Synthesis, structure, and bioactivity of N'-substituted benzylidene-3,4,5-trimethoxybenzohydrazide and 3-acetyl-2-substituted phenyl-5-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1,3,4-oxadiazole derivatives

Some 3-acetyl-2-substituted phenyl-5-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1,3,4-oxadiazole derivatives were synthesized by cyclization reaction of N'-substituted benzylidene-3,4,5-trimethoxybenzohydrazide in acetic anhydride. Their structures were verified by elemental analysis, IR, (1)H NMR, and (13)C NMR. Compound 3i was provided with X-ray crystallographic data. The compounds were evaluated for their antiproliferative activities against some cancer cells in vitro by MTT method. Among them, 2a, 2b, 2c, 2f, 3l, and 3m were highly effective against PC3 cells and 2a, 2c, and 2f showed moderate activities against Bcap37 and BGC823 cells. The IC(50) values of high active compounds 2a, 2b, 2c, 2f, 3l, and 3m against PC3 cells were 0.2, 1.8, 0.2, 1.2, 1.7, and 0.3muM, respectively.     

Synthesis, X-ray crystallographic analysis, and antitumor activity of N-(benzothiazole-2-yl)-1-(fluorophenyl)-O,O-dialkyl-alpha-aminophosphonates

Alpha-aminophosphonates containing benzothiazole and fluorine moiety, 4a-4m, were synthesized by Mannich-type addition in ionic liquid media with high yield and short reaction time. Their structures were established by IR, (1)H NMR, (13)C NMR, and elemental analysis. The X-ray crystallographic data of compounds 4j and 4m were provided. The newly synthesized compounds were evaluated for their anticancer activities against PC3, A431, A375, and Bcap37 cells in vitro by the MTT method. Compound 4c is highly effective against PC3 cells and moderate to A431 cells. Hence, further study is necessary to find out the potential antitumor activities.     

Synthesis, anti-Toxoplasma gondii and antimicrobial activities of benzaldehyde 4-phenyl-3-thiosemicarbazones and 2-[(phenylmethylene)hydrazono]-4-oxo-3-phenyl-5-thiazolidineacetic acids

In the present communication, a new series of 2-[(phenylmethylene)hydrazono]-4-oxo-3-phenyl-5-thiazolidineacetic acids (2a-p) have been synthesized. Benzaldehyde 4-phenyl-3-thiosemicarbazones substituted (1a-p) were also obtained and used as intermediate to give the title compounds. All synthesized compounds were characterized by IR, (1)H and (13)C NMR. The in vitro anti-Toxoplasma gondii activity of 1a-p and 2a-p was evaluated. The 4-thiazolidinones (2a-p) were screened for their in vitro antimicrobial activity. For anti-Toxoplasma gondii activity, in general, all compounds promoted decreases in the percentage of infected cells leading to parasite elimination. These effects on intracellular parasites also caused a decrease in the mean number of tachyzoites. In addition, most of the 4-thiazolidinones showed more effective toxicity against intracellular parasites, with IC(50) values ranging from 0.05 to 1 mM. According to results of antimicrobial activity, compounds 2f, 2l, and 2p showed best activity against Mycobacterium luteus, 2c was more active against Mycobacterium tuberculosis, and 2g, 2l, and 2n showed same activity as nistatin (standard drug) against Candida sp. (4249).     

Hybrid molecules of carvacrol and benzoyl urea/thiourea with potential applications in agriculture and medicine

Benzoyl phenyl urea, a class of insect growth regulator's acts by inhibiting chitin synthesis. Carvacrol, a naturally occurring monoterpenoid is an effective antifungal agent. We have structurally modified carvacrol (2-methyl-5-[1-methylethyl] phenol) by introducing benzoylphenyl urea linkage. Two series of benzoylcarvacryl thiourea (BCTU, 4a-f) and benzoylcarvacryl urea (BCU, 5a-f) derivatives were prepared and characterized by elemental analysis, IR, (1)H and (13)C NMR and Mass spectroscopy. Derivatives 4b, 4d, 4e, 4f and 5d, 5f showed comparable insecticidal activity with the standard BPU lufenuron against Dysdercus koenigii. BCTU derivatives 4c, 4e and BCU 5c showed good antifungal activity against phytopathogenic fungi viz. Magnaporthe grisae, Fusarium oxysporum, Dreschlera oryzae; food spoilage yeasts viz. Debaromyces hansenii, Pichia membranifaciens; and human pathogens viz. Candida albicans and Cryptococcus neoformans. Compounds 5d, 5e and 5f showed potent activity against human pathogens. Moderate and selective activity was observed for other compounds. All the synthesized compounds were non-haemolytic. These compounds have potential application in agriculture and medicine.     

Early development of CD8-negative and CD8-positive MHC-unrestricted cytotoxic cells induced by alloantigen inoculation in mice

Peritoneal cells (PC) in C57B1/6 (B6, H-2b) mice receiving an intraperitoneal (i.p.) injection of allogeneic BALB/c (H-2d) spleen cells demonstrated potent cytotoxic activity against syngeneic, xenogeneic, third-party allogeneic tumors as well as H-2d derived tumors. Maximum cytotoxic activity against various tumors other than H-2d derived tumor, B16 (H-2b) was elicited on day 3 post allosensitization and decreased drastically thereafter, whereas cytotoxic activity against P815 (H-2d) peaked 3 days after the inoculation and maintained the peak activity thereafter. Surface phenotype of PC responsible for the cytotoxic activity against B16 was Thy-1+/-, Lyt-2-, L3T4-, asialo GM1 (AGM1)+, and that of PC against P815 was Thy-1+, Lyt-2+ (or Lyt-2+/-), L3T4-, AGM1+. These phenotypes showed similar phenotypes to the counterparts against B16 and against P815 in spleen cells induced by intravenous inoculation of alloantigen. When mice were pretreated i.p. with anti-AGM1 antibody before the allosensitization, anti-P815 cytotoxic-activity in PC was completely diminished. Similar activity in spleen, however, was enhanced by i.v. treatment with the antibody before the i.v. inoculation of alloantigen. The data clearly demonstrate that in vivo inoculation of B6 mice with normal allogeneic cells induces "NK-like" CD8- cytotoxic cells and "anomalous" CD8+ cytotoxic cells in PC.     

Synthesis and antibacterial activity of some new 1-heteroaryl-5-amino-3H/methyl-4-phenylpyrazoles

The regioselective synthesis of 1-heteroaryl-5-amino-4-phenylpyrazoles 3a-g and 1-heteroaryl-5-amino-3-methyl-4-phenylpyrazoles 3h-n was achieved by the treatment of heteroarylhydrazines 1a-g with alpha-phenylformylacetonitrile 2a and alpha-phenylacetylacetonitrile 2b, respectively. The structures of the compounds 3 were established by the combined use of 1H and 13C NMR spectroscopy. All the fourteen compounds were tested for their in vitro antibacterial activity against three Gram-positive and two Gram-negative bacteria. Six compounds 3a, 3d, 3e, 3g, 3l, and 3n from this series were found to be equipotent or more potent than the commercial antibiotics (Linezolid and Cefroxime axetil).     

Efficient synthesis, spectral analysis and antimicrobial studies of nitrogen and sulfur containing spiro heterocycles from 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones

Acetyl and propionyl group substituted thiadiazole derivatives (4a-4h, 5a-5h, 6a, 6b, 7a and 7b) have been synthesized by the cyclization of 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-one thiosemicarbazones (2a-2h, 3a and 3b) with acetic anhydride/propionic anhydride and were characterized by Elemental analysis, IR, (1)H NMR and (13)C NMR spectral analysis. Single crystal X-ray diffraction has also been recorded for compounds 4c and 5a. From the NMR and Single crystal X-ray diffraction analysis, compounds 4b-4d, 4f-4h, 5b, 5c, 5f-5h, 6a, 7a and 7b were found to adopt twin-chair conformations whereas compounds 4a, 4e, 5a, 5d, 5e and 6b adopt chair and boat conformation of cyclohexane and piperidine rings, respectively. Besides, the synthesized compounds were screened for antibacterial and antifungal activities using serial dilution method. The microbiological analysis showed that the electron withdrawing function substituted phenyl group at C-2 and C-4 of azabicyclononane based thiadiazoles 4c/4h and 5c/5h exposed significant antimicrobial activity against Salmonella typhi, Escherichia coli, Klebsiella pneumoniae, Aspergillus flavus, Aspergillus niger and Candida albicans at MIC of 6.25 μg/ml.     

Synthesis,Anti-Oomycete and Anti-fungal Activities of Novel Cinchona Alkaloid Derivatives Containing Sulfonate Moiety

Using cinchona alkaloid as the lead compound, twenty-four cinchona alkaloid sulfonate derivatives ( 1 a – l , 2 a – c , 3 a – c , 4 a – c , and 5 a – c ) were designed and prepared by modifying their C9 position, and structurally confirmed by ¹H-NMR, ¹³C-NMR, HR-MS and melting points. Moreover, the stereochemical configurations of compounds 1 f and 1 l were unambiguously confirmed by single-crystal X-ray diffraction. Furthermore, we determined the anti-oomycete and anti-fungal activities of these target compounds against Phytophthora capsici and Fusarium graminearum in vitro. The results showed that two compounds 4 b and 4 c exhibited prominent anti-oomycete activity, and the median effective concentration (EC₅₀) values of 4 b and 4 c against P. capsici were 22.55 and 16.32 mg/L, respectively. This study suggested that when the C9 position of cinchona alkaloid sulfonate derivatives is in the S configuration and the 6′-position methoxy group is not present, the anti-oomycete activity is superior. In addition, five compounds 1 e , 1 f , 1 k , 3 c and 4 c displayed significant anti-fungal activity, with EC₅₀ values of 43.64, 45.07, 80.18, 48.58 and 41.88 mg/L against F. graminearum, respectively. This result indicates that only when a specific substituent is introduced into the structural framework of the target compound, the corresponding compound exhibits significant inhibitory activity against fungi.     

Iridoids from the aerial parts of Verbena littoralis (Verbenaceae)

The iridoids, 6S-hydroxy-8S-methyl-4-methylene-hexahydro-cyclopenta[c]pyran-3-one and 6S,9S-dihydroxy-8S-methyl-4-methylene-hexahydro-cyclopenta[c]pyran-3-one, were isolated from the aerial parts of Verbena littoralis. Their structures and stereochemistry were elucidated by means of NMR spectral data analysis. Both compounds showed moderate in vitro activity against gram positive and negative bacteria as well as moderate in vivo intestinal peristaltic action in mouse. The iridoids also showed moderate free radical scavenging activity against l,l-diphenyl-2-picrylhydrazyl (DPPH) as well as antioxidant activity, the latter being evidenced by redox properties measured using E1CD-HPLC.     

Design, synthesis, biological evaluation and molecular modeling of novel 1,3,4-oxadiazole derivatives based on Vanillic acid as potential immunosuppressive agents

In present study, a series of novel 1,3,4-oxadiazole derivatives have been designed, synthesized and purified. All of these compounds are reported for the first time, the chemical structures of these compounds were confirmed by means of (1)H NMR, ESI-MS and elemental analyses. Besides, we evaluated their immunosuppressive activity. Most of these synthesized compounds were proved to have potent immunosuppressive activity and low toxicity. Among them, the bioassay results demonstrated that compounds 5c, 5n, 5p, 5o, 6f and 6g exhibited immunosuppressive activities with IC(50) concentration range from 1.25μM to 7.60 μM against the T cells, and the IC(50) of positive control (csa) is 2.12 μM. Moreover, all the title compounds were assayed for PI3K/AKT signaling pathway inhibition using the ELISA assay. We examined the compounds with potent inhibitory activities against IL-1, IL-6 and IL-10 released in ConA-simulated mouse lymph node cells. The results showed compounds 5o and 6f displayed the most potential biological activity against T cells (IC(50)=1.25 μM and 4.75 μM for T cells). The preliminary mechanism of compound 5o inhibition effects was also detected by flow cytometry (FCM). The results of apoptosis and ELISA assay demonstrated that the immunosuppressive activity of compounds 5o and 6f against T cells may be mediated by the inhibition of PI3Kγ/AKT signaling pathway. Molecular docking was performed to position compounds 5o and 6f into PI3Kγ binding site in order to indicate the potential target.     

Design, synthesis, and in vitro antiproliferative activity of novel Dasatinib derivatives

Two series of novel Dasatinib derivatives have been designed and synthesized, with their in vitro cytostatic effect screened on human chronic myeloid leukemia cell line K562 and human myeloid leukemia cell line U937. Some target compounds demonstrated significant inhibitory activities against both cell lines. Compared to the contrast drug Dasatinib, 1b, 1c, 1d, 1e and 1f were found to demonstrate more potent antitumor activities. The structures of all the newly synthesized compounds were determined by (1)H NMR and (13)C NMR.     

Synthesis,molecular docking,ADME study,and antimicrobial potency of piperazine based cinnamic acid bearing coumarin moieties as a DNA gyrase inhibitor

A series of novel piperazine based cinnamic acid bearing coumarin derivatives were designed and synthesized by piperazine based cinnamic acids esterification with 4-hydroxycoumarin and characterized by various spectral techniques like infrared, ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and mass. The novel bioactive compounds (7a-7m) screen their potential against different bacterial and fungal strains. Compound 7g (minimum inhibitory concentration [MIC] = 12.5 µg/ml) exhibited potent antibacterial activity against Escherichia coli strain. Compounds 7d, 7f, 7g, 7k, 7l , and 7m showed potent antibacterial activity against all bacterial strains. Compounds 7a, 7g, 7h, 7k, 7l , and 7m exhibited potent antifungal activity against all fungal strains. Furthermore, a molecular docking study revealed that compounds 7d, 7f, 7g , and 7k could bind to the active site of E. coli DNA gyrase subunit B protein and form hydrogen bonding with crucial amino acid residues Arg136 in the active sites. Comprehensively, our study recommends that 7d, 7f, 7g , and 7k could be a promising lead for developing more efficient antimicrobial drug candidates and DNA gyrase inhibitors.     

Design and synthesis of benzo[c,d]indolone-pyrrolobenzodiazepine conjugates as potential anticancer agents

A series of benzo[c,d]indol-2(1H)one-PBD conjugates (11a-l) have been designed and synthesized as potential anticancer agents. These compounds were prepared by linking the C8-position of DC-81 with a benzo[c,d]indol-2(1H)one moiety through different alkane spacers in good yields and confirmed by (1)H NMR, mass and HRMS data. The DNA binding ability of these conjugates was evaluated by thermal denaturation studies and interestingly, compound 11l showed enhanced DNA binding ability. These compounds were also evaluated for their anticancer activity in selected human cancer cell lines of lung, skin, colon and prostate by using MTT assay method. These new conjugates showed promising anticancer activity with IC(50) values ranging from 1.05 to 36.49 μM. Moreover, cell cycle arrest in SubG1 phase was observed upon treatment of A549 cells with 1 and 2 μM (IC(50)) concentrations of compound 11l and it induced apoptosis. This is confirmed by Annexin V-FITC, Hoechst staining, caspase-3 activity as well as DNA fragmentation analysis.     

Secondary metabolites from Commiphora opobalsamum and their antiproliferative effect on human prostate cancer cells

A cycloartane-type triterpenoid (1), an aliphatic alcohol glycoside (2), an eudesmane-type sesquiterpenoid (3), and a guaiane-type sesquiterpenoid (4) were isolated from the resinous exudates of Commiphora opobalsamum along with six known sesquiterpenoids (5-10). Their structures were established by extensive analysis of their 1D and 2D NMR spectroscopic data and chemical methods. The isolated compounds 1-3 and 5-9 were tested against human prostate cancer cell PC 3 and LNCaP. Among them, 1 and 2 showed moderate antiproliferative effects on human prostate cancer cell lines with IC50 values ranging from 5.7 to 23.6 microM; they were also able to inhibit the expression of androgen receptor (AR) in LNCaP cells. The six sesquiterpenoids were inactive in the bioassays.     

Synthesis of novel 3-cyclohexylpropanoic acid-derived nitrogen heterocyclic compounds and their evaluation for tuberculostatic activity

A series of novel 3-cyclohexylpropanoic acid derivatives and 3-cyclohexylpropanoic acid-derived nitrogen heterocyclic compounds (1-8) have been synthesized and evaluated for tuberculostatic activity. Compounds 1a, 1c, 1e and 1f bearing benzimidazole or benzimidazole-like systems showed the most potent tuberculostatic activity against Mycobacterium tuberculosis strains with MIC values ranging from 1.5 to 12.5μg/mL. More importantly 1a (6-chloro-2-(2-cyclohexylethyl)-4-nitro-1H-benzo[d]imidazole) and 1f (2-(2-cyclohexylethyl)-1H-imidazo[4,5-b]phenazine) appeared selective for M. tuberculosis as compared with eukaryotic cells (human fibroblasts), and other antimicrobial strains. These compounds may thus represent a novel, selective class of antitubercular agents. Additionally compound 1a stimulated type I collagen output by fibroblasts, in vitro.     

Steroids from Commiphora mukul display antiproliferative effect against human prostate cancer PC3 cells via induction of apoptosis

Two new stigmastane-type steroids, stigmasta-5,22E-diene-3β,11α-diol (1) and stigmasta-5,22E-diene-3β,7α,11α-triol (2), together with eight known compounds, were isolated from the resinous exudates of Commiphora mukul. Their structures were established by extensive analysis of their HR-MS, 1D- and 2D-NMR (COSY, HMQC, HMBC and NOESY) spectra. The isolates were evaluated for their antiproliferative activities against four human cancer cell lines. Compound 2 demonstrated inhibitory effects with IC(50) values of 5.21, 9.04, 10.94 and 16.56 μM, respectively, against K562, MCF-7, PC3 and DU145 human cancer cell lines. Further study showed that 2 was able to enforce the PC3 cell cycle arrest in the G2/M phase, and induce the apoptosis of PC3 cells by activation of Bax, caspases 3 and 9, and by inhibition of Bcl-2. It was also found that 1 inhibited proliferation of PC3 cells via G0/G1 phase arrest of the cell cycle.     

Potent 1,3-disubstituted-9H-pyrido[3,4-b]indoles as new lead compounds in antifilarial chemotherapy.

Substituted 9H-pyrido[3,4-b]indoles (beta-carbolines) identified in our laboratory as potential pharmacophore for designing macrofilaricidal agents, have been explored further for identifying the pharmacophore responsible for high order of adulticidal activity. This has led to syntheses and macrofilaricidal evaluations of a number of 1-aryl-9H-pyrido[3,4-b]indole-3-carboxylate derivatives (3-7). The macrofilarical activity was initially evaluated in vivo against Acanthoeilonema viteae. Amongst all the synthesized compounds, only twelve compounds namely 3a, 3c, 3d, 3f, 4c, 4d, 4f, 5a, 6f, 6h, 6i and 7h have exhibited either > 90% micro- or macrofilaricidal activity or sterilization of female worms. These compounds have also been screened against Litomosoides carinii and of these only 3f and 5a have also been found to be active. Finally these two compounds have been evaluated against Brugia malayi. The structure activity relationship (SAR) associated with position-1 and 3 substituents in beta-carbolines have been discussed. It has been observed that the presence of carbomethoxy at position-3 and an aryl substituent at position- in beta-carbolines effectively enhance antifilarial activity particularly against A. viteae. Amongst the various compounds screened, methyl 1-(4-methylphenyl)-9H-pyrido[3,4-b]indole-3-carboxylate (4c) has shown highest adulticidal activity and methyl 1-(4-chlorophenyl)-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxyla te (3a) has shown highest microfilaricidal action against A. viteae at 50 mg/ kg x 5 days (i.p.). Another derivative of this compound namely 1-(4-chlorophenyl)-3-hydroxymethyl-9H-pyrido[3,4-b]indole (5a) exhibited highest activity against L. carinii at 30 mg/kg x 5 days (i.p.) and against B. malayi at 50 mg/kg x 5 days (i.p.) or at 200 mg/kg x 5 days (p.o.).     

Highly potent inhibitors of proprotein convertase furin as potential drugs for treatment of infectious diseases

Optimization of our previously described peptidomimetic furin inhibitors was performed and yielded several analogs with a significantly improved activity. The most potent compounds containing an N-terminal 4- or 3-(guanidinomethyl)phenylacetyl residue inhibit furin with K(i) values of 16 and 8 pM, respectively. These analogs inhibit other proprotein convertases, such as PC1/3, PC4, PACE4, and PC5/6, with similar potency, whereas PC2, PC7, and trypsin-like serine proteases are poorly affected. Incubation of selected compounds with Madin-Darby canine kidney cells over a period of 96 h revealed that they exhibit great stability, making them suitable candidates for further studies in cell culture. Two of the most potent derivatives were used to inhibit the hemagglutinin cleavage and viral propagation of a highly pathogenic avian H7N1 influenza virus strain. The treatment with inhibitor 24 (4-(guanidinomethyl)phenylacetyl-Arg-Val-Arg-4-amidinobenzylamide) resulted in significantly delayed virus propagation compared with an inhibitor-free control. The same analog was also effective in inhibiting Shiga toxin activation in HEp-2 cells. This antiviral effect, as well as the protective effect against a bacterial toxin, suggests that inhibitors of furin or furin-like proprotein convertases could represent promising lead structures for future drug development, in particular for the treatment of infectious diseases.     

Synthesis, biological evaluation and molecular docking studies of 3-(1,3-diphenyl-1H-pyrazol-4-yl)-N-phenylacrylamide derivatives as inhibitors of HDAC activity

In present study, a series of 3-(1,3-diphenyl-1H-pyrazol-4-yl)-N-phenylacrylamide derivatives (5a-8d) were designed, synthesized, and evaluated for HDAC inhibition and tumor cell antiproliferation. All of these compounds are reported for the first time, the chemical structures of these compounds were confirmed by means of (1)H NMR, ESI-MS and elemental analyzes. Among the compounds, compound 8c showed the most potent biological activity against HCT116 cancer cell line (IC(50) of 0.42 ± 0.02 μM for HDAC-1 and IC(50)=0.62 ± 0.02 for HCT116). Docking simulation was performed to position compound 8c into the HDAC active site to determine the probable binding model. The results of antiproliferative assay and western-blot demonstrated that compound 8c with potent inhibitory activity in tumor growth inhibition may be a potential anticancer agent against HCT116 cancer cell.     

Design,synthesis, and biological evaluation of novel triazoloquinazolinone derivatives as SHP2 protein inhibitors

A novel series of triazoloquinazolinone derivatives were designed, synthesised, and evaluated for their in vitro biological activities against the SHP2 protein. Moreover, some compounds were evaluated against A375 cells. The results revealed that target compounds possessed moderate to excellent inhibitory activity against SHP2 protein, whereas compounds 12f, 12l, 12j, 17e, and 17f have strong antiproliferative activity on A375 cells. The compound 12l showed remarkable cytotoxicity against A375 cells and a strong inhibitory effect against SHP2 protein when compared with SHP244. The structure-activity relationships (SARs) indicated that electron-donating groups (EDGs) on phenyl rings are beneficial for improving the antitumor activity; compounds with a hydroxyl substituent at the 2-position of phenyl ring exhibited superior activities than compounds with a substituent at the 4-position. In addition, compound 12l displayed improved physicochemical properties as well as metabolic stability compared to SHP244. Our efforts identified 12l as a promising SHP2 protein inhibitor, warranting its further investigation.