Administration Of Oleanolic Acid Research Articles

Cytotoxic Autophagy: A Novel Treatment Paradigm against Breast Cancer Using Oleanolic Acid and Ursolic Acid

Background: Oleanolic acid (OA) and Ursolic acid (UA) are bioactive triterpenoids. Reported activities vary with the dose used for testing their activities in vitro. Studies using doses of ≥20 µM showed apoptosis activities in cancer cells. However, reported drug levels in circulation achieved by oral administration of UA and OA are ≤2 µM, thus limiting their use for treatment or delivering a combination treatment. Materials and Methods: The present report demonstrates the efficacy of OA, UA, and OA + UA on tumor cell-specific cytotoxicity at low doses (5 µM to 10 µM) in breast cancer (BrCa) cell lines MCF7 and MDA-MB231. Results: The data show that both OA and UA killed BrCa cells at low doses, but were significantly less toxic to MCF-12A, a non-tumorigenic cell line. Moreover, OA + UA at ≤10 µM was lethal to BrCa cells. Mechanistic studies unraveled the significant absence of apoptosis, but their cytotoxicity was due to the induction of excessive autophagy at a OA + UA dose of 5 µM each. A link to drug-induced cytotoxic autophagy was established by demonstrating a lack of their cytotoxicity by silencing the autophagy-targeting genes (ATGs), which prevented OA-, UA-, or OA + UA-induced cell death. Further, UA or OA + UA treatment of BrCa cells caused an inhibition of PI3 kinase-mediated phosphorylation of Akt/mTOR, the key pathways that regulate cancer cell survival, metabolism, and proliferation. Discussion: Combinations of a PI3K inhibitor (LY294002) with OA, UA, or OA + UA synergistically inhibited BrCa cell survival. Therefore, the dominance of cytotoxic autophagy by inhibiting PI3K-mediated autophagy may be the primary mechanism of PTT-induced anticancer activity in BrCa cells. Conclusion: These results suggest it would be worthwhile testing combined OA and UA in clinical settings.

Oleanolic acid administered during neonatal stage preserves granule cell layer volume, cell density and neurogenesis in the dentate gyrus of Sprague-Dawley rats fed a high fructose diet

Excessive fructose consumption induces metabolic syndrome (MetS) characterised by hyperglycaemia, dyslipidaemia, obesity and a decline in cognitive capacity, partly due to derangements in the hippocampus. We evaluated the potential protective effects of neonatally administering oleanolic acid (OA) against high fructose-induced reduction in granule cell layer volume, cell density and neurogenesis in the rat dentate gyrus (DG). Sprague Dawley rat pups (seven days old) were randomly assigned to three groups and administered orally: distilled water (DW), high fructose diet (20%w/v) and oleanolic acid (OA; 60 mg/kg) for 7 days. The rats were weaned (21 days old) onto normal rat chow diets up to post-natal day 55. From post-natal day 56-110, half of the rats in each experimental group were continued on plain water while the other half on a high fructose solution to drink. The rats were euthanized on day 112, before blood, visceral fat and brain tissue samples were collected. Body adiposity and impact on lipid metabolism was determined by measuring plasma triglycerides and visceral fat accumulation while brain tissue was used for histology. High fructose (HF) consumption led to the development of body adiposity (increased visceral fat accumulation), dyslipidaemia (increased triglyceride levels) and apoptosis in the DG. In addition, HF led to significant (p<0.05) reductions in volume, cell density and neurogenic activity in the dentate gyrus of the hippocampus. However, administration of OA during the neonatal period attenuated these deleterious effects of high fructose. We conclude that orally administered OA in the neonatal period may potentially be used to prevent the development of fructose-induced deleterious effects on the brain and most likely cognitive function. National Research Foundation of South Africa (grant number IRF 2010041900009). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of oleanolic acid administration on renal NF-kB, IL-18, IL-6, YKL-40, and KIM-1 in experimental diabetic rats.

Neuropathy, retinopathy, and nephropathy, known as the triopathy of diabetes, are the consequences of microvascular complications of diabetes. The present study aimed to investigate the potential protective effects of oleanolic acid (OA) administration against diabetic nephropathy considering biochemical and histopathological parameters. The rats with fasting blood glucose levels of 200 mg/dl and above were considered diabetic after induction of diabetes via injecting STZ. The other half of the rats were not injected with STZ (healthy rats). Both healthy and diabetic rats were then divided randomly into two subgroups to be administered with either OA (5 mg/kg) with 1 ml tap water by oral gavage or 1 ml tap water in the same route for 21 days. Serum urea-N, Ca, P, and Mg as well as renal tissue MDA, SOD, NF-κB, IL-6, IL-18, AMPK, YKL-40, and KIM-1 levels were measured. OA administration partially decreased levels of serum urea-N and P, as well as levels of renal tissue MDA and inflammation markers (NF-κB, IL-6, IL-18, YKL-40, and KIM-1) in the diabetic rats. It also partially increased serum Ca and renal tissue AMPK levels in diabetic rats. These positive effects were also seen in renal tissue histopathology. OA treatment partially alleviated renal damage inflammatory and oxidative profiles in diabetic rats.

Oleanolic Acid Alleviates Cerebral Ischemia/Reperfusion Injury via Regulation of the GSK-3β/HO-1 Signaling Pathway.

Oleanolic acid (OA), a bioactive ingredient of Panax ginseng, exhibits neuroprotective pharmacological effects. However, the protective role of OA in cerebral ischemia and involved mechanisms remain unclear. This study attempted to explore the therapeutic effects of OA both in vitro and in vivo. OA attenuated cytotoxicity and overproduction of intracellular reactive oxygen species (ROS) by regulation of glycogen synthase kinase-3β (GSK-3β)/heme oxygenase-1 (HO-1) signal in oxygen-glucose deprivation/reoxygenation (OGD/R)-exposed SH-SY5Y cells. Additionally, OA administration significantly reduced the area of cerebral infarction and the neurological scores in the rat models of cerebral ischemia with middle cerebral artery occlusion (MCAO). The OA administration group showed a higher percentage of Nissl+ and NeuN+ cells, along with lower TUNEL+ ratios in the infarct area of MCAO rats. Moreover, OA administration reduced ROS production while it suppressed the GSK-3β activation and upregulated the HO-1 expression in infarcted tissue. Our results illustrated that OA significantly counteracted cerebral ischemia-mediated injury through antioxidant effects induced by the regulation of the GSK-3β/HO-1 signaling pathway, implicating OA as a promising neuroprotective drug for the therapy of ischemic stroke.

Oleanolic Acid Provides Neuroprotection against Ischemic Stroke through the Inhibition of Microglial Activation and NLRP3 Inflammasome Activation.

Oleanolic acid (OA), a natural pentacyclic triterpenoid, has been reported to exert protective effects against several neurological diseases through its anti-oxidative and anti-inflammatory activities. The goal of the present study was to evaluate the therapeutic potential of OA against acute and chronic brain injuries after ischemic stroke using a mouse model of transient middle cerebral artery occlusion (tMCAO, MCAO/reperfusion). OA administration immediately after reperfusion significantly attenuated acute brain injuries including brain infarction, functional neurological deficits, and neuronal apoptosis. Moreover, delayed administration of OA (at 3 h after reperfusion) attenuated brain infarction and improved functional neurological deficits during the acute phase. Such neuroprotective effects were associated with attenuation of microglial activation and lipid peroxidation in the injured brain after the tMCAO challenge. OA also attenuated NLRP3 inflammasome activation in activated microglia during the acute phase. In addition, daily administration of OA for 7 days starting from either immediately after reperfusion or 1 day after reperfusion significantly improved functional neurological deficits and attenuated brain tissue loss up to 21 days after the tMCAO challenge; these findings supported therapeutic effects of OA against ischemic stroke-induced chronic brain injury. Together, these findings showed that OA exerted neuroprotective effects against both acute and chronic brain injuries after tMCAO challenge, suggesting that OA is a potential therapeutic agent to treat ischemic stroke.

Oleanolic acid blocks the purine salvage pathway for cancer therapy by inactivating SOD1 and stimulating lysosomal proteolysis

Metabolic reprogramming is a core hallmark of cancer and is key for tumorigenesis and tumor progression. Investigation of metabolic perturbation by anti-cancer compounds would allow a thorough understanding of the underlying mechanisms of these agents and identification of new anti-cancer targets. Here, we demonstrated that the administration of oleanolic acid (OA) rapidly altered cancer metabolism, particularly suppressing the purine salvage pathway (PSP). PSP restoration significantly opposed OA-induced DNA replication and cell proliferation arrest, underscoring the importance of this pathway for the anti-cancer activity of OA. Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and 5′-nucleotidase (5′-NT), two metabolic enzymes essential for PSP activity, were promptly degraded by OA via the lysosome pathway. Mechanistically, OA selectively targeted superoxide dismutase 1 (SOD1) and yielded reactive oxygen species (ROS) to activate the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/macroautophagy pathway, thus eliciting lysosomal degradation of HGPRT and 5′-NT. Furthermore, we found that the PSP was overactivated in human lung and breast cancers, with a negative correlation with patient survival. The results of this study elucidated a new anti-cancer mechanism of OA by restraining the PSP via the SOD1/ROS/AMPK/mTORC1/macroautophagy/lysosomal pathway. We also identified the PSP as a new target for cancer treatment and highlighted OA as a potential therapeutic agent for cancers with high PSP activity.

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.

Effects of oleanolic acid on inflammation and metabolism in diabetic rats

ABSTRACT Diabetes mellitus (DM) is a chronic metabolic disease that threatens the health of the world population. We investigated the effects of oleanolic acid (OA) administration on inflammation status and metabolic profile in streptozotocin (STZ) induced diabetic rats. Four experimental groups were established: healthy rats not administered OA, healthy rats administered OA, diabetic rats not administered OA, diabetic rats administered OA. OA, 5 mg/kg, was administered by oral gavage for 21 days. Serum samples collected at the end of the experiment and analyzed for toll–like receptor–9, interleukin-18, nuclear factor kappa B, malondialdehyde MDA, glucose, total cholesterol, triglycerides, high–density lipoprotein, low-density lipoprotein, calcium, phosphorus, magnesium and potassium. Pancreas tissue was examined for pathology. Induction of DM caused increased serum concentrations of inflammation and oxidative damage markers. DM also caused hyperglycemia-hyperlipidemia and decreased serum concentration of minerals. The islets of Langerhans were degenerated and necrotic. Administration of OA reversed the adverse effects of DM. OA treatment can ameliorate inflammation and oxidative damage due to DM by normalizing hyperglycemia and decreasing TLR-9, IL-18, NF-κB and MDA levels.

Oleanolic Acid Induces Autophagy and Apoptosis via the AMPK-mTOR Signaling Pathway in Colon Cancer.

Aims The purpose of this study was to explore the biological functions of the mTOR and AMPK signaling pathways in colon cancer (CC). The potential molecular mechanisms by which oleanolic acid (OA) induces autophagy and apoptosis were also investigated. Methods The biological functions of mTOR were analyzed by GeneCards, the Search Tool for the Retrieval of Interacting Genes (STRING), and the Database for Annotation, Visualization and Integrated Discovery (DAVID). Least absolute shrinkage and selection operator (LASSO) regression analysis was used to obtain prognostic and survival data of CC patients from the Gene Expression Omnibus (GEO) database. The effects of OA on the CC cell lines HCT-116 and SW-480 were analyzed by CCK-8, colony formation assay, and high-content system (HCS) array scan. The apoptosis rate of SW-480 and HCT-116 cells was detected by flow cytometry. The mRNA and protein expression levels in HCT-116 and SW-480 cells and NCM-460 normal colonic epithelial cells were detected by RT-PCR and Western blotting. Results mTOR was highly expressed in CC patients and acted as an oncogene. The AMPK signaling pathway mediated by mTOR predicted the poor prognosis of CC patients. OA effectively inhibited the proliferation and viability of CC cells. Furthermore, the apoptosis rate of CC cells was clearly increased following OA administration. Regarding the molecular mechanism of OA, the results indicated that mTOR and the antiapoptosis gene Bcl-2 were downregulated by OA. In addition, regulator genes of autophagy and apoptosis, including BAX, caspase-9, caspase-8, and caspase-3, were significantly upregulated by OA. Moreover, OA upregulated AMPK and its downstream proteins, including TSC2, BAX, Beclin 1, LC3B-II, and ULK1, to induce autophagy and apoptosis in CC cells. Conclusion The findings from this study demonstrate that OA could effectively inhibit the proliferation and viability of CC cells. The anti-CC activity of OA is closely related to the activation of the AMPK-mTOR signaling pathway. Activation of AMPK and inhibition of mTOR are involved in the induction of autophagy and apoptosis by OA. OA induced autophagy and apoptosis mainly in an AMPK activation-dependent manner in CC cells.

Oleanolic acid mitigates interleukin-1β-induced chondrocyte dysfunction by regulating miR-148-3p-modulated FGF2 expression.

microRNA (miR)-mediated post-transcriptional repression has been reported in the process of chondrocyte dysfunction. The present study aimed to investigate the molecular mechanisms underlying in oleanolic acid (OLA)-prevented interleukin (IL)-1β-induced chondrocyte dysfunction via the miR-148-3p/fibroblast growth factor-2 (FGF-2) signaling pathway. Candidate miRs were filtrated using miR microarray assays in chondrocytes with or without IL-1β stimulation. Gene expression of candidate miRs and protein expression of FGF2 were analyzed using a quantitative reverse transcriptase-polymerase chain reaction and western blotting, respectively. Cell growth was evaluated using cell counting kit-8 assays. Cell apoptosis was detected using Annexin V-fluorescein isothiocyanate double staining. Treatment with OLA counteracted IL-1β-evoked chondrocyte growth inhibition, apoptosis, caspase3 production, and release of malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine. Additionally, FGF2 protein expression levels elevated by IL-1β were down-regulated by OLA and transfection with miR-148-3p mimics. IL-1β-induced down-regulation of miR-148-3p in chondrocytes was evaluated by OLA administration. Bioinformatics algorithms and experimental measurements indicated that FGF2 might be a direct target of miR-148-3p. miR-148-3p mimics exhibited equal authenticity of OLA to protect against IL-1β-induced chondrocyte dysfunction. Our present findings highlight a protective effect of OLA on IL-1β-induced chondrocyte dysfunction, and a novel signal cascade comprising the miR-148-3p/FGF2 signaling pathway might be a potential therapeutic target of OLA with respect to preventing the progression of osteoarthritis.

Plant-derived oleanolic acid ameliorates markers of subclinical inflammation and innate immunity activation in diet-induced pre-diabetic rats.

Aims:Sub-clinical inflammation during pre-diabetes is one of the predisposing factors that facilitates the progression of pre-diabetes to type 2 diabetes. The administration of oleanolic acid (OA) with or without dietary intervention ameliorates the metabolic and cardiovascular complications in diet-induced pre-diabetes animal models of pre-diabetes. This study aimed to investigate whether OA can also suppress immune activation and ameliorate pro-inflammatory markers.Methods:Pre-diabetes was induced by feeding Sprague Dawley rats a high-fat high carbohydrate diet for 20 weeks. The pre-diabetic rats were then treated with OA (80 mg/kg) or metformin (500 mg/kg) in the presence or absence of dietary interventions for a period of 12 weeks. At the end of the treatment period, the animals were euthanised and whole blood was used for platelet and immune cell count while plasma was used for fibrinogen, cluster differentiation 40 ligand and pro-inflammatory cytokine evaluation.Results:The results of this study revealed that OA, with or without dietary intervention, improved lipid metabolism by restoring high-density lipoprotein (HDL) and low-density lipoproteins (LDLs) as well as reducing platelets and immune cell counts. Furthermore, OA also decreased plasma proinflammatory cytokines, including tumour necrosis factor-α and -1β. Markers of immune activation such as C-reactive protein, fibrinogen, and CD40L were also decreased upon administration of OA with or without dietary intervention.Conclusion:The findings of this study suggest that OA may provide an alternative to prevent the progression of pre-diabetes to overt diabetes. This was evident by the reduction of differential white blood cell count and proinflammatory cytokines that exercebate insulin resistance. However, more studies are needed to elucidate the molecular mechanisms and to improve efficacy.

The Haematological Effects of Oleanolic Acid in Streptozotocin-Induced Diabetic Rats: Effects on Selected Markers.

Background Sustained hyperglycaemia leads to the development of haematological alterations which, if left untreated, is associated with cardiovascular complications. Insulin is the mainstay drug in type 1 diabetes mellitus (T1D); however, the use of insulin is associated with haematological alterations that could further worsen cardiovascular complications. Therefore, the aim of the study was to investigate the haematological effects of oleanolic acid (OA) in streptozotocin- (STZ-) induced diabetic rats. Methods The animals were separated into five groups; the nondiabetic group (ND), the diabetic control group (DC), and the treatment groups of insulin (170 μg/kg, s.c), metformin (500 mg/kg, p.o), and OA (80 mg/kg, p.o). OA was administered orally twice a day. Thereafter, the animals were sacrificed, and blood and tissues were collected for haematological, hormonal, and oxidative status analysis. Results Untreated diabetic rats exhibited hyperglycaemia, elevated glycated haemoglobin (HbA1c), oxidative stress, and a reduced erythropoietin (EPO) concentration when compared to ND rats. However, administration of OA attenuated hyperglycaemia, HbA1c, and EPO concentrations compared to DC rats. The reduction of blood glucose concentration, HbA1c, and improved EPO concentrations was further associated with a notable increase in red blood cell (RBC) count and other RBC indices. We also observed an increase in the antioxidant status of the RBCs with a concomitant decrease in oxidative stress. Conclusion These findings suggest that OA improves diabetes-induced haematological changes caused by hyperglycaemia and attenuates the progression of cardiovascular complications in DM individuals.

Plant-derived oleanolic acid ameliorates markers associated with non-alcoholic fatty liver disease in a diet-induced pre-diabetes rat model.

BackgroundThe increased prevalence of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus (T2DM) patients is becoming a worldwide health burden. Studies have indicated, however, that the onset of NAFLD occurs during pre-diabetes, a condition that often precedes the onset of T2DM. Oleanolic acid has been reported to improve glucose homeostasis in diet-induced pre-diabetes; however, the effects of this triterpene on liver function have not been evaluated.PurposeThis study was aimed at evaluating the therapeutic effects of oleanolic acid (OA) on selected markers of NAFLD in a pre-diabetes rat model.Methods and materialsPre-diabetes was induced by exposing Sprague Dawley rats to a high-fat high-carbohydrate diet for 20 weeks. The pre-diabetic rats were then treated with OA (80 mg/kg) or metformin (500 mg/kg) in the presence and absence of dietary interventions for a period of 12 weeks. The effects of OA were evaluated on parameters including plasma triglycerides (TGs), very low-density lipoprotein (VLDL) particles, bilirubin, AST, ALT, SREBP and antioxidant profile while the livers were collected for histological analysis.ResultsThe findings of this study showed that the administration of OA to pre-diabetic rats ameliorated body/liver weights ratio and significantly decreased plasma triglycerides (TGs) and VLDL. Furthermore, OA also ameliorated hepatic oxidative stress, lowered the SREBP expression and intrahepatic TGs. In addition, OA administration decreased plasma concentrations of bilirubin and liver damage enzyme biomarkers.ConclusionThe findings of the study suggest that OA ameliorates the risk of developing pre-diabetes-related NAFLD through the prevention of intrahepatic fat accumulation while also lowering hepatic inflammation.

Short-Term Neonatal Oral Administration of Oleanolic Acid Protects against Fructose-Induced Oxidative Stress in the Skeletal Muscles of Suckling Rats.

Nutritional manipulations in the neonatal period are associated with the development of negative or positive health outcomes later in life. Excessive fructose consumption has been attributed to the increase in the global prevalence of metabolic syndrome (MetS) and the development of oxidative stress. Oleanolic acid (OA) has anti-diabetic and anti-obesity effects. We investigated the protective potential of orally administering OA in the neonatal period, to prevent fructose-induced oxidative stress, adverse health outcomes and maturation of the gastrointestinal tract (GIT) in suckling rats. Seven-day old Sprague-Dawley rats (N = 30) were gavaged daily with 10 mL/kg of: distilled water (DW), oleanolic acid (OA; 60 mg/kg), high fructose solution (HF; 20% w/v), or OAHF for 7 days. On day 14, tissue samples were collected to determine clinical health profiles, hepatic lipid content, and activity of anti-oxidant enzymes. Furthermore, biomarkers of oxidative stress and anti-oxidant capacity in the skeletal muscles were assessed. The gastrointestinal tract (GIT) morphometry was measured. Rats in all groups grew over the 7-day treatment period. There were no significant differences in the terminal body masses, GIT morphometry, surrogate markers of general health, liver lipid content across all treatment groups (p < 0.05). Neonatal fructose administration decreased the activity of catalase, depleted GSH and increased lipid peroxidation. However, the level of GSH and catalase activity were improved by neonatal OA treatment. Short-term oral OA administration during the critical developmental period protects against fructose-induced oxidative stress without adverse effects on health outcomes associated with MetS or precocious development of the GIT in suckling male and female rats.

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.

Plant-Derived Oleanolic Acid (OA) Ameliorates Risk Factors of Cardiovascular Diseases in a Diet-Induced Pre-Diabetic Rat Model: Effects on Selected Cardiovascular Risk Factors.

The pathogenesis of prediabetes is associated with risk factors such as chronic consumption of an unhealthy diet. Recent studies have reported that diet-induced pre-diabetes is also associated with risk factors of cardiovascular complications, hence this study was aimed at evaluating the effects of oleanolic acid (OA) on pre-diabetes rats. Pre-diabetes was induced by chronic exposure of Sprague Dawley rats (SD) to high-fat high-carbohydrate diet (20 weeks), whereas the non-pre-diabetes control (NC) was given standard rat chow. Pre-diabetes animals were grouped into five groups namely prediabetes control (PC), metformin treated (Met), metformin with diet intervention (Met + DI), oleanolic acid treated (OA), and oleanolic acid with diet intervention (OA + DI) then treated for 12 weeks. At the end of treatment, all animals were sacrificed where organs and tissues were harvested for biochemical analysis and histological studies. The results showed that PC had a significantly higher triglycerides (TGs), low density lipoprotein cholesterol (LDL-C, interleukin-6(IL-6), tumor necrosis factor alpha (TNFα), C-reactive protein (CRP), mean arterial pressure (MAP) and hearts weights in comparison to NC (p < 0.05). However, the administration of OA, in both the presence and absence of dietary intervention showed a significant decrease in TGs, LDL-C, IL-6, TNFα, CRP, MAP, hearts weights (p < 0.05). In conclusion, the administration of OA was able to lower the risks of developing CVDs in pre-diabetes rat model through ameliorating dyslipidaemia, oxidative stress, hypertension, and low-grade inflammation. Therefore OA has the potential to be used as an alternative treatment to prevent the onset of CVDs during pre-diabetes stage even in the absence of dietary and lifestyle intervention.

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

BackgroundConsumption of fructose-rich diets has been implicated in the increasing global prevalence of metabolic syndrome (MetS). Interventions during periods of early ontogenic developmental plasticity can cause epigenetic changes which program metabolism for positive or negative health benefits later in life. The phytochemical oleanolic acid (OA) possesses anti-diabetic and anti-obesity effects. We investigated the potential protective effects of neonatal administration of OA on the subsequent development of high fructose diet-induced metabolic dysfunction in rats.MethodMale and female (N = 112) suckling rats were randomly assigned to four groups and administered orally: distilled water (DW), oleanolic acid (OA; 60 mg/kg), high-fructose solution (HF; 20% w/v) or OA + HF for 7 days. The rats were weaned onto normal commercial rat chow up to day 55. From day 56, half of the rats in each treatment group were continued on plain water and the rest on a high fructose solution as drinking fluid for 8 weeks. On day 110, the rats were subjected to an oral glucose tolerance test and then euthanased on day 112. Tissue and blood samples were collected to determine the effects of the treatments on visceral fat pad mass, fasting plasma levels of cholesterol, insulin, glucose, triglycerides, insulin resistance (HOMA-IR) and glucose tolerance.ResultsRats which consumed fructose as neonates and then later as adults (HF + F) and those which consumed fructose only in adulthood (DW + F) had significant increases in terminal body mass (females only), visceral fat mass (males and females), serum triglycerides (females only), epididymal fat (males only), fasting plasma glucose (males and females), impaired glucose metabolism (females only), β-cell dysfunction and insulin resistance (males and females) compared to the other treatment groups (P < 0.05). There were no differences in fasting serum cholesterol levels across all treatment groups in both male and female rats (P > 0.05).ConclusionWe conclude that neonatal oral administration of OA during the critical window of developmental plasticity protected against the development of health outcomes associated with fructose-induced metabolic disorders in the rats.

A Study on Neonatal Intake of Oleanolic Acid and Metformin in Rats (Rattus norvegicus) with Metabolic Dysfunction: Implications on Lipid Metabolism and Glucose Transport.

Metabolic syndrome, a cluster of different disorders which include diabetes, obesity and cardiovascular diseases, is a global epidemic that is growing at an alarming rate. The origins of disease can be traced back to early developmental stages of life. This has increased mortalities and continues to reduce life expectancies of individuals across the globe. The aim of this study was to investigate the sub-acute and long term effects of neonatal oral administration of oleanolic acid and metformin on lipids (free fatty acids, FFAs) and genes associated with lipid metabolism and glucose transport using a neonatal rat experimental model. In the first study, seven days old pups were randomly grouped into control—distilled water (DW); oleanolic acid (60 mg/kg), metformin (500 mg/kg), high fructose diet (20% w/v, HF), oleanolic acid (OA) + high fructose diet (OA + HF), and Metformin + high fructose diet (MET + HF) groups. The pups were treated for 7 days, and then terminated on postnatal day (PD) 14. In the second study, rat pups were initially treated similarly to study 1 and weaned onto normal rat chow and plain drinking water on PD 21 till they reached adulthood (PD112). Tissue and blood samples were collected for further analyses. Measurement of the levels of free fatty acids (FFAs) was done using gas chromatography-mass spectrometry. Quantitative polymerase chain reaction (qPCR) was used to analyze the gene expression of glut-4, glut-5, fas, acc-1, nrf-1 and cpt-1 in the skeletal muscle. The results showed that HF accelerated accumulation of saturated FFAs within skeletal muscles. The HF fed neonatal rats had increased stearic acid, which was associated with decreased glucose, suppressed expression of glut-4, glut-5, nrf-1 and cpt-1 genes, and increased expression of acc-1 (p < 0.01) and fas. OA + HF and MET + HF treated groups had increased mono- and polyunsaturated FFAs; oleic, and octadecadienoic acids than the HF group. These unsaturated FFAs were associated with increased glut-4, glut-5 and nrf-1 (p < 0.01) and decreased acc-1 and fas (p < 0.05) in both OA + HF and MET + HF treated groups. Conclusions: The present study shows that neonatal oral administration of oleanolic acid and metformin potentially protects against the development of fructose-induced metabolic dysfunction in the rats in both short and long time periods.

Role of Oleanolic acid in maintaining BBB integrity by targeting p38MAPK/VEGF/Src signaling pathway in rat model of subarachnoid hemorrhage

Vasogenic brain edema after subarachnoid hemorrhage (SAH) is an independent risk factor for death and poor prognosis. Disruption of the blood-brain barrier (BBB) is the main cause of vasogenic brain edema induced by SAH. Oleanolic acid (OA) is a natural pentacyclic triterpenoid with various biological functions. Previous studies have shown that prophylactic administration of OA could prevent the BBB disruption in autoimmune encephalomyelitis mice. In this context, we speculate that OA may play a neuroprotective role by protecting the integrity of the BBB and reducing vasogenic cerebral edema after SAH. To validate this hypothesis, a SAH model was established on Sprague Dawley rats using a standard intravascular puncture model. The effects of OA on various physiological indexes were observed, including SAH grades, mortality, neurological function score, brain edema and BBB permeability. Related proteins of the brain endothelial cell junction complex were also detected, including tight junctions (TJs) and adherent junctions (AJs). Results showed that OA significantly reduced the permeability of BBB and relieved brain edema by increasing protein expression of TJs and AJs, and decreased the SAH grades by increasing the protein expression of heme oxygenase-1 (HO-1) in SAH rats. Additionally, we found OA could inhibit up-regulation of VEGF and the phosphorylation of p38 mitogen-activated protein kinase (MAPK), and suppress p38MAPK/VEGF/Src signaling pathway which involved in BBB disruption following SAH. From the experimental results, we speculate that OA effectively alleviated SAH-induced vasogenic edema by targeting p38 MAPK/VEGF/Src axis.

Lipid-lowering effects of oleanolic acid in hyperlipidemic patients

Oleanolic acid (OA) is a pentacyclic triterpenoid compound extracted from olea europaeal, a traditional Chinese medicine herb. OA has been used in the clinic as a hepatoprotective medicine in China since 1970s. In our previous study, we observed that OA could ameliorate hyperlipidemia in animal models. In the present study, we conducted a small-scale clinical trial to evaluate the hypolipidemia effect of OA in hyperlipidemic patients. Hyperlipidemic patients were administrated with OA for four weeks (4 tablets once, three times a day). The blood samples of the patients were collected before and after OA treatment. The biological parameters were measured. Furthermore, three patients' blood samples were studied with DNA microarray. After OA administration, the TC, TG, and HDLC levels in serum decreased significantly. DNA microarray analysis results showed that the expressions of 21 mRNAs were significantly changed after OA treatment. Bioinformatics analysis showed 17 mRNAs were up-regulated and 4 mRNAs were down-regulated significantly after OA treatment. Five mRNAs (CACNA1B, FCN, STEAP3, AMPH, and NR6A1) were selected to validate the expression levels by qRT-PCR. Therefore, OA administration differentially regulated the expression of genes involved in lipid metabolism. The data showed a clinical evidence that OA could improve hyperlipidemia and also unveiled a new insight into the molecular mechanisms underlying the pharmacological effect of OA on hyperlipidemia.