Design, Synthesis, and Biological Evaluation of Novel Nitrogen Heterocycle-Containing Ursolic Acid Analogs as Antitumor Agents

Quinoline- and Isoindoline-Integrated Polycyclic Compounds as Antioxidant, and Antidiabetic Agents Targeting the Dual Inhibition of α-Glycosidase and α-Amylase Enzymes

Novel analogs of quinoline and isoindoline containing various heterocycles, such as tetrazole, triazole, pyrazole, and pyridine, were synthesized and characterized using FT-IR, NMR, and mass spectroscopy, and their antioxidant and antidiabetic activities were investigated. The previously synthesized compound 1 was utilized in conjugation with ketone-bearing tetrazole and isoindoline-1,3-dione to synthesize Schiff's bases 2 and 3. Furthermore, hydrazide 1 was treated with aryledines to provide pyrazoles 4a-c. Compound 5 was obtained by treating 1 with potassium thiocyanate, which was then cyclized in a basic solution to afford triazole 6. On the other hand, pyridine derivatives 7a-d and 8a-d were synthesized using 2-(4-acetylphenyl)isoindoline-1,3-dione via a one-pot condensation reaction with aryl aldehydes and active methylene compounds. From the antioxidant and antidiabetic studies, compound 7d showed significant antioxidant activity with an EC50 = 0.65, 0.52, and 0.93 mM in the free radical scavenging assays (DPPH, ABTS, and superoxide anion radicals). It also displayed noteworthy inhibitory activity against both enzymes α-glycosidase (IC50: 0.07 mM) and α-amylase (0.21 mM) compared to acarbose (0.09 mM α-glycosidase and 0.25 mM for α-amylase), and higher than in the other compounds. During in silico assays, compound 7d exhibited favorable binding affinities towards both α-glycosidase (-10.9 kcal/mol) and α-amylase (-9.0 kcal/mol) compared to acarbose (-8.6 kcal/mol for α-glycosidase and -6.0 kcal/mol for α-amylase). The stability of 7d was demonstrated by molecular dynamics simulations and estimations of the binding free energy throughout the simulation session (100 ns).

Ursolic acid ameliorates traumatic brain injury in mice by regulating microRNA-141-mediated PDCD4/PI3K/AKT signaling pathway

BACKGROUND

Neuronal apoptosis and inflammation are the key pathogenic features of secondary brain injury, which results in the neurological impairment that traumatic brain injury (TBI) patients experience. Ursolic Acid (UA) has been shown to have neuroprotective properties against brain damage, however, detailed mechanisms have not been fully disclosed. Research on brain-related microRNAs (miRNAs) has opened up new possibilities for the neuroprotective treatment of UA by manipulating miRNAs. The present study was designed to investigate the impact of UA on neuronal apoptosis and the inflammatory response in TBI mice.

METHODS

The mice's neurologic condition was assessed using the modified neurological severity score (mNSS) and the learning and memory abilities were assessed using the Morris water maze (MWM). Cell apoptosis, oxidative stress, and inflammation were utilized to examine the impact of UA on neuronal pathological damage. miR-141-3p was selected to evaluate whether UA influences miRNAs in a way that has neuroprotective benefits.

RESULTS

The results showed that UA markedly decreased brain edema and neuronal mortality through oxidative stress and neuroinflammation in TBI mice. Using data from the GEO database, we found that miR-141-3p was considerably downregulated in TBI mice and that this downregulation was reversed by UA treatment. Further studies have shown that UA regulates miR-141-3p expression to exhibit its neuroprotective effect in mouse models and cell injury models. Then, miR-141-3p was discovered to directly target PDCD4 in TBI mice and neurons, a well-known PI3K/AKT pathway regulator in the neurons. Most importantly, the upregulation of phosphorylated (p)-AKT and p-PI3K provided the most compelling evidence that UA reactivated the PI3K/AKT pathway in the TBI mouse model, which was through regulating miR-141-3p.

CONCLUSION

Our findings support the notion that UA can improve TBI by modulating miR-141 mediated PDCD4/PI3K/AKT signaling pathway.

Synthesis, Anti-Influenza H1N1 and Anti-Dengue Activity of A-Ring Modified Oleanonic Acid Polyamine Derivatives

A series of sixteen A-ring modified (2,3-indolo-, 2-benzylidene) oleanonic acid derivatives, holding some cyclic amines, linear polyamines and benzylaminocarboxamides at C28, has been synthesized and screened for antiviral activity against influenza A/PuertoRico/8/34 (H1N1) and Dengue virus serotypes of DENV-1, -2, -3, -4. It was found that 28-homopiperazine 2 and 3-N-phthalyl 22 amides of oleanonic acid demonstrated high potency with selectivity index SI 27 (IC₅₀ 21 μM) and 42 (IC₅₀ 12 μM). Oleanonic acid aminoethylpiperazine amide 6 and C-azepano-erythrodiol 23 appeared to be the most effective compounds against DENV-1 (IC_50's 67 and 107 μM) and -2 (IC_50's 86 and 68 μM correspondingly) serotypes.

Novel Triterpenic Acid—Benzotriazole Esters Act as Pro-Apoptotic Antimelanoma Agents

Pentacyclic triterpenes, such as betulinic, ursolic, and oleanolic acids are efficient and selective anticancer agents whose underlying mechanisms of action have been widely investigated. The introduction of N-bearing heterocycles (e.g., triazoles) into the structures of natural compounds (particularly pentacyclic triterpenes) has yielded semisynthetic derivatives with increased antiproliferative potential as opposed to unmodified starting compounds. In this work, we report the synthesis and biological assessment of benzotriazole esters of betulinic acid (BA), oleanolic acid (OA), and ursolic acid (UA) (compounds 1–3). The esters were obtained in moderate yields (28–42%). All three compounds showed dose-dependent reductions in cell viability against A375 melanoma cells and no cytotoxic effects against healthy human keratinocytes. The morphology analysis of treated cells showed characteristic apoptotic changes consisting of nuclear shrinkage, condensation, fragmentation, and cellular membrane disruption. rtPCR analysis reinforced the proapoptotic evidence, showing a reduction in anti-apoptotic Bcl-2 expression and upregulation of the pro-apoptotic Bax. High-resolution respirometry studies showed that all three compounds were able to significantly inhibit mitochondrial function. Molecular docking showed that compounds 1–3 showed an increase in binding affinity against Bcl-2 as opposed to BA, OA, and UA and similar binding patterns compared to known Bcl-2 inhibitors.

Green synthesis of methadone in eutectic solvent

Eutectic solvents (DES), have attracted much attention in the last decade. With the advantages of nonflammability, thermal and chemical stability, high solubility and partial vapor pressure, non-toxicity and reasonable prices, these solvents are suggested as useful solvents. On the other hand, the eutectic solvents developed by Abbott are the new generation of ionic liquids. The mixture of eutectics is from an ammonium salt and a hydrogen bonding compound such as urea, acid, amine, and non-toxic amines. Choline chloride and urea, are quite environmentally friendly and are known practically as green solvents. The purpose of the present research is to present the synthesis of diphenyl acetonitrile with 1-dimethylamino-2-chloropropane by a eutectic’s solvent. In addition, methadone is synthesized from the reaction of 2,2-Diphenyl-4-dimethylaminovaleronitrile with ethyl magnesium bromide in the presence of solvent eutectic, which is in optimal and environmentally compatible conditions and by principles of green chemistry.

Naturally occurring heterocyclic anticancer compounds

Naturally occurring heterocyclic scaffolds are key ingredients for the development of various therapeutics employed for biomedical applications. Heterocyclic pharmacophores are widely disseminated and have been befallen in almost all categories of drugs for the alleviation of myriad ailments including diabetes, neurodegenerative, psychiatric, microbial infections, disastrous cancers etc. Countless fused heterocyclic anticancerous templates are reported to display antimetabolite, antioxidant, antiproliferative, cytostatic etc. pharmacological actions via targeting different signaling pathways (cell cycle, PI-3kinase/Akt, p53, caspase extrinsic pathway etc.), overexpressive receptors (EGRF, HER2, EGF, VEGF etc.) and physiological enzymes (topoisomerase I and II, cyclin dependent kinase etc.). A compiled description on various natural sources (plants, microbes, marine) containing anticancer agents comprising heterocyclic ring specified with presence of nitrogen (vincristine, vinblastine, indole-3-carbinol, meridianins, piperine, lamellarins etc.), oxygen (paclitaxel, halichondrin B, quercetin, myricetin, kaempferol etc.) and sulphur atoms (brugine, fucoidan, carrageenan etc.) are displayed here along with their molecular level cytotoxic action and therapeutic applications.

Piperazine skeleton in the structural modification of natural products: a review

Piperazine moiety is a cyclic molecule containing two nitrogen atoms in positions 1 and 4, as well as four carbon atoms. Piperazine is one of the most sought heterocyclics for the development of new drug candidates with a wide range of applications. Over 100 molecules with a broad range of bioactivities, including antitumor, antibacterial, anti-inflammatory, antioxidant, and other activities, were reviewed. This article reviewed investigations regarding piperazine groups for the modification of natural product derivatives in the last decade, highlighting parameters that affect their biological activity.

Pentacyclic Triterpenoids with Nitrogen-Containing Heterocyclic Moiety, Privileged Hybrids in Anticancer Drug Discovery

Pentacyclic triterpenoids are well-known phytochemicals with various biological activities commonly found in plants as secondary metabolites. The wide range of biological activities exhibited by triterpenoids has made them the most valuable sources of pharmacological agents. A number of novel triterpenoid derivatives with many skeletal modifications have been developed. The most important modifications are the formation of analogues or derivatives with nitrogen-containing heterocyclic scaffolds. The derivatives with nitrogen-containing heterocyclic compounds are among the most promising candidate for the development of novel therapeutic drugs. About 75% of FDA-approved drugs are nitrogen-containing heterocyclic moieties. The unique properties of heterocyclic compounds have encouraged many researchers to develop new triterpenoid analogous with pharmacological activities. In this review, we discuss recent advances of nitrogen-containing heterocyclic triterpenoids as potential therapeutic agents. This comprehensive review will assist medicinal chemists to understand new strategies that can result in the development of compounds with potential therapeutic efficacy.

The crystal structure of 3-oxo-urs-12-en-28-oic acid, C30H46O3·1/6H2O

C30H46O3·1/6H2O, monoclinic, C2 (no. 5), a = 29.4307(4) Å, b = 15.42797(17) Å, c = 18.4667(2) Å, β = 104.4652(12)°, V = 8119.11(17) Å3, Z = 12, R gt(F) = 0.0432, wR ref(F 2) = 0.1197, T = 293(2) K.

CCDC no.: 2016692

Ursolic Acid-Based Derivatives as Potential Anti-Cancer Agents: An Update

Ursolic acid is a pharmacologically active pentacyclic triterpenoid derived from medicinal plants, fruit, and vegetables. The pharmacological activities of ursolic acid have been extensively studied over the past few years and various reports have revealed that ursolic acid has multiple biological activities, which include anti-inflammatory, antioxidant, anti-cancer, etc. In terms of cancer treatment, ursolic acid interacts with a number of molecular targets that play an essential role in many cell signaling pathways. It suppresses transformation, inhibits proliferation, and induces apoptosis of tumor cells. Although ursolic acid has many benefits, its therapeutic applications in clinical medicine are limited by its poor bioavailability and absorption. To overcome such disadvantages, researchers around the globe have designed and developed synthetic ursolic acid derivatives with enhanced therapeutic effects by structurally modifying the parent skeleton of ursolic acid. These structurally modified compounds display enhanced therapeutic effects when compared to ursolic acid. This present review summarizes various synthesized derivatives of ursolic acid with anti-cancer activity which were reported from 2015 to date.