Inhibition of cytochrome P450 activities by oleanolic acid and ursolic acid in human liver microsomes

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.

Determination of antioxidant, DNA protection, enzyme inhibition potential and molecular docking studies of a biomarker ursolic acid in Nepeta species

Ursolic acid (UA), which has many biological properties such as anti-cancer, anti-inflammatory and antioxidant, and regulates some pharmacological processes, has been isolated from the flowers, leaves, berries and fruits of many plant species. In this work, UA was purified from the methanol-chloroform crude extract of Nepeta species (N. aristata, N. baytopii, N. italica, N. trachonitica, N. stenantha) using a silica gel column with chloroform or ethyl acetate solvents via bioactivity-guided isolation. The most active sub-fractions were determined under bioactivities using antioxidant and DNA protection activities and enzyme inhibitions. UA was purified from these fractions and its structure was elucidated by NMR spectroscopy techniques. The highest amount of UA was found in N. stenantha (8.53 mg UA/g), while the lowest amount of UA was found in N. trachonitica (1.92 mg UA/g). The bioactivities of UA were evaluated with antioxidant and DNA protection activities, enzyme inhibitions, kinetics and interactions. The inhibition values (IC50) of α-amylase, α-glucosidase, urease, CA, tyrosinase, lipase, AChE, and BChE were determined between 5.08 and 181.96 µM. In contrast, Ki values of enzyme inhibition kinetics were observed between 0.04 and 0.20 mM. In addition, Ki values of these enzymes for enzyme-UA interactions were calculated as 0.38, 0.86, 0.45, 1.01, 0.23, 0.41, 0.01 and 2.24 µM, respectively. It is supported that UA can be widely used as a good antioxidant against oxidative damage, an effective DNA protector against genetic diseases, and a suitable inhibitor for metabolizing enzymes.Communicated by Ramaswamy H. Sarma.

Therapeutic potential of oleanolic acid in liver diseases

Liver-associated diseases affect millions of individuals worldwide. In developed countries, the incidence of viral hepatitis is reducing due to advancements in disease prevention, diagnosis, and treatment. However, with improvements in living standards, the prevalence of metabolic liver diseases, such as non-alcoholic fatty liver disease and alcohol-related liver disease, is expected to increase; notably, this rise in the prevalence of metabolic liver disease can lead to the development of more severe liver diseases, including liver failure, cirrhosis, and liver cancer. The growing demand for natural alternative therapies for chronic diseases has highlighted the importance of studying the pharmacology of bioactive compounds in plants. One such compound is oleanolic acid (OA), a pentacyclic triterpenoid known for its antioxidant, anti-inflammatory, anti-ulcer, antibacterial, antiviral, antihypertensive, anti-obesity, anticancer, anti-diabetic, cardioprotective, hepatoprotective, and anti-neurodegenerative properties. Recent studies have demonstrated that OA treatment can reduce the risk of pathological liver damage, ultimately alleviating liver dysregulation and restoring overall liver function. This review aims to explore the latest research on the biological effects of OA and its derivatives. Notably, it explores the mechanisms of action of these compounds in both in vitro and in vivo research models and, ultimately, highlights OA as a promising candidate for alternative therapies in the treatment and management of chronic liver disease.

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.

Oleanolic acid inhibits the tumor progression by regulating Lactobacillus through the cytokine-cytokine receptor interaction pathway in 4T1-induced mice breast cancer model

The therapeutic mechanism of oleanolic acid (OA) in breast cancer has been widely reported, but little has been known about the combined effects of transcriptome and gut microbiome. In this study, the phenotypic effect of oleanolic acid on mice was tested at the end of the administration cycle, and RNA sequencing on murine tumor tissue and 16S-rRNA sequencing on intestinal contents were conducted to analyze gene expression profiles and microbial diversity between the control group and OA treated group using 4T1-induced mice breast cancer model. As a result, it has been confirmed that oleanolic acid would play a significant inhibitory effect on the development of breast tumors in mice. Based on the integrative analysis of the transcriptomic and metagenomic data, it was found that the abundance of Lactobacillus in the intestinal flora of mice significantly increased in the OA group. Moreover, the up-regulation of Il10 had a significant effect on inhibiting the tumor progression, which played a role through cytokine-cytokine receptor interaction pathway.

Effects of oleanolic acid and ursolic acid on depression-like behaviors induced by maternal separation in mice

Oleanolic acid (OA) and ursolic acid (UA) are structural isomeric triterpenoids. Both triterpenoids have been reported to be able to improve depression. However, no studies have compared their effects in the same system. Whether OA or UA could ameliorate depression-like behaviors in maternal separation (MS)-induced depression-like model was investigated. MS model is a well-accepted mouse model that can reflect the phenotype and pathogenesis of depression. Depression is a mental illness caused by neuroinflammation or changes in neuroplasticity in certain brain regions, such as the prefrontal cortex and hippocampus. Depression-like behaviors were measured using splash test or forced swimming test. In addition, anxiety-like behaviors were also measured using the open field test or elevated plus-maze test. MS-treated female mice showed greater depression-like behaviors than male mice, and that OA improved several depression-like behaviors, whereas UA only relieved anxiety-like behavior of MS-treated mice. Microglial activation, expression levels of TNF-α, and mRNA levels of IDO1 were increased in the hippocampi of MS-treated female mice. However, OA and UA treatments attenuated such increases. In addition, expression levels of synaptophysin and PSD-95 were decreased in the hippocampi of MS-treated female mice. These decreased expression levels of synaptophysin were reversed by both OA and UA treatments, although decreased PSD-95 expression levels were only reversed by OA treatment. Our findings suggest that MS cause depression-like behaviors through female-specific neuroinflammation, changes of tryptophan metabolism, and alterations of synaptic plasticity. Our findings also suggest that OA could reverse MS-induced depression-like behaviors more effectively than UA.

Inhibition of the CYP Enzymatic System Responsible of Heterocyclic Amines Bioactivation by an Asclepias subulata Extract

Asclepias subulata plant extract has previously demonstrated antiproliferative activity and antimutagenicity against heterocyclic aromatic amines (HAAs) commonly found in cooked meat. The objective of this work was to evaluate the in vitro ability of an ethanolic extract from the medicinal plant Asclepias subulata extract (ASE), non-heated and heated (180 °C), to inhibit the activity of CYP1A1 and CYP1A2, which are largely responsible for HAAs bioactivation. Ethoxyresorufin and methoxyresorufin O-dealkylation assays were performed in rat liver microsomes exposed to ASE (0.002-960 µg/mL). ASE exerted an inhibitory effect in a dose-dependent manner. The half inhibitory concentration (IC₅₀) for unheated ASE was 353.6 µg/mL and 75.9 µg/mL for heated ASE in EROD assay. An IC₄₀ value of 288.4 ± 5.8 µg/mL was calculated for non-heated ASE in MROD assay. However, after heat treatment, the IC₅₀ value was 232.1 ± 7.4 µg/mL. Molecular docking of corotoxigenin-3-O-glucopyranoside, one of the main components of ASE, with CYP1A1/2 structure, was performed. Results show that the interaction of corotoxigenin-3-O-glucopyranoside with CYP1A1/2s' α-helices, which are related with the active site and the heme cofactor, may explain the plant extract's inhibitory properties. Results showed that ASE inhibits CYP1A enzymatic subfamily and may potentially act as a chemopreventive agent by inhibiting bioactivation of promutagenic dietary HAAs.

Ursolic acid: a natural modulator of signaling networks in different cancers

Incidence rate of cancer is estimated to increase by 40% in 2030. Furthermore, the development of resistance against currently available treatment strategies has contributed to the cancer-associated mortality. Scientists are now looking for the solutions that could help prevent the disease occurrence and could provide a pain-free treatment alternative for cancers. Therefore, efforts are now put to find a potent natural compound that could sever this purpose. Ursolic acid (UA), a triterpene acid, has potential to inhibit the tumor progression and induce sensitization to conventional treatment drugs has been documented. Though, UA is a hydrophobic compound therefore it is usually chemically modified to increase its bioavailability prior to administration. However, a thorough literature indicating its mechanism of action and limitations for its use at clinical level was not reviewed. Therefore, the current study was designed to highlight the potential mechanism of UA, its anti-cancer properties, and potential applications as therapeutic compound. This endeavour is a valuable contribution in understanding the hurdles preventing the translation of its potential at clinical level and provides foundations to design new studies that could help enhance its bioavailability and anti-cancer potential for various cancers.

Treatment opportunities with Fernandoa adenophylla and recent novel approaches for natural medicinal phytochemicals as a drug delivery system

Fernandoa adenophylla (FA, Heterophragma adenophyllum) is a plant, cultivated throughout Africa and Southeast Asia. It contains potent phytochemicals such as novel naphthoquinones, their derivatives (peshwaraquinone, dilapachone, adenophyllone, indadone, and lapachol), and triterpenoids [ursolic acid (UA), β-sitosterol (BS), α-amyrin, and oleanolic acid (OA)] that have been assessed and reported to show potential pharmacological activities. The crude extract obtained from the plant has been investigated for certain pharmacological activities such as antibacterial, antifungal, anti-tubercular (TB), antihypertensive, and leishmanicidal activity. A novel drug delivery systems (NDDS) is the latest technique that combines innovative development, formulations, new technology, and methodologies for the safe delivery of pharmaceutical substances in the body. The present study reports the possible treatment opportunities of FA and recent possible novel drug delivery approaches for the natural medicinal phytochemicals.

Bioanalysis by LC-MS/MS and preclinical pharmacokinetic interaction study of ribociclib and oleanolic acid

Background: Ribociclib (RIBO), approved in 2017 for HR-positive and HER-2-negative metastatic breast cancer treatment is reported to have the potential to induce hepatobiliary toxicity in patients. Oleanolic acid (OLA) has hepatoprotective potential that can be beneficial if coadministered with RIBO. Methodology & results: The primary scope of this study was to develop quantitative bioanalytical methods for RIBO and OLA. Two methods (for +ve electrospray ionization [ESI] and -ve ESI) were developed and validated according to USFDA bioanalytical guidelines. Discussion/conclusion: A single and simple sample preparation method was developed with >75% recovery. The accuracy and precision for RIBO and OLA were within acceptable limits over the calibration range of 5-500 ng/ml. This work reports, for the first time, the drug-drug interaction potential between RIBO and OLA.

Anti-rheumatic, and analgesic effects by the parent tuberous roots of Aconitum jaluense in adjuvant induced arthritis rats

AIM OF THE STUDY

The aim of this study was to test the anti-rheumatic effects of A. jaluense tubers in acute and chronic arthritis rats, and to assign its ingredients through UHPLC-TOF/MS.

MATERIALS AND METHODS

Subcutaneous injection of carrageenan for acute arthritis and complete Freund's adjuvant (CFA) for chronic arthritis was carried out in the hind paw of SD rats. The paw volume was measured by a plethysmometer thermal hyperalgesia was tested using a thermal plantar tester, and mechanical hyperalgesia was evaluated by ankle flexion evoked vocalizations. The expression of c-Fos in the brain hippocampus was measured with the avidin-biotin-peroxidase technique. The ingredients were assigned by UHPLC-TOF/MS, chromatography was performed by UHPLC system with DAD detector and BEH C₁₈ column, and spectroscopy was conducted by ESI-MS system.

RESULTS AND DISCUSSION

The 80% ethanoic extract of A. jaluense tubers showed an acute anti-inflammatory effect by suppressing the edema volume in the hind paw of carrageenan-stimulated rats. In addition, A. jaluense tubers exerted an anti-rheumatic activity by reducing the secondary swelling volume from an immunological reaction in the left hind paw of CFA-induced chronic arthritis rats. Additionally, oral treatment with the 80% ethanoic extract -showed potent analgesic effects in the arthritis rats by recovering the paw withdrawal latency stimulated by the thermal hyperalgesia and by reducing the vocalization scores evoked by ankle flexion on both hind paws. Moreover, its treatment also indicated an anti-psychiatric effect by controlling the c-Fos protein expression of the brain hippocampus in CFA-stimulated arthritis rats. These results suggested that these therapeutic effects were exhibited by less toxic mono-esterified diterpenoid alkaloids (MDAs), and nontoxic non-esterified diterpenoid alkaloids (NDAs).

CONCLUSION

A. jaluense tubers may act as viable therapeutic or preventive candidates for acute and chronic arthritis, particularly, for immune-inflammatory rheumatoid arthritis to suppress the pain and psychiatric condition.

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.

Anti-inflammatory, and anti-arthritic effects by the twigs of Cinnamomum cassia on complete Freund's adjuvant-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The young branches of C. cassia Blume (Cinnamomi Ramulus; Guizhi; ; C. cassia twigs) have long been used as an anti-pyretic, anti-rheumatic, anti-spasmodic and stomachic in traditional medicine.

AIM OF THE STUDY

The aim of this study was to test the anti-inflammatory, anti-nociceptive, and anti-arthritic effects of Cinnamomum cassia twigs in acute and chronic arthritis rats.

MATERIALS AND METHODS

Subcutaneous injection of carrageenan for acute inflammation and complete Freund's adjuvant (CFA) for chronic arthritis was carried out in the hind paw of SD rats. The paw volume was measured by a plethysmometer; thermal hyperalgesia was tested using a thermal plantar tester; hyperalgesia was evaluated by ankle flexion evoked vocalizations. The c-Fos expression in the lumbar spinal cord was measured with the avidin-biotin-peroxidase technique. The nitric oxide (NO) generation in lipopolysaccharide (LPS)-induced RAW 264.7 cells was tested by Griess assay.

RESULTS AND DISCUSSION

An 80% ethanoic extract of the C. cassia twigs exhibited chronic anti-inflammatory and anti-arthritic activities by reducing the edema volume in the paws of CFA-induced chronic arthritis in rats. In addition, it showed analgesic effects through the recovery of the paw withdrawal latency stimulated by thermal hyperalgesia, and suppressing the vocalization scores evoked by ankle flexion in the hind paws of the arthritis rats. It also controlled c-Fos expression in the lumbar spinal cord of the arthritis rats. Moreover, the addition its 80%-ethanoic extract, specifically, its ethyl acetate fraction, powerfully suppressed the paw swelling in carrageenan-stimulated arthritis and the NO production in LPS-induced murine immune cells.

CONCLUSION

C. cassia twigs may act as a viably sufficient therapeutic or preventive candidate for osteoarthritis and rheumatoid arthritis; additionally, it could prevent gastrointestinal damage with its gastric protection.

Ursolic Acid and Related Analogues: Triterpenoids with Broad Health Benefits

Ursolic acid (UA) is a well-studied natural pentacyclic triterpenoid found in herbs, fruit and a number of traditional Chinese medicinal plants. UA has a broad range of biological activities and numerous potential health benefits. In this review, we summarize the current data on the bioavailability and pharmacokinetics of UA and review the literature on the biological activities of UA and its closest analogues in the context of inflammation, metabolic diseases, including liver and kidney diseases, obesity and diabetes, cardiovascular diseases, cancer, and neurological disorders. We end with a brief overview of UA’s main analogues with a special focus on a newly discovered naturally occurring analogue with intriguing biological properties and potential health benefits, 23-hydroxy ursolic acid.

Herb-drug interactions and toxicity: Underscoring potential mechanisms and forecasting clinically relevant interactions induced by common phytoconstituents via data mining and computational approaches

Herbals in the form of medicine are employed extensively around the world. Herbal and conventional medicine combination is a potentially dangerous practice mainly in comorbid, hepato insufficient and frail patients leading to perilous herb-drug interactions (HDI) and toxicity. This study features potential HDI of 15 globally famous plant species through data mining and computational methods. Several plant species were found to mimic warfarin. Phytochemicals from M. charantia induced hypoglycemica. M. chamomila and G. biloba possessed anticoagulant activities. S. hispanica reduces postprandial glycemia. R. officinalis has been reported to inhibit the efflux of anticancer substrates while A. sativum can boost the clearance of anticancer agents. P. ginseng can alter blood coagulation. A cross link of the biological and in silico data revealed that a plethora of herbal metabolites such as ursolic and rosmarinic acid among others are possible/probable inhibitors of specific CYP450 enzymes. Consequently, plant species/metabolites with a given pharmacological property/metabolizing enzyme should not be mixed with drugs having the same pharmacological property/metabolizing enzyme. Even if combined with drugs, herbal medicines must be used at low doses for a short period of time and under the supervision of a healthcare professional to avoid potential adverse and toxic effects.

Regioselective Hydroxylation of Oleanolic Acid Catalyzed by Human CYP3A4 to Produce Hederagenenin, a Chiral Metabolite

Oleanolic acid (OA) is a pentacyclic triterpenoid widely found in plants and foods as an aglycone of triterpenoid saponins or as a free acid. OA exhibits beneficial activities for humans, including antitumor, antivirus, and hepatoprotection properties without apparent toxicity. The metabolites produced by the cytochrome P450 (P450) enzymes are critical for the evaluation of the efficacy and safety of drugs. In this study, the potential metabolites of OA were investigated by P450-catalyzed oxidation reactions. Among the various tested human P450s, only human CYP3A4 was active for the hydroxylation of OA. The major metabolite was characterized by a set of analyses using HPLC, LC–MS, and NMR. It was found to be 4-epi-hederagenenin, a chiral product, by regioselective hydroxylation of the methyl group at the C-23 position. These results indicated that CYP3A4 can hydroxylate an OA substrate to make 4-epi-hederagenenin. Possible drug–food interactions are discussed.

A systems-based analysis to explore the multiple mechanisms of Shan Zha for treating human diseases

Shan Zha has garnered increasing attention in the field of functional foods and medicines due to its widely reported healing effects. However, the potential mechanisms of Shan Zha for human health benefits have not been fully interpreted. Therefore, in the current study, a systems-based method that integrates ADME evaluation, target fishing, gene ontology enrichment analysis, network pharmacology, and pathway analysis is proposed to clarify the underlying pharmacological mechanisms of Shan Zha. As a result, 45 active components of Shan Zha that interacted with 161 protein targets were screened and identified. Moreover, gene ontology enrichment, network and pathway analysis indicated that Shan Zha is beneficial for the treatment of cardiovascular system diseases, digestive system diseases, immune system diseases, inflammatory diseases, cancer, and other diseases through multiple mechanisms. Our study not only proposed an integrated method to comprehensively elucidate the complicated mechanisms of Shan Zha for the treatment of various disorders at the system level, but also provided a reference approach for the mechanistic research of other functional foods.

Potential Herb-Drug Interactions in the Management of Age-Related Cognitive Dysfunction

Late-life mild cognitive impairment and dementia represent a significant burden on healthcare systems and a unique challenge to medicine due to the currently limited treatment options. Plant phytochemicals have been considered in alternative, or complementary, prevention and treatment strategies. Herbals are consumed as such, or as food supplements, whose consumption has recently increased. However, these products are not exempt from adverse effects and pharmacological interactions, presenting a special risk in aged, polymedicated individuals. Understanding pharmacokinetic and pharmacodynamic interactions is warranted to avoid undesirable adverse drug reactions, which may result in unwanted side-effects or therapeutic failure. The present study reviews the potential interactions between selected bioactive compounds (170) used by seniors for cognitive enhancement and representative drugs of 10 pharmacotherapeutic classes commonly prescribed to the middle-aged adults, often multimorbid and polymedicated, to anticipate and prevent risks arising from their co-administration. A literature review was conducted to identify mutual targets affected (inhibition/induction/substrate), the frequency of which was taken as a measure of potential interaction. Although a limited number of drugs were studied, from this work, interaction with other drugs affecting the same targets may be anticipated and prevented, constituting a valuable tool for healthcare professionals in clinical practice.

Ursolic Acid Protects Against Proliferation and Inflammatory Response in LPS-Treated Gastric Tumour Model and Cells by Inhibiting NLRP3 Inflammasome Activation

Background

Inflammation is considered as one of the hallmarks of cancer development and progression. Ursolic acid (UA) showed strong effects as an anti-inflammatory and antioxidant. However, the anti-cancer effects of ursolic acid require further study.

Methods

This study aimed to investigate the role of ursolic acid in a lipopolysaccharide (LPS)-treated gastric tumour mouse model and in a human gastric carcinoma cell line (BGC-823 cells). This study also aimed to confirm whether ursolic acid can protect against proliferation and the inflammatory response induced by LPS, by inhibiting the activation of the NLRP3 inflammasome via the NF-κB pathway.

Results

The present study demonstrated that ursolic acid significantly attenuated LPS-treated proliferation in a gastric tumour mouse model and the human gastric carcinoma BGC-823 cell line, reduced the expression of the NLRP3 inflammasome and suppressed the release of pro-inflammatory cytokines. In addition, ursolic acid inhibited the LPS-induced activation of NF-κB. Furthermore, the NF-κB pathway regulated the activation of the NLRP3 inflammasome.

Conclusion

In conclusion, these results demonstrated that ursolic acid could suppress proliferation and the inflammatory response in an LPS-induced mouse gastric tumour model and human BGC-823 cells by inhibiting the activation of the NLRP3 inflammasome via the NF-κB pathway. This indicates that ursolic acid can be a potential therapeutic agent for the treatment of gastric cancer.

PXR-ABC drug transporters/CYP-mediated ursolic acid transport and metabolism in vitro and vivo

The transporting kinetics and metabolic kinetics of ursolic acid were studied in transgenic cell models. Then, the pharmacokinetics features of ursolic acid and the expression of ATP-binding cassette transporters (ABC transporter) and cytochrome P450 (CYP) enzymes in tissues after pregnane X receptor (PXR) activation by 5-pregnen-3β-ol-20-one-16α-carbonitrile (PCN) were investigated in rats. After silencing of PXR in Caco2-siRNA-PXR cells, there was a decrease in the protein abundance of P-glycoprotein, breast cancer-resistant protein, multidrug resistance-associated protein 2 (MRP2), and CYP2C9. The apparent permeability (PDR) values of 10, 20, and 50 µM ursolic acid in Caco2 cells were 2.19 ± 0.44, 1.40 ± 0.17, and 1.25 ± 0.07, respectively, whereas in Caco2-siRNA-PXR cells, they were 1.85 ± 0.36, 1.24 ± 0.11, and 1.19 ± 0.04, respectively. PXR-RXRα would significantly activate ABC transporter expression in Caco2 cells. Compared with Caco2 cells, when the concentrations of ursolic acid were 10, 20, and 50 µM, the PDR values increased in Caco2-PXR-RXRα cells after PXR activation: 1.60 ± 0.31 versus 1.97 ± 0.21, 1.46 ± 0.08 versus 2.01 ± 0.19, and 1.32 ± 0.26 versus 2.09 ± 0.22, respectively. Simultaneously, PXR-RXRα would activate the expression of CYP2C9; metabolic kinetics of ursolic acid in CYP metabolizing enzyme lysate of Caco2 cells and Caco2-PXR-RXR cells was studied and it was found that the Km values were 81.99 ± 44.32 and 60.05 ± 29.62 µg/ml, and Vmax values were 3.77 ± 0.86 and 3.41 ± 0.96 µg · ml-1  · min-1 , respectively. However, in human CYP metabolizing recombinase, we found that both CYP2C9 and CYP34A were involved in the metabolism of ursolic acid. Vm and Km values for CYP3A4 and CYP2C9 were 3.57 ± 1.12 µg · ml-1  · min-1 and 81.71 ± 18.38 µg/ml, 3.85 ± 1.46 µg · ml-1  · min-1 and 62.18 ± 14.56 µg/ml, respectively. As a strong agonist for mouse pxr, PCN could significantly affect pharmacokinetics of ursolic acid in rats, and it showed discrepant effects on messenger RNA expression of cyp and transporters in tissues.

Antimutagenic effect of an Asclepias subulata extract against heterocyclic aromatic amines commonly found in cooked meat and its heat stability

The antimutagenicity of an extract from the medicinal plant Asclepias subulata (ASE) against heterocyclic aromatic amines (HAAs) commonly found in cooked meat, as well as its stability to heat treatment (HT), was evaluated. HT (180 °C/3 min) had no effect on the content in ASE of the bioactive compound corotoxigenin-3-O-glucopyranoside; conversely, calotropin significantly decreased by 72%. ASE exerted antimutagenicity against PhIP, MelQ, and MelQx in TA98 and TA100 Salmonella strains, and this activity was not affected by heat, with the exception of MelQ (p < 0.05). Since HAAs can induce colorectal cancer, the thermal stability of ASE's antiproliferative effect against colorectal cancer cells was also evaluated. HT decreased (p < 0.05) the antiproliferative activity of ASE; however, the remaining activity was still strong with an IC₅₀ of 16.8 ± 2.03 µg/mL. Therefore, ASE can be used as a food ingredient to reduce the carcinogenic potential of thermally induced HAAs.

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.

Interactions between clopidogrel and traditional Chinese medicine

The use of traditional Chinese medicine (TCM) has obtained more and more acceptance all over the world due to its multi-target and multi-level function characteristics. Clopidogrel is a major therapeutic option to reduce atherothrombotic events in patients with acute coronary syndrome, recent myocardial infarction, recent stroke or established peripheral arterial disease. These patients probably take TCM. Are there any interactions between clopidogrel and TCM? Whether TCM will affect the efficacy of clopidogrel or increase the adverse reactions of bleeding? Clarifying this information will help physicians make better use of TCM. A literature search was carried out using Web of Science, PubMed and the Cochrane Library to analyze the pharmacokinetic or pharmacodynamic interactions of clopidogrel and TCM. Some herbs can increase the AUC or C_max of clopidogrel, such as Scutellarin, Danggui, Gegen, Sauchinone and Dengzhan Shengmai capsules. Whereas others can decrease clopidogrel, for example, Ginkgo and Danshen. Furthermore, some herbs can increase the AUC or C_max of clopidogrel active metabolite, including Ginkgo and Xuesaitong tablet. And others can decrease the clopidogrel active metabolite, such as Scutellarin, Danshen, Fufang Danshen Dripping Pill and Dengzhan Shengmai capsules. Additionally, Schisandra chinensis, Danggui, Gegen and Fufang Danshen Dripping Pill can decrease the AUC or C_max of the clopidogrel inactive metabolite, while Curcumin on the contrary. The pharmacodynamics of Panax notoginseng, Notoginsenoside Ft1, Hypericum perforatum, Shexiang baoxin pills, Naoxintong capsule increased the antiplatelet activity compared with clopidogrel alone, while Danshen decreased the platelet inhibition. In adverse reactions, Danggui can enhance the adverse effects of clopidogrel on the bleeding time. With more awareness and understanding on potential drug-herb interactions of clopidogrel and TCM, it may be possible to combine clopidogrel with TCM herbs to yield a better therapeutic outcome.

Oleanolic Acid and Ursolic Acid Induce UGT1A1 Expression in HepG2 Cells by Activating PXR Rather Than CAR

Background: Oleanolic acid (OA) and its isomer ursolic acid (UA) have recently emerged as research foci based on their biologic activities. We previously demonstrated that UA can inhibit the activities of UGT1A3 and UGT1A4, and OA inhibits UGT1A3 activity in liver microsomes. However, whether OA and UA affect the expression of UGT1As in HepG2 cells and the underlying regulatory mechanism remain unclear.

Purpose: The present study aimed to explore the effect of OA and UA on the expression of UGT1As in HepG2 cells and the regulatory mechanisms on UGT1A1 based on the pregnane X receptor (PXR) and constitutive androstane receptor (CAR) signaling pathways.

Methods: We analyzed the effect of OA and UA on UGT1A expression and on the PXR/CAR regulatory pathway in HepG2 cells, hPXR-silenced HepG2 cells, and hCAR-silenced HepG2 cells by Q-PCR, Western blotting, and dual-luciferase reporter gene assays.

Results: In HepG2 cells, OA and UA both significantly induced the expression of UGT1A1, UGT1A3, UGT1A4, and UGT1A9 and upregulated the expression of PXR. However, OA and UA did not affect CAR expression. A dual-luciferase reporter assay showed that OA and UA could markedly promote PXR-mediated UGT1A1 luciferase activity, whereas OA and UA did not affect CAR-mediated UGT1A1 luciferase activity. In hPXR-silenced HepG2 cells, OA and UA did not elevate UGT1A1 activity compared to the control group. However, the expression of UGT1A1 in hCAR-silenced HepG2 cells was markedly elevated compared to the control group or with non-silenced HepG2 cells treated with OA (10, 20, and 40 μM) or UA (10, 20, and 40 μM).

Conclusions: OA and UA significantly induce the expression of UGT1A1, UGT1A3, UGT1A4, and UGT1A9 in HepG2 cells, and their induction on UGT1A1 is mediated by PXR activation, not CAR.

Synergism of cisplatin-oleanolic acid co-loaded calcium carbonate nanoparticles on hepatocellular carcinoma cells for enhanced apoptosis and reduced hepatotoxicity

Background: Cisplatin (CDDP), a widely used chemotherapeutic agent against hepatocellular carcinoma (HCC), faces severe resistance and hepatotoxicity problems which can be alleviated through combination therapy.

Purpose: The objective of this study was to develop a pH-dependent calcium carbonate nano-delivery system for the combination therapy of CDDP with oleanolic acid (OA).

Methods: A microemulsion method was employed to generate lipid coated cisplatin/oleanolic acid calcium carbonate nanoparticles (CDDP/OA-LCC NPs), and the loading concentration of CDDP and OA was measured by atomic absorption spectroscopy and HPLC respectively.Transmission electron microscopy (TEM) was used to examine the nanoparticles morphology while its pH dependent release characteristics were investigated through in vitro release study. Cellular uptake was examined through a fluorescence microscopy. Apoptotic assays and western blot analysis were conducted to explore the synergistic apoptotic effect of OA on CDDP against HCC cells. The hepatoprotective of OA for CDDP was evaluated through H&E staining.

Results: TEM analysis revealed nanoparticles spherical shape with an average particle size of 206±15 nm, and the overall entrapment efficiency was 63.70%±3.9%. In vitro drug release study confirmed the pH-dependent property of the formulation, with the maximum CDDP release of 70%±4.6% at pH 5.5, in contrast to 28%±4.1% CDDP release at pH 7.4. Annexin V-FITC/PI assay and cell cycle analysis confirmed that CDDP and OA synergistically promoted greater HepG2 cells apoptosis for the CDDP/OA-LCC NPs as compared to their individual free drug solutions and NPs-treated groups. Western blot analysis also proved that CDDP/OA-LCC NPs induced the apoptosis by enhancing the proapoptotic protein expressions through downregulating P13K/AKT/mTOR pathway and upregulating p53 proapoptotic pathway. OA helped CDDP to overcome the resistance by downregulating the expression of proteins like XIAP, Bcl-2 via NF-κB pathway. OA also significantly alleviated CDDP-induced hepatotoxicity as evident from the decreased alanine transaminase, aspartate transaminase levels and histochemical evaluation. The possible mechanism may be related to the Nrf-2 induction via its antioxidant mechanism to maintain the redox balance and reduction in CYP2E1 activity which can lead to ROS-mediated oxidative stress.

Conclusion: These results suggest that CDDP/OA-LCC NPs have promising applications for co-delivering CDDP and OA to synergize their anti-tumor activity against HCC and to utilize OA’s protective effect against CDDP-induced hepatotoxicity.

Modulations of bovine hepatic microsomal metabolism of benzimidazoles by secondary plant metabolites

The study was aimed to estimate the effect of plant secondary metabolites present in ruminants diet and phytogenic feed additives on liver microsomal metabolism of albendazole and fenbendazole. The selected phytocompounds comprised of flavonoids (apigenin, quercetin) and saponins (hederagenin, medicagenic acid). The experiments were performed on liver microsomal fraction obtained from routinely slaughtered cows. The intensity of albendazole and fenbendazole metabolism in the presence of flavonoids and saponins was analyzed in equimolar concentration (100 μM). The obtained results revealed that both flavonoids and saponins intensify the metabolism of albendazole and fenbendazole in bovine microsomes. In the case of albendazole, apigenin and quercetin doubled the amount of degraded drug and the amount of produced albendazole sulfoxide. Additionally, both flavonoids increased the amount of produced albendazole sulfone. Saponins, hederagenin, and medicagenic acid intensified the degradation of albendazole (1.8-fold) and the production of albendazole sulfoxide (twofold). Medicagenic acid inhibited the production of albendazole sulfone. In the case of fenbendazole, the degradation of the drug and the production of oxfendazole were increased four and five times in the presence of saponins and flavonoids, respectively. The enhancement of benzimidazoles' metabolism caused by the studied plant metabolites could change pharmacokinetics and the efficacy of benzimidazoles' treatment in cattle.

Can ursolic acid be beneficial against diabetes in rats?

Objective:

Diabetes mellitus, a heteregenous metabolic and chronic disease, is a growing health problem especially in developing countries. It is claimed that diabetes associated with increased formation of free radicals and decrease in antioxidant potential and also alterations in lipid profile and enzyme levels. Ursolic acid is commonly used in traditional Chinese medicine due to its beneficial effects. The aim of this study was to investigate the effects of ursolic acid on streptozotocin-induced diabetes in Wistar albino rats.

Methods:

DNA damage was evaluated in the blood and liver cells of rats by alkaline comet assay. The activities of antioxidant enzymes, oxidative stress parameters, biochemical parameters, hepatic enzyme levels and lipid profile parameters were also evaluated.

Results:

The results of this study demonstrate that diabetes caused genotoxic damage, changes in hepatic enzyme and lipid profile, biochemical and antioxidant enzyme activities and oxidative stress parameters in rats. Ursolic acid was found to be protective against diabetes induced effects in blood and liver samples of rats.

Conclusions:

According to our results, it seems that ursolic acid may be beneficial against diabetes and its adverse effects in rats.

Ameliorative effect of ursolic acid on renal fibrosis in adenine-induced chronic kidney disease in rats

Ursolic acid (UA), an ursane-type pentacyclic triterpenoid commonly found in apple peels and holy basil has been shown to possess many beneficial effects. Renal fibrosis is a complication of kidney injury and associated with increased risk of morbidity and mortality. In our previous investigation, a lupane-type pentacyclic triterpenoid, betulinic acid (BA) was found to have protective effect on chronic kidney disease (CKD) and renal fibrosis. This prompted us to explore the therapeutic value of UA, a chemically related compound to BA in CKD. CKD was induced by feeding adenine with the feed at a concentration of 0.75% for 28 days. UA at the dose rate of 30 mg/kg in 0.5% carboxy methyl cellulose (CMC) was administered by oral route, simultaneously with adenine feeding for 28 days. Adenine feeding increased the kidney weight to body weight index, decreased the kidney function due to injury as indicated by increased markers like serum urea, uric acid, creatinine, cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) and initiated the fibrotic response in kidney by increasing the profibrotic proteins viz. transforming growth factor-beta (TGF-β), connective tissue growth factor (CTGF), fibronectin and collagen. However, treatment with UA reversed the damage induced by adenine as shown by reduced kidney injury and fibrosis markers which was further clearly evident in histological picture indicating the suitability of UA for use in CKD.

Inhibition of Cytochrome P450 Activities by Extracts of Hyptis verticillata Jacq.: Assessment for Potential HERB-Drug Interactions

Understanding the potential for adverse drug reactions (ADRs), from herb-drug interactions, is a key aspect of medicinal plant safety, with particular relevance for public health in countries where medicinal plant use is highly prevalent. We undertook an in-depth assessment of extracts of Hyptis verticillata Jacq., via its impact on activities of key cytochrome P450 (CYP) enzymes (CYPs 1A1, 1A2, 1B1, 3A4 and 2D6), its antioxidant properties (determined by DPPH assays) and chemical characterisation (using LC-MS). The dried plant aqueous extract demonstrated potent inhibition of the activities of CYPs 1A1 (7.6 µg/mL), 1A2 (1.9 µg/mL), 1B1 (9.4 µg/mL) and 3A4 (6.8 µg/mL). Further analysis of other crude extracts demonstrated potent inhibition of CYP1A2 activity for a dried plant ethanol extract (1.5 µg/mL), fresh plant ethanol extract (3.9 µg/mL), and moderate activity for a fresh plant aqueous extract (27.8 µg/mL). All four extracts demonstrated strong antioxidant activity, compared to the positive control (ascorbic acid, 1.3 µg/mL), with the dried plant ethanol extract being the most potent (1.6 µg/mL). Analysis of the dried plant aqueous extract confirmed the identity of seven phytochemicals, five lignans and two triterpenes. Individual screening of these phytochemicals against the activity of CYP1A2 identified yatein as a moderate inhibitor (71.9 μM), likely to contribute to the plant extract’s potent bioactivity. Further analysis on the impact of this plant on key drug metabolizing enzymes in vivo appears warranted for likely ADRs, as well as furthering development as a potential chemopreventive agent.

Synthesis and anti-hepatocellular carcinoma activity of novel O2-vinyl diazeniumdiolate-based nitric oxide-releasing derivatives of oleanolic acid

Considering that high levels of nitric oxide (NO) exert anti-cancer effect and the derivatives of oleanolic acid (OA) have shown potent anti-cancer activity, new O²-vinyl diazeniumdiolate-based NO releasing derivatives (5a-l, 11a-l) of OA were designed, synthesized, and biologically evaluated in the present study. These derivatives could release different amounts of NO in liver cells. Among them, 5d, 5i, 5j, 11g, 11h, and 11j released more NO in SMMC-7721 cells and displayed stronger proliferative inhibition against SMMC-7721 and HepG2 cells than OA and other tested compounds. The most active compound 5j showed almost 20-fold better solubility than OA in aqueous solution, released larger amounts of NO in liver cancer cells than that in normal ones, and exhibited potent anti-hepatocellular carcinoma activity but little effect on the normal liver cells. The inhibitory activity against the cancer cells was significantly diminished upon addition of an NO scavenger, suggesting that NO may contribute, at least in part, to the activity of 5j.

Modulation of pregnane X receptor (PXR) and constitutive androstane receptor (CAR) activation by ursolic acid (UA) attenuates rifampin-isoniazid cytotoxicity

BACKGROUND

Interactions between transcriptional inducers of cytochrome P450 (CYP450) enzymes and therapeutic drugs may be prevented by antagonizing the activation of a nuclear receptor (NR), pregnane X receptor (PXR, NR1I2), thus improving therapeutic efficacy.

PURPOSE

In the present study, we aim to identify that ursolic acid (UA), a widely distributed pentacyclic triterpene, may act as an effective antagonist of PXR and its sister NR receptor, constitutive androstane receptor (CAR, NR1I3).

METHODS

The hepatocellular carcinoma cell line, HepG2, was used to evaluate the promoter activity of PXR and CAR target genes, CYP3A4 and CYP2B6, respectively. Catalytic activities, mRNA, and protein expression of CYP3A4 and CYP2B6 were evaluated in a differentiated HepaRG cell line. Coregulation of PXR with coregulators on CYP3A4 promoter response elements was also been characterized.

RESULTS

Transient transfection assays showed that UA effectively attenuated CYP3A4 and CYP2B6 promoter activities mediated by rifampin (RIF, human PXR agonist) and CITCO (human CAR agonist). These inhibitory effects were well correlated with the expression and catalytic activities of CYP3A4 and CYP2B6. Furthermore, the interaction of co-regulators with PXR and the transcriptional complexes in the CYP3A4 promoter activity and CYP3A4 promoter xenobiotic response element (everted repeat 6, ER6), respectively, were disrupted in the presence of UA. UA showed an antagonistic effect against PXR, and reversed the cytotoxic effects of isoniazid (INH) induced by RIF. Taken together, these results show that UA inhibits the transactivation effects of PXR and CAR, and reduces the expression and function of CYP3A4 and CYP2B6.

CONCLUSION

The present study suggests that UA could be a powerful agent for reducing potentially dangerous interactions between transcriptional inducers of CYP enzymes and therapeutic drugs.

Cancer chemoprevention revisited: Cytochrome P450 family 1B1 as a target in the tumor and the microenvironment

Cancer chemoprevention is the use of synthetic, natural or biological agents to prevent or delay the development or progression of malignancies. Intriguingly, many phytochemicals with anti-inflammatory and anti-angiogenic effects, recently proposed as chemoprevention strategies, are inhibitors of Cytochrome P450 family 1B1 (CYP1B1), an enzyme overexpressed in a wide variety of tumors and associated with angiogenesis. In turn, pro-inflammatory cytokines were reported to boost CYP1B1 expression, suggesting a key role of CYP1B1 in a positive loop of inflammatory angiogenesis. Other well-known pro-tumorigenic activities of CYP1B1 rely on metabolic bioactivation of xenobiotics and steroid hormones into their carcinogenic derivatives. In contrast to initial in vitro observations, in vivo studies demonstrated a protecting role against cancer for the other CYP1 family members (CYP1A1 and CYP1A2), suggesting that the specificity of CYP1 family inhibitors should be carefully taken into account for developing potential chemoprevention strategies. Recent studies also proposed a role of CYP1B1 in multiple cell types found within the tumor microenvironment, including fibroblasts, endothelial and immune cells. Overall, our review of the current literature suggests a positive loop between inflammatory cytokines and CYP1B1, which in turn may play a key role in cancer angiogenesis, acting on both cancer cells and the tumor microenvironment. Strategies aiming at specific CYP1B1 inhibition in multiple cell types may translate into clinical chemoprevention and angioprevention approaches.

In vivo pharmacokinetic interaction by ethanolic extract of Gymnema sylvestre with CYP2C9 (Tolbutamide), CYP3A4 (Amlodipine) and CYP1A2 (Phenacetin) in rats

Gymnema sylvestre (GS) is a medicinal herb used for diabetes mellitus (DM). Herbs are gaining popularity as medicines in DM for its safety purpose. The aim of the present study was to evaluate in vivo pharmacokinetic (PK) interaction between allopathic drugs tolbutamide (TOLBU), amlodipine (AMLO), and phenacetin (PHENA) at low (L) and high (H) doses with ethanolic extract (EL) from GS. EL was extracted and subjected to TLC, total triterpenoid content (19.76 ± 0.02 W/W) and sterol content (0.1837 ± 0.0046 W/W) estimation followed by identification of phytoconstituents using HRLC-MS and GC-MS. PK interaction study with CYP2C9, CYP3A4 and CYP1A2 enzymes were assessed using TOLBU, AMLO and PHENA respectively to index cytochrome (CYP) mediated interaction in rats after concomitant administration of EL extract (400 mg/kg) from GS for 7 days. The rats were divided into four groups for each PK study where, group I and II were positive control for low and high dose of test drugs (CYP substrates) while group II and IV were orally administered EL. The PK study result of PHENA indicated that area under the plasma concentration-time curve (AUC_0-24) was significantly (P < 0.0001) increased by 1.4 (L) and 1.3-fold (H), plasma concentration (C_max) was significantly (P < 0.001) increased by 1.6 (L) and 1.4-fold (H). Whereas for TOLBU; clearance rate (CL) was significantly (P < 0.0001) decreased by 2.4 (L) and 2.3-fold (H), C_max, was significantly (P < 0.001) decreased by 26.5% (L) and 50.4% (H) and AUC_0-24 was significantly (P < 0.0001) decreased by 59.8% (L) and 57.5% (H). Thus, EL is seen to be interacting with CYP1A2 by inhibiting its metabolic activity. HRLC-MS and GC-MS helped identify the presence of gymnemic acid (GA), triterpenoids and steroids in EL which could be the reason for PK interaction of CYP1A2 and CYP2C9. Also, in silico structure based site of metabolism study showed Fe accessibility and intrinsic activity for GA-IV, GA-VI, GA-VII and GA-X with CYP2C9. PK parameters of AMLO were not significantly affected by pre-treatment of EL. Thereby our findings indicate that co-administration of GS with drugs that are metabolized by CYP2C9 and CYP1A2 could lead to potential HDI.

Polymeric nanoparticles developed by vitamin E-modified aliphatic polycarbonate polymer to promote oral absorption of oleanolic acid

Oleanolic acid (OA) exhibited good pharmacological activities in the clinical treatment of hypoglycemia, immune regulation, acute jaundice and chronic toxic hepatitis. However, the oral delivery of OA is greatly limited by its inferior water solubility and poor intestinal mucosa permeability. Herein, we developed a novel polymeric nanoparticle (NP) delivery system based on vitamin E modified aliphatic polycarbonate (mPEG-PCC-VE) to facilitate oral absorption of OA. OA encapsulated mPEG-PCC-VE NPs (OA/mPEG-PCC-VE NPs) showed uniform particle size of about 170 nm with high drug loading capability (8.9%). Furthermore, the polymeric mPEG-PCC-VE NPs, with good colloidal stability and pH-sensitive drug release characteristics, significantly enhanced the in vitro dissolution of OA in the alkaline medium. The in situ single pass intestinal perfusion (SPIP) studies performed on rats demonstrated that the OA/mPEG-PCC-VE NPs showed significantly improved permeability in the whole intestinal tract when compared to OA solution, especially for duodenum and colon. As a result, the in vivo pharmacokinetics study indicated that the bioavailability of OA/mPEG-PCC-VE NPs showed 1.5-fold higher than commercially available OA tablets. These results suggest that mPEG-PCC-VE NPs are a promising platform to facilitate the oral delivery of OA.

Oleanolic Acid-Mediated Inhibition of Pregnane X Receptor and Constitutive Androstane Receptor Attenuates Rifampin-Isoniazid Cytotoxicity

Interactions between transcriptional inducers of cytochrome P450 (CYP450) and pharmacological agents might decrease drug efficacy and induce side effects. Such interactions could be prevented using an antagonist of the pregnane X receptor (PXR) and constitutive androstane receptor (CAR). Here, we aimed to determine the antagonistic effect of oleanolic acid (OA) on PXR and CAR. OA attenuated the promoter activities, expressions, and enzyme catalytic activities of CYP3A4 and CYP2B6 mediated by rifampin (RIF) and CITCO. Moreover, OA displayed species specificity for rodent PXR. Interaction of coregulators with PXR and transcriptional complexes on the CYP3A4 promoter was disrupted by OA. Additionally, OA reversed the cytotoxic effects of isoniazid induced by RIF. These data demonstrate that OA inhibited the transactivation of PXR and CAR, reduced the expression and function of CYP3A4 and CYP2B6, and may therefore serve as an effective agent for reducing probability adverse interactions between transcriptional inducers of CYP450 and therapeutic drugs.

Interactions between erythromycin, flunixin meglumine, levamisole and plant secondary metabolites towards bovine gastrointestinal motility-in vitro study

Continued ingestion of plant secondary metabolites by ruminants can provoke pharmacological interactions with pharmaceutical agents used in animals. As some drugs and phytocompounds affect smooth muscle activity, the aim of this study was to verify the possible interaction between selected pharmaceutical agents and plant secondary metabolites towards bovine gastrointestinal motility. The interactions between phytocompounds-apigenin, quercetin, hederagenin, medicagenic acid-and medicines-erythromycin, flunixin meglumine and levamisole-were evaluated on bovine isolated abomasal and duodenal specimens obtained from routinely slaughtered cows. The obtained results confirmed the contractile effect of all three drugs used solely. Hederagenin and medicagenic acid (0.001 μM) enhanced the contractile effect of levamisole. Hederagenin additionally increased the impact of erythromycin. Both saponins (100 μM) showed synergistic effects with all tested pharmaceuticals. Apigenin and quercetin (0.001 μM) intensified the contractile response induced by erythromycin and levamisole. Moreover, both flavonoids (100 μM) showed an antagonistic interaction with all tested drugs which in that situation were devoid of the prokinetic effect. To conclude, plant metabolic metabolites such as saponins and flavonoids are potent modifiers of the effect of drugs towards gut motility. The synergy observed between phytocompounds and selected medicines can be beneficial in the treatment of cows with hypomotility disorders.

In vitro inhibition of UGT1A3, UGT1A4 by ursolic acid and oleanolic acid and drug-drug interaction risk prediction

1. Ursolic acid (UA) and oleanolic acid (OA) may have important activity relevant to health and disease prevention. Thus, we studied the activity of UA and OA on UDP-glucuronosyltransferases (UGTs) and used trifluoperazine as a probe substrate to test UGT1A4 activity. Recombinant UGT-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was used as a probe reaction for other UGT isoforms. 2. UA and OA inhibited UGT1A3 and UGT1A4 activity but did not inhibit other tested UGT isoforms. 3. UA-mediated inhibition of UGT1A3 catalyzed 4-MU-β-d-glucuronidation was via competitive inhibition (IC50 0.391 ± 0.013 μM; Ki 0.185 ± 0.015 μM). UA also competitively inhibited UGT1A4-mediated trifluoperazine-N-glucuronidation (IC50 2.651 ± 0.201 μM; Ki 1.334 ± 0.146 μM). 4. OA offered mixed inhibition of UGT1A3-mediated 4-MU-β-d-glucuronidation (IC50 0.336 ± 0.013 μM; Ki 0.176 ± 0.007 μM) and competitively inhibited UGT1A4-mediated trifluoperazine-N-glucuronidation (IC50 5.468 ± 0.697 μM; Ki 6.298 ± 0.891 μM). 5. Co-administering OA or UA with drugs or products that are substrates of UGT1A3 or UGT1A4 may produce drug-mediated side effects.

A smart pH-responsive nano-carrier as a drug delivery system for the targeted delivery of ursolic acid: suppresses cancer growth and metastasis by modulating P53/MMP-9/PTEN/CD44 mediated multiple signaling pathways

Ursolic acid (UA) has been recently used as a promising anti-tumor and cancer metastatic chemo-preventive agent due to its low toxicity and liver-protecting property. However, the low bioavailability and nonspecific tumor targeting restrict its further clinical application. To address the problem, a silica-based mesoporous nanosphere (MSN) controlled-release drug delivery system (denoted UA@M-CS-FA) was designed and successfully synthesized, and was functionalized with folic acid (FA) and pH-sensitive chitosan (CS) for the targeted delivery of UA to folate receptor (FR) positive tumor cells. UA@M-CS-FA were spherical with mean diameter below 150 nm, and showed about -20 mV potential. Meanwhile, UA@M-CS-FA exhibited a pH-sensitive release manner and high cellular uptake in FR over-expressing HeLa cancer cells. Also, in vitro cellular assays suggested that UA@M-CS-FA inhibited cancer cell growth, invasion and migration. Mechanistically, UA@M-CS-FA induced cancer cell apoptosis and inhibited migration via cell cycle arrest in the G0/G1 stage, regulating the PARP/Bcl-2/MMP-9/CD44/PTEN/P53. Importantly, in vivo experiments further confirmed that UA@M-CS-FA significantly suppressed the tumor progression and lung metastasis in tumor-bearing nude mice. Immunohistochemical analysis revealed that UA@M-CS-FA treatment regulated CD44, a biomarker of cancer metastasis. Overall, our data demonstrated that a CS and FA modified MSN controlled-release drug delivery system could help broaden the usage of UA and reflect the great application potential of the UA as an anticancer or cancer metastatic chemopreventive agent.

The antioxidant, cytotoxic, and antigenotoxic effects of galangin, puerarin, and ursolic acid in mammalian cells

Phenolic compounds not only contribute to the sensory qualities of fruits and vegetables but also exhibit several health protective properties. Galangin, puerarin, and ursolic acid are commonly used plant phenolics in folk medicine. In this study, the antioxidant capacities of galangin, puerarin, and ursolic acid by the trolox equivalent antioxidant capacity (TEAC) assay and the cytotoxic effects by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in V79 cells were investigated. The genotoxic potentials of galangin, puerarin, and ursolic acid were evaluated by micronucleus (MN) and alkaline COMET assays in human lymphocytes and in V79 cells. Galangin, puerarin, and ursolic acid (10, 100, 500, 1000, 2000, 5000, 10 000, and 20 000 μM) were found to have antioxidant activities at the studied concentrations. IC50 values of galangin, puerarin, and ursolic acid in V79 cells were found to be 275.48 μM, 2503.712 μM, and 224.85 μM, respectively. Galangin, puerarin, and ursolic acid, at the all concentrations, have not exerted genotoxic effects and galangin, puerarin, and ursolic acid revealed a reduction in the frequency of MN and DNA damage induced by H2O2.

β-Amyrin, a pentacyclic triterpene, exhibits anti-fibrotic, anti-inflammatory, and anti-apoptotic effects on dimethyl nitrosamine–induced hepatic fibrosis in male rats

Hepatic fibrosis is a leading cause of morbidity and mortality worldwide. Attenuation of fibrogenic process can significantly lower the mortality rate. However, pharmaceutical intervention at fibrogenesis stage remains a major task in medicine. So there is a need for a natural compound to treat hepatic fibrosis. This study was outlined to investigate the anti-fibrotic effect of β-amyrin in dimethylnitrosamine (DMN)-induced hepatic fibrosis male rats. Serum liver function markers (aspartate transaminase, alanine transaminase, alkaline phosphatase and lactate dehydrogenase), oxidative stress markers (malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase, glutathione reduced content and vitamin C), tissue inflammatory marker (tumor necrosis factor α (TNF-α)), apoptosis marker (caspase 3) and fibrolytic marker (tissue inhibitor of metalloproteinase 1 (TIMP-1)) were evaluated before and after β-amyrin treatment in DMN-induced rat. β-Amyrin treatment attenuated the altered levels of the serum enzyme markers produced by DMN and caused a subsequent recovery toward normalization. Oxidative stress markers and TNF-α levels were reduced significantly ( p < 0.001) as well as proteins’ (caspase-3 and TIMP-1) expression was reduced in β-amyrin –treated DMN rats. By virtue of β-amyrin properties of inhibiting oxidative stress, apoptosis, inflammation, and fibrogenesis, it might act as an ideal anti-inflammatory and anti-fibrogenic agent to halt the progression of liver fibrosis to chronicity.

The inhibitory effects of nor-oleanane triterpenoid saponins from Stauntonia brachyanthera towards UDP-glucuronosyltransferases

The inhibition of UDP-glucuronosyltransferases (UGTs) by herbal components might be an important reason for clinical herb-drug interaction (HDI). The inhibitory effects on UGTs via nor-oleanane triterpenoid saponins, which were the bioactive ingredients from Stauntonia brachyanthera, a traditional Chinese folk medicines with highly biological values, were evaluated comprehensively with recombinant UGT isoforms as enzyme source and a nonspecific substrate 4-methylumbelliferone (4-MU) as substrate. The results showed that there are seven compounds, 2, 3, 4, 8, 9, 13 and 14, respectively, exhibited potential inhibitions towards UGT1A1, UGT1A3 and UGT1A10 among all 23 compounds isolated from the plants. The IC50 values were 17.1μM, 13.5μM, 9.5μM, 15.7μM, 16.3μM, 1.1μM, and 0.3μM, respectively. Data fitting using Dixon and Lineweaver-Burk plots demonstrated that the inhibition of UGT1A10, UGT1A1 and UGT1A3 was best fit to noncompetitive type and competitive, respectively. The inhibition kinetic parameter (Ki) was calculated to be 39μM, 17μM, 3.3μM, 10μM, 9.3μM, 0.19μM, and 0.016μM, respectively. All these experimental data suggested that HDI might occur when compounds containing herbs were co-administered with drugs which mainly undergo UGTs-mediated metabolism.

Oleanolic Acid Prevents Increase in Blood Pressure and Nephrotoxicity in Nitric Oxide Dependent Type of Hypertension in Rats

Background:

Recently, we have reported antihypertensive activity of oleanolic acid (OA) in glucocorticoid-induced hypertension with restoration of nitric oxide (NO) level. However, the involvement of NO-releasing action of OA was unclear.

Objective:

To explore antihypertensive activity of OA in N^ω-nitro-L-arginine methyl ester (L-NAME) hypertensive rats wherein NO is completely blocked, which would allow exploring the possibility of involvement of NO-releasing action of OA.

Materials and Methods:

Five groups of rats were investigated as normal control, L-NAME (40 mg/kg/day), L-NAME + enalapril (15 mg/kg/day), L-NAME + l-arginine (100 mg/kg/day), and L-NAME + OA (60 mg/kg/day) for 4 weeks. The systolic blood pressure, body weight, and heart rate were measured weekly for 4 weeks. Serum nitrate/nitrite (NOx) level, urine electrolytes concentration, cardiac mass index, and serum creatinine level were determined followed by organ histopathology.

Results:

OA and enalapril delayed the rise in blood pleasure following L-NAME administration. Decreased serum NOx level was not significantly increased with any of the treatment. OA produced a small, though nonsignificant, increase in the NOx level. L-NAME administration did not affect cardiac mass index. There was an increase in serum creatinine upon L-NAME administration which was prevented by OA. Decreased urine volume, urine sodium and potassium were reversed by OA.

Conclusion:

These results suggest that the antihypertensive effect of OA in L-NAME hypertension is due to diuresis and nephroprotection. However, OA has nonsignificantly affected the NO levels.

Transdermal potential and anti-arthritic efficacy of ursolic acid from niosomal gel systems

The aim of the present study was to optimize niosomes by experimental design for enhanced transdermal delivery of ursolic acid for the effective treatment of arthritis. The experimental design (3 factor 3 levels, Box-Behnken design) was used to study individual and combined effects of different formulation variables. The variables cholesterol (X1), span 60 (X2) and phospholipid (X3) were taken as independent factors and their effect was observed on size (Y1) entrapment efficiency (Y2), and transflux (Y3). The formulation composition with span 60 (85mg), cholesterol (12.3mg), and phospholipid (65mg) was found to fulfil requisites of optimized ursolic acid niosome formulation (URNF). URNF had shown vesicle size of 665.45nm, entrapment efficiency of 92.74% with transflux of 17.25μg/cm(2)/h. The in vivo bioactivity showed that the prepared URNF-gel was able to provide good anti-arthritic activity due to enhanced permeation of UA through the skin and results were found to be comparable to standard gel (Omni gel). The radiographical image confirmed that, the developed URNF-gel was found to be effective to treat arthritis. Thus niosomal gel of ursolic acid would be a promising alternative to conventional therapy for safe and efficient treatment of arthritis and musculoskeletal disorders.