Combination of curcumin and piperine prevents formation of gallstones in C57BL6 mice fed on lithogenic diet: whether NPC1L1/SREBP2 participates in this process?

Characterization, in vitro elderly digestion, and organoids cell uptake of curcumin-loaded nanoparticles

Curcumin, a bioactive compound, showed versatile in anti-inflammatory and anti-cancer ability, while their biological fate in elderly is unclear. In this study, curcumin-loaded nanoparticles based on octyl succinate hydrate (OSA) starch and sodium caseinate were prepared and the in vitro elderly digestion and absorption fate was investigated. The loading capacity of curcumin-loaded nanoparticles prepared from OSA starch (HI), sodium caseinate (SC) and OSA starch‑sodium caseinate (HS) were all higher than 15%. Curcumin release behavior of the three nanoparticles during in vitro digestion conformed to first-order kinetics. Meanwhile, the transport efficiency of curcumin for HI, SC, and HS increased significantly than the free curcumin (near 1-fold), and the permeability were 1.9, 2.0, and 2.0 times, respectively. The gene expressions of TNF-α, SREBP2 and NPC1L1 in the organoids were enhanced than control group. This study provided scientific reference and guidance for encapsulation of curcumin and digestion and absorption properties in elderly.

Pathophysiological consequences and treatment strategy of obstructive jaundice

Obstructive jaundice (OJ) is a common problem in daily clinical practice. However, completely understanding the pathophysiological changes in OJ remains a challenge for planning current and future management. The effects of OJ are widespread, affecting the biliary tree, hepatic cells, liver function, and causing systemic complications. The lack of bile in the intestine, destruction of the intestinal mucosal barrier, and increased absorption of endotoxins can lead to endotoxemia, production of proinflammatory cytokines, and induce systemic inflammatory response syndrome, ultimately leading to multiple organ dysfunction syndrome. Proper management of OJ includes adequate water supply and electrolyte replacement, nutritional support, preventive antibiotics, pain relief, and itching relief. The surgical treatment of OJ depends on the cause, location, and severity of the obstruction. Biliary drainage, surgery, and endoscopic intervention are potential treatment options depending on the patient's condition. In addition to modern medical treatments, Traditional Chinese medicine may offer therapeutic benefits for OJ. A comprehensive search was conducted on PubMed for relevant articles published up to August 1970. This review discusses in detail the pathophysiological changes associated with OJ and presents effective strategies for managing the condition.

Curcumin protects against high-fat diet-induced non-alcoholic simple fatty liver by inhibiting intestinal and hepatic NPC1L1 expression via down-regulation of SREBP-2/HNF1α pathway in hamsters

Niemann-pick C1-like 1 (NPC1L1) mediates cholesterol absorption and plays a key role in the pathogenesis of non-alcoholic simple fatty liver (NASFL). Our previous study showed that curcumin reduced NPC1L1 expression and cholesterol absorption in Caco-2 cells. This study aimed to investigate whether curcumin could inhibit intestinal and hepatic NPC1L1 expression through suppressing sterol regulatory element binding protein-2 (SREBP-2) / hepatocyte nuclear factor 1α (HNF1α) pathway, then exert anti-NASFL effects. Six-week hamsters were fed high-fat diet (HFD) with or without 0.1% curcumin for 12 weeks. Curcumin supplementation lowered blood total cholesterol (TC), triglycerides (TG) and low density lipoprotein cholesterol levels (20.2%, 48.7% and 36.5%), and reduced liver TC and TG contents (26.1% and 26.5%). Oil Red O staining demonstrated that curcumin significantly alleviated HFD-induced liver fat accumulation and hepatic steatosis, which was accompanied by reduced intestinal and hepatic NPC1L1, SREBP-2 and HNF1α expression (p < 0.05) and increased fecal neutral sterol excretion (114.5%). Furthermore, curcumin decreased cholesterol absorption in Caco-2 cells and HepG2 cells (49.2 % and 52.7 %). The inhibitory effects of curcumin on NPC1L1 expression and cholesterol absorption could be prevented by blockade of the SREBP-2 and HNF1α pathway. These findings indicated that curcumin protected against HFD-induced NASFL by inhibiting intestinal and hepatic NPC1L1 expression via down-regulation of SREBP-2/HNF1α pathway, thus reducing intestinal cholesterol absorption and hepatic biliary cholesterol reabsorption, consequently alleviating liver cholesterol accumulation and steatosis. Our study provides evidence for curcumin as a potential nutritional therapy for NASFL by regulating NPC1L1 and enterohepatic circulation of cholesterol.

Kidney Stone Prevention

Kidney stone disease (KSD) (alternatively nephrolithiasis or urolithiasis) is a global health care problem that affects almost people in developed and developing countries. Its prevalence has been continuously increasing with a high recurrence rate after stone removal. Although effective therapeutic modalities are available, preventive strategies for both new and recurrent stones are required to reduce physical and financial burdens of KSD. To prevent kidney stone formation, its etiology and risk factors should be first considered. Low urine output and dehydration are the common risks of all stone types, whereas hypercalciuria, hyperoxaluria, and hypocitraturia are the major risks of calcium stones. In this article, up-to-date knowledge on strategies (nutrition-based mainly) to prevent KSD is provided. Important roles of fluid intake (2.5-3.0 L/d), diuresis (>2.0-2.5 L/d), lifestyle and habit modifications (for example, maintain normal body mass index, fluid compensation for working in high-temperature environment, and avoid cigarette smoking), and dietary management [for example, sufficient calcium at 1000-1200 mg/d, limit sodium at 2 or 3-5 g/d of sodium chloride (NaCl), limit oxalate-rich foods, avoid vitamin C and vitamin D supplements, limit animal proteins to 0.8-1.0 g/kg body weight/d but increase plant proteins in patients with calcium and uric acid stone and those with hyperuricosuria, increase proportion of citrus fruits, and consider lime powder supplementation] are summarized. Moreover, uses of natural bioactive products (for example, caffeine, epigallocatechin gallate, and diosmin), medications (for example, thiazides, alkaline citrate, other alkalinizing agents, and allopurinol), bacterial eradication, and probiotics are also discussed. Adv Nutr 2023;x:xx-xx.

Piperine attenuates hepatic steatosis and insulin resistance in high-fat diet-induced obesity in Sprague-Dawley rats

Substantial evidence suggests that pepper consumption is associated with a reduced risk of obesity-related complications. However, whether piperine, the main component of pepper, improves obesity-induced hepatic lipid accumulation and insulin resistance and the action mechanism of piperine still remain unclear. We hypothesized that piperine attenuates high-fat diet (HFD)-induced obesity and improves the related metabolic complications in HFD-induced obese rats. Adult Sprague-Dawley (SD) male rats were fed a control diet (CON) or an HFD for 16 weeks. Obese rats were divided into 4 groups: HFD and HFD with daily gavage of piperine 2.7 mg/kg body weight (PIP-Low), 13.5 mg/kg body weight (PIP-Medium), and 27 mg/kg body weight (PIP-High) for another 8 weeks. Rats were euthanized after an 8-hour fast, and the liver, heart, kidney, and white adipose tissue were collected and stored at -80 °C. Piperine administration significantly reduced weight gain, plasma insulin, and glucose concentration. For oral piperine at a dose of 27 mg/kg body weight, body weight significantly decreased by 5.7% compared with that in the HFD group. Additionally, oral piperine administration considerably reduced serum triglyceride concentration. Furthermore, piperine administration reversed the HFD-induced downregulation of adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling molecules and increased the plasma levels of adiponectin and the messenger RNA expression of the adiponectin receptor; additionally, it increased the phosphorylation of phosphatidylinositol-3 kinase (PI3K) and protein kinase B. Overall, oral piperine administration reversed HFD-induced liver lipid accumulation and insulin resistance, possibly via the inactivation of adiponectin-AMPK and PI3K-Akt signaling. These findings imply that piperine could serve as an effective agent for healthy weight loss.

A Unifying Perspective in Blunting the Limited Oral Bioavailability of Curcumin: A Succinct Look

BACKGROUND

Curcumin is a polyphenolic compound derived from rhizomes of Curcuma longa, the golden spice. Curcumin has drawn much attention in recent years of biomedical research owing to its wide variety of biologic and pharmacologic actions. It exerts antiproliferative, antifibrogenic, anti-inflammatory, and antioxidative effects, among various imperative pharmacologic actions. In spite of its well-documented efficacies against numerous disease conditions, the limited systemic bioavailability of curcumin is a continuing concern. Perhaps, the poor bioavailability of curcumin may have curtailed its significant development from kitchen to clinic as a potential therapeutic agent. Subsequently, there have been a considerable number of studies over decades researching the scientific basis of curcumin's reduced bioavailability and eventually improvement of its bioavailability employing a variety of therapeutic approaches, for instance, in combination with piperine, the bio-active constituent of black pepper. Piperine has remarkable potential to modulate the functional activity of metabolic enzymes and drug transporters, and thus there has been a great interest in the therapeutic application of this widely used spice as alternative medicine and bioavailability enhancer. Growing body of evidence supports the synergistic potential of curcumin against numerous pathologic conditions when administered with piperine.

CONCLUSION

In light of current challenges, the major concern pertaining to poor systemic bioavailability of curcumin, its improvement, especially in combination with piperine, and the necessity of additional research in this setting are together described in this review. Besides, the recent advances in the potential therapeutic rationale and efficacy of curcumin-piperine combination, a promising duo, against various pathologic conditions are delineated.

Curcumae rhizoma and its major constituents against hepatobiliary disease: Pharmacotherapeutic properties and potential clinical applications

BACKGROUND

Hepatobiliary disease currently serves as an urgent health issue in public due to health-modulating factors such as extension of life expectancy, increasingly sedentary lifestyles and over-nutrition. A definite treatment remains lacking owing to different stages of the disease itself and its intricate pathogenesis. Traditional Chinese medicine (TCM) has been gradually popularized in clinic with the satisfactory efficacy and good safety. Curcumae Rhizoma (called E Zhu, EZ in Chinese) is a representative herb, which has been used to treat hepatobiliary disease for thousands of years.

PURPOSE

To systematically summarize the recent research advances on the pharmacological activities of EZ and its constituents, explain the underlying mechanisms of preventing and treating hepatobiliary diseases, and assess the shortcomings of existing work. Besides, ethnopharmacology, phytochemicals, and toxicology of EZ have been researched.

METHODS

The information about EZ was collected from various sources including classic books about Chinese herbal medicine, and scientific databases including Web of Science, PubMed, ScienceDirect, Springer, ACS, SCOPUS, CNKI, CSTJ, and WANFANG using keywords given below and terms like pharmacological and phytochemical details of this plant.

RESULTS

The chemical constituents isolated and identified from EZ, such as terpenoids including β-elemene, furanodiene, germacrone, etc. and curcuminoids including curcumin, demethoxycurcumin, bisdemethoxycurcumin, etc. prove to have hepatoprotective effect, anti-liver fibrotic effect, anti-fatty liver effect, anti-liver neoplastic effect, and cholagogic effect through TGF-β1/Smad, JNK1/2-ROS, NF-κB and other anti-inflammatory and antioxidant signaling pathways. Also, EZ is often combined with other Chinese herbs in the treatment of hepatobiliary diseases with good clinical efficacy and no obvious adverse reactions.

CONCLUSION

It provides a preclinical basis for the efficacy of EZ as an effective therapeutic agent for the prevention and treatment of hepatobiliary diseases. Even so, the further studies still needed to alleviate hepatotoxicity and expand clinical application.

Curcumin Supplementation Ameliorates Bile Cholesterol Supersaturation in Hamsters by Modulating Gut Microbiota and Cholesterol Absorption

Curcumin is a polyphenol that has been shown to have prebiotic and cholesterol-lowering properties. This study aimed to investigate the impact of curcumin on bile cholesterol supersaturation and the potential mechanistic role of intestinal microbiota and cholesterol absorption. Male hamsters (n = 8) were fed a high-fat diet (HFD) supplemented with or without curcumin for 12 weeks. Results showed that curcumin significantly decreased cholesterol levels in the serum (from 5.10 to 4.10 mmol/L) and liver (from 64.60 to 47.72 nmol/mg protein) in HFD-fed hamsters and reduced the bile cholesterol saturation index (CSI) from 1.64 to 1.08 due to the beneficial modifications in the concentration of total bile acids (BAs), phospholipids and cholesterol (p < 0.05). Gut microbiota analysis via 16S rRNA sequencing revealed that curcumin modulated gut microbiota, predominantly increasing microbiota associated with BA metabolism and short-chain fatty acid production, which subsequently up-regulated the expression of hepatic cholesterol 7-alpha hydroxylase and increased the synthesis of bile acids (p < 0.05). Furthermore, curcumin significantly down-regulated the expression of intestinal Niemann−Pick C1-like protein 1(NPC1L1) in hamsters and reduced cholesterol absorption in Caco-2 cells (p < 0.05). Our results demonstrate that dietary curcumin has the potential to prevent bile cholesterol supersaturation through modulating the gut microbiota and inhibiting intestinal cholesterol absorption.

Hypothyroidism Increases Cholesterol Gallstone Prevalence in Mice by Elevated Hydrophobicity of Primary Bile Acids

Background: Thyroid hormone (TH) deficiency has been associated with increased cholesterol gallstone prevalence. Hypothyroidism impacts hepatic lipid homeostasis, biliary secretion, gallbladder motility, and gallstone (LITH) gene expression, all potential factors contributing to cholesterol gallstone disease (CGD). However, how TH deficiency may lead to gallstone formation is still poorly understood. Therefore, we performed molecular studies in a CGD mouse model under lithogenic conditions and modulation of TH status. Methods: Male, three-month-old C57BL/6 mice were randomly divided into a control (euthyroid) group, a hypothyroid (hypo) group, a gallstone (litho) group, and a gallstone+hypothyroid (litho+hypo) group and were treated for 2, 4, and 6 weeks (n = 8/treatment period). Gallstone prevalence, biliary composition and cholesterol crystals, hepatic expression of genes participating in cholesterol, bile acid (BA), and phosphatidylcholine synthesis (Hmgcr, Cyp7a1, Pcyt1a), and canalicular transport (Abcg5, Bsep, Abcb4) were investigated. Results: Increased cholesterol gallstone prevalence was observed in hypothyroid mice under lithogenic diet after 4 and 6 weeks of treatment (4 weeks: 25% vs. 0%; 6 weeks: 75% vs. 37.5%). Interestingly, neither the composition of the three main biliary components, cholesterol, BAs, and phosphatidylcholine, nor the hepatic expression of genes involved in synthesis and transport could explain the differences in cholesterol gallstone formation in the mice. However, TH deficiency resulted in significantly increased hydrophobicity of primary BAs in bile. Furthermore, downregulation of hepatic sulfonation enzymes Papss2 and Sult2a8 as well as diminished biliary BA sulfate concentrations in mice were observed under hypothyroid conditions all contributing to a lithogenic biliary milieu as evidenced by microscopic cholesterol crystals and macroscopic gallstone formation. Conclusions: We describe a novel pathogenic link between TH deficiency and CGD and suggest that the increased hydrophobic character of biliary BAs due to the diminished expression of hepatic detoxification enzymes promotes cholesterol crystal precipitation and enhances cholesterol gallstone formation in the bile of hypothyroid mice.

Rodent models of cholestatic liver disease: A practical guide for translational research

Cholestatic liver disease denotes any situation associated with impaired bile flow concomitant with a noxious bile acid accumulation in the liver and/or systemic circulation. Cholestatic liver disease can be subdivided into different types according to its clinical phenotype, such as biliary atresia, drug-induced cholestasis, gallstone liver disease, intrahepatic cholestasis of pregnancy, primary biliary cholangitis and primary sclerosing cholangitis. Considerable effort has been devoted to elucidating underlying mechanisms of cholestatic liver injuries and explore novel therapeutic and diagnostic strategies using animal models. Animal models employed according to their appropriate applicability domain herein play a crucial role. This review provides an overview of currently available in vivo animal models, fit-for-purpose in modelling different types of cholestatic liver diseases. Moreover, a practical guide and workflow is provided which can be used for translational research purposes, including all advantages and disadvantages of currently available in vivo animal models.

Curcumin inhibits the proteolytic process of SREBP-2 by first inhibiting the expression of S1P rather than directly inhibiting SREBP-2 expression

Many studies have demonstrated that curcumin can downregulate mRNA levels of sterol regulatory element-binding proteins (SREBP-2); however, our study did not find similar results. This study was designed to demonstrate that curcumin inhibits the proteolytic process of SREBP-2 by first inhibiting the expression of membrane-bound transcription factor site-1 protease (S1P) rather than directly inhibiting SREBP-2 expression. After curcumin treatment, Caco-2 cells were collected to observe the dose- and time-dependent dynamics of precursor and mature SREBP-2, transcription factor-specific protein 1 (SP-1), and SREBP cleavage-activating protein (SCAP). After curcumin treatment, SREBP-2 distribution was detected in the cells and S1P protein expression was examined. Curcumin could downregulate mRNA levels of SREBP2, SP-1 and SCAP, but it did not simultaneously downregulate the expression of precursor SREBP-2 (pSREBP-2) and SCAP. Curcumin can inhibit the proteolytic process of SREBP-2, reduce the production of mature SREBP-2 (mSREBP-2), and change the cellular distribution of SREBP-2. The inhibitory effect of curcumin on SP-1 protein expression is short-acting. Curcumin could downregulate the mRNA and protein expression of S1P, but has no obvious inhibitory effect on the mRNA and protein expression of S2P (site-2 protease). Curcumin can inhibit the SREBP-2 proteolytic process to reduce mSREBP-2 which functions as a transcription factor, affecting the regulation of cholesterol metabolism-related genes. Curcumin does not directly inhibit the expression of mSREBP-2 protein, and it has no such inhibitory effect for at least a short period of time, although curcumin does reduce the amount of mSREBP-2 protein. S1P is a key protease in the hydrolysis of pSREBP-2 into mSREBP-2. Therefore, curcumin may decrease the amount of mSREBP-2 by directly inhibiting the expression of S1P mRNA and protein.

Novel Lactobacillus reuteri HI120 Affects Lipid Metabolism in C57BL/6 Obese Mice

Intestinal probiotics are a primary focus area of current medical research. Probiotics such as bifidobacteria and lactobacilli can positively impact obesity and other metabolic diseases by directly or indirectly affecting lipid metabolism. However, the precise mechanisms of these effects remain unclear. In our previous work, the novel strain Lactobacillus reuteri HI120 was isolated and identified. HI120 expresses high levels of linoleic isomerase, resulting in the production of large amounts of conjugated linoleic acid (CLA) when mixed with linoleic acid (LA). As HI120 can efficiently transform LA into CLA, the effect of HI120 on the lipid metabolism in C57BL/6 obese mice was studied and the underlying molecular mechanism was explored in vitro. The results revealed no significant change in the diet, body weight, and serum triglyceride levels in mice. However, serum cholesterol levels were significantly decreased. The underlying mechanism may involve a CLA-mediated reduction in the gene expression levels of NPC1L1, SREBP-2, and HMG-CR, resulting in reduced cholesterol synthesis and absorption. Thus, HI120 can be developed as a potential probiotic formulation. After oral administration, LA from certain food sources can be converted into CLA in the human intestine to contribute to the prevention and treatment of obesity and hyperlipidemia.

Cellular and molecular mechanisms of curcumin in prevention and treatment of disease

Curcumin is a naturally occurring polyphenolic compound present in rhizome of Curcuma longa belonging to the family zingiberaceae. Growing experimental evidence revealed that curcumin exhibit multitarget biological implications signifying its crucial role in health and disease. The current review highlights the recent progress and mechanisms underlying the wide range of pharmacological effects of curcumin against numerous diseases like neuronal, cardiovascular, metabolic, kidney, endocrine, skin, respiratory, infectious, gastrointestinal diseases and cancer. The ability of curcumin to modulate the functions of multiple signal transductions are linked with attenuation of acute and chronic diseases. Numerous preclinical and clinical studies have revealed that curcumin modulates several molecules in cell signal transduction pathway including PI3K, Akt, mTOR, ERK5, AP-1, TGF-β, Wnt, β-catenin, Shh, PAK1, Rac1, STAT3, PPARγ, EBPα, NLRP3 inflammasome, p38MAPK, Nrf2, Notch-1, AMPK, TLR-4 and MyD-88. Curcumin has a potential to prevent and/or manage various diseases due to its anti-inflammatory, anti-oxidant and anti-apoptotic properties with an excellent safety profile. In contrast, the anti-cancer effects of curcumin are reflected due to induction of growth arrest and apoptosis in various premalignant and malignant cells. This review also carefully emphasized the pharmacokinetics of curcumin and its interaction with other drugs. Clinical studies have shown that curcumin is safe at the doses of 12 g/day but exhibits poor systemic bioavailability. The use of adjuvant like piperine, liposomal curcumin, curcumin nanoparticles and curcumin phospholipid complex has shown enhanced bioavailability and therapeutic potential. Further studies are warranted to prove the potential of curcumin against various ailments.

Non-surgical treatment of cholesterol gallstones: An update on recent developments

Cholesterol gallstones (CS) are a common disease of the digestive system. The imbalance of cholesterol and bile acid metabolism tends to result in the deposition of cholesterol crystals, which is the basis of gallstone formation. Current guidelines recommend cholecystectomy for CS patients with any symptoms. Nevertheless, there are still some patients without surgical indications, surgical conditions, or surgical consent, who may be benefit from non-surgical treatment. However, there are not too many tips for non-surgical treatment of CS in latest guidelines, nor sufficient attention paid form clinicians. This paper reviews the relevant recent literature on non-surgical treatment of CS, with an aim to help clinicians be familiar with non-surgical treatment of CS.

Risperidone-induced metabolic dysfunction is attenuated by Curcuma longa extract administration in mice

Antipsychotics, such as risperidone, increase food intake and induce alteration in glucose and lipid metabolism concomitantly with overweight and body fat increase, these biological abnormalities belong to the metabolic syndrome definition (high visceral adiposity, hypertriglyceridemia, hyperglycemia, low HDL-cholesterol and high blood pressure). Curcumin is a major component of traditional turmeric (Curcuma longa) which has been reported to improve lipid and glucose metabolism and to decrease weight in obese mice. We questioned the potential capacity of curcumin, contained in Curcuma longa extract (Biocurcuma™), to attenuate the risperidone-induced metabolic dysfunction. Two groups of mice were treated once a week, for 22 weeks, with intraperitoneal injection of risperidone (Risperdal) at a dose 12.5 mpk. Two other groups received intraperitoneal injection of the vehicle of Risperdal following the same schedule. Mice of one risperidone-treated groups and of one of vehicle-treated groups were fed a diet with 0.05% Biocurcuma™ (curcumin), while mice of the two other groups received the standard diet. Curcumin limited the capacity of risperidone to reduce spontaneous motricity, but failed to impede risperidone-induced increase in food intake. Curcumin did not reduce the capacity of risperidone to induce weight gain, but decreased visceral adiposity and decreased the risperidone-induced hepatomegaly, but not steatosis. Furthermore, curcumin repressed the capacity of risperidone to induce the hepatic over expression of enzymes involved in lipid metabolism (LXRα, FAS, ACC1, LPL, PPARγ, ACO, SREBP2) and decreased risperidone-induced glucose intolerance and hypertriglyceridemia. Curcumin decreased risperidone-induced increases in serum markers of hepatotoxicity (ALAT, ASAT), as well as of one major hepatic pro-inflammatory transcription factor (NFκB: p105 mRNA and p65 protein). These findings support that nutritional doses of curcumin contained in Curcuma longa extract are able to partially counteract the risperidone-induced metabolic dysfunction in mice, suggesting that curcumin ought to be tested to reduce the capacity of risperidone to induce the metabolic syndrome in human.

Curcumin in Hepatobiliary Disease: Pharmacotherapeutic Properties and Emerging Potential Clinical Applications

Curcumin, an aromatic phytoextract from the turmeric (Curcuma longa) rhizome, has been used for centuries for a variety of purposes, not the least of which is medicinal. A growing body of evidence suggests that curcumin has a broad range of potentially therapeutic pharmacological properties, including anti-inflammatory, anti-fibrotic, and anti-neoplastic effects, among others. Clinical applications of curcumin have been hampered by quality control concerns and limited oral bioavailability, although novel formulations appear to have largely overcome these issues. Recent in vitro and in vivo studies have found that curcumin's cytoprotective and other biological activities may play a role in an array of benign and malignant hepatobiliary conditions, including but not limited to non-alcoholic fatty liver disease, cholestatic liver disease (e.g. primary sclerosing cholangitis), and cholangiocarcinoma. Here we provide an overview of fundamental principles, recent discoveries, and potential clinical hepatobiliary applications of this pleiotropic phytocompound.

Curcumin inhibited growth of human melanoma A375 cells via inciting oxidative stress

Curcumin, a polyphenol compound, possesses potent pharmacological properties in preventing cancers, which make it as a potential anti-cancer mediator. However, it is still unknown that whether Curcumin induced melanoma A375 cell was associated with oxidative stress. Here, we firstly found a fascinating result that Curcumin could reduce the proliferation and induced apoptosis of human melanoma A375 cells. Meanwhile, IC₅₀ of Curcumin on A375 cells is 80μM at 48h. In addition, Curcumin caused oxidative stress through inducing further ROS burst, decreasing GSH, and wrecking mitochondria membrane potential (MMP), which were reversed by ROS inhibitor N-acetylcysteine (NAC). Moreover, MMP disruption led to the release of Cytochrome c from mitochondria and subsequently led to intracellular apoptosis. Furthermore, we found that ROS-dependent HIF-1α and its downstream proteins also play an important role on Curcumin induced apoptosis. In conclusion, our results shed new lights on the therapy of melanoma that Curcumin may be a promising candidate.

Osteopontin deficiency protects mice from cholesterol gallstone formation by reducing expression of intestinal NPC1L1

Homeostasis of cholesterol is regulated by absorption in the intestine and synthesis in the liver. The authors previously demonstrated that OPN (osteopontin) exhibits the ability to alter hepatic cholesterol metabolism, thus affecting cholesterol gallstone formation in mice. The present study investigated the role of OPN in cholesterol gallstone formation, focusing on its effect on intestinal absorption of cholesterol. OPN gene knockout (OPN−/−) mice and wild-type mice were respectively fed with a chow or lithogenic diet (LD) for 8 weeks. Following an 8-week LD period, the incidence of gallstone, bile composition, level of serum and fecal lipids and the expression of intestinal associated genes were analyzed. OPN−/− mice were protected from gallstone formation induced by 8 weeks' LD-feeding. This protective effect from OPN deficiency was associated with alterations in bile composition, including a reduced concentration of biliary cholesterol. Additionally, plasma cholesterol level was decreased in LD-fed OPN−/− mice. The alterations primarily resulted from the decreased expression of intestinal Niemann-Pick C1-like (NPC1 L) 1, which is important in the intestinal absorption of cholesterol. The present study demonstrated that OPN deficiency reduced intestinal absorption of cholesterol by suppressing the expression of NPC1L1, thus protecting mice from cholesterol gallstone formation.

Piperine regulates UCP1 through the AMPK pathway by generating intracellular lactate production in muscle cells

This study characterizes the human metabolic response to piperine, a curcumin extract, and the details of its underlying molecular mechanism. Using ¹H-NMR-based metabolome analysis, we showed the metabolic effect of piperine on skeletal muscle and found that piperine increased the level of intracellular lactate, an important metabolic intermediate that controls expression of several genes involved in mitochondrial activity. Piperine also induced the phosphorylation of AMP-activated protein kinase (AMPK) and its downstream target, acetyl-CoA carboxylase (ACC), while additionally stimulating glucose uptake in an AMPK dependent manner. Piperine also stimulates the p38 mitogen-activated protein kinase (p38 MAPK), an effect that was reversed by pretreatment with compound C, an AMPK inhibitor. Inhibition of p38 MAPK resulted in no piperine-induced glucose uptake. Increased level of lactate resulted in increased expression of mitochondrial uncoupling protein 1 (UCP1), which regulates energy expenditure, thermogenesis, and fat browning. Knock-down of AMPK blocked piperine-induced UCP1 up-regulation, demonstrating the required role of AMPK in this effect. Taken together, these results suggest that piperine leads to benign metabolic effects by activating the AMPK-p38 MAPK signaling pathway and UCP1 expression by activating intracellular lactate production in skeletal muscle.

Hypocholesterolemic Activity of Curcumin Is Mediated by Down-regulating the Expression of Niemann-Pick C1-like 1 in Hamsters

We previously demonstrated that curcumin reduces cholesterol absorption in Caco-2 cells through down-regulating Niemann-Pick C1-like 1 (NPC1L1) expression, but the in vivo effect of curcumin on intestinal cholesterol absorption remains unknown. The present study aimed to investigate the effects and mechanisms of curcumin consumption on cholesterol absorption in hamsters. Male hamsters were fed a high-fat diet supplemented with or without curcumin (0.05% w/w) for 12 weeks. Curcumin supplementation significantly decreased serum total cholesterol (TC) (from 6.86 ± 0.27 to 3.50 ± 0.24 mmol/L), triglyceride (TG) (from 5.07 ± 0.34 to 3.72 ± 0.40 mmol/L), and low-density lipoprotein cholesterol (from 2.58 ± 0.19 to 1.71 ± 0.15 mmol/L) levels as well as liver TC (from 11.6 ± 0.05 to 7.2 ± 0.03 mg/g) and TG (from 30.3 ± 0.22 to 25.2 ± 0.18 mg/g) levels (P < 0.05 for all). In contrast, curcumin treatment markedly enhanced fecal cholesterol output (P < 0.01). Moreover, curcumin supplementation down-regulated the mRNA and protein expressions of sterol regulatory element binding protein-2 (SREBP-2) and NPC1L1 in the small intestine (P < 0.05). Our current results indicate that curcumin inhibits cholesterol absorption in hamsters by suppressing SREBP-2 and subsequently down-regulating NPC1L1 expression, which may be responsible for the hypocholesterolemic effects of curcumin.