Pawan Kaushik

Synthesis and biological evaluation of some pyrazolylpyrazolines as anti-inflammatory-antimicrobial agents

A new series of pyrazolylpyrazolines (5a-k) was synthesized by the reaction of appropriate chalcones (3a-k) with 4-hydrazinobenzenesulfonamide hydrochloride (4) in ethanol. All the newly synthesized target compounds (5a-k) were screened for their anti-inflammatory activity using carrageenan-induced rat paw edema assay. Compounds 5g and 5j showed pronounced anti-inflammatory activity comparable to the reference standard nimesulide, whereas, compounds 5b, 5d and 5h displayed good anti-inflammatory activity. Additionally, the synthesized compounds were evaluated for their in vitro antimicrobial activity against two Gram-positive bacteria and two Gram-negative bacteria. Four compounds 5c, 5h-5j showed good broad spectrum activity against all the tested Gram-positive and Gram-negative bacterial strains. Compound 5j could be identified as the most biologically active member within this study with an interesting dual anti-inflammatory and antibacterial profile.

Synthesis and pharmacological evaluation of some novel 2-(5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazol-1-yl)-4-(coumarin-3-yl)thiazoles.

A series of novel 2-(5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazol-1-yl)-4-(coumarin-3-yl)thiazoles (6) were synthesized by condensing 3-(2-bromoacetyl)coumarins (4) with various 5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazol-1-thiocarboxamides (5), obtained by the reaction of thiosemicarbazide with trifluoromethyl-β-diketones. All the tested compounds displayed significant to moderate in vivo anti-inflammatory activity when compared to the standard drug indomethacin, and good broad spectrum in vitro antibacterial activity against three Gram-positive and four Gram-negative bacteria when compared with cefixime.

Analgesic and Anti-Inflammatory Activity of Pinus roxburghii Sarg.

The Chir Pine, Pinus roxburghii, named after William Roxburgh, is a pine native to the Himalaya. Pinus roxburghii Sarg. (Pinaceae) is traditionally used for several medicinal purposes in India. As the oil of the plant is extensively used in number of herbal preparation for curing inflammatory disorders, the present study was undertaken to assess analgesic and anti-inflammatory activities of its bark extract. Dried and crushed leaves of Pinus roxburghii Sarg. were defatted with petroleum ether and then extracted with alcohol. The alcoholic extract at the doses of 100 mg/kg, 300 mg/kg, and 500 mg/kg body weight was subjected to evaluation of analgesic and anti-inflammatory activities in experimental animal models. Analgesic activity was evaluated by acetic acid-induced writhing and tail immersion tests in Swiss albino mice; acute and chronic anti-inflammatory activity was evaluated by carrageenan-induced paw oedema and cotton pellet granuloma in Wistar albino rats. Diclofenac sodium and indomethacin were employed as reference drugs for analgesic and anti-inflammatory studies, respectively. In the present study, the alcoholic bark extract of Pinus roxburghii Sarg. demonstrated significant analgesic and anti-inflammatory activities in the tested models.

Synthesis of novel celecoxib analogues by bioisosteric replacement of sulfonamide as potent anti-inflammatory agents and cyclooxygenase inhibitors

Two series of celecoxib analogues having 1,5-diaryl relationship were synthesized. The key strategy of the molecular design was oriented towards exploring bioisosteric modifications of the sulfonamide moiety of celecoxib. First series (2a-2i) of celecoxib analogues bearing cyano functionality in place of sulfonamide moiety was synthesized by the reaction of appropriate trifluoromethyl-β-diketones (5a-5i) with 4-hydrazinylbenzonitrile hydrochloride (4) in ethanol. Cyano moiety of pyrazoles 2 was then converted into corresponding carbothioamides 3 by bubbling H2S gas in the presence of triethylamine. All the synthesized compounds (2a-2i and 3a-3i) were screened for their in vivo anti-inflammatory (AI) activity using carrageenan-induced rat paw edema assay. COX-1 and COX-2 inhibitory potency was evaluated through in vitro cyclooxygenase (COX) assays. Compounds 2a, 2b, 2c, 2e and 3c showed promising AI activity at 3-4h after the carrageenan injection that was comparable to that of the standard drug indomethacin. Although compounds 3d, 3e and 3f exhibited more pronounced COX-2 inhibition but they also inhibit COX-1 effectively thus being less selective against COX-2. Three compounds 2a, 2f and 3a were found to have a COX profile comparable to the reference drug indomethacin. However 2e, 3b, 3c and 3i compounds were the most potent selective COX-2 inhibitors of this study with 3b showing the best COX-2 profile. In order to better rationalize the action and the binding mode of these compounds, docking studies were carried out. These studies were in agreement with the biological data.

Synthesis, biological evaluation and molecular modeling study of 5-trifluoromethyl-Δ2-pyrazoline and isomeric 5/3-trifluoromethylpyrazole derivatives as anti-inflammatory agents

Searching for new anti-inflammatory agents, we have prepared a series of potential COX-2 inhibitors, 1-(4,6-dimethylpyrimidin-2-yl)-5-hydroxy-5-trifluoromethyl-Δ(2)-pyrazolines (3) and 1-(4,6-dimethylpyrimidin-2-yl)-3-trifluoromethylpyrazoles (4), by refluxing 2-hydrazino-4,6-dimethylpyrimidine (1) with a number of trifluoromethyl-β-diketones (2) in ethanol. Further dehydration of compounds (3) to the corresponding 1-(4,6-dimethylpyrimidin-2-yl)-5-trifluoromethylpyrazoles (5) was also achieved. Fifteen of these compounds were screened for their anti-inflammatory activity using the carrageenan-induced rat paw edema assay. While all the compounds exhibited significant anti-inflammatory activity (47-76%) as compared to indomethacin (78%), 3-trifluoromethylpyrazoles (4) were found to be the most effective agents (62-76%). To rationalize this anti-inflammatory activity, docking experiments molecular dynamics simulations were performed to study the ability of these compounds to bind into the active site of the COX-2 enzyme.

Alstonia scholaris: It's Phytochemistry and pharmacology

Complementary therapies based on herbal medicines are the worlds oldest form of medicine and recent reports suggest that such therapies still enjoy vast popularity, especially in developing countries where most of the population does not have easy access to modern medicine. Alstonia scholaris (L.) R.Br (Apocynaceae) is an evergreen tropical tree native to Indian sub-continent and South East Asia, having grayish rough bark and milky sap rich in poisonous alkaloid. It is reported to contain various iridoids, alkaloids, coumarins, flavonoids, leucoanthocyanins, reducing sugars, simple phenolics, steroids, saponins and tannins. It has been reported to possess antimicrobial, antiamoebic, antidiarrheal, antiplasmodial, hepatoprotective, immunomodulatory, anticancer, antiasthmatic, free radical scavenging, antioxidant, analgesic, anti-inflammatory, antiulcer, antifertility and wound healing activities. In other parts of the world, it is used as a source cure against bacterial infection, malarial fever, toothache, rheumatism, snakebite, dysentery, bowl disorder, etc. Reports on the pharmacological activities of many isolated constituents from A. scholaris (L.) R.Br are lacking, which warrants further pharmacological studies.

Dual evaluation of some novel 2-amino-substituted coumarinylthiazoles as anti-inflammatory–antimicrobial agents and their docking studies with COX-1/COX-2 active sites

Abstract Synthesis of total eighteen 2-amino-substituted 4-coumarinylthiazoles including sixteen new compounds (3a–o and 5b) bearing the benzenesulfonamide moiety is described in the present report. All the synthesized target compounds were examined for their in vivo anti-inflammatory (AI) activity and in vitro antimicrobial activity. Results revealed that six compounds (3d, 3f, 3g, 3h, 3j and 3n) exhibited pronounced anti-inflammatory activity comparable to the standard drug indomethacin. AI results were further confirmed by the docking studies of the most active (3n) and the least active compound (3a) with COX-1 and COX-2 active sites. In addition, most of the compounds exhibited moderate antimicrobial activity against Gram-positive bacteria as well as fungal yeast, S. cervisiae. Comparison between 3 and 5 indicated that incorporation of additional substituted pyrazole nucleus into the scaffold significantly enhanced AI activity.

Synthesis and biological evaluation of pyrazolylthiazole carboxylic acids as potent anti-inflammatory–antimicrobial agents

Current Letter presents design, synthesis and biological evaluation of a novel series of pyrazolylthiazole carboxylates 1a-1p and corresponding acid derivatives 2a-2p. All 32 novel compounds were tested for their in vivo anti-inflammatory activity by carrageenan-induced rat paw edema method as well as for in vitro antimicrobial activity. All the tested compounds exhibited excellent AI activity profile. Three compounds 1p (R=Cl, R(1)=Cl), 2c (R=H, R(1)=F) and 2n (R=Cl, R(1)=OCH3) were identified as potent anti-inflammatory agents exhibiting edema inhibition of 93.06-89.59% which is comparable to the reference drug indomethacin (91.32%) after 3h of carrageenan injection while most of the other compounds displayed inhibition ⩾80%. In addition, pyrazolylthiazole carboxylic acids (2a-2p) also showed good antimicrobial profile. Compound 2h (R=OCH3, R(1)=Cl) showed excellent antimicrobial activity (MIC 6.25μg/mL) against both Gram positive bacteria comparable with the reference drug ciprofloxacin (MIC 6.25μg/mL).

Pharmacophore Modeling and Molecular Docking Studies on Pinus roxburghii as a Target for Diabetes Mellitus

The present study attempts to establish a relationship between ethnopharmacological claims and bioactive constituents present in Pinus roxburghii against all possible targets for diabetes through molecular docking and to develop a pharmacophore model for the active target. The process of molecular docking involves study of different bonding modes of one ligand with active cavities of target receptors protein tyrosine phosphatase 1-beta (PTP-1β), dipeptidyl peptidase-IV (DPP-IV), aldose reductase (AR), and insulin receptor (IR) with help of docking software Molegro virtual docker (MVD). From the results of docking score values on different receptors for antidiabetic activity, it is observed that constituents, namely, secoisoresinol, pinoresinol, and cedeodarin, showed the best docking results on almost all the receptors, while the most significant results were observed on AR. Then, LigandScout was applied to develop a pharmacophore model for active target. LigandScout revealed that 2 hydrogen bond donors pointing towards Tyr 48 and His 110 are a major requirement of the pharmacophore generated. In our molecular docking studies, the active constituent, secoisoresinol, has also shown hydrogen bonding with His 110 residue which is a part of the pharmacophore. The docking results have given better insights into the development of better aldose reductase inhibitor so as to treat diabetes related secondary complications.

Bioassay Guided Fractionation and ñ-Amylase Inhibitory Activity ofFlavanoid Isolated from Pinus roxburghii Sarg.

Pinus roxburghii Sarg. is a traditional plant used in the treatment of diabetes mellitus ethnopharmacology in India and Africa. In this written report, we looked into the antidiabetic activity using α-amylase inhibitory assay on extracts from the bark of Pinus roxburghii Sarg. by bioassay guided fractionation. The ethanol extract (43.4% inhibition) and the isolated compound (49.6% inhibition) exhibited significant enzyme inhibitory activity against α-amylase. This is reported, from this plant, for the first time. The 1H and 13C NMR, IR and mass spectral studies of isolated compound suggested it as quercetin. Our study revealed, for the first time, the isolation and α-amylase inhibitory activity of quercetin from Pinus roxburghii Sarg. bark.