Oleanolic acid attenuates PCBs-induced adiposity and insulin resistance via HNF1b-mediated regulation of redox and PPARγ signaling

Principal Bioactive Properties of Oleanolic Acid, Its Derivatives, and Analogues

Natural products have always played an important role in pharmacotherapy, helping to control pathophysiological processes associated with human disease. Thus, natural products such as oleanolic acid (OA), a pentacyclic triterpene that has demonstrated important activities in several disease models, are in high demand. The relevant properties of this compound have motivated re-searchers to search for new analogues and derivatives using the OA as a scaffold to which new functional groups have been added or modifications have been realized. OA and its derivatives have been shown to be effective in the treatment of inflammatory processes, triggered by chronic diseases or bacterial and viral infections. OA and its derivatives have also been found to be effective in diabetic disorders, a group of common endocrine diseases characterized by hyperglycemia that can affect several organs, including the liver and brain. This group of compounds has been reported to exhibit significant bioactivity against cancer processes in vitro and in vivo. In this review, we summarize the bioactive properties of OA and its derivatives as anti-inflammatory, anti-bacterial, antiviral, anti-diabetic, hepatoprotective, neuroprotective, and anticancer agents.

Oleanolic acid alleviates obesity-induced skeletal muscle atrophy via the PI3K/Akt signaling pathway

Oleanolic acid (OA) is a pentacyclic triterpene with reported protective effects against various diseases, including diabetes, hepatitis, and different cancers. However, the effects of OA on obesity-induced muscle atrophy remain largely unknown. This study investigated the effects of OA on skeletal muscle production and proliferation of C2C12 cells. We report that OA significantly increased skeletal muscle mass and improved glucose intolerance and insulin resistance. OA inhibited dexamethasone (Dex)-induced muscle atrophy in C2C12 myoblasts by regulating the PI3K/Akt signaling pathway. In addition, it also inhibited expression of MuRF1 and Atrogin1 genes in skeletal muscle of obese mice suffering from muscle atrophy, and increased the activation of PI3K and Akt, thereby promoting protein synthesis, and eventually alleviating muscle atrophy. Taken together, these findings suggest OA may have potential for the prevention and treatment of muscle atrophy.

The Effect and Mechanism of Oleanolic Acid in the Treatment of Metabolic Syndrome and Related Cardiovascular Diseases

Metabolic syndromes (MetS) and related cardiovascular diseases (CVDs) pose a serious threat to human health. MetS are metabolic disorders characterized by obesity, dyslipidemia, and hypertension, which increase the risk of CVDs' initiation and development. Although there are many availabile drugs for treating MetS and related CVDs, some side effects also occur. Considering the low-level side effects, many natural products have been tried to treat MetS and CVDs. A five-cyclic triterpenoid natural product, oleanolic acid (OA), has been reported to have many pharmacologic actions such as anti-hypertension, anti-hyperlipidemia, and liver protection. OA has specific advantages in the treatment of MetS and CVDs. OA achieves therapeutic effects through a variety of pathways, attracting great interest and playing a vital role in the treatment of MetS and CVDs. Consequently, in this article, we aim to review the pharmacological actions and potential mechanisms of OA in treating MetS and related CVDs.

Integrating network pharmacology and animal experimental validation to investigate the action mechanism of oleanolic acid in obesity

BACKGROUND

Obesity, a condition associated with the development of widespread cardiovascular disease, metabolic disorders, and other health complications, has emerged as a significant global health issue. Oleanolic acid (OA), a pentacyclic triterpenoid compound that is widely distributed in various natural plants, has demonstrated potential anti-inflammatory and anti-atherosclerotic properties. However, the mechanism by which OA fights obesity has not been well studied.

METHOD

Network pharmacology was utilized to search for potential targets and pathways of OA against obesity. Molecular docking and molecular dynamics simulations were utilized to validate the interaction of OA with core targets, and an animal model of obesity induced by high-fat eating was then employed to confirm the most central of these targets.

RESULTS

The network pharmacology study thoroughly examined 42 important OA targets for the treatment of obesity. The key biological processes (BP), cellular components (CC), and molecular functions (MF) of OA for anti-obesity were identified using GO enrichment analysis, including intracellular receptor signaling, intracellular steroid hormone receptor signaling, chromatin, nucleoplasm, receptor complex, endoplasmic reticulum membrane, and RNA polymerase II transcription Factor Activity. The KEGG/DAVID database enrichment study found that metabolic pathways, PPAR signaling pathways, cancer pathways/PPAR signaling pathways, insulin resistance, and ovarian steroidogenesis all play essential roles in the treatment of obesity and OA. The protein-protein interaction (PPI) network was used to screen nine main targets: PPARG, PPARA, MAPK3, NR3C1, PTGS2, CYP19A1, CNR1, HSD11B1, and AGTR1. Using molecular docking technology, the possible binding mechanism and degree of binding between OA and each important target were validated, demonstrating that OA has a good binding potential with each target. The molecular dynamics simulation's Root Mean Square Deviation (RMSD), and Radius of Gyration (Rg) further demonstrated that OA has strong binding stability with each target. Additional animal studies confirmed the significance of the core target PPARG and the core pathway PPAR signaling pathway in OA anti-obesity.

CONCLUSION

Overall, our study utilized a multifaceted approach to investigate the value and mechanisms of OA in treating obesity, thereby providing a novel foundation for the identification and development of natural drug treatments.

Effects of oleanolic acid on acute liver injury triggered by lipopolysaccharide in broiler chickens

1. Infectious injury caused by lipopolysaccharide (LPS), a metabolite of gram-negative bacteria, can induce stress responses in animals and is a significant cause of morbidity and mortality in young birds. The purpose of this study was to investigate the effects of dietary supplementation with oleanolic acid (OA) on acute liver injury in broiler chickens challenged with LPS.2. In total, 120 broiler chickens were randomly divided into six groups and fed a basal diet containing 0, 50, 100, or 200 mg/kg OA or 100 mg/kg aureomycin. On d 15, broiler chickens were injected with either LPS or an equivalent volume of normal saline. Six hours after LPS injection, two broiler chicks were randomly selected for sampling in each replicate.3. The results indicated that dietary aureomycin was ineffective in alleviating LSP-associated liver injury, but protected broiler chickens from LPS-induced liver damage. This promoted a significant reduction in the levels of malondialdehyde and an increase in the levels of superoxide dismutase in liver. In addition, OA was found to cause significant reductions in the relative expression of IL-1β, IL-6, and TNF-α in broiler liver tissues, whereas the relative expression of IL-10 was significantly increased.4. In conclusion, oleanolic acid can alleviate oxidative stress and injury in the livers of broiler chickens induced by lipopolysaccharide. Consequently, oleanolic acid has potential utility as a novel anti-inflammatory and antioxidant feed additive.

Angelica sinensis polysaccharide improves mitochondrial metabolism of osteoarthritis chondrocytes through PPARγ/SOD2/ROS pathways

Osteoarthritis (OA) is a common degenerative joint disease, which is characterized by wear of articular cartilage and narrow joint space, resulting in joint movement disorder. At present, accurate molecular mechanisms and effective interventions are still being explored. Here, we propose that angelica sinensis polysaccharide (ASP) alleviates OA progression by activating peroxisome proliferator-activated receptor gamma (PPARγ). Therapeutic effect of ASP improving mitochondrial metabolism of OA chondrocytes was evaluated in vitro and in vivo, respectively. During cell experiments, the concentration and time response of tert butyl hydroperoxide (TBHP) and ASP were determined by cell viability. Apoptosis was detected by flow cytometry. Mitochondrial metabolism was detected by reactive oxygen species (ROS), mitochondrial membrane potential (MMP), release of cytochrome C, adenosine triphosphate (ATP) production, and superoxide dismutase 2 (SOD2) activity. Expressions of Aggrecan, collagen type II (Col2a1), PPARγ, and SOD2 were detected by qRT-PCR and western blot. In animal experiments, we detected cell apoptosis and target protein expression separately through terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining and immunohistochemistry. Pretreatment of ASP significantly activated PPARγ and SOD2 in rat chondrocytes incubated with TBHP, cleared ROS, improved mitochondrial metabolism, increased chondrocytes viability, and alleviated chondrocytes apoptosis. In vivo, the administration of ASP could effectively ameliorate cartilage degeneration in OA rats, promote extracellular matrix synthesis, and decelerate the progress of OA. Our research identifies the role of ASP in mitochondrial metabolism of OA chondrocytes through PPARγ/SOD2/ROS pathways, which provides a new idea for the treatment of OA.

"Turn-on" fluorescent sensor for oleanolic acid based on o-phenyl-bridged bis-tetraphenylimidazole

Fluorescent sensors had been extensively applied on sensing various biomolecules effectively, but no fluorescent sensor for oleanolic acid was presented up to now. In this work, the first fluorescent sensor for oleanolic acid was designed and synthesized based on o-phenyl-bridged bis-tetraphenylimidazole (PTPI). PTPI was prepared by bridging two tetraphenylimidazole units and o-phenylenediamine via Schiff-base condensation in yield of 86%. PTPI showed high sensing selectivity for oleanolic acid among 26 biomolecules and ions. The blue fluorescence at 482 nm was enhanced by 4.5 times after sensing oleanolic acid in aqueous media. The fluorescence sensing ability of PTPI for oleanolic acid maintained stable in pH = 5-9. The detecting limitation was as low as 0.032 μM. The detecting mechanism was clarified as 1:1 binding stoichiometry by fluorescence Job's plot, mass spectrometry, ¹H nuclear magnetic resonance and fourier transform infrared spectroscopy. The detecting ability of PTPI for oleanolic acid was successfully used for paper test and real samples of grapes and Kuding tea with recoveries in the range of 96.0%-106.0%, indicating the good application potential for on-site detecting oleanolic acid in real samples of fruits and food.

A color-change fluorescence sensor for oleanolic acid based on chiral camphanic decorated bis-cyanostilbene

Although various fluorescent sensors for biomolecules had been extensively reported, the effective fluorescent sensor was seldom reported for detecting oleanolic acid up to now. This work reports the first color-change fluorescence sensor for oleanolic acid based on a bridging bis-cyanostilbene derivative with chiral camphanic groups (C-BCS). C-BCS possessed the chartreuse fluorescence in aqueous media, which transferred to strong blue fluorescence in the presence of oleanolic acid. This sensing ability of C-BCS for oleanolic acid exhibited the high selectivity among all kinds of biomolecules and ions. The good linearity between the fluorescence intensity and concentration of oleanolic acid was acquired in the range of 0.2 × 10^-6 to 8.0 × 10^-6 M with the detecting limitation of 0.0582 μM. The 1:1 binding process was clarified as oleanolic acid located in the opening cavity composed of two bridging cyanostilbene units and two chiral camphanic groups based on multiple hydrogen bonds and hydrophobic interaction. The detecting ability of C-BCS was applied on sensing oleanolic acid in thin-layer chromatography analysis, imprinting experiment, tap water, and tea samples, suggesting the effective on-site sensing abilities of C-BCS for oleanolic acid in real samples and daily life.

Role of potential bioactive metabolites from traditional Chinese medicine for type 2 diabetes mellitus: An overview

Type 2 diabetes mellitus (T2DM) is a metabolic disease with persistent hyperglycemia primarily caused by insulin resistance (IR). The number of diabetic patients globally has been rising over the past decades. Although significant progress has been made in treating diabetes mellitus (DM), existing clinical drugs for diabetes can no longer fully meet patients when they face complex and huge clinical treatment needs. As a traditional and effective medical system, traditional Chinese medicine (TCM) has a unique understanding of diabetes treatment and has developed many classic and practical prescriptions targeting DM. With modern medicine and pharmacy advancements, researchers have discovered that various bioactive metabolites isolated from TCM show therapeutic on DM. Compared with existing clinical drugs, these bioactive metabolites demonstrate promising prospects for treating DM due to their excellent biocompatibility and fewer adverse reactions. Accordingly, these valuable metabolites have attracted the interest of researchers worldwide. Despite the abundance of research works and specialized-topic reviews published over the past years, there is a lack of updated and systematic reviews concerning this fast-growing field. Therefore, in this review, we summarized the bioactive metabolites derived from TCM with the potential treatment of T2DM by searching several authoritative databases such as PubMed, Web of Science, Wiley Online Library, and Springer Link. For the convenience of readers, the content is divided into four parts according to the structural characteristics of these valuable compounds (flavonoids, terpenoids, alkaloids, and others). Meanwhile, the detailed mechanism and future directions of these promising compounds curing DM are also summarized in the related sections. We hope this review inspires increasingly valuable and significant research focusing on potential bioactive metabolites from TCM to treat DM in the future.

Recent advances in medicinal chemistry of oleanolic acid derivatives

Oleanolic acid (OA), a ubiquitous pentacyclic oleanane-type triterpene isolated from edible and medicinal plants, exhibits a wide spectrum of pharmacological activities and tremendous therapeutic potential. However, the undesirable pharmacokinetic properties limit its application and development. Numerous researches on structural modifications of OA have been carried out to overcome this limitation and improve its pharmacokinetic and therapeutic properties. This review aims to compile and summarize the recent progresses in the medicinal chemistry of OA derivatives, especially on structure-activity relationship in the last few years (2010-2021). It gives insights into the rational design of bioactive derivatives from OA scaffold as promising therapeutic agents.

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part I)

Triterpenic acids are phytocompounds with a widespread range of biological activities that have been the subject of numerous in vitro and in vivo studies. However, their underlying mechanisms of action in various pathologies are not completely elucidated. The current review aims to summarize the most recent literature, published in the last five years, regarding the mechanism of action of three triterpenic acids (asiatic acid, oleanolic acid, and ursolic acid), corelated with different biological activities such as anticancer, anti-inflammatory, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, and antimicrobial. All three discussed compounds share several mechanisms of action, such as the targeted modulation of the PI3K/AKT, Nrf2, NF-kB, EMT, and JAK/STAT3 signaling pathways, while other mechanisms that proved to only be specific for a part of the triterpenic acids discussed, such as the modulation of Notch, Hippo, and MALAT1/miR-206/PTGS1 signaling pathway, were highlighted as well. This paper stands as the first part in our literature study on the topic, which will be followed by a second part focusing on other triterpenic acids of therapeutic value.

Molecular Mechanisms Underlying the Effects of Olive Oil Triterpenic Acids in Obesity and Related Diseases

Dietary components exert protective effects against obesity and related metabolic and cardiovascular disturbances by interfering with the molecular pathways leading to these pathologies. Dietary biomolecules are currently promising strategies to help in the management of obesity and metabolic syndrome, which are still unmet medical issues. Olive oil, a key component of the Mediterranean diet, provides an exceptional lipid matrix highly rich in bioactive molecules. Among them, the pentacyclic triterpenic acids (i.e., oleanolic acid) have gained clinical relevance in the last decade due to their wide range of biological actions, particularly in terms of vascular function, obesity and insulin resistance. Considering the promising effects of these triterpenic compounds as nutraceuticals and components of functional foods against obesity and associated complications, the aim of our review is to decipher and discuss the main molecular mechanisms underlying these effects driven by olive oil triterpenes, in particular by oleanolic acid. Special attention is paid to their signaling and targets related to glucose and insulin homeostasis, lipid metabolism, adiposity and cardiovascular dysfunction in obesity. Our study is aimed at providing a better understanding of the impact of dietary components of olive oil in the long-term management of obesity and metabolic syndrome in humans.

Pentacyclic triterpene oleanolic acid protects against cardiac aging through regulation of mitophagy and mitochondrial integrity

Advanced aging exhibits altered cardiac geometry and function involving mitochondrial anomaly. Natural compounds display promises in the regulation of cardiac homeostasis via governance of mitochondrial integrity in aging. This study examined the effect of oleanolic acid (OA), a natural pentacyclic triterpenoid with free radical scavenging and P450 cyclooxygenase-regulating properties, on cardiac aging and mechanisms involved with a focus on mitophagy. Young (4-5 month-old) and old (22-24 month-old) mice were treated with OA for 6 weeks prior to assessment of cardiac function, morphology, ultrastructure, mitochondrial integrity, cell death and autophagy. Our data revealed that OA treatment alleviated aging-induced changes in myocardial remodeling (increased heart weight, chamber size, cardiomyocyte area and interstitial fibrosis), contractile function and intracellular Ca²⁺ handling, apoptosis, necroptosis, inflammation, autophagy and mitophagy (LC3B, p62, TOM20 and FUNDC1 but not BNIP3 and Parkin). OA treatment rescued aging-induced anomalies in mitochondrial ultrastructure (loss of myofilament alignment, swollen mitochondria, increased circularity), mitochondrial biogenesis and O₂^- production without any notable effect at young age. Interestingly, OA-offered benefit against cardiomyocyte aging was nullified by deletion of the mitophagy receptor FUNDC1 using FUNDC1 knockout mice, denoting an obligatory role for FUNDC1 in OA-elicited preservation of mitophagy. OA reconciled aging-induced changes in E3 ligase MARCH5 but not FBXL2, and failed to affect aging-induced rises in IP3R3. Taken together, our data indicated a beneficial role for OA in attenuating cardiac remodeling and contractile dysfunction in aging through a FUNDC1-mediated mechanism.

The Role of Persistent Organic Pollutants in Obesity: A Review of Laboratory and Epidemiological Studies

Persistent organic pollutants (POPs) are considered as potential obesogens that may affect adipose tissue development and functioning, thus promoting obesity. However, various POPs may have different mechanisms of action. The objective of the present review is to discuss the key mechanisms linking exposure to POPs to adipose tissue dysfunction and obesity. Laboratory data clearly demonstrate that the mechanisms associated with the interference of exposure to POPs with obesity include: (a) dysregulation of adipogenesis regulators (PPARγ and C/EBPα); (b) affinity and binding to nuclear receptors; (c) epigenetic effects; and/or (d) proinflammatory activity. Although in vivo data are generally corroborative of the in vitro results, studies in living organisms have shown that the impact of POPs on adipogenesis is affected by biological factors such as sex, age, and period of exposure. Epidemiological data demonstrate a significant association between exposure to POPs and obesity and obesity-associated metabolic disturbances (e.g., type 2 diabetes mellitus and metabolic syndrome), although the existing data are considered insufficient. In conclusion, both laboratory and epidemiological data underline the significant role of POPs as environmental obesogens. However, further studies are required to better characterize both the mechanisms and the dose/concentration-response effects of exposure to POPs in the development of obesity and other metabolic diseases.

Oleanolic Acid: Extraction, Characterization and Biological Activity

Oleanolic acid, a pentacyclic triterpenoid ubiquitously present in the plant kingdom, is receiving outstanding attention from the scientific community due to its biological activity against multiple diseases. Oleanolic acid is endowed with a wide range of biological activities with therapeutic potential by means of complex and multifactorial mechanisms. There is evidence suggesting that oleanolic acid might be effective against dyslipidemia, diabetes and metabolic syndrome, through enhancing insulin response, preserving the functionality and survival of β-cells and protecting against diabetes complications. In addition, several other functions have been proposed, including antiviral, anti-HIV, antibacterial, antifungal, anticarcinogenic, anti-inflammatory, hepatoprotective, gastroprotective, hypolipidemic and anti-atherosclerotic activities, as well as interfering in several stages of the development of different types of cancer; however, due to its hydrophobic nature, oleanolic acid is almost insoluble in water, which has led to a number of approaches to enhance its biopharmaceutical properties. In this scenario, the present review aimed to summarize the current knowledge and the research progress made in the last years on the extraction and characterization of oleanolic acid and its biological activities and the underlying mechanisms of action.

Regulation of reactive oxygen species by phytochemicals for the management of cancer and diabetes

Cancer and diabetes mellitus are served as typical life-threatening diseases with common risk factors. Developing therapeutic measures in cancers and diabetes have aroused attention for a long time. However, the problems with conventional treatments are in challenge, including side effects, economic burdens, and patient compliance. It is essential to secure safe and efficient therapeutic methods to overcome these issues. As an alternative method, antioxidant and pro-oxidant properties of phytochemicals from edible plants have come to the fore. Phytochemicals are naturally occurring compounds, considered promising agent applicable in treatment of various diseases with beneficial effects. Either antioxidative or pro-oxidative activity of various phytochemicals were found to contribute to regulation of cell proliferation, differentiation, cell cycle arrest, and apoptosis, which can exert preventive and therapeutic effects against cancer and diabetes. In this article, the antioxidant or pro-oxidant effects and underlying mechanisms of flavonoids, alkaloids, and saponins in cancer or diabetic models demonstrated by the recent studies are summarized.

A Review on Recent Developments in the Anticancer Potential of Oleanolic acid and its analogs (2017-2020)

Oleanolic acid (OA) is a pentacyclic triterpenoid class of natural product known to possess a broad range of biological activities, specifically, anticancer. Considering the anticancer potential of OA, a large number of analogs have been prepared by several researchers through modifications at C-3, C-12 and C-28 -COOH to develop the potent anticancer agents with improved cytotoxicity and pharmaceutical properties. Some of the synthesized derivatives have been assessed in clinical trials also. This review summarizes the most recent synthetic and biological efforts in the development of oleanolic acid and its analogs during the period 2017-2020. Reports published during this period revealed that both OA and its analogs possess a remarkable potential for the development of effective anticancer agents along with several others such as anti-inflammatory, anti-viral, anti-microbial and anti-diabetic agents.

Oleanolic Acid Improves Obesity-Related Inflammation and Insulin Resistance by Regulating Macrophages Activation

The chronic low-grade inflammation of adipose tissues, primarily mediated by adipose tissue macrophages (ATMs), is the key pathogenic link between obesity and metabolic disorders. Oleanolic acid (OA) is a natural triterpenoid possessing anti-diabetic and anti-inflammation effects, but the machinery is poorly understood. This study investigated the detailed mechanisms of OA on adipose tissue inflammation in obese mice. C57BL/6J mice were fed with high-fat diet (HFD) for 12 weeks, then daily intragastric administrated with vehicle, 25 and 50 mg/kg OA for 4 weeks. Comparing with vehicle, OA administration in obese mice greatly improved insulin resistance, and reduced adipose tissue hypertrophy, ATM infiltration as well as the M1/M2 ratio. The pro-inflammatory markers were significantly down-regulated by OA in both adipose tissue of obese mice and RAW264.7 macrophages treated with interferon gamma/lipopolysaccharide (IFN-γ/LPS). Furthermore, it was found that OA suppressed activation of mitogen-activated protein kinase (MAPK) signaling and NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome through decreasing voltage dependent anion channels (VDAC) expression and reactive oxygen species (ROS) production. This is the first report that oleanolic acid exerts its benefits by affecting mitochondrial function and macrophage activation.

Exposure to a low concentration of mixed organochlorine pesticides impairs glucose metabolism and mitochondrial function in L6 myotubes and zebrafish

More realistic effects on glucose metabolic dysfunction can be evaluated by applying organochlorine (OCP) mixtures than individual OCPs. We formulated an equal ratio mixture of five OCPs (chlordane, heptachlor, p,p'-dichlorodiphenyltrichloroethane, β-hexachlorocyclohexane, and hexachlorobenzene) and treated L6 myotubes with this OCP mixture to investigate effects on glucose uptake and the underlying mechanism. Exposure to the OCP mixture reduced 2-NBDG staining, representing glucose uptake, and stimulated the excessive production of reactive oxygen species (ROS). Reduced 2-NBDG uptake and ROS overproduction were compensated by insulin treatment. The expression of proteins such as IRβ, PI3K, and AKT was downregulated, indicating that ROS overproduction contributed to the inhibition of insulin-dependent glucose uptake. Reduction in mitochondria quantity and decreased expression levels of PGC-1α, PDH, and GLUT4 proteins were observed, suggesting that mitochondrial dysfunction played a causative role in the disruption of glucose uptake. The inhibition of glucose uptake and ROS overproduction caused by the OCP mixture were also found in zebrafish as an in vivo model. We demonstrated that exposure to the OCP mixture, even at the lowest concentration, perturbed glucose uptake, which was associated with mitochondrial dysfunction, suggesting that an OCP mixture could be a potential environmental factor in type 2 diabetes-related effects on skeletal muscles.

Transcriptional control by HNF-1: Emerging evidence showing its role in lipid metabolism and lipid metabolism disorders

The present review focuses on the roles and underlying mechanisms of action of hepatic nuclear factor-1 (HNF-1) in lipid metabolism and the development of lipid metabolism disorders. HNF-1 is a transcriptional regulator that can form homodimers, and the HNF-1α and HNF-1β isomers can form heterodimers. Both homo- and heterodimers recognize and bind to specific cis-acting elements in gene promoters to transactivate transcription and to coordinate the expression of target lipid-related genes, thereby influencing the homeostasis of lipid metabolism. HNF-1 was shown to restrain lipid anabolism, including synthesis, absorption, and storage, by inhibiting the expression of lipogenesis-related genes, such as peroxisome proliferator-activated receptor γ (PPARγ) and sterol regulatory element-binding protein-1/2 (SREBP-1/2). Moreover, HNF-1 enhances the expression of various genes, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), glutathione peroxidase 1 (GPx1), and suppressor of cytokine signaling-3 (SOCS-3) and negatively regulates signal transducer and activator of transcription (STAT) to facilitate lipid catabolism in hepatocytes. HNF-1 reduces hepatocellular lipid decomposition, which alleviates the progression of nonalcoholic fatty liver disease (NAFLD). HNF-1 impairs preadipocyte differentiation to reduce the number of adipocytes, stunting the development of obesity. Furthermore, HNF-1 reduces free cholesterol levels in the plasma to inhibit aortic lipid deposition and lipid plaque formation, relieving dyslipidemia and preventing the development of atherosclerotic cardiovascular disease (ASCVD). In summary, HNF-1 transcriptionally regulates lipid-related genes to manipulate intracorporeal balance of lipid metabolism and to suppress the development of lipid metabolism disorders.

Development and Evaluation of Oleanolic Acid Dosage Forms and Its Derivatives

Oleanolic acid is a pentacyclic triterpenoid compound that exists widely in medicinal herbs and other plants. Because of the extensive pharmacological activity, oleanolic acid has attracted more and more attention. However, the structural characteristics of oleanolic acid prevent it from being directly made into new drugs, which limits the application of oleanolic acid. Through the application of modern preparation techniques and methods, different oleanolic acid dosage forms and derivatives have been designed and synthesized. These techniques can improve the water solubility and bioavailability of oleanolic acid and lay a foundation for the new drug development. In this review, the recent progress in understanding the oleanolic acid dosage forms and its derivatives are discussed. Furthermore, these products were evaluated comprehensively from the perspective of characterization and pharmacokinetics, and this work may provide ideas and references for the development of oleanolic acid preparations.

Eriobotrya japonica leaf triterpenoid acids ameliorate metabolic syndrome in C57BL/6J mice fed with high-fat diet

BACKGROUND

It has been demonstrated in some studies that triterpenoid acid extract fromEriobotrya japonica leaf is beneficial to prevent hyperlipidemia or insulin resistance. However, the effect of triterpenoid acids in Eriobotrya japonica leaf on a series of typical symptoms of metabolic syndrome (MetS) has been rarely studied systematically. Therefore, the present study aims to systematically evaluate the effect of Eriobotrya japonica leaf triterpenoid acids (ELTA) on MetS and explore its potential mechanism.

METHODS

ELTA (HPLC purity 95.2 %) was prepared and administered orally (200 mg/kg) to C57BL/6 J mice fed with a high-fat diet (HFD) for 12 weeks. Pioglitazone (30 mg/kg) was used as a positive control drug. Food intake, body weight, total lipid in feces, lipid profiles, inflammatory factors in serum, hepatic glutathione, and lipid peroxide were measured. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed to evaluate insulin sensitivity. RT-qPCR and molecular docking were performed to explore the potential mechanism.

RESULTS

ELTA administration reduced body weight gain, relative liver weight, and relative visceral adipose weight. The levels of serum total cholesterol, triglycerides, low-density lipoprotein cholesterol, hepatic total cholesterol, and hepatic triglycerides were also reduced. ELTA reduced the area under curve (AUC) of blood glucose curves in OGTT and ITT. Relative mRNA level analysis of genes related to MetS showed that ELTA can effectively increase the transcriptional levels of Nrf2, HO-1, PPAR-γ, GluT2, GK, FXR, while effectively decrease those of PTP1B, p65, TNF-α, IL-6, SREBP, 11βHSD-1. Molecular docking showed that the ligands in ELTA can bind to 11βHSD-1, GK, PPAR-γ, and JNK, the important targets involved in MetS.

CONCLUSIONS

ELTA can effectively alleviate visceral central obesity, insulin resistance, dyslipidemia, oxidative stress, and inflammation of HFD-induced MetS in C57BL/6 J mice. This is possibly achieved by acting on 11βHSD-1, GK, PPAR-γ, and JNK.

Modulation of Lipid Transport and Adipose Tissue Deposition by Small Lipophilic Compounds

Small lipophilic molecules present in foods of plant origin have relevant biological activities at rather low concentrations. Evidence suggests that phytosterols, carotenoids, terpenoids, and tocopherols can interact with different metabolic pathways, exerting beneficial effects against a number of metabolic diseases. These small molecules can modulate triacylglycerol absorption in the intestine and the biosynthesis of chylomicrons, the lipid carriers in the blood. Once in the bloodstream, they can impact lipoprotein clearance from blood, thereby affecting fatty acid release, incorporation into adipocytes and triglyceride reassembling and deposit. Consequently, some of these molecules can regulate pathophysiological processes associated to obesity and its related conditions, such as insulin resistance, metabolic syndrome and type-2 diabetes. The protective capacity of some lipophilic small molecules on oxidative and chemotoxic stress, can modify the expression of key genes in the adaptive cellular response, such as transcription factors, contributing to prevent the inflammatory status of adipose tissue. These small lipophilic compounds can be incorporated into diet as natural parts of food but they can also be employed to supplement other dietary and pharmacologic products as nutraceuticals, exerting protective effects against the development of metabolic diseases in which inflammation is involved. The aim of this review is to summarize the current knowledge of the influence of dietary lipophilic small biomolecules (phytosterols, carotenoids, tocopherols, and triterpenes) on lipid transport, as well as on the effects they may have on pathophysiological metabolic states, related to obesity, insulin resistance and inflammation, providing an evidence-based summary of their main beneficial effects on human health.

Oleanolic Acid Derived from Plants: Synthesis and Pharmacological Properties of A-ring Modified Derivatives

Background:

Oleanolic Acid (OA) is a ubiquitous product of triterpenoid compounds. Due to its inexpensive availability, unique bioactivities, pharmacological effects and non-toxic properties, OA has attracted tremendous interest in the field of drug design and synthesis. Furthermore, many OA derivatives have been developed for ameliorating the poor water solubility and bioavailability.

Objective:

Over the past few decades, various modifications of the OA framework structure have led to the observation of enhancement in bioactivity. Herein, we focused on the synthesis and medicinal performance of OA derivatives modified on A-ring. Moreover, we clarified the relationship between structures and activities of OA derivatives with different functional groups in A-ring. The future application of OA in the field of drug design and development also was discussed and inferred.

Conclusion:

This review concluded the novel achievements that could add paramount information to the further study of OA-based drugs.

PDGFRα/β-PI3K-Akt pathway response to the interplay of mitochondrial dysfunction and DNA damage in Aroclor 1254-exposed porcine granulosa cells

Metabolic dysfunction and genomic instability are known to affect female fertility. Aroclor 1254 (A1254) is an endocrine disruptor that affects mitochondrial function following ingestion, inhalation, or dermal exposure. Numerous studies to date have addressed associations between A1254 toxicity and chronic neurological disorders, while A1254 exposure is little known to have a toxic effect on the female reproductive system. Furthermore, interactive mechanisms between metabolic dysfunction and the repair of DNA damage deserve further investigation. In this paper, an in vitro porcine primary granulosa cell (GC) culture model was used to investigate the mechanisms of exposure and effects of the exogenous chemical carcinogen A1254 on reproductive toxicology. High-throughput RNA sequencing obtained 2329 differentially expressed genes (DEGs) to be analyzed using COG classification, GO, and KEGG. When combined with immunofluorescence, Western blot analysis, and real-time RT-PCR analysis, this data showed that the mitochondrial-ROS-driven feed-forward loop increased phospho-PDGFRα/β, which stimulates apoptosis by suppressing the PI3K-Akt pathway. We also noticed that inhibition of the Akt-PDP1-PDK1 axis attenuated mitochondrial function. In contrast, following iPath analysis, partial metabolic pathways were enhanced. Importantly, we found that A1254 activated a DNA damage response, the major regulators of which belong to the PI3K-related protein kinases (PIKKs) and oncogenes, which led to the "Warburg effect". It is not easy to restore the damage that A1254 causes to metabolism through dysregulation and the Warburg effect, owing to the fact that oncogenes can regulate cytoplasmic metabolism. Therefore, we suspect that the PDGFR-PI3K-Akt pathway may be a latent interaction between mitochondrial dysfunction and the response of DNA damage.

Homeostasis of gut microbiota protects against polychlorinated biphenyl 126-induced metabolic dysfunction in liver of mice

Polychlorinated biphenyls (PCBs) exposure is closely associated with the prevalence of metabolic diseases, including fatty liver and dyslipidemia. Emerging literature suggests that disturbance of gut microbiota is related to PCB126-induced metabolic disorders. However, the causal role of dysbiosis in PCB126-induced fatty liver is still unknown. To clarify the role of the gut microbiome in the detoxification of PCB126 in intestine or PCB126-induced toxicity in liver, mice were administrated with drinking water containing antibiotics (ampicillin, vancomycin, neomycin, and metronidazole) or Inulin. We showed that PCB126 resulted in significant hepatic lipid accumulation, inflammation, and fibrosis. PCB126, Antibiotics, and Inulin significantly affected the structure and shifted community membership of gut microbiome. 7 KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways at level 2 and 39 KEGG pathways at level 3 were significantly affected. Antibiotics alleviated PCB126-induced fibrosis in the liver but increased inflammation. Inulin treatment ameliorated both inflammation and fibrosis in the liver of PCB126-treated mice. Neither Antibiotics nor Inulin had significant effect on PCB126-induced hepatic steatosis. The more specific intervention of gut microbiota is needed to alleviate PCB126-induced fatty liver. These data demonstrate that homeostasis of gut microbiota is critical for the defense against PCB126 toxicity and dysbiosis plays a fundamental role in the development of inflammation and fibrosis in liver of PCB126-treated mice.

Prophylactic and therapeutic roles of oleanolic acid and its derivatives in several diseases

Oleanolic acid (OA) and its derivatives are widely found in diverse plants and are naturally effective pentacyclic triterpenoid compounds with broad prophylactic and therapeutic roles in various diseases such as ulcerative colitis, multiple sclerosis, metabolic disorders, diabetes, hepatitis and different cancers. This review assembles and presents the latest in vivo reports on the impacts of OA and OA derivatives from various plant sources and the biological mechanisms of OA activities. Thus, this review presents sufficient data proposing that OA and its derivatives are potential alternative and complementary therapies for the treatment and management of several diseases.

Obesity-induced reduced expression of the lncRNA ROIT impairs insulin transcription by downregulation of Nkx6.1 methylation

AIMS/HYPOTHESIS

Although obesity is a predisposing factor for pancreatic beta cell dysfunction, the mechanisms underlying its negative effect on insulin-secreting cells is still poorly understood. The aim of this study was to identify islet long non-coding RNAs (lncRNAs) involved in obesity-mediated beta cell dysfunction.

METHODS

RNA sequencing was performed to analyse the islets of high-fat diet (HFD)-fed mice and those of normal chow-fed mice (NCD). The function in beta cells of the selected lncRNA 1810019D21Rik (referred to in this paper as ROIT [regulator of insulin transcription]) was assessed after its overexpression or knockdown in MIN6 cells and primary islet cells, as well as in siRNA-treated mice. Then, RNA pull-down, RNA immunoprecipitation, coimmunoprecipitation and bisulphite sequencing were performed to investigate the mechanism of ROIT regulation of islet function.

RESULTS

ROIT was dramatically downregulated in the islets of the obese mice, as well as in the sera of obese donors with type 2 diabetes, and was suppressed by HNF1B. Overexpression of ROIT in MIN6 cells and islets led to improved glucose homeostasis and insulin transcription. Investigation of the mechanism involved showed that ROIT bound to DNA methyltransferase 3a and caused its degradation through the ubiquitin proteasome pathway, which blocked the methylation of the Nkx6.1 promoter.

CONCLUSIONS/INTERPRETATION

These findings functionally suggest a novel link between obesity and beta cell dysfunction via ROIT. Elucidating a precise mechanism for the effect of obesity on lncRNA expression will broaden our understanding of the pathophysiological development of diabetes and facilitate the design of better tools for diabetes prevention and treatment.

DATA AVAILABILITY

The raw RNA sequencing data are available from the NCBI Gene Expression Omnibus (GEO series accession number GSE139991).

Oleanolic acid inhibits mouse spinal cord injury through suppressing inflammation and apoptosis via the blockage of p38 and JNK MAPKs

Spinal cord injury (SCI) is reported as a devastating disease, leading to tissue loss and neurologic dysfunction. However, there is no effective therapeutic strategy for SCI treatment. Oleanolic acid (OA), as a triterpenoid, has anti-oxidant, anti-inflammatory, and anti-apoptotic activities. However, its regulatory effects on SCI have little to be elucidated, as well as the underlying molecular mechanisms. In this study, we attempted to explore the role of OA in SCI progression. Behavior tests suggested that OA treatments markedly alleviated motor function in SCI mice. Evans blue contents up-regulated in spinal cords of SCI mice were significantly reduced by OA in a dose-dependent manner, demonstrating the improved blood-spinal cord barrier. Moreover, we found that OA treatments significantly reduced the apoptotic cell death in spinal cord samples of SCI mice through decreasing the expression of cleaved Caspase-3. In addition, pro-inflammatory response in SCI mice was significantly attenuated by OA treatments. Furthermore, SCI mice exhibited higher activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) signaling pathways, but these effects were clearly blocked in SCI mice with OA treatments, as evidenced by the down-regulated phosphorylation of p38, c-Jun-NH 2 terminal kinase (JNK), IκB kinase α (IKKα), inhibitor of nuclear factor κB-α (IκBα) and NF-κB. The protective effects of OA against SCI were confirmed in lipopolysaccharide (LPS)-stimulated mouse neurons mainly through the suppression of apoptosis and inflammatory response, which were tightly associated with the blockage of p38 and JNK activation. Together, our data demonstrated that OA treatments could dose-dependently ameliorate spinal cord damage through impeding p38- and JNK-regulated apoptosis and inflammation, and therefore OA might be served as an effective therapeutic agent for SCI treatment.

Traditional uses, phytochemistry, and pharmacology of Ficus hispida L.f.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus hispida L.f. (Moraceae) has long been used as a traditional medicine in India, China, Sri Lanka, Australia, and Myanmar in the treatment of diarrhea, ulcer, anemia, diabetes, inflammation, and cancer.

AIM OF THE REVIEW

This review provides a systematic comment on the botany, traditional uses, and phytochemical and pharmacological studies of F. hispida, with an aim to make critical update of the current knowledge and obtain opportunities for further therapeutic potential.

MATERIALS AND METHODS

The information was derived from scientific literature databases including PubMed, Baidu Scholar, Google Scholar, Web of Science, and Science Direct. Additional information was gathered from books, Ph.D. and M.Sc. dissertations, and unpublished materials.

RESULTS AND DISCUSSION

F. hispida is used especially in Chinese and Indian traditional medical systems as a remedy for skin disorders, respiratory diseases, and urinary diseases. Wound healing, anti-inflammatory, antinociceptive, sedative, antidiarrheal, antiulcer, antimicrobial, antioxidant, hepatoprotective, antineoplastic, and antidiabetic activities have been reported for crude extracts and isolated metabolites, but the methodologies in these studies often have inadequate design and low technical quality. More than 76 compounds have been isolated from F.hispida, including sesquiterpenoids and triterpenoids, flavonoids, coumarins, phenylpropionic acids, benzoic acid derivatives, alkaloids, steroids, other glycosides, and alkanes, but the method of bioassay-guided fractionation is seldom applied in the isolation from F. hispida.

CONCLUSION

F. hispida is used widely in traditional medicines and has multiple pharmacological effects that could support traditional uses. However, pharmacological studies should be viewed with caution because of the inappropriate experimental design. More in vitro and in vivo research is urgently needed to study the molecular mechanisms and assess the effective and safe dose of F. hispida.

Pomace Olive Oil Concentrated in Triterpenic Acids Restores Vascular Function, Glucose Tolerance and Obesity Progression in Mice

Pomace olive oil, an olive oil sub-product, is a promising source of bioactive triterpenoids such as oleanolic acid and maslinic acid. Considering the vascular actions of pomace olive oil and the potential effects of the isolated oleanolic acid on metabolic complications of obesity, this study investigates for the first time the dietary intervention with a pomace olive oil with high concentrations of the triterpenic acids (POCTA), oleanolic and maslinic acid, during diet-induced obesity in mice. The results demonstrate that obese mice, when switched to a POCTA-diet for 10 weeks, show a substantial reduction of body weight, insulin resistance, adipose tissue inflammation, and particularly, improvement of vascular function despite high caloric intake. This study reveals the potential of a functional food based on pomace olive oil and its triterpenic fraction against obesity progression. Our data also contribute to understanding the health-promoting effects attributable to the Mediterranean diet.

NFκB/Orai1 Facilitates Endoplasmic Reticulum Stress by Oxidative Stress in the Pathogenesis of Non-alcoholic Fatty Liver Disease

Non-esterified fatty acids (NEFAs) promote de novo lipogenesis, which caused abnormal hepatic lipid accumulation, by the NFκB-Orai1 pathway. Oxidative stress and endoplasmic reticulum (ER) stress have been recognized as key mechanisms in non-alcoholic fatty liver disease (NAFLD) pathogenesis. Whether Orai1 facilitates ER stress by oxidative stress remains unknown. The rat model of NAFLD was constructed by feeding high-fat diet (HFD). BRL-3A cells were treated with NEFAs, Orai1inhibtor BTP2, NFκB inhibitor wogonin, or small interfering Orai (siOrai) 1, respectively. The content of intracellular reduced glutathione (GSH) and malondialdehyde (MDA), indicating oxidative stress, was measured by a spectrophotometer. ER stress major proteins PERK, IRE1, ATF6, CHOP, and GRP78 were quantified using Western blot and qRT-PCR analyses. For the intracellular location of reactive oxygen species (ROS) and Orai1 were measured by Western blot and immunofluorescence, and cytosolic Ca²⁺ was measured by flow cytometry. As we expected, the liver of rats with NAFLD showed lipid droplets in HE and Oil Red O. The decreased GSH and increased MDA were found in rats fed with HFD. ER stress major proteins PERK, IRE1, ATF6, GRP78, and CHOP were significantly increased in the HFD group. In BRL-3A cells, GSH content dramatically decreased from 1 h, MDA content dramatically increased from 3 h, and expression levels of ER stress significantly increased from 3 h by NEFA treatment. Furthermore, cytosolic Ca²⁺ increased from 0.5 h by NEFAs treated in BRL-3A cells. It indicated that NEFAs increased cytosolic Ca²⁺ to induce oxidative stress, thus ER stress. The content of oxidative stress and ER stress proteins showed the same trends by NEFAs treated in BRL-3A cells. These effects were reversed by the Orai1 inhibitor BTP2 and the NFκB inhibitor wogonin. Moreover, siOrai1 abrogated NEFAs' influence in BRL-3A cells. Last, ROS was found by NEFAs treated in BRL-3A cells, and NEFA treatment enhanced the nuclear localization of NF-κB p65 and ORAI1. It was considered that high NEFAs increased cytosolic Ca²⁺ and enhanced NFκB-dependent SOCE and its moiety protein Orai1 to decrease GSH and thus induced oxidative stress at earlier stages and furthermore tempted ER stress in the pathologic progress of NAFLD.

Potential Protective Effect of Oleanolic Acid on the Components of Metabolic Syndrome: A Systematic Review

The high prevalence of obesity is a serious public health problem in today’s world. Both obesity and insulin resistance favor the development of metabolic syndrome (MetS), which is associated with a number of pathologies, especially type 2 diabetes mellitus, and cardiovascular diseases. This serious problem highlights the need to search for new natural compounds to be employed in therapeutic and preventive strategies, such as oleanolic acid (OA). This research aimed to systematically review the effects of OA on the main components of MetS as well as oxidative stress in clinical trials and experimental animal studies. Databases searched included PubMed, Medline, Web of Science, Scopus, EMBASE, Cochrane, and CINAHL from 2013 to 2019. Thus, both animal studies (n = 23) and human clinical trials (n = 1) were included in our review to assess the effects of OA formulations on parameters concerning insulin resistance and the MetS components. The methodological quality assessment was performed through using the SYRCLE’s Risk of Bias for animal studies and the Jadad scale. According to the studies in our review, OA improves blood pressure levels, hypertriglyceridemia, hyperglycemia, oxidative stress, and insulin resistance. Although there is scientific evidence that OA has beneficial effects in the prevention and treatment of MetS and insulin resistance, more experimental studies and randomized clinical trials are needed to guarantee its effectiveness.

Scabiosa Genus: A Rich Source of Bioactive Metabolites

The genus Scabiosa (family Caprifoliaceae) is considered large (618 scientific plant names of species) although only 62 have accepted Latin binominal names. The majority of the Scabiosa species are widely distributed in the Mediterranean region and some Scabiosa species are used in traditional medicine systems. For instance, Scabiosa columbaria L. is used traditionally against diphtheria while S. comosa Fisch. Ex Roem. and Schult. is used in Mongolian and Tibetan traditional medical settings to treat liver diseases. The richness of Scabiosa species in secondary metabolites such as iridoids, flavonoids and pentacyclic triterpenoids may contribute to its use in folk medicine. Details on the most recent and relevant pharmacological in vivo studies on the bioactive secondary metabolites isolated from Scabiosa species will be summarized and thoroughly discussed.