Determination of oleanolic acid in human plasma and study of its pharmacokinetics in Chinese healthy male volunteers by HPLC tandem mass spectrometry

Network pharmacology of Epilobium angustifolium metabolites in relation to in vitro analyses of its extracts

Epilobium angustifolium L. is a perennial herbaceous plant known for various therapeutic properties, however its biological activity is not fully explored. In this study, we examined antioxidant activities of extracts of different polarity (n-hexane, ethyl acetate and 70 % ethanol in water) and their potential to inhibit amylase, glucosidase, tyrosinase, acetylcholinesterase and butyrylcholinesterase, as well as cytotoxic effects. Moreover, phytochemical analysis performed with liquid chromatography-mass spectrometry (LC-ESI-QTOF-MS) revealed the presence of hydrolysable tannins (gallotannins and ellagitannins), flavonoids, phenolic acids derivatives and esters of saccharides, triterpenoids and lipids. The aqueous-ethanolic extract exhibited the best radical scavenging and reducing abilities. The identified compounds in the extracts were subjected to Disease Ontology enrichment analysis and screening of potential targets, which identified significant associations with colon carcinoma and gastric adenocarcinoma. The predicted cytotoxicity was checked against cancerous and non-cancerous cell lines. The E. angustifolium aqueous-ethanolic extract showed weak cytotoxicity on non-cancerous monkey kidney fibroblasts (VERO cells) and moderate cytotoxicity against cancer-derived cells (malignant melanoma, human gastric adenocarcinoma, human hypopharyngeal squamous cell carcinoma, human colon cancer), with the highest toxicity and cytotoxic selectivity observed for hypopharyngeal (CC50 = 37.52 μg/mL, SI = 6.39) and colon (CC50 = 37.27 μg/mL, SI = 6.43) cancer-derived cells. Key drug targets were identified using CTD, STRING, GeneCards, and DisGeNET databases, followed by protein-protein interaction network analysis. Molecular docking using AutoDock Vina revealed that compounds gemin D and hamamelitannin demonstrated strong binding affinities with cancer-related proteins. These findings revealed the potential of indicated molecules as anti-proliferative agents and suggest the need for further research to optimize their efficacy.

Monotherapy or Combination Therapy of Oleanolic Acid? From Therapeutic Significance and Drug Delivery to Clinical Studies: A Comprehensive Review

Oleanolic acid is a pentacyclic triterpenoid molecule widely distributed throughout medicinal plants. This naturally occurring oleanolic acid has attracted considerable interest due to its wide range of pharmacological characteristics, notably its cytotoxic effects on various human cancer cell lines, making it a potential candidate for extensive therapeutic uses. In vivo studies have shown that oleanolic acid possesses hepatoprotective, cardioprotective, anti-inflammatory, and antimicrobial properties. The inherent obstacles of oleanolic acid, such as low permeability, limited bioavailability, and poor water solubility, have restricted its therapeutic applicability. However, recent developments in drug delivery techniques have given oleanolic acid an additional advantage by overcoming issues with its solubility, stability, and bioavailability. This review briefly summarises the signalling pathways involved in the pharmacological activities of oleanolic acid as a monotherapy and in combination with other drugs. The review devotes a substantial portion to explaining the formulation developments, emphasising nanotechnology as a key factor in the improvement of the therapeutic potential of oleanolic acid. Several investigated novel formulations have been discussed, including liposomes, nanoemulsions, phospholipids, and polymeric nanoparticles, emerging synergistically as an efficient delivery of oleanolic acid and several other drugs. Based on our literature evaluation, it can be inferred that combination therapy had a more favourable outcome than using oleanolic acid alone in in vivo trials, primarily due to its synergistic effects. However, it is essential to note that this finding was inconsistent across all investigations. The combination of oleanolic acid with other drugs has not yet been considered for clinical trials. However, it is interesting that neither therapy has obtained approval from the U. S. Food and Drug Administration.

Pluronics® F68 and D-α-tocopheryl polyethylene glycol succinate 1000 tailored self-assembled mixed micelles to improve oral bioavailability of oleanolic acid: in vitro and in vivo characterization

Oleanolic acid (OA) ischaracterized by its low water solubility, poor permeability and majorly metabolized by cytochrome P450 (CYP) isozymes in the intestinal tract, particularly CYP3A, which contribute to the low oral bioavailability. OA has multiple pharmacological actions including hepatoprotective, anti-inflammatory, antidiabetic and antiviral effects. OA classified as a BCS IV drug which have restricted its potential clinical application. In this study D-α-Tocopheryl polyethylene glycol succinate (TPGS) and Pluronics F68 based stabilized OA loaded mixed micellar system (OA-MMs) developed to improve the solubility and permeability. Mixed micelles were characterized by dynamic light scattering studies as a function of temperature, salt addition, and OA solubilisation followed byXRD, FE-SEM and IR analysis confirmed the formation of stabilized OA-MMs with the least size and PDI (10.041 ± 1.35 nm, 0.313 ± 0.012). Scattering studies results demonstrates the formation of stable micelles with no significant alterations insize upon salt addition (up to 150mM NaCl), OA incorporation (up to 150 mM) and temperature rise till 40 °C.Solubility of the pure OA and OA-MMs was found to be 0.042 mg/ml and 1.98 mg/ml. The % cumulative release of drug from alone OA, OA + TPGS and OA-MMs was found to be 4.363 ± 0.025%, 57.18 ± 0.034% and 92.269 ± 0.017% respectively up to 24 h. Single-pass intestinal perfusion studies (SPIP) showed that Ka and Peffective of OA-MMs was improved30 fold as compared with that of pure OA and this was mainly due to the improved permeability and inhibitory effect of Pluronic F68 on CYP3A. The in vivo Pharmacokinetic study showed that Cmax increased markedly from 12.76 to 20.49 and 39.17 µg/ml in case of OA alone, OA + TPGS and OA-MMs. Parallel to the Cmax there was an increase in the AUC0-24133.68 to 164.56 and 296.50 respectively. All of the produced OA-MMs formulation's results demonstrated a notable increase in OA's bioavailability through increased permeability and solubility along with metabolic inhibition OA.

Bioavailability of Supplemented Free Oleanolic Acid and Cyclodextrin-Oleanolic Acid in Growing Pigs, and Effects on Growth Performance, Nutrient Digestibility and Plasma Metabolites

Oleanolic acid (OLA) has beneficial health effects in animals, but in vivo efficacy in monogastric animals is questioned due to its low bioavailability. To gain further insight on the nutritional effects of OLA it was administered as part of a diet. We investigated digestibility and plasma OLA in pigs and the associated influence on growth, organs, digestibility of nutrients and plasma biochemical profile. Twenty-four crossbred barrows (23.7 ± 1.0 kg BW) were assigned one of three treatments: Control (basal diet without OLA), OLA-1 (basal diet with 260 mg/free OLA) and OLA-2 (basal diet with 260 mg/kg cyclodextrin-OLA). Diets included chromium oxide to estimate digestibility. Blood samples were collected on day 14 for OLA analysis and feces on days 22-24 for determining digestibility. Pigs were slaughtered on day 31 (39.9 ± 2.43 kg BW) and their blood collected for analysis. Growth and organ weights were not affected (p > 0.05). OLA-1 decreased apparent total tract digestibility (ATTD) of energy (p < 0.05). OLA-2 increased ATTD of dry and organic matter compared with Control pigs (p < 0.05). OLA-1 increased plasma calcium and alkaline phosphatase (p < 0.05). Ileal digestibility of OLA was not affected (0.88), although OLA ATTD increased in OLA-1 compared to Control pigs (0.75 vs. 0.82; p < 0.05). OLA-1 and OLA-2 increased plasma OLA compared to Control pigs (p < 0.05 and p = 0.083). In conclusion, although the OLA was digested and absorbed, plasma concentration was low (4.29 µg/L), and pig growth, organs and plasma parameters were not affected.

Interactions of oleanane pentacyclic triterpenoids with human organic anion transporting polypeptide 1B1 and 1B3

Oleanane pentacyclic triterpenoids have been widely used in clinical practice. However, studies on their interactions with hepatic transporters remain limited. In this study, we systematically investigated the inhibitory effects of 14 oleanane pentacyclic triterpenoids on organic anion transporting polypeptide 1B1 and 1B3 (OATP1B1 and OATP1B3), two liver-specific uptake transporters. Through fluorescence-based cellular uptake assays, we identified three potent OATP1B1 inhibitors (saikosaponin B1, saikosaponin A and 18β-glycyrrhetinic acid) and five potent OATP1B3 inhibitors (echinocystic acid, 3-oxo-16α-hydroxy-olean-12-en-28β-oic acid, chikusetsu saponin IVa, saikosaponin B1 and 18β-glycyrrhetinic acid). Structural analysis revealed that free oleanane triterpenoids inhibited OATP1B1/1B3 more potently than triterpene glycosides. Despite their similar structures, 18β-glycyrrhetinic acid exhibited much stronger inhibition on OATP1B1/1B3 than 18α-glycyrrhetinic acid, while both were substrates of OATP1B3. Interestingly, OATP1B3 overexpression significantly increased reactive oxygen species (ROS) levels in HepG2 cells after treatment with 18β-glycyrrhetinic acid. To conclude, this study highlights the potential interactions of oleanane pentacyclic triterpenoids with OATP1B1/1B3, and provides novel insights into the anti-cancer activity of 18β-glycyrrhetinic acid.

Oleanolic acid and its analogues: promising therapeutics for kidney disease

Kidney diseases pose a significant threat to human health due to their high prevalence and mortality rates. Worryingly, the clinical use of drugs for kidney diseases is associated with more side effects, so more effective and safer treatments are urgently needed. Oleanolic acid (OA) is a common pentacyclic triterpenoid that is widely available in nature and has been shown to have protective effects in kidney disease. However, comprehensive studies on its role in kidney diseases are still lacking. Therefore, this article first explores the botanical sources, pharmacokinetics, derivatives, and safety of OA, followed by a summary of the anti-inflammatory, immunomodulatory, anti-oxidative stress, autophagy-enhancing, and antifibrotic effects of OA and its analogues in renal diseases, and an analysis of the molecular mechanisms, aiming to provide further insights for the development of novel drugs for the treatment of kidney diseases.

Oleanolic acid exerts bone anabolic effects via activation of osteoblastic 25-hydroxyvitamin D 1-alpha hydroxylase

Oleanolic acid (OA) is previously shown to exert bone protective effects in aged animals. However, its role in regulating osteoblastic vitamin D bioactivation, which is one of major causes of age-related bone loss, remains unclear. Our results revealed that treatment of OA significantly increased skeletal CYP27B1 expression and circulating 1,25(OH)2D3 in ovariectomized mice (p <0.01). Moreover, OA upregulated CYP27B1 protein expression and activity, as well as the vitamin D-responsive bone markers alkaline phosphatase (ALP) activity and osteopontin (OPN) protein expression, in human osteoblast-like MG-63 cells (p<0.05). CYP27B1 expression increased along with the osteoblastic differentiation of human bone marrow derived mesenchymal stem cells (hMSCs). CYP27B1 expression and cellular 1,25(OH)2D3 production were further potentiated by OA in cells at mature osteogenic stages. Notably, our study suggested that the osteogenic actions of OA were CYP27B1 dependent. In summary, the bone protective effects of OA were associated with the induction of CYP27B1 activity and expression in bone tissues and osteoblastic lineages. Hence, OA might be a potential approach for management of age-related bone loss.

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

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

Bioavailability and systemic transport of oleanolic acid in humans, formulated as a functional olive oil

Evidence of the pharmacological activity of oleanolic acid (OA) suggests its potential therapeutic application. However, its use in functional foods, dietary supplements, or nutraceuticals is hindered by limited human bioavailability studies. The BIO-OLTRAD trial is a double-blind, randomized controlled study with 22 participants that received a single dose of 30 mg OA formulated as a functional olive oil. The study revealed that the maximum serum concentration of OA ranged from 500 to 600 ng mL-1, with an AUC0-∞ value of 2862.50 ± 174.50 ng h mL-1. Furthermore, we discovered a physiological association of OA with serum albumin and triglyceride-rich lipoproteins (TRL). UV absorption spectra showed conformational changes in serum albumin due to the formation of an adduct with OA. Additionally, we demonstrated that TRL incorporate OA, reaching a maximum concentration of 140 ng mL-1 after 2-4 hours. We conjecture that both are efficient carriers to reach target tissues and to yield high bioavailability.

Pentacyclic Triterpenes from Olive Leaves Formulated in Microemulsion: Characterization and Role in De Novo Lipogenesis in HepG2 Cells

Olea europaea L. leaves contain a wide variety of pentacyclic triterpenes (TTPs). TTPs exhibit many pharmacological activities, including antihyperlipidemic effects. Metabolic alterations, such as dyslipidemia, are an established risk factor for hepatocellular carcinoma (HCC). Therefore, the use of TTPs in the adjunctive treatment of HCC has been proposed as a possible method for the management of HCC. However, TTPs are characterized by poor water solubility, permeability, and bioavailability. In this work, a microemulsion (ME) loading a TTP-enriched extract (EXT) was developed, to overcome these limits and obtain a formulation for oral administration. The extract-loaded microemulsion (ME-EXT) was fully characterized, assessing its chemical and physical parameters and release characteristics, and the stability was evaluated for two months of storage at 4 °C and 25 °C. PAMPA (parallel artificial membrane permeability assay) was used to evaluate the influence of the formulation on the intestinal passive permeability of the TTPs across an artificial membrane. Furthermore, human hepatocarcinoma (HepG2) cells were used as a cellular model to evaluate the effect of EXT and ME-EXT on de novo lipogenesis induced by elevated glucose levels. The effect was evaluated by detecting fatty acid synthase expression levels and intracellular lipid accumulation. ME-EXT resulted as homogeneous dispersed-phase droplets, with significantly increased EXT aqueous solubility. Physical and chemical analyses showed the high stability of the formulation over 2 months. The formulation realized a prolonged release of TTPs, and permeation studies demonstrated that the formulation improved their passive permeability. Furthermore, the EXT reduced the lipid accumulation in HepG2 cells by inhibiting de novo lipogenesis, and the ME-EXT formulation enhanced the inhibitory activity of EXT on intracellular lipid accumulation.

Mesoporous Silica Nanoparticles as a Gene Delivery Platform for Cancer Therapy

Cancer remains a major global health challenge. Traditional chemotherapy often results in side effects and drug resistance, necessitating the development of alternative treatment strategies such as gene therapy. Mesoporous silica nanoparticles (MSNs) offer many advantages as a gene delivery carrier, including high loading capacity, controlled drug release, and easy surface functionalization. MSNs are biodegradable and biocompatible, making them promising candidates for drug delivery applications. Recent studies demonstrating the use of MSNs for the delivery of therapeutic nucleic acids to cancer cells have been reviewed, along with their potential as a tool for cancer therapy. The major challenges and future interventions of MSNs as gene delivery carriers for cancer therapy are discussed.

Safety evaluation and bioassay-guided isolation of antimycobacterial compounds from Morella salicifolia root ethanolic extract

ETHNOPHARMACOLOGICAL RELEVANCE

Although the available medicines can cure almost all tuberculosis drug-susceptible patients some problems including the emergence of multi-drug resistant and extensively drug-resistant strains press for the need of new anti-TB medicines. Morella salicifolia is a common plant that is widely used in traditional medicine for managing HIV and AIDS-related conditions including tuberculosis but no studies have been done to evaluate its safety and efficacy.

AIM OF THE STUDY

This study was designed to investigate the antimycobacterial activity and safety of M. salicifolia extract and its constituents.

MATERIAL AND METHODS

Antimycobacterial activity of the crude extract was tested against non-pathogenic mycobacteria including Mycobacterium aurum (MA), Mycobacterium indicus pranii (MIP) and Mycobacterium madagascariense (MM) using the broth microdilution method. Bioassay-guided fractionation was employed to isolate the active compounds. Some of the isolated active compounds were tested for antimycobacterial activity against the standard and selected clinical isolates of M. tuberculosis. Safety of the crude extract was assessed using cytotoxicity assay and oral acute toxicity testing.

RESULTS

The crude extract exhibited antimycobacterial activity against all the species used. The study led to isolation of six compounds; four pentacyclic triterpenoids; (3β)-3-Hydroxyolean-12-en-28-oic acid (Oleanolic acid) (1), (2α,3β)-2,3-Dihydroxyolean-12-en-28-oic acid (maslinic acid) (2), D-Friedoolean-14-ene-3β,28-diol (taraxerol) (3), and D-Friedoolean-14-en-3β-ol (myricadiol) (4), and two diarylheptanoids; (±)-myricanol (5) and myricanone (6). The six compounds exhibited activity against three nonpathogenic mycobacteria species. Compound 2, was the most active, with MICs of 17, 28 and 56 μg/ml against MM, standard a M. tuberculosis strain H₃₇RV and rifampicin resistant M. tuberculosis clinical isolates, respectively. The crude extract did not show toxicity on peripheral blood mononuclear cells and it was safe in mice following acute oral toxicity test.

CONCLUSION

The results from this study indicate that some isolated compounds in Morella salicifolia could form potential scaffolds for drug development efforts targeting M. tuberculosis. More studies are needed to further explore the potential of the plant extract and its secondary metabolites in the management of HIV and AIDS-related conditions using in-vivo models.

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.

Oleanolic Acid: Extraction, Characterization and Biological Activity

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

Two New Pentacyclic Triterpenoids, an Alkaloid and a Long-chain Fatty Acid from Albizia Coriaria (Welw ex. Oliver)

Herein, we report the occurrence of four new compounds in ethanolic extract of Albizia coriaria Welw ex. Oliver leaves along with other compounds previously reported in this species. The compounds were isolated and characterized using column chromatography, Fourier Transform Infrared (FTIR) and gas chromatography/mass spectrometry. FTIR spectrum of the extract showed phenolic OH stretching (3362.30 cm-1), C=O (1660.08 cm-1), CO stretching (1369.46 cm-1 and 1319.00 cm-1) and CN stretch (1072.44 cm-1) which confirmed the presence of alcohols, carboxylic acids and nitrogen-containing compounds. Oleanolic acid (1), oleanolic acid acetate (2), pterin-6-carboxylic acid (3), undecanol (4), betulinic acid (5), betulin (6) and benzyl alcohol (7) were tentatively identified in the extract. Compounds 1-4 are being reported for the first time in Albizia coriaria.

Shenjinhuoxue Mixture Attenuates Inflammation, Pain, and Cartilage Degeneration by Inhibiting TLR-4 and NF-κB Activation in Rats with Osteoarthritis: A Synergistic Combination of Multitarget Active Phytochemicals

Osteoarthritis (OA), a highly prevalent chronic joint disease, involves a complex network of inflammatory mediators that not only triggers pain and cartilage degeneration but also accelerates disease progression. Traditional Chinese medicinal shenjinhuoxue mixture (SHM) shows anti-inflammatory and analgesic effects against OA with remarkable clinical efficacy. This study explored the mechanism underlying anti-OA properties of SHM and evaluated its efficacy and safety via in vivo experiments. Through network pharmacology and published literature, we identified the key active phytochemicals in SHM, including β-sitosterol, oleanolic acid, licochalcone A, quercetin, isorhamnetin, kaempferol, morusin, lupeol, and pinocembrin; the pivotal targets of which are TLR-4 and NF-κB, eliciting anti-OA activity. These phytochemicals can enter the active pockets of TLR-4 and NF-κB with docking score ≤ -3.86 kcal/mol, as shown in molecular docking models. By using surface plasmon resonance assay, licochalcone A and oleanolic acid were found to have good TLR-4-binding affinity. In OA rats, oral SHM at mid and high doses (8.72 g/kg and 26.2 g/kg) over 6 weeks significantly alleviated mechanical and thermal hyperalgesia (P < 0.0001). Accordingly, the expression of inflammatory mediators (TLR-4, interleukin (IL-) 1 receptor-associated kinase 1 (IRAK1), NF-κB-p65, tumor necrosis factor (TNF-) α, IL-6, and IL-1β), receptor activator of the NF-κB ligand (RANKL), and transient receptor potential vanilloid 1 (TRPV1) in the synovial and cartilage tissue of OA rats was significantly decreased (P < 0.05). Moreover, pathological observation illustrated amelioration of cartilage degeneration and joint injury. In chronic toxicity experiment of rats, SHM at 60 mg/kg demonstrated the safety. SHM had an anti-inflammatory effect through a synergistic combination of active phytochemicals to attenuate pain and cartilage degeneration by inhibiting TLR-4 and NF-κB activation. This study provided the experimental foundation for the development of SHM into a more effective dosage form or new drugs for OA treatment.

Corosolic acid and its structural analogs: A systematic review of their biological activities and underlying mechanism of action

BACKGROUND

The corosolic acid (CA), also known as plant insulin, is a pentacyclic triterpenoid extracted from plants such as Lagerstroemia speciosa. It has been shown to have anti-diabetic, anti-inflammatory and anti-tumor effects. Its structural analogs ursolic acid (UA), oleanolic acid (OA), maslinic acid (MA), asiatic acid (AA) and betulinic acid (BA) display similar individual pharmacological activities to those of CA. However, there is no systematic review documenting pharmacological activities of CA and its structural analogues. This study aims to fill this gap in literature.

PURPOSE

This systematic review aims to summarize the medical applications of CA and its analogues.

METHODS

A systematic review summarizes and compares the extraction techniques, pharmacokinetic parameters, and pharmacological effects of CA and its structural analogs. Hypoglycemic effect is one of the key inclusion criteria for searching Web of Science, PubMed, Embase and Cochrane databases up to October 2020 without language restrictions. 'corosolic acid', 'ursolic acid', 'oleanolic acid', 'maslinic acid', 'asiatic acid', 'betulinic acid', 'extraction', 'pharmacokinetic', 'pharmacological' were used to extract relevant literature. The PRISMA guidelines were followed.

RESULTS

At the end of the searching process, 140 articles were selected for the systematic review. Information of CA and five of its structural analogs including UA, OA, MA, AA and BA were included in this review. CA and its structural analogs are pentacyclic triterpenes extracted from plants and they have low solubilities in water due to their rigid scaffold and hydrophobic properties. The introduction of water-soluble groups such as sugar or amino groups could increase the solubility of CA and its structural analogs. Their biological activities and underlying mechanism of action are reviewed and compared.

CONCLUSION

CA and its structural analogs UA, OA, MA, AA and BA are demonstrated to show activities in lowering blood sugar, anti-inflammation and anti-tumor. Their oral absorption and bioavailability can be improved through structural modification and formulation design. CA and its structural analogs are promising natural product-based lead compounds for further development and mechanistic studies.

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.

Antitumor Effects of Triterpenes in Hepatocellular Carcinoma

BACKGROUND

Triterpenes are a large group of secondary metabolites mainly produced by plants with a variety of biological activities, including potential antitumor effects. Hepatocellular carcinoma (HCC) is a very common primary liver disease spread worldwide. The treatment can consist of surgical intervention, radiotherapy, immunotherapy and chemotherapeutic drugs. These drugs mainly include tyrosine multikinase inhibitors, although their use is limited by the underlying liver disease and displays side effects. For that reason, the utility of natural compounds such as triterpenes to treat HCC is an interesting line of research. No clinical studies are reported in humans so far.

OBJECTIVE

The aim of the present work is to review the knowledge about the effects of triterpenes as a possible coadjuvant tool to treat HCC.

RESULTS

In vitro and xenograft models have pointed out the cytotoxic and anti-proliferative effects as well as improvements in tumor growth and development of many triterpenes. In addition, they have also shown to be chemosensitizing agents when co-administered with chemotherapeutic agents. The mechanisms of action are diverse and involve the participation of mitogen-activated protein kinases, including JNK, p38 MAPK and ERK, and the survival-associated PI3K / Akt signaling pathway. However, no clinical studies are still reported in humans.

CONCLUSION

Triterpenes could become a future strategy to address HCC or at least improve results when administered in combination with chemotherapeutic agents.

The Potential Application of Pentacyclic Triterpenoids in the Prevention and Treatment of Retinal Diseases

Retinal diseases are a leading cause of impaired vision and blindness but some lack effective treatments. New therapies are required urgently to better manage retinal diseases. Natural pentacyclic triterpenoids and their derivatives have a wide range of activities, including antioxidative, anti-inflammatory, cytoprotective, neuroprotective, and antiangiogenic properties. Pentacyclic triterpenoids have great potential in preventing and/or treating retinal pathologies. The pharmacological effects of pentacyclic triterpenoids are often mediated through the modulation of signalling pathways, including nuclear factor erythroid-2 related factor 2, high-mobility group box protein 1, 11β-hydroxysteroid dehydrogenase type 1, and Src homology region 2 domain-containing phosphatase-1. This review summarizes recent in vitro and in vivo evidence for the pharmacological potential of pentacyclic triterpenoids in the prevention and treatment of retinal diseases. The present literature supports the further development of pentacyclic triterpenoids. Future research should now attempt to improve the efficacy and pharmacokinetic behaviour of the agents, possibly by the use of medicinal chemistry and targeted drug delivery strategies.

Ursolic and Oleanolic Acids: Plant Metabolites with Neuroprotective Potential

Ursolic and oleanolic acids are secondary plant metabolites that are known to be involved in the plant defence system against water loss and pathogens. Nowadays these triterpenoids are also regarded as potential pharmaceutical compounds and there is mounting experimental data that either purified compounds or triterpenoid-enriched plant extracts exert various beneficial effects, including anti-oxidative, anti-inflammatory and anticancer, on model systems of both human or animal origin. Some of those effects have been linked to the ability of ursolic and oleanolic acids to modulate intracellular antioxidant systems and also inflammation and cell death-related pathways. Therefore, our aim was to review current studies on the distribution of ursolic and oleanolic acids in plants, bioavailability and pharmacokinetic properties of these triterpenoids and their derivatives, and to discuss their neuroprotective effects in vitro and in vivo.

Pentacyclic Triterpene Profile and Its Biosynthetic Pathway in Cecropia telenitida as a Prospective Dietary Supplement

Promising research over the past decades has shown that some types of pentacyclic triterpenes (PTs) are associated with the prevention of type 2 diabetes (T2D), especially those found in foods. The most abundant edible sources of PTs are those belonging to the ursane and oleanane scaffold. The principal finding is that Cecropia telenitida contains abundant oleanane and ursane PT types with similar oxygenation patterns to those found in food matrices. We studied the compositional profile of a rich PT fraction (DE16-R) and carried out a viability test over different cell lines. The biosynthetic pathway connected to the isolated PTs in C. telenitida offers a specific medicinal benefit related to the modulation of T2D. This current study suggests that this plant can assemble isobaric, positional isomers or epimeric PT. Ursane or oleanane scaffolds with the same oxygenation pattern are always shared by the PTs in C. telenitida, as demonstrated by its biosynthetic pathway. Local communities have long used this plant in traditional medicine, and humans have consumed ursane and oleanane PTs in fruits since ancient times, two key points we believe useful in considering the medicinal benefits of C. telenitida and explaining how a group of molecules sharing a closely related scaffold can express effectiveness.

Development and Evaluation of Oleanolic Acid Dosage Forms and Its Derivatives

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

Natural Products as Modulators of CES1 Activity

Carboxylesterase (CES) 1 is the predominant esterase expressed in the human liver and is capable of catalyzing the hydrolysis of a wide range of therapeutic agents, toxins, and endogenous compounds. Accumulating studies have demonstrated associations between the expression and activity of CES1 and the pharmacokinetics and/or pharmacodynamics of CES1 substrate medications (e.g., methylphenidate, clopidogrel, oseltamivir). Therefore, any perturbation of CES1 by coingested xenobiotics could potentially compromise treatment. Natural products are known to alter drug disposition by modulating cytochrome P450 and UDP-glucuronosyltransferase enzymes, but this issue is less thoroughly explored with CES1. We report the results of a systematic literature search and discuss natural products as potential modulators of CES1 activity. The majority of research reports reviewed were in vitro investigations that require further confirmation through clinical study. Cannabis products (Δ 9-tetrahydrocannabinol, cannabidiol, cannabinol); supplements from various plant sources containing naringenin, quercetin, luteolin, oleanolic acid, and asiatic acid; and certain traditional medicines (danshen and zhizhuwan) appear to pose the highest inhibition potential. In addition, ursolic acid, gambogic acid, and glycyrrhetic acid, if delivered intravenously, may attain high enough systemic concentrations to significantly inhibit CES1. The provision of a translational interpretation of in vitro assessments of natural product actions and interactions is limited by the dearth of basic pharmacokinetic data of the natural compounds exhibiting potent in vitro influences on CES1 activity. This is a major impediment to assigning even potential clinical significance. The modulatory effects on CES1 expression after chronic exposure to natural products warrants further investigation. SIGNIFICANCE STATEMENT: Modulation of CES1 activity by natural products may alter the course of treatment and clinical outcome. In this review, we have summarized the natural products that can potentially interact with CES1 substrate medications. We have also noted the limitations of existing reports and outlined challenges and future directions in this field.

Pharmacokinetics of maslinic and oleanolic acids from olive oil - Effects on endothelial function in healthy adults. A randomized, controlled, dose-response study

To date, pharmacokinetics of maslinic (MA) and oleanolic (OA) acids, at normal dietary intakes in humans, have not been evaluated, and data concerning their bioactive effects are scarce. We assessed MA and OA pharmacokinetics after ingestion of olive oils (OOs) with high and low triterpenic acid contents, and specifically the effect of triterpenes on endothelial function. We performed a double-blind, dose-response, randomized, cross-over nutritional intervention in healthy adults, and observed that MA and OA increased in biological fluids in a dose-dependent manner. MA bioavailability was greater than that of OA, and consumption of pentacyclic triterpenes was associated with improved endothelial function. To the best of our knowledge, this is the first time MA pharmacokinetics, and effects on endothelial function in vivo, have been reported in humans.

Prevention of type 2 diabetes in prediabetic patients by using functional olive oil enriched in oleanolic acid: The PREDIABOLE study, a randomized controlled trial

AIM

To assess whether the regular intake of an oleanolic acid (OA)-enriched olive oil is effective in the prevention of diabetes.

METHODS

In the PREDIABOLE study, prediabetic individuals (impaired fasting glucose and impaired glucose tolerance) of both sexes (176 patients, aged 30-80 years) were randomized to receive 55 mL/day of OA-enriched olive oil (equivalent dose 30 mg OA/day) [intervention group (IG)] or the same oil not enriched [control group (CG)]. The main outcome was the incidence of new-onset type 2 diabetes in both groups.

RESULTS

Forty-eight new diabetes cases occurred, 31 in the CG and 17 in the IG. The multivariate-adjusted hazard ratio was 0.45 (95% CI, 0.24-0.83) for the IG compared with the CG. Intervention-related adverse effects were not reported.

CONCLUSIONS

The intake of OA-enriched olive oil reduces the risk of developing diabetes in prediabetic patients. The results of the PREDIABOLE study promote the use of OA in new functional foods and drugs for the prevention of diabetes in individuals at risk of developing it.

Dual-Targeting Multifuntional Mesoporous Silica Nanocarrier for Codelivery of siRNA and Ursolic Acid to Folate Receptor Overexpressing Cancer Cells

A targeting drug delivery system (TDDS) can selectively deliver antitumor drugs to cancerous parts to improve its anticancer efficacy. Hence, a targeted drug delivery system (UA/siVEGF@MSN-FA) coloading ursolic acid (UA) and vascular endothelial growth factor (VEGF) targeted siRNA (siVEGF) based on mesoporous silica (MSN) nanocarrier modified by a folic acid (FA) molecule was designed and synthesized. The MSN-FA nanoparticles were investigated for shape, diameter, and zeta potential and and by infrared (IR) spectroscopy. FR-overexpressing HeLa cells and FR-negative HepG2 cell lines were used to evaluate the in vitro cellular uptake and the cytotoxicity of MSN-FA nanoparticles. The morphology of HeLa cells transfected with siVEGF@MSN-FA was observed using fluorescence microscopy. Our findings demonstrated that UA@MSN-FA nanoparticles were near-spherical, and the particle size was about 209 ± 9.21 nm. The MSN-FA nanocarrier not only could enhance the in vitro transfection efficiency and the stability of siVEGF but also could further improve the targeted anticancer efficacy of UA and siVEGF via the active targeting property of FA. Overall, the MSN-FA drug delivery system could serve as an excellent material in biomedical applications.

Liquid chromatography tandem mass spectrometric determination of triterpenes in human fluids: Evaluation of markers of dietary intake of olive oil and metabolic disposition of oleanolic acid and maslinic acid in humans

Olive oil is rich in several minor components like maslinic (MA) and oleanolic (OA) acids which have cardioprotective, antitumor, and anti-inflammatory properties. In order to assess the health benefits in humans provided by the olive oil triterpenes (MA and OA), suitable analytical methods able to quantify the low concentrations expected in human fluids are required. In this study, the LC-MS/MS quantification of both OA and MA in plasma and urine has been evaluated. The plasmatic method is based on the direct determination of the analytes. The urinary detection requires more sensitivity which was reached by derivatization with 2-picolylamine. Additionally, the urinary species present after MA and OA ingestion were evaluated by the direct detection of several phase II metabolites previously synthesized. Our results showed that OA is metabolized as both sulfate and glucuronide conjugates whereas MA is mainly excreted as glucuronide. Based on this information, the method for the urinary detection of MA and OA involved an enzymatic hydrolysis. Both plasmatic and urinary methods were validated with suitable precision and accuracy at all tested levels. Required sensitivity was achieved in both matrices. Up to our knowledge, this is the first method able to quantify the low concentration levels of triterpenes present in urine. Samples from two healthy volunteers who received virgin olive oils with different triterpenes content were analyzed. Some preliminary clues on the metabolic disposition of OA and MA after olive oil intake are provided.

Study of a novel disintegrable oleanolic acid-polyvinylpolypyrrolidone solid dispersion

Novel solid dispersions of oleanolic acid-polyvinylpolypyrrolidone (OLA-PVPP SDs) were designed and prepared to improve the apparent solubility of drug, as well as to improve the stability, fluidity and compressibility of SDs. Disintegrable OLA-PVPP SDs were then evaluated both in vitro and in vivo. DSC, XRD, IR and SEM analysis proved the formation of OLA-PVPP SD and its amorphous state. The results of fluidity study, moisture absorption test and stability test showed that OLA-PVPP SD with good fluidity and qualified stability was successfully obtained. Meanwhile excellent dissolution rate was achieved for in vitro studies; dissolution test showed that ∼50-75% of OLA was dissolved from SDs within the first 10 min, which is about 10-15 times of free OLA. In vivo study indicated that the formation of solid dispersion could largely improve the absorption of OLA, resulting in a much shorter T_max (p < .05) and higher C_max (p < .01) than those of free drug. The AUC_0→∞ of OLA-PVPP SDs (1:6) were 155.4 ± 37.24 h·ng/mL compared to the 103.11 ± 26.69 h·ng/mL and 94.92 ± 13.05 h·ng/mL of OLA-PVPP physical mixture (1:6) and free OLA, respectively. These proved PVPP could be a promising carrier of solid dispersions and was industrially feasible alternative carrier in the manufacture of solid dispersions.

Potential use of nanocarriers with pentacyclic triterpenes in cancer treatments

Ursolic, oleanolic and betulinic acids are representative pentacyclic triterpenoids found in various plants and fruits. Despite having marked antitumor potentials, the very poor water solubility of these triterpenes hinders treatment development. Nanotechnology can enhance solubility, stability, bioavailability and phytochemical delivery, improving the therapeutic efficiency of triterpenes. This review focuses on the formulation, characterization and in vitro/in vivo evaluation of several delivery nanosystems used to enhance the physicochemical properties of ursolic, oleanolic and betulinic acids.

Identification of a novel oxidative stress induced cell death by Sorafenib and oleanolic acid in human hepatocellular carcinoma cells

The lack of effective chemotherapies in hepatocellular carcinoma (HCC) is still an unsolved problem and underlines the need for new strategies in liver cancer treatment. In this study, we present a novel approach to improve the efficacy of Sorafenib, today's only routinely used chemotherapeutic drug for HCC, in combination with triterpenoid oleanolic acid (OA). Our data show that cotreatment with subtoxic concentrations of Sorafenib and OA leads to highly synergistic induction of cell death. Importantly, Sorafenib/OA cotreatment triggers cell damage in a sustained manner and suppresses long-term clonogenic survival. Sorafenib/OA cotreatment induces DNA fragmentation and caspase-3/7 cleavage and the addition of the pan-caspase inhibitor zVAD.fmk shows the requirement of caspase activation for Sorafenib/OA-triggered cell death. Furthermore, Sorafenib/OA co-treatment stimulates a significant increase in reactive oxygen species (ROS) levels. Most importantly, the accumulation of intracellular ROS is required for cell death induction, since the addition of ROS scavengers (i.e. α-tocopherol, MnTBAP) that prevent the increase of intracellular ROS levels completely rescues cells from Sorafenib/OA-triggered cell death. In conclusion, OA represents a novel approach to increase the sensitivity of HCC cells to Sorafenib via oxidative stress.

Simultaneous determination of 3-O-acetyloleanolic acid and oleanolic acid in rat plasma using liquid chromatography coupled to tandem mass spectrometry

3-O-Acetyloleanolic acid (OAA) is a triterpenoid compound, and exerts an apoptosis in cancer cell lines, an inhibition of both atopic and allergic contact dermatitis in murine model, and a suppression of inflammatory bone loss in mice. OAA can be converted into oleanolic acid (OA) by hydrolysis in vivo, and OA exhibits several pharmacological effects as well. A liquid chromatographic method using tandem mass spectrometry (MS/MS) was developed for the simultaneous determination of OAA and OA in rat plasma. After liquid-liquid extraction with ethylacetate, both substances were chromatographed on a reversed phase column with a mobile phase of 0.1% formic acid aqueous solution and acetonitrile (1:9, v/v). The accuracy and precision of the assay were in accordance with FDA regulations for the validation of bioanalytical methods. This analytical method was successfully applied to monitor plasma concentrations of both substances over time following an intravenous administration of OAA in rats.

Oleanolic Acid, a Compound Present in Grapes and Olives, Protects against Genotoxicity in Human Mammary Epithelial Cells

Oleanolic acid (AO) and maslinic acid (MA) are constituents of the skins of different fruits, including olives and white or red grapes. Although both compounds are known to have beneficial properties against different types of cancers, thus far, there are no studies about their chemopreventive effects in human breast cancer. Thus, we sought to elucidate whether both compounds possess chemopreventive activity. Two cell lines of human breast cancer cells and one noncancerous human mammary epithelial cells were used to determine the effects of OA and MA. The results showed that OA inhibited the proliferation and increased the oxidative stress of highly invasive cells. Additionally, OA decreased oxidative stress and oxidative damage to the DNA in human mammary epithelial cells. These results suggest that OA could act as a chemopreventive agent in human breast cancer and could inhibit the proliferation of highly invasive breast cancer cells.

GC-FID determination and pharmacokinetic studies of oleanolic acid in human serum

Analytical interest of OA determination in human serum has increased owing to the increasing interest in pharmaceutical research by pharmaceutical properties. A simple, specific, precise and accurate GC method with flame ionization detector (FID) developed and validated for the determination of oleanolic acid (OA) in human serum (HS). To an aliquot of HS, internal standard was added and a combination of liquid-liquid extraction with a mixture of diethyl ether-isopropyl alcohol, filtration and consecutive GC resulted in separation and quantification of OA. The organic phase was analyzed using a GC system equipped with a 30 × 0.25 mm i.d. Rtx-65TG capillary column and FID detection. Total chromatographic time was 10 min and no interfering peaks from endogenous components in blank serum were observed. The OA/internal standard peak area ratio was linearly fitted to the OA concentration (r = 0.992) over the range 10-1500 ng/mL. The mean serum extraction recovery of OA was 96.7 ± 1.0% and the lower limit of quantification based on 5 mL of serum was 10.7 ng/mL. The intra-day coefficient of variation ranged from 1.3 to 3.6% and inter-day varied from 1.4 to 4.5%. The developed method was used to study the pharmacokinetics of OA after oral administration in humans. The assay was simple, sensitive, precise and accurate for the use in the study of the mechanisms of absorption and distribution of OA in humans.

Simultaneous determination of six triterpenic acids in some Chinese medicinal herbs using ultrasound-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography with fluorescence detection

A novel analytical method was developed for simultaneous determination of six triterpenic acids using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) follow by high-performance liquid chromatography (HPLC) with fluorescence detection. Six triterpenic acids (ursolic acid, oleanolic acid, betulinic acid, maslinic acid, betulonic acid and corosolic acid) were extracted by UA-DLLME using chloroform and acetone as the extraction and disperser solvents, respectively. After the extraction and nitrogen flushing, the extracts were rapidly derivatized with 2-(12,13-dihydro-7H-dibenzo[a,g]carbazol-7-yl)ethyl4-methylbenzenesulfonate. The main experimental parameters affecting extraction efficiency and derivatization yield were investigated and optimized by response surface methodology (RSM) combined with Box-Behnken design (BBD). The limits of detection (LODs) and the limits of quantification (LOQs) were in the range of 0.95-1.36 ng mL(-1) and 3.17-4.55 ng mL(-1), respectively. Under the optimum conditions, the method has been successfully applied for the analysis of triterpenic acids in six different traditional Chinese medicinal herbs.

Interactions of the active components of Punica granatum (pomegranate) with the essential renal and hepatic human Solute Carrier transporters

Abstract Context: Solute carrier transporters (SLCs) are membrane proteins responsible for cellular influx of various substances including many pharmaceutical agents; therefore, they largely impact on drug disposition and elimination in body. Punica granatum Linnaeus (Lythraceae), pomegranate, is a fruit with antidiabetic potential. Oleanolic acid (OA), ursolic acid (UA), and gallic acid (GA) are the major bioactive components of pomegranate. Co-administration of these compounds with other drugs could result in altered drug pharmacokinetics, possibly due to competing for transporter proteins.

OBJECTIVE

We investigated the interactions of these three compounds with the essential hepatic and renal SLC transporters.

MATERIALS AND METHODS

Uptake of radiolabeled transporter model substrates was assessed in HEK293 cells over-expressing SLC transporters including the organic anion transporters (OATs), organic anion transporting polypeptides (OATPs) and organic cation transporters (OCTs), in the presence or absence of 10.0 µM UA, OA, or GA. Their IC50 values on specific SLC transporters were also evaluated using varying concentrations of the particular compound (ranging from 0.10 nM to 80.0 µM).

RESULTS

Our results demonstrated UA could significantly inhibit OAT3 and OATP2B1 uptake (IC50: 18.9 ± 8.20 µM and 11.0 ± 5.00 µM, respectively) and GA has a pronounced inhibitory effect on OATP1B3 uptake (IC50: 1.60 ± 0.60 μM).

DISCUSSION AND CONCLUSION

Our study reports the interactions of OA, UA, and GA with the essential SLC transporters. This information may contribute to elucidating the drug-drug/herb interactions involved with these three compounds and form the basis of therapeutic optimization when drugs are co-administered.

Oleanane triterpenoids in the prevention and therapy of breast cancer: current evidence and future perspectives

Breast cancer is one of the most frequently diagnosed cancers and major cause of death in women in the world. Emerging evidence underscores the value of dietary and non-dietary phytochemicals, including triterpenoids, in the prevention and treatment of breast cancer. Oleanolic acid, an oleanane-type pentacyclic triterpenoid, is present in a large number of dietary and medicinal plants. Oleanolic acid and its derivatives exhibit several promising pharmacological activities, including antioxidant, anti-inflammatory, hepatoprotective, cardioprotective, antipruritic, spasmolytic, antiallergic, antimicrobial and antiviral effects. Numerous studies indicate that oleanolic acid and other oleanane triterpenoids modulate multiple intracellular signaling pathways and exert chemopreventive and antitumor activities in various in vitro and in vivo model systems. A series of novel synthetic oleanane triterpenoids have been prepared by chemical modifications of oleanolic acid and some of these compounds are considered to be the most potent anti-inflammatory and anticarcinogenic triterpenoids. Accumulating studies provide extensive evidence that synthetic oleanane derivatives inhibit proliferation and induce apoptosis of various cancer cells in vitro and demonstrate cancer preventive or antitumor efficacy in animal models of blood, breast, colon, connective tissue, liver, lung, pancreas, prostate and skin cancer. This review critically examines the potential role of oleanolic acid, oleanane triterpenoids and related synthetic compounds in the chemoprevention and treatment of mammary neoplasia. Both in vitro and in vivo studies on these agents and related molecular mechanisms are presented. Several challenges and future directions of research to translate already available impressive preclinical knowledge to clinical practice of breast cancer prevention and therapy are also presented.

Enhancement of platelet aggregation by ursolic Acid and oleanolic Acid

The pentacyclic triterpenoid ursolic acid (UA) and its isomer oleanolic acid (OA) are ubiquitous in food and plant medicine, and thus are easily exposed to the population through natural contact or intentional use. Although they have diverse health benefits, reported cardiovascular protective activity is contentious. In this study, the effect of UA and OA on platelet aggregation was examined on the basis that alteration of platelet activity is a potential process contributing to cardiovascular events. Treatment of UA enhanced platelet aggregation induced by thrombin or ADP, which was concentration-dependent in a range of 5-50 μM. Quite comparable results were obtained with OA, in which OA-treated platelets also exhibited an exaggerated response to either thrombin or ADP. UA treatment potentiated aggregation of whole blood, while OA failed to increase aggregation by thrombin. UA and OA did not affect plasma coagulation assessed by measuring prothrombin time and activated partial thromboplastin time. These results indicate that both UA and OA are capable of making platelets susceptible to aggregatory stimuli, and platelets rather than clotting factors are the primary target of them in proaggregatory activity. These compounds need to be used with caution, especially in the population with a predisposition to cardiovascular events.

Bioavailability and activity of natural food additive triterpenoids as influenced by protein

Triterpenoids were thought to be biologically ineffective for a very long time, but aggregating proof on their widely ranging pharmacological activities paired with a dubious toxicity portrait has motivated regenerated attraction for human health and disease. In the current contribution, our central goal was to integratively dissect the biointeraction of two typical triterpenoids, ursolic acid and oleanolic acid, by the most fundamental macromolecule bovine serum albumin (BSA) by employing molecular modeling, steady state and time-resolved fluorescence, and circular dichroism spectra at the molecular scale. Based on molecular modeling, subdomain IIA, which matches Sudlow's site I, was allocated to retain high affinity for triterpenoids, but the affinity of ursolic acid with subdomain IIA is somewhat inferior compared to that of oleanolic acid, probably because the affinity differentiation arises from the different positions of the methyl group on the E-ring in the two triterpenoids. This sustains the site-specific ligands, and hydrophobic 8-anilino-1-naphthalenesulfonic acid probe results in arranging the triterpenoids at the warfarin-azapropazone site. The data of steady state and time-resolved fluorescence indicated that the recognition of triterpenoids by BSA produced quenching by a static type, in other words, the ground state BSA-triterpenoid complex formation with the affinities of 1.507/1.734, 1.042/1.186, and 0.8395/0.9863 × 10(4) M(-1) at 298, 304, and 310 K for ursolic acid/oleanolic acid, respectively. Thermodynamic analyses show that the basic forces acting between BSA and triterpenoids are hydrogen bonds, van der Waals forces, and hydrophobic interactions; this occurrence provoked the alterations of the BSA spatial structure with a noticeable decline of α-helix evoking perturbation of the protein, as stemmed from circular dichroism, synchronous fluorescence, and three-dimensional fluorescence measurements. We anticipate that the complexation of plant triterpenoids with protein delineated here may be exploited as a biologically relevant model for evaluating the physiologically applicable noncovalent complexes in in vivo examination of triterpenoid properties such as accumulation, bioavailability, and distribution.

Oleanolic acid and its synthetic derivatives for the prevention and therapy of cancer: preclinical and clinical evidence

Oleanolic acid (OA, 3β-hydroxyolean-12-en-28-oic acid) is a ubiquitous pentacyclic multifunctional triterpenoid, widely found in several dietary and medicinal plants. Natural and synthetic OA derivatives can modulate multiple signaling pathways including nuclear factor-κB, AKT, signal transducer and activator of transcription 3, mammalian target of rapamycin, caspases, intercellular adhesion molecule 1, vascular endothelial growth factor, and poly (ADP-ribose) polymerase in a variety of tumor cells. Importantly, synthetic derivative of OA, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), and its C-28 methyl ester (CDDO-Me) and C28 imidazole (CDDO-Im) have demonstrated potent antiangiogenic and antitumor activities in rodent cancer models. These agents are presently under evaluation in phase I studies in cancer patients. This review summarizes the diverse molecular targets of OA and its derivatives and also provides clear evidence on their promising potential in preclinical and clinical situations.