Medicinal Chemistry - Volume 19, Issue 10, 2023

Calixarenes have always captured the attention of several researchers. They have the ability to entrap multiple molecules and form inclusion complexes with drugs due to their unique structure. Due to this property, they are being widely used in the development of several classes of drugs, most notably anticancer drugs. This review attempted to summarize the potential applications of calixarenes and its derivatives in the development of anticancer drugs, with a focus on the delivery of drug classes such as DNA intercalators, taxanes, DNA alkylators, and topoisomerase inhibitors. Calixarene-based macromolecular chemistry could therefore have a high potential for overcoming the toxicity of cancer chemotherapy and achieving targeted drug delivery.

Dementia with Lewy Bodies is a neurodegenerative disorder characterised by abnormal α- synuclein aggregate accumulation in Lewy Bodies and Lewy Neurites and the most common form of dementia after Alzheimer’s disease. The presynaptic protein alpha-synuclein (α-Syn) regulates synaptic vesicle trafficking and the subsequent release of neurotransmitters in the brain. These aggregates go through a number of crucial stages, such as aggregation, oligomerization, and fibrillation. Treatment of this disorder is generally symptomatic. This necessitates the development of cuttingedge therapeutic approaches that can either stop or change the course of the diseases. Many studies have shown that α-synuclein is a significant therapeutic target and that inhibiting α-synuclein aggregation, oligomerization, and fibrillation is an important disease-modifying strategy. Since α-syn is a defining feature of Parkinson’s disease, the current review provides an overview of plant phytochemicals and synthetic heterocyclic compounds that target α-syn in Parkinson's disease in order to develop new drugs for Dementia with Lewy Bodies.

In the recent era, developments in the field of bio-inorganic chemistry have improved interest in Schiff base complexes (imine scaffolds) for their pharmacological excellence in different areas. Schiff bases are a kind of synthetic molecule that is synthesized by the condensation reaction between a 1o amine and a carbonyl compound. Imine derivatives are also acknowledged for their ability to form complexes with several metals. Due to their wide range of biological activities, they have acquired prominence in the therapeutic and pharmaceutical industries. Inorganic chemists have continued to be intrigued by the vast range of uses of these molecules. Many of them are also thermally stable and have structural flexibility. Some of these chemicals have been discovered to be beneficial as clinical diagnostic agents as well as chemotherapeutic agents. Because of the flexibility of the reactions, these complexes have a wide range of characteristics and applications in biological systems. Anti-neoplastic activity is one of them. This review attempts to draw attention to the most notable examples of these novel compounds, which have excellent anticancer activity against different cancers. The synthetic scheme of these scaffolds, their metal complexes, and the explanation of their anticancer mechanism reported in this paper lead the researchers to design and synthesize more target-specific Schiff base congeners with little or no side effects in the future.

Introduction: Breast cancer is the most common cancer affecting women worldwide, including Pakistan. More than half of breast cancer patients have hormone-dependent breast cancer, which is developed due to the over-production of estrogen (the main hormone in breast cancer). Methods: The biosynthesis of estrogen is catalyzed by the aromatase enzyme, which thus serves as a target for the treatment of breast cancer. During the current study, biochemical, computational, and STD-NMR methods were employed to identify new aromatase inhibitors. A series of phenyl-3- butene-2-one derivatives 1-9 were synthesized and evaluated for human placental aromatase inhibitory activity. Among them, four compounds 2, 3, 4, and 8 showed a moderate to weak inhibitory activity (IC50 = 22.6 - 47.9 μM), as compared to standard aromatase inhibitory drugs, letrozole (IC50 = 0.0147 ± 1.45 μM), anastrozole (IC50 = 0.0094 ± 0.91 μM), and exemestane (IC50 = 0.2 ± 0.032 μM). Kinetic studies on two moderate inhibitors, 4 and 8, revealed a competitive- and mixed-type of inhibition, respectively. Results: Docking studies on all active compounds indicated their binding adjacent to the heme group and interaction with Met374, a critical residue of aromatase. STD-NMR further highlighted the interactions of these ligands with the aromatase enzyme. Conclusion: STD-NMR-based epitope mapping indicated close proximity of the alkyl chain followed by an aromatic ring with the receptor (aromatase). These compounds were also found to be non-cytotoxic against human fibroblast cells (BJ cells). Thus, the current study has identified new aromatase inhibitors (compounds 4, and 8) for further pre-clinical and clinical research.

Background: Dimeric acylphloroglucinols occurring in species from sections Brathys and Trigynobrathys of the genus Hypericum exhibit acylfilicinic acid and acylphloroglucinol moieties linked by a methylene bridge. However, this chemical feature differs from hyperforin, from H. perforatum (Hypericum section). Some dimeric acylphloroglucinols, such as uliginosin B, display similar pharmacological activities, namely antidepressant and antinociceptive. However, there is no knowledge about the pharmacokinetic profile and no toxicity studies of these compounds in intact mammals. Objective: To perform an in silico evaluation of the similarity, pharmacokinetics and toxicity (ADMET) properties of dimeric acylphloroglucinols from species native to Central and South America. Methods: ADMET prediction of eleven elected phloroglucinols followed by the chemical space evaluation of thirty-five dimeric acylphloroglucinols derivatives labeled according to their prenylation/ geranylation pattern through principal component analysis (PCA). The similarity analysis was performed using the Tanimoto similarity index. ADMET properties were predicted with the opensource software SwissADME and pkCSM-pharmacokinetics. Results: Several compounds showed good human intestinal absorption. However, they may present difficulties in crossing the blood-brain barrier, probably due to the high tPSA values. The predicted toxicity parameters indicated that most compounds have low toxicity. Most non-prenylated phloroglucinols were disposed into Lipinski’s rule limits. Uliginosin B, isouliginosin B and japonicin A seem to be druglike compounds. The PCA model explained 77.49% of the total variance, and molecular similarity analyses revealed some expected similarities between isomers and different compounds. Conclusion: Dimeric acylphloroglucinols may be promising drug candidates and deserve further pharmacological and medicinal chemistry studies.

Background: Combretastatin A-4 (CA-4) binds β-tubulin at the colchicine-binding site preventing tubulin from polymerizing into microtubules. CA-4 and cis combretastatin analogs isomerize to the trans form resulting in decreased cytotoxicity and anti-tubulin activity. However, the excellent anti-cancer potential and relatively simple molecular structure of CA-4 provide an encouraging starting point for the development of new, more stable and more potent anti-tubulin compounds. Objective: This study aimed to synthesize a new series of compounds derived from 4-(3,4,5- trimethoxyphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione derivatives (compounds 10-12) with substituted phenyl group at C5 of the triazole ring (B-ring) as analogs of CA-4, with different alkyl and aryl side chain substituents at the triazole moiety, resulting in the permanent cis configuration of the two phenyl rings. Moreover, the anti-cancer activities of the new compounds were assessed. Methods: Chemical synthesis was carried out by conventional organic methods. The newly synthesized CA-4 analogs were characterized by FT-IR, ¹HNMR, ¹³CNMR, and HR-MS(ESI) techniques. Molecular docking studies, including docking score (ΔG), ADMET, DFT, and molecular similarities, were performed. The anti-proliferative activity of the new compounds against three human cancer cell lines (A549, Hep G2, and HCT-116) and the normal cell line WI-38 was evaluated using the MTT assay, and their ability to inhibit tubulin polymerization, and consequently, their effects on cell cycle progression and induction of apoptosis were assessed. Results: Molecular docking studies showed that compounds 11b and 11d exhibited the highest docking scores (-13.30 and -14.01 Kcal/mol, respectively) into the colchicine-binding site, scores very close to the reference drug colchicine (-13.50 Kcal/mol), and that hydrogen bonding and hydrophobic interaction are essential for binding. The most active cytotoxic compound, 11b, had potent IC50 values against the three human cancer cell lines (3.83, 10.20, and 10.67 μM against Hep G2, HCT- 116, and A549, respectively) while exhibiting low cytotoxicity against non-cancer-human WI-38, suggesting that compound 11b targets rapidly growing cancer cells. Moreover, compound 11b exhibited potent anti-tubulin activity which was comparable to CA-4. Targeting microtubules caused cell cycle arrest at the G2/M phase resulting in the induction of apoptosis. Conclusion: These findings indicate that compound 11b is a promising β-tubulin-binding compound with antimitotic action that has the potential to treat cancer.

Introduction: The attractive biological actions of the eicosatrienoic acids (EETs) and endocannabinoids (eCBs) are terminated by means of enzymatic hydrolysis via soluble epoxide hydrolase (sEH) and fatty acid amide hydrolase (FAAH) enzymes. Simultaneous inhibition of both enzymes is considered a novel approach in the treatment of inflammatory and neuropathic pain. Methods: In this study, a novel series of tetrazole derivatives as dual sEH/FAAH inhibitors were designed, synthesized, and biologically evaluated. Compounds 6c, 7d, and 8a, the most potent inhibitors against FAAH and sEH enzymes with acceptable IC50 values, significantly decreased carrageenan- induced paw edema 5h after carrageenan injection compared to the control group compound. In addition, compound 7d exhibited a significant reduction in pain scores compared to the control group. Results: Docking studies showed that the presented dual inhibitors could bind to the essential residues in the catalytic sites of both enzymes. In silico prediction of several pharmacokinetic properties suggests that these dual inhibitors could potentially be orally active agents. Conclusion: These structures will be a valuable scaffold to develop soluble epoxide hydrolase inhibitors with dual potency towards fatty acid amide hydrolase.

Background: Diabetes mellitus is a metabolic disease that causes multiple complications and common comorbidities, which decreases the quality of life for people affected by the disease. Sodium glucose cotransporter type 2 (SGLT2) participates in the reabsorption of 90% of glucose in the kidneys; therefore, it is an attractive drug target for controlling blood glucose levels. Objective: The aim in this work was to obtain new potential SGLT2 inhibitors. Methods: A ligand-based virtual screening (LBVS) from the ZINC15, PubChem and ChemSpider databases using the maximum common substructure (MCS) scaffold was performed. Result: A total of 341 compounds were obtained and analyzed by molecular docking on the active site of SGLT2. Subsequently, 15 compounds were selected for molecular dynamics (MD) simulation analysis. The compounds derived of spiroketal Sa1, Sa4, and Sa9 (≤ 3.5 Å) in complex with the receptor SGLT2 showed good stability during 120 ns of MD. Conclusion: These compounds are proposed as potential SGLT2 inhibitors.