Synthesis and biological evaluation of oleanolic acid derivatives with electrophilic warheads as antitumor agents.

Aim: The oleanolic acid derivatives containing electrophilic warheads were synthesized, and their antitumor activities were investigated. Materials & methods: The cytotoxicity of compounds against tumor cells were determined by the MTT method. The antitumor effects of compounds 27a, Y03 and Y04 were evaluated in vitro through a wound-healing assay, apoptosis and cell circle analysis, and cellular reactive oxide species determination. The levels of related proteins in MCF-7 cells treated with Y03 was determined through Western blot analysis. Results & conclusion: Compounds 27a, Y03 and Y04 displayed high cytotoxicity against breast cancer cells and inhibited cell migration, induced apoptosis, arrest cell circle at G0/G1 and promoted cellular reactive oxide species generation. The antitumor mechanism involved inhibition of Akt/mTOR and induction of ferroptosis.

The Effect of Oleanolic Acid and Its Four New Semisynthetic Derivatives on Human MeWo and A375 Melanoma Cell Lines.

This study aimed to synthesize four new semisynthetic derivatives of natural oleanolic acid (OA) and, based on an analysis of their cytotoxic and anti-proliferative effects against human MeWo and A375 melanoma cell lines, select those with anti-cancer potential. We also screened the treatment time with the concentration of all four derivatives. We synthesized oxime 2 and performed its acylation with carboxylic acids into new derivatives 3a, 3b, 3c and 3d according to the methods previously described. Colorimetric MTT and SRB assays were used to measure the anti-proliferative and cytotoxic activity of OA and its derivatives 3a, 3b, 3c and 3d against melanoma cells. Selected concentrations of OA, the derivatives, and different time periods of incubation were used in the study. The data were analyzed statistically. The present results revealed the possible anti-proliferative and cytotoxic potential of two selected OA derivatives 3a and 3b, on A375 and MeWo melanoma cells, especially at concentrations of 50 µM and 100 µM at 48 h of incubation (p < 0.05). Further studies will be necessary to analyze the proapoptotic and anti-cancer activities of 3a and 3b against skin and other cancer cells. The bromoacetoxyimine derivative (3b) of OA morpholide turned out to be the most effective against the tested cancer cells.

Synthesis and biological evaluation of pyrazole-fused oleanolic acid derivatives as novel inhibitors of inflammatory and osteoclast differentiation.

A series of pyrazole-fused oleanolic acid derivatives were designed and synthesized. The modification of these analogues focused on the substituents screening on the pyrazole ring. The cytotoxicity of these compounds and their anti-inflammatory activities via inhibiting interleukin-1ß (IL-1ß) production were evaluated in RAW264.7 cells. Most of the derivatives showed significantly improved potency compared with oleanolic acid. Among them, compound 7n exhibited the most potent anti-inflammatory activity on decreasing IL-1ß production with low cytotoxicity. Moreover, the further study found 7n could inhibit RANKL-induced osteoclast differentiation on bone marrow-derived macrophages (BMMs). These findings may provide a potential direction for the drug development of osteoarthritis.

Anticancer activity of oleanolic acid and its derivatives modified at A-ring and C-28 position.

Oleanolic acid (OA) is a five-ring triterpenoid compound, which is widely present in plants. Due to a wide range of pharmacological activities, oleanolic acid has attracted more and more attention. However, oleanolic acid is insoluble in water and has low bioavailability, which limits its clinical application. In this review, we focus on summarizing the anti-cancer activity and mechanism of the A ring or C-28 carboxyl modified derivatives of OA since 2015, to determine the strength of its anti-cancer effectiveness and evaluate whether it could be used as a clinical anti-cancer drug.

Oleanolic Acid's Semisynthetic Derivatives HIMOXOL and Br-HIMOLID Show Proautophagic Potential and Inhibit Migration of HER2-Positive Breast Cancer Cells In Vitro.

Approximately 20-30% of the diagnosed breast cancers overexpress the human epidermal growth factor receptor 2 (HER2). This type of cancer is associated with a more aggressive phenotype; thus, there is a need for the discovery of new compounds that would improve the survival in HER2-positive breast cancer patients. It seems that one of the most promising therapeutic cancer strategies could be based on the biological activity of pentacyclic triterpenes' derivatives and the best-known representative of this group, oleanolic acid (OA). The biological activity of oleanolic acid and its two semisynthetic derivatives, methyl 3-hydroxyimino-11-oxoolean-12-en-28-oate (HIMOXOL) and 12α-bromo-3-hydroxyimonoolean-28→13-olide (Br-HIMOLID), was assessed in SK-BR-3 breast cancer cells (HER2-positive). Viability tests, cell cycle assessment, evaluation of apoptosis, autophagy, and adhesion/migration processes were performed using MTT, clonogenic, cytofluorometry, Western blot, and qPCR. Both derivatives revealed higher cytotoxicity in studied breast cancer cells than the maternal compound, OA. They also decreased cell viability, induced autophagy, and (when applied in sub-cytotoxic concentrations) decreased the migration of SK-BR-3 cells.This study is the first to report the cytostatic, proautophagic (mTOR/LC3/SQSTM/BECN1 pathway), and anti-migratory (integrin ß1/FAK/paxillin pathway) activities of HIMOXOL and Br-HIMOLID in HER2-positive breast cancer cells.

Anti-Cancer Potential of Synthetic Oleanolic Acid Derivatives and Their Conjugates with NSAIDs.

Naturally occurring pentacyclic triterpenoid oleanolic acid (OA) serves as a good scaffold for additional modifications to achieve synthetic derivatives. Therefore, a large number of triterpenoids have been synthetically modified in order to increase their bioactivity and their protective or therapeutic effects. Moreover, attempts were performed to conjugate synthetic triterpenoids with non-steroidal anti-inflammatory drugs (NSAIDs) or other functional groups. Among hundreds of synthesized triterpenoids, still the most promising is 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), which reached clinical trials level of investigations. The new group of synthetic triterpenoids are OA oximes. The most active among them is 3-hydroxyiminoolean-12-en-28-oic acid morpholide, which additionally improves the anti-cancer activity of standard NSAIDs. While targeting the Nrf2 and NF-κB signaling pathways is the main mechanism of synthetic OA derivatives' anti-inflammatory and anti-cancer activity, most of these compounds exhibit multifunctional activity, and affect cross-talk within the cellular signaling network. This short review updates the earlier data and describes the new OA derivatives and their conjugates in the context of modification of signaling pathways involved in inflammation and cell survival and subsequently in cancer development.

Synthesis and antitumor activity of α,ß-unsaturated carbonyl moiety- containing oleanolic acid derivatives targeting PI3K/AKT/mTOR signaling pathway.

Oleanolic acid (OA) and its semi-synthetic derivatives have been reported to have a wide range of biological activities. The introduction of electrophilic Michael acceptor group can increase the reactivity of OA to cellular targets and thus improve the anti-tumor activity. In this work, a series of novel α,ß-unsaturated carbonyl derivatives of OA were designed and synthesized. Their in vitro cytotoxic activity against MCF-7, HepG2 and HeLa cells were tested. Most derivatives exhibited improved cell growth inhibitory activity, especially for 3d with an IC50 of 0.77 µM in MCF-7 cells. Moreover, 3d inhibited the migration of MCF-7 and HeLa cells at the concentration of 4 µM. Flow cytometric analysis revealed that 3d induced cell apoptosis and S phase arrest in a concentration-dependent manner. Western blotting experiment demonstrated that 3d inhibited the phosphorylation of AKT and mTOR. These results suggest that this series of OA derivatives bearing exocyclic methylene ketone pharmacophore are promising anticancer agents as potential PI3K/AKT/mTOR pathway inhibitors.

Morpholide derivative of the novel oleanolic oxime and succinic acid conjugate diminish the expression and activity of NF-κB and STATs in human hepatocellular carcinoma cells.

Naturally occurring oleanolic acid (OA) possesses a hepatoprotective activity and ability to inhibit proliferation of human hepatocellular carcinoma cells. Both properties might be related to its anti-inflammatory activity. Its low bioavailability justifies the search for more hydrophilic OA derivatives. The aim of this study was the design and synthesis of four novel OA oxime derivatives conjugated with succinic acid at the C-3 position of oleanane skeleton structure and evaluation of their effect on NF-κB and STATs expression and activation in HepG2 cells. The expression of NF-κB and cyclooxygenase-2 (COX-2), STAT5A/B and STAT3 with its target genes: BAX, BCL-XL and MYC was evaluated after 24 h treatment with tested compounds. The comparison of the levels of cytosolic and nuclear NF-κB subunits p50, p65 and STATs proteins was used as the measure of their activation. The results pointed out the 3-succinyloxyiminoolean-12-en-28-oic acid morpholide (SMAM) as the most potent modulator of NF-κB and STAT3. SMAM significantly reduced the expression and activation of NF-κB as well as its nuclear protein level of p65 subunit. This compound also reduced the expression and activation of STAT3 and STAT5A/B. Combined effect of SMAM on these transcription factors resulted in reduced expression of COX-2, MYC and anti-apoptotic BCL-XL genes. Simultaneously, the increased expression of pro-apoptotic BAX gene was observed. In the cells treated with 3-succinyloxyiminoolean-12-en-28-oic acid (SMAA) the increased expression of BAX was also found. The effects of 3-succinyloxyiminoolean-12-en-28-oic acid benzyl ester (SMAEB) and 3-succinyloxyiminoolean-12-en-28-oic acid methyl ester (SMAEM) were moderate and ambiguous in relation to the tested factors. Moreover, the coordinated action of SMAM on NF-κB and STAT3 confirms their close association in HepG2 cells. We conclude that SMAM efficiently downregulates the key elements of signaling pathways involved in inflammatory driven HCC. Thus, may be considered as a potential chemopreventive or therapeutic agent in this type of cancer.

Design, synthesis, and antitumor activity of oleanolic acid derivatives.

Using the techniques of computer-aided drug design, the docking of survivin and known active small molecules was simulated and then the key amino acid residue fragments of the target protein were analyzed. It led to the discovery of active groups capable of binding to the critical sites. Through the use of the natural product, oleanolic acid, as a lead compound, the introduction of the active groups onto the A-ring, and the modification of the carboxyl group at the C-28 position using esterification or amidation, 20 new oleanolic acid derivatives had been designed and synthesized. HepG2 and SGC-7901 cells were used to screen the antitumor activity through the standard MTT method. The compounds, II3, III5 and IV4, exhibited more potent cytotoxicity than positive drugs. Western blot experiment demonstrated that compound II3 can effectively inhibit the proliferation of HepG2 cells.

Synthesis and biological evaluation of oleanolic acid analogs based on survivin target / 中国药学杂志

OBJECTIVE: To design and synthesize a series of oleanolic acid analogs posessing anti-tumor activity based on survivin target. METHODS: Using the techniques of computer-aided drug design, the docking of Survivin and known active small molecules was simulated and then the key amino acid residue fragment of the target protein was analyzed. It led to the discovery of active groups capable of binding to the critical sites. Through using the natural product, oleanolic acid, as a lead compound, the active groups were introduced onto its A-ring, and the carboxyl group at the C-28 position was modified using amidation. SGC-7901 and A549 cells were used to screen the antitumor activity in vitro through the standard MTT method. RESULTS: Ten new oleanolic acid derivatives were designed and synthesized,and their structures were confirmed by MS and NMR. The compounds 5 and Ⅱ5 exhibited more potent cytotoxicity than the positive control drugs. CONCLUSION: The novel oleanolic acid analogues have better antitumor activity than the parent compound, which are worthy of further study.

Targeting PDGF receptor inhibitors: synthesis and biological evaluation of oleanolic acid analogs / 药学学报

The computer-aided design was used to simulate the docking of PDGF receptor with known active compounds, and the active groups that can bind to key sites were identified by analyzing the key amino acid residue fragments that exerted active effects on the target proteins. The natural product oleanolic acid was used as the parent, and the active group was introduced into the 2-position, and the C-28 carboxyl group was esterified and amidated. A series of oleanolic acid analogues targeting PDGF receptor inhibitors were designed and synthesized. Their structures were confirmed by MS and NMR. Through MTT assay, SGC-7901 and A549 cells were selected for preliminary in vitro anti-tumor activity screening. PDGF receptor protein inhibition test was performed on I3 and Ⅱ5 by FPIA. The activity tests showed that I3 and Ⅱ5, compared with the positive control drug, had stronger inhibition. FPIA test showed that Ⅱ5 and PDGF receptor protein had good binding ability. The newly synthesized oleanolic acid analogues have significantly higher antitumor activity than the parent compound and deserve further study.

A Series of Oleanolic Acid Derivatives as Anti-Hepatitis B Virus Agents: Design, Synthesis, and in Vitro and in Vivo Biological Evaluation.

A series of oleanolic acid derivatives were synthesized by diverse reactions, including the introduction of conjugated alkadiene and epoxy ring moieties formed by means of photosensitized oxidation. Eosin Y was used as photosensitizer during this process. Next the cytotoxicity of the products was evaluated on HepG2.2.15 cells to determine the appropriate treatment concentration for the subsequent experiments. Most of the OA derivatives exhibited anti-HBV antigens secretion activity in HepG2.2.15 cells. Among the tested compounds, OA-4 (3.13 µg/mL) showed significant activity against the secretion of HBsAg, HBeAg, and HBV DNA replication with inhibitory ratios of 90.52% ± 1.78%, 31.55% ± 3.65%, and 94.57% ± 3.11% after 6 days, respectively. Besides, OA-4 was further investigated in a duck model with DHBV infection. When OA-4 was administered at a dosage of 500 mg/kg, the results revealed a significant inhibitory effects of DHBV at 19.94% ± 2.87%, 28.80% ± 3.62% and 29.25% ± 2.65% at days 5, 10, and 3 after the cessation of OA-4 treatment, respectively. It's worth noting that OA-4 is superior to lamivudine in the inhibition of rebound of viral replication rate. The structure-activity relationships of OA derivatives had been preliminary discussed, which should be useful to explore further novel anti-HBV agents.

Proapoptotic activity and ABCC1-related multidrug resistance reduction ability of semisynthetic oleanolic acid derivatives DIOXOL and HIMOXOL in human acute promyelocytic leukemia cells.

One of the main problems of present-day oncology is the ability of neoplastic cells to develop different mechanisms of resistance to chemotherapeutic agent. A natural compound oleanolic acid (OA) was found to be active against many types of neoplastic cells. This paper examines the influence of eight semisynthetic oleanolic acid derivatives on drug-sensitive human acute promyelocytic leukemia cell line HL-60 and its multidrug resistant subline ABCC1 overexpressing HL-60/AR. Viability inhibition, proapoptotic activity, as well as influence on the ABCC1 gene expression level, ability to inhibit the transport function of multidrug resistance associated protein 1 (ABCC1) and to alter its level by the tested compounds, were evaluated. The most potent compounds were DIOXOL (methyl 3,11-dioxoolean-12-en-28-oate) and HIMOXOL (methyl 3-hydroxyimino-11-oxoolean-12-en-28-oate). DIOXOL was most efficient in inducing apoptosis of HL-60 cells. It activated both intrinsic and extrinsic pathways of apoptotic cell death. Proapoptotic properties of DIOXOL were probably related to the significant decrease of p65 NFκB level and inhibition of its translocation to the nucleus. In turn, HIMOXOL was the most potent compound against resistant HL-60/AR cells. It inhibited ABCC1 transport function (short time response) and decreased the level of ABCC1 protein (long time response) as a result of reduction of ABCC1 expression.

Synthesis of oleanolic acid derivatives: In vitro, in vivo and in silico studies for PTP-1B inhibition.

Non-insulin dependent diabetes mellitus is a multifactorial disease that links different metabolic routes; a point of convergence is the enzyme PTP-1B which turns off insulin and leptin receptors involved in glucose and lipid metabolism, respectively. Pentacyclic acid triterpenes such as oleanolic acid (OA) have proved to be excellent PTP-1B inhibitors, thus, the purpose of current work was to generate a series of derivatives that improve the pharmacological effect of OA. Our findings suggest that the presence of the carboxylic acid and/or its corresponding reduction product carbinol derivative (H-bond donor) in C-28 is required to maintain the inhibitory activity; moreover, this is further enhanced by ester or ether formation on C-3. The most active derivatives were cinnamoyl ester (6) and ethyl ether (10). Compound 6 showed potent in vitro inhibitory activity and significantly decrease of blood glucose levels on in vivo experiments. Meanwhile, 10 showed contrasting outcomes, since it was the compound with higher inhibitory activity and selectivity over PTP-1B and has improved interaction with site B, according with docking studies, the in vivo antidiabetic effect was similar to oleanolic acid. In conclusion, oleanolic acid derivatives have revealed an enhanced inhibitory effect over PTP-1B activity by increasing molecular interactions with either catalytic or allosteric sites and producing a hypoglycaemic effect on non insulin dependent diabetes mellitus rat model.

The molecular mechanisms underpinning the therapeutic properties of oleanolic acid, its isomer and derivatives for type 2 diabetes and associated complications.

Recent research has uncovered the molecular mechanisms responsible for the therapeutic properties of oleanolic acid (OA), its isomer ursolic acid (UA), and derivatives. In particular, recent reports have highlighted the benefits of these compounds in the prevention and treatment of type 2 diabetes and associated life-threatening complications, such as nonalcoholic fatty liver disease, nephropathy, retinopathy, and atherosclerosis. The prevalence of type 2 diabetes is of major concern since it is reaching global epidemic levels. Treatments targeting the signaling pathways altered in type 2 diabetes are being actively investigated, and OA and UA in natural and derivative forms are potential candidates to modulate these pathways. We will explore the findings from in vitro and in vivo studies showing that these compounds: (i) improve insulin signaling and reduce hyperglycemia; (ii) reduce oxidative stress by upregulating anti-oxidants and; (iii) reduce inflammation by inhibiting proinflammatory signaling. We will discuss the molecular mechanisms underpinning these therapeutic properties in this review in order to provide a rationale for the future use of OA, UA, and their derivatives for the prevention and treatment of type 2 diabetes and associated comorbidities.

Studies on chemical constituents from Semiliquidambar cathayensis / 中草药

Object To isolate and identiified the chemical constituents from the EtOAc soluble fraction of the rhizome of Semiliquidambar cathayensis Chang with anti inflammatory activity Methods The EtOAc soluble fraction of anti inflammatory activity was determined on the basis of the mouse ear irritant assay by croton oil The chemical constituents were isolated by silica gel column chromatography, and their structures were identiified by IR, MS and NMR spectroscopic methods including HMQC and HMBC experiments Results Four oleanolic acid derivatives, oleanolic acid, 3 oxo olean 12 en 28 oic acid 2?, 3? dihydroxyolean 12 en 28 oic acid, 2?, 3?, 23 trihydroxyolean 12 en 28 oic acid (arjunolic acid); three ellagic acid derivatives, ellagic acid 3, 3′ dimethylether, ellagic acid 3, 3′, 4 trimethylether, and ellagic acid 4 O ? D xylopyranoside 3, 3′ dimethylether, together with ? sitosterol and octadecylic acid were obtained and identified Conclusion All the nine compounds were isolated for the first time from the title plant