphorylation and the expression levels of thermogenic proteins (peroxisome proliferator-activated receptor-γ coactivator 1-α, PR domain containing 16 and uncoupling protein 1) and an autophagic protein (LC3-II). Overall, these results suggested that SNAP inhibited lipid droplet accumulation by suppressing adipogenesis and promoting lipolysis, thermogenesis and autophagy.

Intragastric Safflower Yellow Alleviates HFD Induced Metabolic Dysfunction-Associated Fatty Liver Disease in Mice through Regulating Gut Microbiota and Liver Endoplasmic Reticulum Stress

The gut microbiota was reported to play a significant role in the progression of the metabolic associated fatty liver disease (MAFLD). Our recent study suggested that gastrointestinal tract and liver were important targets mediating the anti-obesity effects of intragastric safflower yellow (SY). Therefore, our present study aims to investigate the effect of intragastric SY on MAFLD and possible mechanism. DIO mice were treated with 125 mg/kg/d SY for 12 weeks by gavage. We found intragastric SY significantly slowed weight gain of body, reduced the food intake and liver weight, improved hepatic steatosis, liver function and glucose metabolism in DIO mice. The comparison between OGTT and IPGTT illustrated OGTT produced a better improvement of glucose tolerance after SY treatment. We also found intragastric SY significantly increased the energy expenditure and locomotor activity of DIO mice. SY obviously decreased the expression of lipogenesis-associated and ERS-related genes in liver of DIO mice and PA-induced MAFLD hepatocyte model. Gut microbiota analysis demonstrated intragastric SY apparently changed the diversity and composition of gut microbiota of DIO mice. Further function prediction analysis indicated that gut microbiotas in SY-treated mice was positively related with energy metabolism, lipid metabolism and endocrine system. Intragastric SY has a significant therapeutic effect on MAFLD, which is mediated partly by modulating gut microbiota and improving liver ERS.

Nuciferine blocks MIB2-mediated CARD6 polyubiquitination and degradation in the amelioration of high fructose-induced liver lipid accumulation

Dietary alkaloid nuciferine isolated from the leaves of Nelumbo nucifera can ameliorate dyslipidemia and liver lipid accumulation, but the underlying mechanism remains unclear. Caspase recruitment domain protein family member 6 (CARD6) is suggested to play an important role in metabolic diseases. This study aimed to investigate the role and the upstream regulator of CARD6 in high fructose-induced liver lipid accumulation and whether and how the anti-lipid accumulation effect of nuciferine was related to CARD6. Herein, we found that high fructose decreased CARD6 expression and increased ASK1 and JNK1/2 phosphorylation in rat livers and hepatocytes, which were attenuated by nuciferine. Furthermore, after the transfection with HA-CARD6, CARD6 siRNA and MIB2 siRNA, the data showed that CARD6 overexpression blocked high fructose-induced upregulation of ASK1 and JNK1/2 phosphorylation as well as lipid accumulation in hepatocytes. CARD6 siRNA reversed the amelioration of nuciferine to high fructose-induced upregulation of ASK1 and JNK1/2 phosphorylation in hepatocyte lipid accumulation. Mechanistically, high fructose upregulated MIB2 expression by interacting with CARD6 and promoting K48-linked CARD6 polyubiquitination and degradation in high fructose-stimulated hepatocytes which were explored by immunoblotting, immunofluorescence, and immunoprecipitation. However, MIB2 siRNA reversed high fructose-induced downregulation of CARD6 and lipid accumulation in hepatocytes. Notably, nuciferine reduced MIB2 expression and thus decreased K48-linked CARD6 polyubiquitination and degradation in the amelioration of high fructose-induced lipid accumulation in hepatocytes. These results suggested that nuciferine exhibited a protective effect against high fructose-induced liver lipid accumulation through blocking MIB2-mediated CARD6 polyubiquitination and degradation.

Purification, identification and hypolipidemic activities of three novel hypolipidemic peptides from tea protein

In this study, hypolipidemic peptides were obtained from tea protein by enzymatic hydrolysis, ultrafiltration and high-performance liquid chromatography. Subsequently, the hypolipidemic peptides were identified by mass spectrometry and screened through molecular docking technology, and the hypolipidemic activities and mechanisms of the active peptides were explored. The results showed that the hydrolysate of hypolipidemic peptides obtained by pepsin hydrolysis for 3 h had good bile salt binding ability. After purification, identification and molecular docking screening, three novel hypolipidemic peptides FLF, IYF and QIF were obtained. FLF, IYF and QIF can interact with the receptor proteins 1LPB and 1F6W through hydrogen bonds, π-π bonds, hydrophobic interactions and van der Waals forces, thus exerting hypolipidemic activities. Activity studies showed that, compared with the positive controls, FLF, IYF and QIF had excellent sodium taurocholate binding abilities, pancreatic lipase inhibitory activities and cholesterol esterase inhibitory activities. Moreover, FLF, IYF and QIF can effectively inhibit lipogenic differentiation of 3T3-L1 preadipocytes, reduce intracellular lipid and low-density lipoprotein content and increase high-density lipoprotein content. These results indicated that the three novel hypolipidemic peptides screened in this study had excellent hypolipidemic activities and were expected to be used as natural-derived hypolipidemic active ingredients for the development and application in functional foods.

Preparation of microgel co-loaded with nuciferine and epigallocatechin-3-gallate for the regulation of lipid metabolism

This study aims to enhance the stability and bioavailability of nuciferine (NF) and epigallocatechin-3-gallate (EGCG) by loading NF into liposomes and then incorporating the liposomes and EGCG into porous microgels (NFEG-microgel) prepared with chitosan and proanthocyanidin. Analysis of particle size (0.5-3.0 μm), electron microscopy, rheology, stability, and simulated gastrointestinal release confirmed that the prepared microgels had high encapsulation rate and good stability and release characteristics. Intervention experiments were performed by orally administering NFEG-microgel to high-fat diet rats to evaluate its efficacy and regulatory mechanism for blood lipid metabolism. NFEG-microgel intervention significantly reduced the body weight and serum lipid level, and the mechanism was related to the expression regulation of key genes involved in lipid metabolism and miRNAs (miR-126a-5p and miR-30b-5p) in serum extracellular vesicles. In addition, NFEG-microgel improved the diversity of gut microbiota by enriching short-chain fatty acids (SCFA)-producing bacteria and reducing harmful bacteria, suggesting that it can ameliorate lipid metabolism by regulating the intestinal flora community in rats.

Medicinal and edible plants in the treatment of dyslipidemia: advances and prospects

Dyslipidemia is an independent risk factor of cardiovascular diseases (CVDs), which lead to the high mortality, disability, and medical expenses in the worldwide. Based on the previous researches, the improvement of dyslipidemia could efficiently prevent the occurrence and progress of cardiovascular diseases. Medicinal and edible plants (MEPs) are the characteristics of Chinese medicine, and could be employed for the disease treatment and health care mostly due to their homology of medicine and food. Compared to the lipid-lowering drugs with many adverse effects, such as rhabdomyolysis and impaired liver function, MEPs exhibit the great potential in the treatment of dyslipidemia with high efficiency, good tolerance and commercial value. In this review, we would like to introduce 20 kinds of MEPs with lipid-lowering effect in the following aspects, including the source, function, active component, target and underlying mechanism, which may provide inspiration for the development of new prescription, functional food and complementary therapy for dyslipidemia.

Intragastric safflower yellow and its main component HSYA improve leptin sensitivity before body weight change in diet-induced obese mice

Our previous studies found that safflower yellow (SY) and its main component hydroxysafflor yellow A (HSYA) could alleviate obesity and improve leptin resistance in high-fat diet (HFD) induced obese mice. Therefore, our present study aimed to investigate whether the above effect of SY/HSYA was a direct effect or follow-up effect of weight loss and whether leptin was essential for the anti-obesity effect of SY/HSYA or not. HFD-induced obese mice were treated with SY or HSYA for 4 weeks, while ob/ob mice were treated with SY for 10 weeks. Body weight, food intake, fat mass, and serum leptin levels were measured. The leptin sensitivity experiment was conducted in HFD-induced obese mice. The expressions of leptin and its signaling-related genes were detected by RT-qPCR and Western blot methods. SY/HSYA treatment had no effect on food intake, energy expenditure, body weight, fat mass, and serum leptin levels in HFD-induced obese mice. However, the leptin sensitivity experiment showed that the food intake decreased by 18.4% in the HFD-SY group and the body weight gain decreased by 104.6% in the HFD-HSYA group, respectively (both P < 0.05). Furthermore, the expressions of leptin and leptin signaling inhibitory regulators were significantly decreased, while the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) were notably increased in WAT of HFD-induced obese mice, fully differentiated 3T3-L1 adipocytes after SY/HSYA intervention (all P < 0.05). Interestingly, SY treatment was ineffective on body weight, fat mass, and glucose metabolism in leptin-deficient ob/ob mice. SY/HSYA administration could firstly improve peripheral leptin resistance in adipose tissue of HFD-induced obese mice before their body weight was significantly changed, and leptin was essential for the anti-obesity effect of SY.

Distinct AMPK-Mediated FAS/HSL Pathway Is Implicated in the Alleviating Effect of Nuciferine on Obesity and Hepatic Steatosis in HFD-Fed Mice

Nuciferine (Nuci), the main aporphine alkaloid component in lotus leaf, was reported to reduce lipid accumulation in vitro. Herein we investigated whether Nuci prevents obesity in high fat diet (HFD)-fed mice and the underlying mechanism in liver/HepG2 hepatocytes and epididymal white adipose tissue (eWAT) /adipocytes. Male C57BL/6J mice were fed with HFD supplemented with Nuci (0.10%) for 12 weeks. We found that Nuci significantly reduced body weight and fat mass, improved glycolipid profiles, and enhanced energy expenditure in HFD-fed mice. Nuci also ameliorated hepatic steatosis and decreased the size of adipocytes. Furthermore, Nuci remarkably promoted the phosphorylation of AMPK, suppressed lipogenesis (SREBP1, FAS, ACC), promoted lipolysis (HSL, ATGL), and increased the expressions of adipokines (FGF21, ZAG) in liver and eWAT. Besides, fatty acid oxidation in liver and thermogenesis in eWAT were also activated by Nuci. Similar results were further observed at cellular level, and these beneficial effects of Nuci in cells were abolished by an effective AMPK inhibitor compound C. In conclusion, Nuci supplementation prevented HFD-induced obesity, attenuated hepatic steatosis, and reduced lipid accumulation in liver/hepatocytes and eWAT/adipocytes through regulating AMPK-mediated FAS/HSL pathway. Our findings provide novel insight into the clinical application of Nuci in treating obesity and related complications.

Nuciferine administration in C57BL/6J mice with gestational diabetes mellitus induced by a high-fat diet: the improvement of glycolipid disorders and intestinal dysbacteriosis

Gestational diabetes mellitus (GDM) has become a global health concern as the main result of its contribution to the high risk of adverse pregnancy outcomes for both the mother and fetus. However, there is absence of an ideal and widely acceptable therapy. Nuciferine has previously been shown to exert beneficial effects in various metabolic diseases. This study aimed to investigate the potential therapeutic efficacy of nuciferine on GDM in C57BL/6J mice induced by a high-fat diet (HFD), which has not been reported before. The results showed that nuciferine improved glucose intolerance, reduced lipid accumulation and increased the glycogen content within hepatocytes, and decreased placental lipid and glycogen deposition, thus ameliorating glycolipid disorders in GDM mice. Additionally, nuciferine protected against histological degeneration of metabolism-associated critical organs including the liver, pancreas, and abdominal adipose tissue. Most interestingly, nuciferine could correct intestinal dysbacteriosis in GDM mice, as evidenced by the elevation of probiotic abundances consisting of Akkermansia, Lactobacillus, and Bifidobacterium, which were all negatively correlated with serum and liver triglyceride (TG) and positively associated with hepatic glycogen, and the reduction of conditional pathogen abundances including Escherichia-Shigella and Staphylococcus, and the latter was positively related to serum and liver TG and negatively linked with liver glycogen. Collectively, these findings suggest that nuciferine as a food-borne strategy played important roles in the management of GDM.

Natural Aporphine Alkaloids with Potential to Impact Metabolic Syndrome

The incidence and prevalence of metabolic syndrome has steadily increased worldwide. As a major risk factor for various diseases, metabolic syndrome has come into focus in recent years. Some natural aporphine alkaloids are very promising agents in the prevention and treatment of metabolic syndrome and its components because of their wide variety of biological activities. These natural aporphine alkaloids have protective effects on the different risk factors characterizing metabolic syndrome. In this review, we highlight the activities of bioactive aporphine alkaloids: thaliporphine, boldine, nuciferine, pronuciferine, roemerine, dicentrine, magnoflorine, anonaine, apomorphine, glaucine, predicentrine, isolaureline, xylopine, methylbulbocapnine, and crebanine. We particularly focused on their impact on metabolic syndrome and its components, including insulin resistance and type 2 diabetes mellitus, endothelial dysfunction, hypertension and cardiovascular disease, hyperlipidemia and obesity, non-alcoholic fatty liver disease, hyperuricemia and kidney damage, erectile dysfunction, central nervous system-related disorder, and intestinal microbiota dysbiosis. We also discussed the potential mechanisms of actions by aporphine alkaloids in metabolic syndrome.