Design and Synthesis of Benzimidazole Carboxamide Cysteine Protease Inhibitors as Promising Anti-leishmanial Agents.

INTRODUCTION: More than 20 protozoan species of Leishmania are responsible for causing Leishmaniasis, an infection spread by blood-feeding phlebotomine sandflies. A narrow pool of drugs is currently available rendering the current drug stratagem to treat this infection . Development of novel, less toxic, and more effective regimens is thus a need of the hour. Design and synthesis of benzo[d]imidazole carboxamides as agents to combat Leishmaniasis are also required. METHODS: 14 benzo[d]imidazole carboxamides were synthesized and gauged against L. donovani promastigotes and intramacrophage amastigote forms. All of the tested compounds exhibited significant anti-promastigote properties with IC50 well below 10 uM. Compounds 4a, 4b, and 4d, showing the highest anti-parasitic activity against promastigote forms (IC50 0.91- 1.33 µM), were also found to be associated with better anti-leishmanial potential (IC50 0.78- 1.67 µM) against the intramacrophage amastigotes comparable to Amphotericin-B (0.13 µM), a drug used for Leishmaniasis. Compound (4a), namely N-(2-(trifluoromethyl)-1Hbenzo[ d]imidazol-5-yl)benzo[d][1,3]-5-carboxamide-dioxole, was found to be most potent against L. donovani amastigotes among all the tested compounds, and demonstrated better antileishmanial properties (IC50 0.78 µM) when compared to the standard. Compound 4a was also assessed for its toxicity profile against THP-1 human monocytic cells. To establish the molecular target(s) in silico, molecular docking studies were performed against cysteine protease, a putative virulence factor of Leishmania parasites, and nucleoside diphosphate kinase, an enzyme with a critical role in nucleotide recycling, also associated with resistance in Leishmania strains. Compound 4a showed better binding affinity than the standard to these targets; furthermore, the molecular dynamic simulation studies further affirmed the stability of compound 4a, within the active site of the targets. In vitro, cysteine protease inhibitory activity (IC50 8.53 µM) using Bz-Arg-AMC hydrochloride fluorogenic peptide substrate established the promising potential of 4a as a cysteine protease inhibitor. RESULT: Computational ADMET analysis indicated appropriate pharmacokinetic profile and physicochemical characteristics for all members of the synthesized library. CONCLUSION: Both in vitro and in silico studies indicate that the synthesized imidazole carboxamides can act as potent hits and that N-(2-(trifluoromethyl)-1H-benzo[d]imidazol-5- yl)benzo[d][1,3]-5-carboxamide-dioxole 4a can be an effective hit molecule which can be further developed into potent lead molecule (s) to fight Leishmania donovani.

Design, synthesis, in vitro antiproliferative evaluation and GSK-3ß kinase inhibition of a new series of pyrimidin-4-one based amide conjugates.

A new series of novel amide conjugates of pyrimidin-4-one and aromatic/heteroaromatic /secondary cyclic amines has been synthesized and their in vitro antiproliferative activities against a panel of 60 human cancer cell lines of nine different cancer types were tested at NCI. Among the synthesized compounds, compound (4i) showed significant anti-proliferative activity. Compound (4i) displayed most potent activity against the breast tumor cell line T-47D and CNS tumor cell line SNB-75 exhibiting a growth of 1.93 % and 14.63 %, respectively. ADMET studies of the synthesized compounds were also performed and they were found to exhibit good drug like properties. Compound (4i) was found to exhibit potential inhibitory effect over GSK-3ß with IC50 value of 71 nM. The molecular docking studies revealed that (4i) showed good binding affinity to GSK-3ß and revealed multiple H-bonding and p-cation interactions with important amino acid residues on the receptor site. Compound (4i) may thus serve as a potential candidate for further development of novel anticancer therapeutics.

Novel 2,4-dichlorophenoxy acetic acid substituted thiazolidin-4-ones as anti-inflammatory agents: Design, synthesis and biological screening.

A library of fourteen 2-imino-4-thiazolidinone derivatives (1a-1n) has been synthesized and evaluated for in vivo anti-inflammatory activity and effect on ex-vivo COX-2 and TNF-α expression. Compounds 1k (5-(2,4-dichloro-phenooxy)-acetic acid (3-benzyl-4-oxo-thiazolidin-2-ylidene)-hydrazide) and 1m (5-(2,4-dichloro-phenooxy)-acetic acid (3-cyclohexyl-4-oxo-thiazolidin-2-ylidene)-hydrazide) exhibited in vivo inhibition of 81.14% and 78.80% respectively after 5h in comparison to indomethacin which showed 76.36% inhibition of inflammation without causing any damage to the stomach. Compound 1k showed a reduction of 68.32% in the level of COX-2 as compared to the indomethacin which exhibited 66.23% inhibition of COX-2. The selectivity index of compound 1k was found to be 29.00 in comparison to indomethacin showing selectivity index of 0.476. Compounds 1k and 1m were also found to significantly suppress TNF-α concentration to 70.10% and 68.43% in comparison to indomethacin which exhibited 66.45% suppression.

Natural and synthetic bioactive inhibitors of glycogen synthase kinase.

Glycogen synthase kinase-3 is a multi-functional serine-threonine kinase and is involved in diverse physiological processes, including metabolism, cell cycle, and gene expression by regulating a wide variety of known substrates like glycogen synthase, tau-protein and ß-catenin. Aberrant GSK-3 has been involved in diabetes, inflammation, cancer, Alzheimer's and bipolar disorder. In this review, we present an overview of the involvement of GSK-3 in various signalling pathways, resulting in a number of adverse pathologies due to its dysregulation. In addition, a detailed description of the small molecule inhibitors of GSK-3 with different mode of action discovered or specifically developed for GSK-3 has been presented. Furthermore, some clues for the future optimization of these promising molecules to develop specific drugs inhibiting GSK-3, for the treatment of associated disease conditions have also been discussed.

Synthesis of pyrimidin-4-one-1,2,3-triazole conjugates as glycogen synthase kinase-3ß inhibitors with anti-depressant activity.

GSK-3 specific inhibitors are promising candidates for the treatment of devastating pathologies such as diabetes, neurodegenerative diseases and cancers. We have synthesized a library of pyrimidin-4-one-1,2,3-triazole conjugates using click-chemistry approach and evaluated them as glycogen synthase kinase-3ß inhibitors. Compounds 3g, 3j, 3n and 3r were found to be most potent among the eighteen pyrimidin-4-one-1,2,3-triazole conjugates synthesized and they were further evaluated for their in vivo anti-depressant activity. Compound 3n (2-((1-(3,4-dimethylphenyl)-1H-1,2,3-triazol-4-yl)methylthio)-3-methyl-6-phenylpyrimidin-4(3H)-one) exhibited the most potent inhibitory activity against GSK-3ß with IC50 value of 82nM and was also found to exhibit significant antidepressant activity at 50mg/kg, when compared with fluoxetine, a known antidepressant drug. The molecular docking studies were performed to elucidate the binding modes of the compounds with the GSK-3ß target and two crucial interactions namely, hydrogen bond formation with Val 135 and Lys 183 residues in the active site of GSK-3ß were observed.

Antidiabetic effect of novel benzenesulfonylureas as PPAR-γ agonists and their anticancer effect.

Twenty one pyrazoline containing benzenesulfonylureas were synthesized and docked against PPAR-γ target. All the compounds were first screened for their antidiabetic potential by oral glucose tolerance test and then six active compounds were assessed on STZ diabetic model. It was found that five compounds showed significantly high antidiabetic activity in comparison to glibenclamide as well as rosiglitazone (standard drugs). The active compounds were evaluated for their effect on body weight since weight management is one of the main concerns associated with sulfonylureas. Finally, the most active compound 6f was shown to elevate PPAR-γ gene expression. The synthesized compounds were also screened for anticancer activity by National Cancer Institute. Five compounds (5i, 6e, 6g, 6i and 6j) were selected at one dose level and showed potency against cancers.

Ameliorative effects of Trichosanthes dioica Extract in suppressing inflammatory mediators and attenuating oxidative stress.

The present study aimed to investigate the anti-inflammatory activity of the ethanolic extract of the aerial parts of Trichosanthes dioica and its successive fractions. The effect on oxidative stress involved in the pathogenesis of inflammation was evaluated. The ethanolic extract and its successive fractions were administered at a dose of 150 and 300 mg/kg b. w. for testing their anti-inflammatory activity by a carrageenan-induced edema model. The results showed that the ethyl acetate fraction exhibited significant potency against inflammation. Pertaining to mechanistic insight, the anti-inflammatory effect might be attributed to the attenuation in tumor necrosis factor-α level (ELISA assay) and reduced expression of cyclooxygenase-2 and nuclear transcription factor-κB (immunohistochemistry). The alleviation in oxidative stress has been pertinent to the elevation in the activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione) by active fractions. Furthermore, the ulcerogenic effect was insignificant even at a three times higher dose. Finally, it was concluded that the ethyl acetate fraction which showed significant biological potential against inflammation and oxidative stress could be viewed as a source of effective treatment.

1,3,4-Thiadiazoles: a potent multi targeted pharmacological scaffold.

Despite a significant work on thiadiazoles, continuous efforts are still being made to identify novel heterocyclic compounds with potent biological activities. This review may help the medicinal chemists to develop new leads possessing 1,3,4-thiadiazole nucleus with higher efficacy and reduced side effects. This review throws light on the detailed synthetic approaches which have been used for the synthesis of thiadiazoles. This has been followed by the in depth analysis of the thiadiazoles with respect to their medicinal significance.

Design and Synthesis of Butenolide-based Novel Benzyl Pyrrolones: Their TNF-α based Molecular Docking with In vivo and In vitro Anti-inflammatory Activity.

A focused library of novel benzyl pyrrolones has been synthesized and their in silico molecular docking studies carried out against TNF-α target. Among all the docked molecules, compound 3f showed best glide score of -6.89. All the synthesized compounds were evaluated for in vivo anti-inflammatory activity by carrageenan-induced paw edema model. Compounds showing significant anti-inflammatory activity were further tested for their in vitro TNF α expression. Compounds 3b and 2b were found to show significant inhibition of 76.22% and 71.47%, respectively after 5 h in comparison with standard drug indomethacin, which showed 80.98% inhibition of inflammation. Compounds 3b and 2b also suppressed TNF α level by 65.03% and 60.90% as compared indomethacin, which showed 68.84% of inhibition. Compound 3b showed significant analgesic activity of 60.04%, and its activity was comparable with indomethacin (64.04%). Compounds 3b and 2b were also tested for their effect on protein expression of COX-2 and NF-κB in the liver tissues. Compounds 3b and 2b were further evaluated for their gastric risk and lipid peroxidation action and showed superior GI safety along with reduction of LPO as compared to indomethacin. Hepatotoxicity study showed that these two compounds did not cause any damage to liver.

Novel benzenesulfonylureas containing thiophenylpyrazoline moiety as potential antidiabetic and anticancer agents.

In the present study a library of twenty six benzenesulfonylureas containing thiophenylpyrazoline moiety has been synthesized. All the compounds were docked against PPAR-γ target. Most of the compounds displayed higher dock score than standard drugs, glibenclamide and rosiglitazone. All the synthesized compounds were primarily evaluated for their antidiabetic effect by oral glucose tolerance test. Further assessment of antidiabetic potential of sixteen active compounds was then done on STZ induced diabetic model. The results of in vivo activity by both the methods were found to be consistent with each other as well as with docking studies. Change in body weight of STZ induced animals post treatment was also assessed at the end of study. In vitro PPAR-γ transactivation assay was performed on active compounds in order to validate docking results and the most active compound 3 k was also shown to elevate gene expression of PPAR-γ. Furthermore, the compounds were screened by National Cancer Institute, Bethesda for anticancer effect and two compounds 3h and 3 i were selected at one dose level since they exhibited sensitivity towards tumor cell lines (mainly melanoma).

Synthesis and evaluation of pyrazolines bearing benzothiazole as anti-inflammatory agents.

The present study aims at the synthesis of pyrazolines bearing benzothiazole and their evaluation as anti-inflammatory agents. The synthesized compounds were evaluated for their anti-inflammatory potential using carrageenan induced paw edema model. Two compounds 5a and 5d alleviated inflammation more than the standard drug celecoxib. Eight compounds 5 b, 5 c, 5 e, 5 g, 5 h, 6 b, 6 e and 6 f showed anti-inflammatory activity comparable to celecoxib. To understand the mode of action, COX-2 enzyme assay and TNF-α assay were carried out. All the active compounds were assessed for their cytotoxicity. The ulcerogenic risk evaluation was performed on the active compounds that were not found to be cytotoxic. Out of ten active compounds, two compounds (5 d and 6 f) were finally found to be the most potent anti-inflammatory agents attributing to the suppression of the COX-2 enzyme activity and TNF-α production without being either cytotoxic or ulcerogenic.

Attenuation of inflammatory mediators, oxidative stress and toxic risk evaluation of Aporosa lindleyana Baill bark extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditionally, Aporosa lindleyana Baill. has been used against various ailments viz. jaundice, fever, headache, seminal loss and insanity. The present study aims to evaluate the anti-inflammatory and anti-oxidant activity of the ethanolic extract of Aporosa lindleyana Baill. bark and its fractions. METHOD: The anti-inflammatory activity of ethanolic extract of Aporosa lindleyana Baill. bark and its various fractions at doses of 200mg/kg and 300mg/kg b.w. has been carried out by a carrageenan induced hind paw edema method. To establish the probable mechanism of action, TNF-α and NO levels have been estimated by an ELISA method and the effect of active fraction on COX-2 and NF-κB expressions has been evaluated. The effect on the levels of anti-oxidative enzymes (CAT, SOD & GPX) by the ethanolic extract and its fractions has also been investigated. Furthermore, peptic ulcer and hepatotoxic risk evaluation has also been carried out at three times higher dose than that used in inflammatory in vivo model. RESULTS: Among the extract and its various fractions tested for anti-inflammatory activity, the methanolic fraction at a dose of 300mg/kg showed significant inhibition in paw edema by 73% as compared to Indomethacin which showed 77% inhibition after 5h. The same dose of methanolic fraction also caused significant reduction in TNF-α (59.27%) and NO concentration (57.12%) while Indomethacin showed inhibition of 63.91% and 60.12%. The active methanolic fraction was also found to inhibit the expression of NF-κB and COX-2 induced by carrageenan. Histological studies showed that the ethanolic extract and its fractions did not cause any damage to the stomach as well as to liver. Moreover, the active fractions also decreased lipid peroxidation levels and increased the antioxidant enzyme activities (SOD, CAT, GPX). CONCLUSION: The results of present study demonstrated that significant anti-inflammatory activity of methanolic fraction of Aporosa lindleyana may be attributed to the modulation of pro-inflammatory mediators. Same fraction was also found to be effective against oxidative stress as it was found to elevate the levels of anti-oxidative enzymes. It can therefore be concluded that the methanolic fraction could be explored as a disease modifying agent against inflammation and oxidative stress.

Synthesis of novel 2-mercaptobenzoxazole based 1,2,3-triazoles as inhibitors of proinflammatory cytokines and suppressors of COX-2 gene expression.

A library of novel bis-heterocycles containing 2-mercaptobenzoxazole based 1,2,3-triazoles has been synthesized using click chemistry approach. The compound 4 exhibited the most potent in vivo anti-inflammatory activity with 66.66% and 61.11% inhibition in comparison to celecoxib which showed 72.22% and 65.55% inhibition after 3 h and 5 h respectively. The compounds 4 and 9 suppressed the COX-2 gene expression by 0.94 and 0.79 fold and exhibited a selective index (COX-1/COX-2) of 64.79 and 66.47 respectively in comparison to celecoxib (SI value of 75.56). The in silico molecular docking studies showed the interactions of these molecules with Tyr-59, Tyr-119 and Gly-121. When compared with the standard drug celecoxib, compounds 4, 5, 7, 9 and 16 did not cause any gastric ulceration.

Trapa natans L. root extract suppresses hyperglycemic and hepatotoxic effects in STZ-induced diabetic rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: Trapa natans L. has a folkloric reputation as nutrient, appetizer and astringent. Its utility as antidiabetic, anticancer, diuretic, aphrodisiac, antidiarrhoeal and in many other maladies is well reported in the literature. Therefore, the present study has been carried out to study the antihyperglycemic effect of root extract of Trapa natans L. and its various fractions. Furthermore, hepatotoxic effects and lipid peroxidation risks have also been evaluated. METHODS: The ethanol extract and its successive fractions obtained from roots of Trapa natans have been administered in sucrose loaded and STZ- induced diabetic Wistar rats at doses of 50, 100 and 200mg/kg b.w. Glibenclamide was used as positive control. The evaluation of protective effects of extract as well as fractions against hepatotoxicity and lipid peroxidation at 600mg/kg b.w. has also been carried out. RESULTS: The methanol fraction emerged as the most potent antihyperglycemic fraction. It has also been found that the ethanolic extract as well as its fractions did not cause any lipid peroxidation and hepatotoxicity risks. CONCLUSION: It can be concluded that the intense investigations of the methanol fraction obtained from Trapa natans root extract can be done to provide an alternative natural therapy for hyperglycemia.

Synthesis of novel 1,2,3-triazole based benzoxazolinones: their TNF-α based molecular docking with in-vivo anti-inflammatory, antinociceptive activities and ulcerogenic risk evaluation.

A library of novel bis-heterocycles containing benzoxazolinone based 1,2,3-triazoles has been synthesized using click chemistry approach. The compound 3f exhibited potent selective COX-2 inhibition of 59.48% in comparison to standard drug celecoxib (66.36% inhibition). The compound 3i showed significant (p < 0.001, 50.95%), TNF-α inhibitory activity as compared to indomethacin (p < 0.001, 64.01%). The results of the carrageenan induced hind paw oedema showed that compounds 3a, 3f, 3i, 3o, and 3e exhibited potent anti-inflammatory activity in comparison to Indomethacin. The molecular docking studies revealed that 3i exhibits strong inhibitory effect due to the extra stability of the complex because of an extra π-π bond. The histopathology report showed that none of the compounds caused gastric ulceration.

Anti-inflammatory and anti-nociceptive activities of ethanolic extract and its various fractions from Adiantum capillus veneris Linn.

AIM OF THE STUDY: To investigate the anti-inflammatory and anti-nociceptive activities of the crude ethanolic extract of Adiantum capillus veneris Linn. (Adiantaceae) and its various fractions. MATERIALS AND METHODS: The ethanolic extract and its fractions were given at a dose of 200 mg/kg po and 300 mg/kg po for testing their anti-inflammatory activity by carrageenan induced hind paw edema. The analgesic activity of the ethanolic extract and its fractions has been carried out by tail-flick method and writhing test at a dosage of 300 mg/kg po. Gastric ulceration studies have been further carried out to study the antiulcer effect of the ethanolic extract and its various fractions at dose of 900 mg/kg body weight. RESULTS: Amongst the tested fractions, the ethyl acetate fraction exhibited better inhibition (67.27%) at 300 mg/kg po dosage when compared to the standard drug Indomethacin (63.63%) after 3h in the carrageenan induced hind paw edema. The anti-inflammatory activity of the ethanolic extract and its various fractions appear to be related to the inhibition of NO release, and the decreasing TNF-α level. The ethanolic extract and all its fractions especially the ethyl acetate (p<0.01) showed significant analgesic activity with insignificant ulceration as compared to the standard drug, i.e. ibuprofen. The histopathological study of ethanolic extract and its fractions reveals that none of them cause ulcer. CONCLUSION: The present study indicates that Adiantum capillus veneris Linn. has significant anti-inflammatory and analgesic effect.

Synthesis of some new 1,3,5-trisubstituted pyrazolines bearing benzene sulfonamide as anticancer and anti-inflammatory agents.

Thirteen new 2-pyrazoline derivatives bearing benzenesulfonamide moiety (2a-m) were synthesized by condensing appropriate chalcones with 4-hydrazinonbenzenesulfonamide hydrochloride and tested for anticancer and anti-inflammatory actions. According to the protocol of the National Cancer Institute (NCI) in vitro disease-oriented human cells screening panel assay compounds 2b, 2c, 2e, 2f and 2g exhibited considerable antitumor activities against the entire tested tumor cell lines and showed effective growth inhibition GI(50) (MG-MID) values of 2.63, 2.57, 6.61, 3.31 and 2.57µM, respectively, beside a cyclostatic activity TGI (MG-MID) 9.54, 8.51, 24.0, 19.9 and 8.71µM, respectively. Two compounds 2g and 2k showed more potent anti-inflammatory activity than celecoxib at 5h in carrageenan-induced rat paw edema bioassay. These compounds (2g and 2k) proved to have superior gastrointestinal safety profiles as compared to celecoxib, when tested for their ulcerogenic effects. Compounds 2g and 2k showed no inhibition against the enzymatic activity of bovine COX-2 (in vitro).

Two new bioactive oleanane triterpene glycosides from Terminalia arjuna.

Two new oleanane-type triterpene glycosides designated as Termiarjunoside I and Termiarjunoside II were isolated from stem bark of Terminalia arjuna (Combretaceae) and characterized as olean-1alpha,3beta,9alpha,22alpha-tetraol-12-en-28-oic acid-3beta-D-glucopyranoside (1) and olean-3alpha,5alpha,25-triol-12-en-23,28-dioic acid-3alpha-D-glucopyranoside (2) based on chemical and spectral data evidences. Both compounds 1 and 2 potently suppressed the release of nitric oxide and superoxide from macrophages and also inhibited aggregation of platelets.

Antiinflammatory evaluation of alcoholic extract of galls of Quercus infectoria.

Galls of Quercus infectoria Olivier (Fagaceae) possess pleiotropic therapeutic activities, with particular efficacy against inflammatory diseases. The present study was undertaken to evaluate the effect of alcoholic extract of Q. infectoria galls on various in vivo and in vitro experimental models of inflammation. Oral administration of gall extract significantly inhibited carrageenan, histamine, serotonin and prostaglandin E2 (PGE2) induced paw oedemas, while topical application of gall extract inhibited phorbol-12-myristate-13-acetate (PMA) induced ear inflammation. The extract also inhibited various functions of macrophages and neutrophils relevant to the inflammatory response. In vitro exposure of rat peritoneal macrophages to gall extract ameliorated lipopolysaccharide (LPS) stimulated PGE2 and nitric oxide (NO) production and PMA stimulated superoxide (O2*-) production in a dose dependent manner. Gall extract also scavenged NO and O2*-. Probing into mechanism of NO inhibition in macrophages revealed gall extract to ameliorate the induction of inducible NO synthase (iNOS), respectively without any inhibitory effect on its catalytic activities even at higher concentrations. Gall extract also significantly inhibited formyl-Met-Leu-Phe (fMLP) stimulated degranulation in neutrophils. These results suggest that alcoholic extract of galls of Q. infectoria exerts in vivo antiinflammatory activity after oral or topical administration and also has the ability to prevent the production of some inflammatory mediators.

Terminoside A, a new triterpene glycoside from the bark of Terminalia arjuna inhibits nitric oxide production in murine macrophages.

Terminoside A (1), a new oleanane-type triterpene was isolated from the acetone fraction of the ethanolic extract of stem bark of Terminalia arjuna. The structure was established as olean-1alpha,3beta,22beta-triol-12-en-28-oic acid-3beta-D-glucopyranoside. On the basis of spectral data and chemical reactions, terminoside A, potently inhibited nitric oxide (NO) production and decreased inducible nitric oxide synthase (iNOS) levels in lipopolysaccharide-stimulated macrophages.