Synthesis, biological evaluation, and docking studies of 3-(substituted)-aryl-5-(9-methyl-3-carbazole)-1H-2-pyrazolines as potent anti-inflammatory and antioxidant agents

Design, synthesis and evaluation of some pyrazolo[3,4-d]pyrimidines as anti-inflammatory agents

New pyrazolo[3,4-d]pyrimidines substituted with various functionalities or attached to a substituted pyrazole ring through different linkages were synthesized. The synthesized compounds were evaluated for their anti-inflammatory activity using in vitro COX-1/COX-2 inhibition assay and in vivo formalin induced paw edema and cotton pellet-induced granuloma assays. Results revealed that compounds 17b and 18 possessed COX-1/COX-2 selectivity indices higher than diclofenac sodium and celecoxib. However, compounds 16a,b exhibited selectivity indices higher than diclofenac sodium and nearly equivalent to celecoxib, whereas, 9b displayed selectivity index comparable to diclofenac sodium. In vivo anti-inflammatory data showed that compounds 9b, 16a, 18 displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, the pyrazolyl derivatives 9b, 16b and 17b displayed anti-inflammatory activity about 2-2.5-fold that of diclofenac sodium and nearly 8-10.5-fold that of celecoxib in the cotton pellet-induced granuloma assay. The ulcerogenic effect of the active compounds was also investigated and results revealed that compounds 16a, 17a,b and 18 showed good gastrointestinal safety profile. Based on this, compounds 16a and 18 were considered as safe and effective leads in managing acute inflammation, while, 17b was prominent in controlling chronic inflammation.

Design, synthesis and biological evaluation of new carbazole derivatives as anti-cancer and anti-migratory agents

Based on the efficacy of EHop-016 as an inhibitor of migration and Rac1 activation, a new series of carbazole derivatives has been synthesized. Cytotoxic and anti-migratory effects of these compounds were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines. Preliminary investigations of their anticancer activity demonstrated that several compounds have moderate antiproliferative effects on cancer cell lines with GI50 values in the range of 13-50 µM. Furthermore, compounds 3b and 11b inhibit migration activity of metastatic cell line MDA-MB-231 by 32% and 34%, respectively. Compound 11b was shown to inhibit activation of the Rho GTPase Rac1 by 55% at 250 nM in both MDA-MB-231 and MDA-MB-435 cell lines. Compared with the IC50 of Rac1 inhibition by lead compound EHop-016 of 1.1 µM, compound 11b demonstrates 4X improved in vitro efficacy.

Anticancer and anti-inflammatory activities of girinimbine isolated from Murraya koenigii

Therapy that directly targets apoptosis and/or inflammation could be highly effective for the treatment of cancer. Murraya koenigii is an edible herb that has been traditionally used for cancer treatment as well as inflammation. Here, we describe that girinimbine, a carbazole alkaloid isolated from M. koenigii, induced apoptosis and inhibited inflammation in vitro as well as in vivo. Induction of apoptosis in human colon cancer cells (HT-29) by girinimbine revealed decreased cell viability in HT-29, whereas there was no cytotoxic effect on normal colon cells. Changes in mitochondrial membrane potential, nuclear condensation, cell permeability, and cytochrome c translocation in girinimbine-treated HT-29 cells demonstrated involvement of mitochondria in apoptosis. Early-phase apoptosis was shown in both acridine orange/propidium iodide and annexin V results. Girinimbine treatment also resulted in an induction of G0/G1 phase arrest which was further corroborated with the upregulation of two cyclin-dependent kinase proteins, p21 and p27. Girinimbine treatment activated apoptosis through the intrinsic pathway by activation of caspases 3 and 9 as well as cleaved caspases 3 and 9 which ended by triggering the execution pathway. Moreover, apoptosis was confirmed by downregulation of Bcl-2 and upregulation of Bax in girinimbine-treated cells. In addition, the key tumor suppressor protein, p53, was seen to be considerably upregulated upon girinimbine treatment. Induction of apoptosis by girinimbine was also evidenced in vivo in zebrafish embryos, with results demonstrating significant distribution of apoptotic cells in embryos after a 24-hour treatment period. Meanwhile, anti-inflammatory action was evidenced by the significant dose-dependent girinimbine inhibition of nitric oxide production in lipopolysaccharide/interferon-gamma-induced cells along with significant inhibition of nuclear factor-kappa B translocation from the cytoplasm to nucleus in stimulated RAW 264.7 cells. Girinimbine was also shown to have considerable antioxidant activity whereby 20 μg/mL of girinimbine was equivalent to 82.17±1.88 μM of Trolox. In mice with carrageenan-induced peritonitis, oral pretreatment with girinimbine helped limit total leukocyte migration (mainly of neutrophils), and reduced pro-inflammatory cytokine levels (interleukin-1beta and tumor necrosis factor-alpha) in the peritoneal fluid. These findings strongly suggest that girinimbine could act as a chemopreventive and/or chemotherapeutic agent by inducing apoptosis while suppressing inflammation. There is a potential for girinimbine to be further investigated for its applicability in treating early stages of cancer.

Synthesis, Spectral Characterization and Fluorescent Assessment of 1,3,5-Triaryl-2-pyrazoline Derivatives: Experimental and Theoretical Studies

Two new pyrazoline derivatives, namely 5-(4-bromophenyl)-3-(5-chlorothiophen-2-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (3) and 5-(4-bromophenyl)-3-(2,5-dichlorothiophen-3-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (4) have been synthesized and characterized based on their spectral (IR, (1)H and (13)C NMR and MS) data and microanalysis. The fluorescence properties of 3 and 4 were studied by UV-Vis and emission spectroscopy. For compound 3, a fluorescence emission was observed in the blue region of the visible spectrum. The effect of different solvents on fluorescence was also investigated. Density Functional Theory calculations have also been performed to gain insight into geometric, electronic and spectroscopic properties of the pyrazoline derivatives. Both structures are analysed and compared in order to rationalize the different behaviour in 3 and 4.

Development of Antioxidant COX-2 Inhibitors as Radioprotective Agents for Radiation Therapy-A Hypothesis-Driven Review

Radiation therapy (RT) evolved to be a primary treatment modality for cancer patients. Unfortunately, the cure or relief of symptoms is still accompanied by radiation-induced side effects with severe acute and late pathophysiological consequences. Inhibitors of cyclooxygenase-2 (COX-2) are potentially useful in this regard because radioprotection of normal tissue and/or radiosensitizing effects on tumor tissue have been described for several compounds of this structurally diverse class. This review aims to substantiate the hypothesis that antioxidant COX-2 inhibitors are promising radioprotectants because of intercepting radiation-induced oxidative stress and inflammation in normal tissue, especially the vascular system. For this, literature reporting on COX inhibitors exerting radioprotective and/or radiosensitizing action as well as on antioxidant COX inhibitors will be reviewed comprehensively with the aim to find cross-points of both and, by that, stimulate further research in the field of radioprotective agents.

Synthesis, characterization, antiproliferative and molecular docking study of new half sandwich Ir(III), Rh(III) and Ru(II) complexes

The new carbazole N,N' ligand containing [(η(5)-C5Me5)MCl(L)]PF6, (M=Ir (1) and Rh (2)) and [(η(6)-C6H6)RuCl(L)]PF6 (3) (C5Me5=pentamethylcyclopentadienyl, L=9-ethyl-N-(pyridine-2-yl methylene)-9H-carbazole-3-amine) complexes has been synthesized and characterized by (1)H NMR, (13)C NMR, 2D NMR, melting point analysis, electronic absorption, infrared spectroscopy, HR-Mass spectroscopy and elemental analyses. The crystal structure of the [(η(5)-C5Me5)RhCl(L)]PF6 has been confirmed by single crystal XRD. The anticancer study of the synthesized complexes 1-3 clearly showed a potent inhibitor of human breast cancer cells (MCF-7) under in vitro conditions. The inhibitory concentrations (IC50) of the complexes 1-3 were determined at low (5, 6 and 8μM) concentration against the MCF-7 human breast cancer cell line. Further cytotoxic, cell cycle and nuclear studies confirmed that the novel half sandwich Ir(III), Rh(III) and Ru(II) complexes could be effective against MCF-7 human breast cancer cell proliferation. Moreover the results indicate that anticancer in vitro activity of complexes 1-3 falls in the order of 1>2>3. A molecular docking study of the complexes 1-3 showed the nature of binding energy, H-bond and hydrophobic interactions with the cyclooxygenase-2 (COX-2) receptor.

Synthesis and in silico investigation of thiazoles bearing pyrazoles derivatives as anti-inflammatory agents

Searching novel, safe and effective anti-inflammatory agents has remained an evolving research enquiry in the mainstream of inflammatory disorders. In the present investigation series of thiazoles bearing pyrazole as a possible pharmacophore were synthesized and assessed for their anti inflammatory activity using in vitro and in vivo methods. In order to decipher the possible anti-inflammatory mechanism of action of the synthesized compounds, cyclooxygenase I and II (COX-I and COX-II) inhibition assays were also carried out. The results obtained clearly focus the significance of compounds 5d, 5h and 5i as selective COX-II inhibitors. Moreover, compound 5h was also identified as a lead molecule for inhibition of the carrageenin induced rat paw edema in animal model studies. Molecular docking results revealed significant interactions of the test compounds with the active site of COX-II, which perhaps can be explored for design and development of novel COX-II selective anti-inflammatory agents.

Design, synthesis, and biological evaluation of novel carbazole aminothiazoles as potential DNA-targeting antimicrobial agents

Synthesis of a series of carbazole aminothiazoles as a new type of potential antimicrobial agents, and preliminary interactions with DNA indicated a possible intercalation mechanism.

Synthesis and biological evaluation of novel carbazolyl glyoxamides as anticancer and antibacterial agents

A new library of 24 carbazolyl glyoxamides14a–xwere designed and synthesized from glyoxalic acids and arylamines in the presence of HATU as a coupling reagent under MW irradiation.

Recent Developments and Biological Activities of N-Substituted Carbazole Derivatives: A Review

Carbazoles represent an important class of heterocycles. These have been reported to exhibit diverse biological activities such as antimicrobial, antitumor, antiepileptic, antihistaminic, antioxidative, anti-inflammatory, antidiarrhoeal, analgesic, neuroprotective and pancreatic lipase inhibition properties. A series of carbazole derivatives such as N-substituted carbazoles, benzocarbazoles, furocarbazoles, pyrrolocarbazoles, indolocarbazoles, imidazocarbazoles, etc. have been synthesized. The N-substituted derivatives have gained the attention of researchers due to their therapeutic potential against neurological disorders and cell proliferation. Herein an attempt is made to review the medicinal importance of recently synthesized N-substituted carbazoles.

Flavonoids as a scaffold for development of novel anti-angiogenic agents: An experimental and computational enquiry

Relationship between structural diversity and biological activities of flavonoids has remained an important discourse in the mainstream of flavonoid research. In the current study anti-angiogenic, cytotoxic, antioxidant and cyclooxygenase (COX) inhibitory activities of diverse class of flavonoids including hydroxyl and methoxy substituted flavones, flavonones and flavonols have been evaluated in the light of developing flavonoids as a potential scaffold for designing novel anti-antiangiogenic agents. We demonstrate anti-angiogenic potential of flavonoids using in vivo chorioallantoic membrane model (CAM) and further elaborate the possible structural reasoning behind observed anti-angiogenic effect using in silico methods. Additionally, we report antioxidant potential and kinetics of free radical scavenging activity using DPPH and SOR scavenging assays. Current study indicates that selected flavonoids possess considerable COX inhibition potential. Furthermore, we describe cytotoxicity of flavonoids against selected cancer cell lines using MTT cell viability assay. Structural analysis of in silico docking poses and predicted binding free energy values are not only in accordance with the experimental anti-angiogenic CAM values from this study but also are in agreement with the previously reported literature on crystallographic data concerning EGFR and VEGFR inhibition.

Schiff's bases of quinazolinone derivatives: Synthesis and SAR studies of a novel series of potential anti-inflammatory and antioxidants

A series of quinazolinone derived Schiff base derivatives 7-28 were synthesized and characterized as novel antioxidants and anti-inflammatory agents. The in vitro antioxidant activities of these compounds were evaluated and compared with commercial antioxidants ascorbic acid (AA), gallic acid (GA), butylatedhydroxytoluene (BHT), butylatedhydroxyanisole (BHA) employing 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay, 2,2-azinobis-(3-ethylbenzothiazoline-6-sufonic acid) (ABTS) assay and N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) assay. The results revealed that IC50 of 17, 18, 23, 24, 25, 27 and 28 were lower than the IC50 of standards in all the three performed antioxidant assays indicating good activities of these compounds. In addition, in vitro anti-inflammatory activity of the synthesized compounds were evaluated and the results demonstrate that the compounds 9-12 exhibited excellent anti-inflammatory activity. Preliminary structure-activity relationship revealed that the compounds 17, 18, 23, 24, 25, 27 and 28 with electron donating moiety (OH, OCH3) were found to be excellent antioxidants and compounds 9, 10, 11 and 12 with electron withdrawing moiety (Cl, NO2) were found to be excellent anti-inflammatory agents.

Crystal structure of 9-butyl-3-(9-butyl-9H-carbazol-3-yl)-9H-carbazole

In the title carbazole derivative, C32H32N2, the mol-ecule resides on a crystallographic twofold axis, which runs through the central C-C bond. The carbazole ring system is almost planar, with a maximum deviation of 0.041 (1) Å for one of the ring-junction C atoms. The crystal packing is stabilized by C-H⋯π inter-actions only, which form a C(7) chain-like arrangement along [110] in the unit cell.

Novel metronidazole-chalcone conjugates with potential to counter drug resistance in Trichomonas vaginalis

Trichomoniasis is the most prevalent, curable sexually transmitted disease (STD), which increases risk of viral STDs and HIV. However, drug resistance has been developed by some strains of Trichomonas vaginalis against Metronidazole (MTZ), the FDA approved drug against trichomoniasis. In the present study twenty two chalcone hybrids of metronidazole have been synthesized in a quest to get new molecules with higher potential against metronidazole-resistant T. vaginalis. All new hybrid molecules were found active against T. vaginalis with varying levels of activity against MTZ-susceptible and resistant strains. Eight compounds (4a, 4c, 4d, 4e, 4f, 4h, 4q and 4s) were found as active as the standard drug with an MIC of 1.56 μg/ml against MTZ-susceptible strain. However, compounds 4e, 4h and 4m were 4-times more active than MTZ against drug-resistant T. vaginalis, amongst which 4e and 4h were most promising against both susceptible and resistant strains.

Synthesis and biological evaluation of new pyrazolone-pyridazine conjugates as anti-inflammatory and analgesic agents

A new series of pyrazolone-pyridazine conjugates 3 and 4a-l were synthesized and characterized by spectroscopic means and elemental analyses. All compounds were tested in vivo for their anti-inflammatory and analgesic properties against diclofenac, as reference compound. The synthesized compounds were also evaluated for their ability to inhibit the production of certain inflammatory cytokines such as TNF-α and IL-6 in serum samples. The ulcerogenic potential of the synthesized compounds was also determined. IC50 values for inhibition of COX-1 and COX-2 enzymes were investigated in vitro for the most active candidates. Molecular docking was performed on the active site of COX-2 to predict their mode of binding to the amino acids. Among the synthesized derivatives, compounds 4c and 4e showed good analgesic and anti-inflammatory activities with lower ulcer index than the reference drug.

Design and synthesis of novel carbazolo–thiazoles as potential anti-mycobacterial agents using a molecular hybridization approach

A series of novel carbazolo–thiazoles was synthesized and evaluated for in vitro anti-mycobacterial activity.

Microwave Assisted Synthesis of Novel Imidazolopyridinyl Indoles as Potent Antioxidant and Antimicrobial Agents

We describe herein the design, synthesis, and pharmacological evaluation of novel series of imidazolopyridinyl indole analogues as potent antioxidants and antimicrobials. These novel compounds (3a–i) were synthesized by reacting 3,5-disubstituted-indole-2-carboxylic acid (1a–i) with 2,3-diamino pyridine (2) in excellent yield. The novel products were confirmed by their IR,1H NMR,13C NMR, mass spectral, and analytical data. These compounds were screened for their antioxidant and antimicrobial activities. Among the compounds tested,3a–dshowed the highest total antioxidant capacity, scavenging, and antimicrobial activities. Compounds3c-dand3g-hhave shown excellent ferric reducing activity.

Cytotoxic constituents from the stems of Clausena lansium (Lour.) Skeels

Six compounds were isolated from the stems of Clausena lansium (Lour.) Skeels by repeated sillica gel column chromatography. Their chemical structures were elucidated on the basic of physicochemical and spectroscopic data. Among them, 8-geranyloxypsolaren (3) and 2-methoxy-1-(3-methyl-buten-1-yl)-9H-carbazole-3-carbaldehyde (6) were isolated for the first time from this plant. These compounds were screened for cytotoxicity in human cervical cancer (Hela), leukemia (K562), lung cancer (A549), non-small lung carcinoma (H1299) and liver cancer (SMMC-7721). Within the series of cytotoxic tests, compounds 4-6 displayed potent cytotoxic activity against H1299 and SMMC-7721, with the IC₅₀ values of 6.19 to 26.84 μg/mL.

Synthesis and antioxidant activity of novel Mannich base of 1,3,4-oxadiazole derivatives possessing 1,4-benzodioxan

A new series of Mannich base of 1,3,4-oxadiazole derivatives possessing 1,4-benzodioxan (6a-6ae) were synthesized and characterized by (1)H NMR, ESI-MS and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction. All these novel compounds were screened for their in vitro antioxidant activity employing 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+)) and ferric reducing antioxidant power (FRAP) scavenging assays. Due to the combination of 1,4-benzodioxan, 1,3,4-oxadiazoles and substituted phenyl ring, most of them exhibited nice antioxidant activities. In all of these three assays mentioned above, compounds 6f and 6e showed significant radical scavenging ability comparable to the commonly used antioxidants, BHT and Trolox. Seven compounds with representative substituents or activities were selected for further assays in chemical simulation biological systems-inhibition of microsomal lipid peroxidation (LPO) and protection against 2,2'-azobis (2-amidinopropane hydrochloride) (AAPH) induced DNA strand breakage, in which, 6f and 6e were demonstrated to be of the most potent antioxidant activities.

Discovery of novel N-substituted carbazoles as neuroprotective agents with potent anti-oxidative activity

Carbazole moiety is an important scaffold with a variety of biological applications, for example, anti-oxidative stress. Our previous synthesized carbazoles were screened for their neuroprotective properties against two individual oxidative stresses. Some of the new carbazole derivatives were observed with modest to good neuroprotective effects on neuronal cells HT22 against cell injury induced by glutamate or homocysteic acid (HCA). Substituents introduced to the carbazole ring system play crucial roles in their biological activities. In particular, a bulky group favors the neuroprotective activity of the compounds. One of the new compounds, 6, showed the best neuroprotective effects, which might result from its anti-oxidative activity with a GSH-independent mechanism. These findings might provide an alternative strategy for the development of novel carbazole derivatives for the treatment of CNS diseases such as Alzheimer's disease.

Novel pyrazoline amidoxime and their 1,2,4-oxadiazole analogues: synthesis and pharmacological screening

A novel series of pyrazoline amidoxime (2a-d) and pyrazoly-1,2,4-oxadiazole (3a-p) and (4) of pharmacological significance have been synthesised. Structures of newly synthesised compounds were characterized by spectral studies. New compounds were screened for their in vitro antioxidant, antimicrobial and antiinflammatory activities. Among the synthesized compounds, compound 2a, 3l and 3o were found to be active antimicrobial agents in addition to having potent antioxidant activity, while the compound 3f showed promising antiinflammatory activity in comparison with standard drug.