The protective effect of neonatal oral administration of oleanolic acid against the subsequent development of fructose-induced metabolic dysfunction in male and female rats

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.

Erzhiwan Ameliorates Restraint Stress- and Monobenzone-Induced Depigmentation in Mice by Inhibiting Macrophage Migration Inhibitory Factor and 8-Hydroxy-2-Deoxyguanosine

Purpose

Vitiligo is an autoimmune disease that results in the loss of epidermal melanocytes. The treatments for patients with vitiligo remain lacking. Erzhiwan (EZW), a traditional Chinese Medicine composed of Ligustri Lucidi Fructus and Ecliptae Herba, was used to ameliorate depigmentation since ancient China. This study aims to investigate the effect of EZW on vitiligo-related depigmentation.

Methods

A vitiligo-related depigmentation mouse model was induced by monobenzone and restraint stress. The experimental depigmentation mice were treated with EZW. Histological observation of skin was conducted. Cutaneous oxidative damage and inflammation were determined. A network pharmacology analysis was carried out.

Results

EZW reduced depigmentation score (p<0.01), cutaneous inflammatory infiltration (p<0.01), and CD8α-positive expression (p<0.01), and increased cutaneous melanin content in experimental depigmentation mice. EZW reduced stress reaction in experimental depigmentation mice (p<0.01). EZW inhibited 8-hydroxy-2-deoxyguanosine (8-OHdG)-related DNA oxidative damage in the skin (p<0.05, p<0.01). In addition, EZW reduced cutaneous macrophage migration inhibitory factor (MIF)-CD74-NF-κB signaling (p<0.01). The network pharmacology analysis demonstrated that EZW regulated necroptosis, apoptosis, and FoxO signaling pathways in vitiligo. An in vitro experiment showed that the main ingredient of EZW, specnuezhenide, protected against monobenzone and MIF-induced cell death in HaCaT cells (p<0.01).

Conclusion

EZW ameliorates restraint stress- and monobenzone-induced depigmentation via the inhibition of MIF and 8-OHdG signaling. The findings provide a data basis of an utilization of EZW in vitiligo.

Prophylactic Use of Natural Products against Developmentally Programmed Metabolic Syndrome

Parental dietary choices and/or nutritional interventions in the offspring are critical to early life development, especially during the periods of active developmental plasticity in the offspring. Exposure to a high-fructose, high-fat diet during the fetal or neonatal period predisposes the affected individuals to the development of one or more features of metabolic syndrome, such as dyslipidemia, insulin resistance, diabetes, and associated cardiovascular diseases, later in their life. Owing to the increasing global prevalence of metabolic syndrome and multiple side effects that accompany conventional medicines, much attention is directed towards medicinal plants and phytochemicals as alternative interventions. Several studies have investigated the potential of natural agents to prevent programmed metabolic syndrome. This present review, therefore, highlights an inextricable relationship between the administration of medicinal plants or phytochemicals during the intrauterine or neonatal period, and the prevention of metabolic dysfunction in adulthood, while exploring the mechanisms by which they exert such an effect. The review also identifies plant products as a novel approach to the prevention and management of metabolic syndrome.

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.

Early-Life Origins of Metabolic Syndrome: Mechanisms and Preventive Aspects

One of the leading global public-health burdens is metabolic syndrome (MetS), despite the many advances in pharmacotherapies. MetS, now known as "developmental origins of health and disease" (DOHaD), can have its origins in early life. Offspring MetS can be programmed by various adverse early-life conditions, such as nutrition imbalance, maternal conditions or diseases, maternal chemical exposure, and medication use. Conversely, early interventions have shown potential to revoke programming processes to prevent MetS of developmental origins, namely reprogramming. In this review, we summarize what is currently known about adverse environmental insults implicated in MetS of developmental origins, including the fundamental underlying mechanisms. We also describe animal models that have been developed to study the developmental programming of MetS. This review extends previous research reviews by addressing implementation of reprogramming strategies to prevent the programming of MetS. These mechanism-targeted strategies include antioxidants, melatonin, resveratrol, probiotics/prebiotics, and amino acids. Much work remains to be accomplished to determine the insults that could induce MetS, to identify the mechanisms behind MetS programming, and to develop potential reprogramming strategies for clinical translation.

Zingerone Administered Neonatally Prevents the Subsequent Development of High Dietary Fructose-Induced Fatty Liver in Sprague Dawley Rats

Consumption of high-fructose diets early in life increases the risk of developing metabolic disorders, including nonalcoholic fatty liver disease (NAFLD). Zingerone, an alkaloid isolated from Zingiber officinale, has been demonstrated to reverse obesity and fatty liver in adult male rats. We investigated the potential preventive effects of neonatally administered zingerone on the development of fructose-induced NAFLD in male and female rats. Four-day-old male (n = 35) and female (n = 44) rat pups were randomized and gavaged with: 10 mL/kg body weight (bwt) of distilled water (C), 10 mL/kg bwt of 20% fructose solution (Fr), 10 mL/kg bwt of 20% fructose solution +40 mg/kg bwt of zingerone (ZFr), and 40 mg/kg bwt of zingerone (Z) daily for 14 days. After weaning, all groups continued on unlimited standard rat feed; however, groups C and Z had plain drinking water, whereas groups Fr and ZFr had unlimited 20% fructose solution to drink for 10 weeks. Rats on the high-fructose diet (Fr) compared with the negative controls (C) had significantly increased hepatic lipid content (in %, males: P = .0002; females: P < .0001, analysis of variance [ANOVA]) and hepatic steatosis score (in %, males: P = .0018; females: P < .0022, Kruskal-Wallis ANOVA). Zingerone prevented (P < .05) the fructose-induced increase in hepatic steatosis in both sexes. The plasma alanine aminotransferase activity, levels of uric acid, TBARS (thiobarbituric acid reactive substances), IL-6 (interleukin-6), and TNF-α (tumor necrosis factor alpha) were not different (P > .05, ANOVA) across the different treatment groups in both sexes. No difference (P > .05, ANOVA) was observed between the two sexes for treatment, sex and interaction effects with regard to hepatic lipid content, and measured blood parameters. The use of zingerone neonatally should be further investigated as a strategic prophylactic intervention for the prevention of long-term high-fructose diet-induced NAFLD.

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.

Oil and extract of safflower seed improve fructose induced metabolic syndrome through modulating the homeostasis of trace elements, TNF-α and fatty acids metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Safflower (Carthamus tinctorius) has many applications in folk medicine. Its oil is used traditionally to treat obesity and other metabolic disorders. The anti-hypercholesterolemic and antioxidant effects of this plant have been well documented, but the anti-inflammatory effects and its role on fatty acid oxidation and homeostasis of trace elements are not fully understood.

OBJECTIVE

The aim of this study was to evaluate the protective effects of different doses of oil and extract of safflower seed against fructose induced metabolic syndrome by investigating the homeostasis of trace elements, TNF-α, and fatty acids metabolism.

METHODS

Eighty adult male Sprague-Dawley rats were randomly divided into ten groups and treated daily for 16 weeks. At the end of the study, plasma levels of liver enzymes, lipid profiles, blood glucose, insulin and TNF-α were measured. The levels of antioxidant enzymes and lipid peroxidation were also measured along with the expression of CD36, fatty acyl-CoA synthetase (FAS), and Carnitine palmitoyl transferase I (CPT-1) beta genes in the liver.

RESULTS

The antioxidant enzymes activity significantly decreased and lipid peroxidation, lipid profiles, liver enzymes, and TNF-α significantly increased in fructose-induced metabolic syndrome compared to the control groups, as well as the level of some trace elements significantly changed (p < 0.05). Treatment with oil and safflower seed extract in a dose dependent manner could improve biochemical parameters in groups of metabolic syndrome treated with oil and extract compared to metabolic syndrome (p < 0.05). The results also showed that the expression of above mentioned genes significantly increased in groups of metabolic syndrome treated with oil and extract compared to control and metabolic syndrome groups (p < 0.05).

CONCLUSION

It can be concluded that safflower seed extract and its oil can improve fructose-induced metabolic syndrome through antioxidant and anti-inflammatory effects, adjustment of homeostasis of trace elements, and enhancing the beta-oxidation capacity of the liver by increasing the expression of CD36, FAS, and CPT-1beta genes.

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.

Long-Term Impact of Neonatal Intake of Oleanolic Acid on the Expression of AMP-Activated Protein Kinase, Adiponectin and Inflammatory Cytokines in Rats Fed with a High Fructose Diet

AMP-activated protein kinase (AMPK) is known to regulate both glucose and lipid metabolism, which play vital roles in the development of metabolic syndrome. One way of regulating AMPK is through hormonal activation using adiponectin. Patients diagnosed with type-2 diabetes (T2D) and obesity exhibit low adiponectin concentration levels in their blood. Moreover, studies have also shown that inflammatory processes play a significant role in the etiology of these metabolic diseases. In this study, the long-term effects of neonatal intake of oleanolic acid (OA) on the AMPK gene, genes associated with glucose transport and lipid metabolism, adiponectin levels, and inflammatory biomarkers in rats fed with a high fructose diet were investigated. Seven day old pups were randomly divided into five groups and treated as follows; 0.5% dimethylsulphoxide v/v in distilled water vehicle control (CON), oleanolic acid (OA, 60 mg/kg), high fructose diet (HF, 20% w/v), high fructose diet combined with oleanolic acid (HF+OA), and high fructose diet combined with metformin (HF+MET, 500 mg/kg). The treatments were administered once daily until day 14. The rats were then weaned at day 21 and fed standard rat chow and had ad libitum access to plain drinking water until day 112. The quantitative polymerase chain reaction (qPCR) was used to analyze the gene expressions of AMPK, Glut-4, Cpt-1, AdipoR1, AdipoR2, TNF-α, and IL-6 in the skeletal muscles. Bio-Plex Pro magnetic bead-based assay was used to measure plasma levels of inflammatory markers (TNF-α, IL-6, VEGF, and MCP-1) while ELISA kits were used to measure adiponectin concentration in blood plasma. The results obtained in this study showed that neonatal supplementation with OA significantly increased AMPK gene expression approximately ~4-fold in OA fed rats compared to those that were fed with HF alone. In addition, glut-4 gene expression was also significantly higher in the OA treatment group compared to all the other experimental groups except the CON group whereas Cpt-1 gene was more expressed when OA was administered alone. Together, these results indicated that OA can play a role in glucose and lipid metabolism gene regulation. Furthermore, the results showed that the OA group had ~1.5-fold increase in adiponectin concentration when comparedto the HF group. Moreover, HF increased levels of inflammatory cytokines, which was attenuated by neonatal administration of OA. Plasma concentration and gene expression in the skeletal muscle for TNF-α and IL-6 were significantly increased in rats that were treated with HF alone when compared to all the other groups. On the contrary, the high levels of TNF-α and IL-6 were reduced when OA was administered. These findings suggest that intake of oleanolic acid during the neonatal stage of development could be a potential strategic intervention for the long-term prevention of metabolic diseases such as T2D and obesity.