Designing novel anti-plasmodial quinoline-furanone hybrids: computational insights, synthesis, and biological evaluation targeting Plasmodium falciparum lactate dehydrogenase.

To combat resistance against current antimalarials, modifying key pharmacophores and exploring novel parasite-specific drug targets remained one of the key drug design strategies. The resistance to quinoline-based antimalarials arises often due to the efflux of the drug. Hence, the development of newer agents containing bulkier pharmacophores will enable medicinal chemists to counteract drug resistance. In view of this, herein we designed bulkier quinoline-furanone hybrids. Initially, virtual drug-likeness and ADMET screening were conducted to optimize physicochemical properties followed by docking of the hybrids against the Plasmodium falciparum lactate dehydrogenase (PfLDH) enzyme. The most potent hybrids that emerged from the computational screening were synthesized and screened for their bioactivity against the resistant strain of Plasmodium through Schizont Maturation Inhibition assays. Among the compounds tested, 5g and 6e demonstrated the best activity, with IC50 values similar to chloroquine (CQ), and 5g exhibited superior LDH inhibition compared to CQ. Compounds 5f, 7a, and 7f showed IC50 values comparable to CQ and moderate LDH inhibition. Structure-activity relationship (SAR) analysis revealed that halogen substitutions, particularly Br and Cl, enhanced antimalarial activity, while strong electron-withdrawing (-NO2) or -donating (-OH) groups led to diminished activity. Additionally, bulkier aromatic substitutions were favoured for antimalarial activity and LDH inhibition. The investigation successfully found potent anti-plasmodial quinoline-furanone hybrids, demonstrating promising prospects for combating malaria.

In-Silico Design, Synthesis, and Pharmacological Evaluation of Oxadiazole-Based Selective Cyclo-oxygenase-2 Inhibitors.

A series of oxadiazole-based five-membered heterocyclic derivatives was designed and synthesized with the intent of exclusive cyclo-oxygenase-2 (COX-2) inhibition to acquire anti-inflammatory activity without the presence of gastric toxicity. Oxadiazole-based novel analogs were designed by using bioisosteric substitutions and were screened against the macromolecular target by using docking-based virtual screening to identify their potential inhibitors. These selective COX-2 inhibitors were further evaluated for their stability within the binding cavity of macromolecular complex by performing molecular dynamic simulation for 100 ns. Selected compounds were synthesized by using Naphthalene-2-yl-acetic acid as a starting material based on the fundamental structure of naphthalene. The naphthalene ring and methylene bridge of naphthalene-2-yl-acetic acid were retained in the rational molecular design by replacing the carboxyl group with biologically significant groups like 1,3,4-oxadiazoles, with the goal of obtaining a novel, superior, and relatively safe anti-inflammatory molecule with better efficacy and optimized pharmacokinetics. Anti-inflammatory as well as analgesic properties of the compounds were evaluated experimentally for their pharmacological efficiency.

Pyrazole based Furanone Hybrids as Novel Antimalarial: A Combined Experimental, Pharmacological and Computational Study.

BACKGROUND: Malaria parasite strains are resistant to the therapeutic effect of prophylactics medicines presently available. This resistance now poses a significant challenge to researchers to beat malaria parasitic infections. Strategies such as investigating newer hybrid chemical entities and specified drug targets may help us spot new efficient derivatives that bind to the parasites in a more specific manner and inhibit their growth. OBJECTIVE: To scientifically perform the experimental, pharmacological, and computational studies of pyrazole-based furanone hybrids as novel antimalarial agents. METHODS: A series of new furanone-based pyrazole derivatives were synthesized and investigated as potential antimalarial agents by performing in vitro antimalarial activity. To get further optimization, these synthesized derivatives were virtually screened based on ADME-T filters, and molecular docking studies were also accomplished on the crystal structures of Plasmodium falciparum lactate dehydrogenase (PfLDH). Furthermore, the in-silico prediction was supported by performing an LDH assay. RESULTS: The docking data suggested that the designed hybrid of furanone-pyrazole may act as PfLDH inhibitors. It was found that the results of experimental in vitro antimalarial activity and in silico analysis correlate well to each other to a good extent. The compounds (7d), (7g), and (8e) were found to be the most potent derivatives with IC50 values of 1.968, 1.983, and 2.069 µg/ml, respectively. CONCLUSION: From the results, it may be concluded that compounds that are active in low doses might be adopted as a lead compound for the development of more active antimalarial agents. The synthesized compounds (7d), (7g), and (8e) exhibited good antimalarial activity with PfLDH inhibition. The best compounds can be explored further in the future for designing the potent inhibitors of PfLDH as new potent antimalarial agents.

Synthesis, Molecular Docking, and Biological Evaluation of Some Novel 2- (5-Substituted 1,3,4-oxadiazole-2-yl)-1,3-benzothiazole Derivatives as Anticonvulsant Agents.

BACKGROUND: Benzothiazole is an organosulfur heterocyclic compound that has a considerable place in drug discovery due to significant pharmacological actions. OBJECTIVE: The main objective of the present study was to synthesize some novel 2-(5-substituted 1,3,4-oxadiazole-2-yl)-1,3-benzothiazole derivatives and evaluate them for their anticonvulsant activity using in silico and in vivo methods. METHODS: A set of sixteen 2-(5-substituted 1, 3, 4-oxadiazole-2-yl)-1, 3-benzothiazole derivatives were prepared using multi-step reactions starting from o-amino-thiophenol and characterized by suitable spectral techniques. The synthesized compounds were evaluated for anticonvulsant activity using in silico and in vivo methods. In silico molecular docking study was performed using Molegro Virtual Docker software to analyze binding modes of compounds with the internal ligand of PDB ID: 1OHY and 1OHV; and in vivo pharmacological activities were tested for both generalized tonic-clonic seizures and generalized absence (petit mal) seizures using Maximal Electrical Shock and PTZ-induced seizure models, respectively. RESULTS: Some new 2-(5-substituted-1,3,4-oxadiazole-2-yl)-1,3- benzothiazole (5a-5p) were successfully synthesized by finally refluxing 1, 3-benzothiazole-2-carboxyhydrazide with different aromatic acids in phosphoryl chloride. Docking results showed that compounds 5c, 5j, and 5m were found to have the highest number of H-bond interactions; i.e. 4, 4, and 7 respectively with target proteins 1OHY and 6, 3, and 4 respectively with target protein 1OHV, whereas phenytoin showed only two H-bonding with both proteins. In the Maximal electroshock seizure method, the synthesized compounds 5h, 5k and 5o demonstrated potent anticonvulsant activity against the tonic seizure with a significant decrease in tonic hind leg extension period with a mean duration of 7.9, 7.4, and 7.0 sec respectively, as compared to the other synthesized compounds. In contrast, in the PTZ-induced seizure model, compounds 5c, 5h, and 5m showed protection against clonic convulsion with significant elevation in the onset time of clonic convulsion at 311.2, 308.0, and 333.11 sec, respectively. CONCLUSION: Thus, from the results, it can be concluded that compound 5h, a benzothiazole derivative endowed with an oxadiazole ring, can be developed as a potential anticonvulsant agent.

Triazole analogues as potential pharmacological agents: a brief review.

BACKGROUND: A large number of studies have recently reported that, because of their significant biological and pharmacological properties, heterocyclic compounds and their derivatives have attracted a strong interest in medicinal chemistry. The triazole nucleus is one of the most important heterocycles which has a feature of natural products as well as medicinal agents. Heterocyclic nitrogen is abundantly present in most medicinal compounds. The derivatization of triazole ring is based on the phenomenon of bio-isosteres in which substituted the oxygen atom of oxadiazole nucleus with nitrogen triazole analogue. MAIN TEXT: This review focuses on recent synthetic procedure of triazole moiety, which comprises of various pharmacological activities such as antimicrobial, anticonvulsant, anti-inflammatory, analgesic, antitubercular, anthelmintic, antioxidant, antimalarial, antiviral, etc.. CONCLUSION: This review highlights the current status of triazole compounds as different multi-target pharmacological activities. From the literature survey, triazole is the most widely used compound in different potential activities.

Recent Patents, Formulation Techniques, Classification and Characterization of Liposomes.

BACKGROUND: During past decades, liposomes have emerged as efficient carriers for drugs, diagnostics, vaccines, nutrients and other bioactive agents. Liposomes, the spherical vesicles consisting of phospholipids bilayer have the ability to encapsulate both lipophilic and hydrophilic drugs. Extensive studies have been done in the past for investigating a number of drugs and genes for controlled release with liposomal formulation. Liposomes have also been investigated for their use in cancer treatment. Liposomes offer various advantages because of their biocompatible, biodegradable, nontoxic and non-immunogenic nature. METHODS: Liposomes have cell-specific targeting with important applications in the fields of nanotechnology like cancer therapy, diagnosis, gene delivery, cosmetics, agriculture and in food technology. They are prepared by various methods like sonication method, ethanol injection method, lipid film hydration method, micro-emulsion method. CONCLUSION: This review will provide an overview of classification, the various formulation methods, characterization, patented formulations and applications of liposomes with future prospects.

Toward the Synthesis and Improved Biopotential of an N-methylated Analog of a Proline-Rich Cyclic Tetrapeptide from Marine Bacteria.

An N-methylated analog of a marine bacteria-derived natural proline-rich tetracyclopeptide was synthesized by coupling the deprotected dipeptide fragments Boc-l-prolyl-l-N-methylleucine-OH and l-prolyl-l-N-methylphenylalanine-OMe. A coupling reaction was accomplished utilizing N,N'-Dicyclohexylcarbodidimde (DCC) and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC·HCl) as coupling agents and Triethylamine (TEA) or N-methylmorpholine (NMM) as the base in the presence of the racemization suppressing agent. This was followed by the cyclization of the linear tetrapeptide fragment under alkaline conditions. The structure of the synthesized cyclooligopeptide was confirmed using quantitative elemental analysis, FTIR (Fourier-transform infrared spectroscopy), ¹H NMR (Nuclear magnetic resonance spectroscopy), 13C NMR, and mass spectrometry. From the bioactivity results, it was clear that the newly synthesized proline-rich tetracyclopeptide exhibited better anthelmintic potential against Megascoplex konkanensis, Pontoscotex corethruses, and Eudrilus eugeniae at a concentration of 2 mg/mL as well as improved antifungal activity against pathogenic dermatophytes Trichophyton mentagrophytes and Microsporum audouinii at a concentration of 6 µg/mL, as compared to non-methylated tetracyclopeptide. Moreover, N-methylated tetracyclopeptide displayed significant activity against pathogenic Candida albicans.

Total Synthesis and Pharmacological Investigation of Cordyheptapeptide A.

The present investigation reports the synthesis of a phenylalanine-rich N-methylated cyclopeptide, cordyheptapeptide A (8), previously isolated from the insect pathogenic fungus Cordyceps sp. BCC 1788, accomplished through the coupling of N-methylated tetrapeptide and tripeptide fragments followed by cyclization of the linear heptapeptide unit. Structure elucidation of the newly synthesized cyclopolypeptide was performed by means of FT-IR, ¹H-NMR, 13C-NMR, and fast atom bombardment mass spectrometry (FABMS), and screened for its antibacterial, antidermatophytic, and cytotoxic potential. According to the antimicrobial activity results, the newly synthesized N-Methylated cyclopeptide exhibited potent antibacterial activity against Gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae and antifungal activity against dermatophytes Trichophyton mentagrophytes and Microsporum audouinii at a concentration of 6 µg/mL, in comparison to the reference drugs, gatifloxacin and griseofulvin. In addition, cyclopolypeptide 8 displayed suitable levels of cytotoxicity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines.

Quinoline based furanones and their nitrogen analogues: Docking, synthesis and biological evaluation.

A small library of twenty-four quinoline based butenolides also known as furanones and their nitrogen analogues was prepared by using two different aroylpropionic acids, viz. 3-(2-naphthoyl)propionic acid (3) and 3-(biphenyl-4-yl)propionic acid (4), as starting materials. The 3-aroylpropionic acids were reacted with different 6-substituted-2-chloroquinolin-3-carbaldehydes (2a-d) to obtain the corresponding furan-2(3H)-ones (5a-h). The purified and characterized furanones were then converted into their corresponding 2(3H)-pyrrolones (6a-h) and N-benzyl-pyrrol-2(3H)-ones (7a-h). The antimicrobial activities of the title compounds were evaluated against two strains of each Gram +ve (Staphylococcus aureus and Bacillus subtilis), Gram -ve bacteria (Escherichia coli and Pseudomonas aeruginosa) and against fungal strains of Aspergillus niger and Aspergillus flavus. In vivo anti-inflammatory potential of the title compounds was investigated by standard method. Majority of the compounds showed significant antibacterial activity against both the Gram +ve strains. Eight most potent anti-inflammatory compounds (5b, 5d, 5h, 6b, 7b, 7d, 7f, 7h) which exhibited >53% inhibition in edema, were also screened for their in vivo analgesic activity. All the tested compounds were found to have significant reduction in ulcerogenic action but only three compounds (5d, 5h and 7h) showed comparable analgesic activity to standard drug, diclofenac. The results were also validated using in silico approach and maximum mol doc score was obtained for compounds 7a-h. On comparing the in vivo and in silico anti-inflammatory results of synthesized compounds, N-benzyl pyrrolones (7a-h) emerged as the potent anti-inflammatory agents. It was also observed that compounds that possess electron withdrawing group such as -Cl or NO2 are more biologically active.

Ethnobotany and phytopharmacology of Pinus roxburghii Sargent: a plant review.

Traditional medicine is a blend of information gathered over generations from various communities and cultures. Pinus roxburghii Sargent (Pinaceae) commonly known as "chir pine" is widely used in traditional and folkloric systems of medicine. The all parts of the plant are believed to possess medicinal qualities in Ayurvedic and Unani systems of medicine. In these traditional systems of medicine, the plant is used to heal many diseases, including afflictions of the eyes, ears, throat, blood, and skin. The plant parts are rich in various bioactive compounds such as α-pinene, abietic acid, quercetin and xanthone. Resin acids and flavanoid form a major portion of these bioactive compounds. This review presents examples of traditional medicinal uses for P. roxburghii, and subsequently explores the current understanding of the chemical, pharmacological, and biochemical properties of the extracts and the main active constituents found in each tissue of the plant. Clinical trial information is also included where available. Careful evaluation of these data may be helpful for scientists and researchers to discover and evaluate the specific chemical entities responsible for the traditional medicinal uses of P. roxburghii.

Ethnobotany and phytopharmacology of Pinus roxburghii Sargent: a plant review / 中西医结合学报

Traditional medicine is a blend of information gathered over generations from various communities and cultures. Pinus roxburghii Sargent (Pinaceae) commonly known as "chir pine" is widely used in traditional and folkloric systems of medicine. The all parts of the plant are believed to possess medicinal qualities in Ayurvedic and Unani systems of medicine. In these traditional systems of medicine, the plant is used to heal many diseases, including afflictions of the eyes, ears, throat, blood, and skin. The plant parts are rich in various bioactive compounds such as α-pinene, abietic acid, quercetin and xanthone. Resin acids and flavanoid form a major portion of these bioactive compounds. This review presents examples of traditional medicinal uses for P. roxburghii, and subsequently explores the current understanding of the chemical, pharmacological, and biochemical properties of the extracts and the main active constituents found in each tissue of the plant. Clinical trial information is also included where available. Careful evaluation of these data may be helpful for scientists and researchers to discover and evaluate the specific chemical entities responsible for the traditional medicinal uses of P. roxburghii.

Synthesis of some novel N4-(naphtha[1,2-d]thiazol-2-yl)semicarbazides as potential anticonvulsants.

A series of N(4)-(naphtha[1,2-d]thiazol-2-yl)semicarbazides were designed and synthesized to meet the structural requirements essential for anticonvulsant activity. Anticonvulsant activity was determined after intraperitoneal (i.p.) administration to mice by maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ)-induced seizure tests and minimal motor impairment was determined by rotorod test. A majority of the compounds exhibited significant anticonvulsant activity after intraperitoneal administration. Some of the selected compounds were evaluated orally in rats for activity in scPTZ test at several time points (50 mg/kg). The most active compounds carry bromo, fluoro and nitro substituents at 4-position in the phenyl ring. The biochemical estimations of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) from brain homogenate not only clearly implicated the role of free radicals in PTZ-induced convulsion but also explained the possible mechanism of protective effect of semicarbazides, through the reduced formation of MDA and increased formation of SOD and GSH-Px.