Synthesis and biological evaluation of novel naphthocarbazoles as potential anticancer agents

We report the efficient synthesis involving palladium-catalyzed reactions and biological evaluation of new naphthocarbazoles designed as potential anticancer agents. The use of 5- and 6-benzyloxyindoles generated three substitution sites which were successively exploited to introduce several hydrophilic side chains. The cytotoxicity of the newly designed compounds was evaluated on three cell lines. Several compounds showed a marked cytotoxicity with IC(50) values in the sub-micromolar range. This is the case for the 3-hydroxy-naphthopyrrolocarbazoledione 37, bearing a dimethylaminoethyl side chain, which is extremely cytotoxic to L1210 and DU145 cells (IC(50): 36 nM, 108 nM) and induces an accumulation of L1210 cells in the G2+M phases of the cell cycle. Some of the most cytotoxic compounds were tested for inhibition of CDK-5, GSK-3 and topoisomerase I, and their interaction with DNA was also evaluated. Interaction with DNA was detected, suggesting that nucleic acids represent a privileged target for these molecules.     

Synthesis and biological evaluation of novel hydroquinone dimethyl ethers as potential anticancer and antimicrobial agents

The synthesis of two novel series of quinol dimethyl ethers linked to either various functionalities or to some biologically active nitrogenous heterocycles is described. Nine of the newly synthesized quinol dimethyl ethers 5a, b, 9b, 10a, d, 12a, b, and 13a, b were selected by the NCI and were tested initially at a single high dose (10 μM) in the full NCI 60 cell panel. Four of the screened quinol dimethyl ethers bearing unsubstituted phenylhydrazone 5a, 4-chlorophenylhydrazone 5b, 4-chlorophenyl-3-sulfanyl-1,2,4-triazole 9b, as well as 4-chloroanilino-1,3,4-oxadiazole 12b moieties satisfied the threshold antitumor screen. 4-Chlorophenylhydrazone 5b showed very promising results and accordingly was chosen for in vivo antitumor screening. Thus, compound 5b of the series could be considered as the potential lead for development of novel anticancer agents. In addition, compounds 5a–c, 6a–c, 9a–c, 10a, b, d, e, g, h, 11a–c, 12a–c, and 13a–c were screened for their in vitro antimicrobial activity. Some of the tested compounds exhibited special high activity comparable to the reference ampicillin against Pseudomonas aeruginosa and Escherichia coli.     

Synthesis and biological evaluation of some novel fused pyrazolopyrimidines as potential anticancer and antimicrobial agents

Synthesis and evaluation of anticancer and antimicrobial activity of some novel pyrazolopyrimidines and fused pyrazolopyrimidines are reported. Twelve analogs were selected to be evaluated for their in vitro anticancer potential against a panel of three human tumor cell lines: hepatocellular carcinoma HepG2, cervical carcinoma HelaS3 and colon carcinoma CaCo. The obtained data revealed that eight compounds namely; 6b, 6d, 7c, 8c, 10b, 12b, 13a and 13b were able to exhibit variable degrees of anticancer activities against the three used cell lines, of which compound 6d proved to be the most active. On the other hand, all the newly synthesized compounds were subjected to in vitro antibacterial and antifungal screening. Almost all the tested compounds were found to possess variable degrees of antimicrobial activities. Collectively, compounds 7c, 8c, 12b, 13a and 13b could be considered as possible agents with dual anticancer and antimicrobial activities.     

Synthesis and biological evaluation of substituted pyrrolidines and pyrroles as potential anticancer agents

A series of polysubstituted pyrrolidines obtained via ruthenium-catalyzed cascade cyclization of diazo pyruvates and anilines as well as their corresponding pyrrole analogs obtained via dehydration were evaluated for their antiproliferation activities. Pyrrolidines 3h and 3k showed good proliferation inhibitory effects toward 10 cancer cell lines with IC₅₀ values ranging from 2.9 to 16 μM. Furthermore, pyrrolidine 3k induced cell cycle arrest at the G0/G1 phase and time- and dose-dependent cellular apoptosis in both HCT116 and HL60 cells, suggesting that this type of pyrrolidine structure might be a good candidate for future anticancer therapies.     

Synthesis and biological evaluation of novel benzoquinones as potential antimicrobial agents

New series of 2,5-dihydroxyphenyl-1,3-thiazoles 4a–l was synthesized by reacting 2,5-dihydroxyphenacyl bromide with various 4-aryl thiosemicarbazones 3a–l that on oxidation with ferric chloride yielded the corresponding N ¹-substituted benzylidene-N ²-[3-aryl-4-(1,4-benzoquinon-2-yl)-1,3-thiazol-2-ylidene]hydrazines 5a–l. They were evaluated for antibacterial activity against Staphylococcus aureus and Bacillus subtilis as Gram-positive bacteria, Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria. They were also evaluated for their in vitro antifungal potential against Candida albicans. Almost all tested compounds were found to possess variable degrees of antimicrobial activity. The obtained data revealed that compounds 4b–h and 5e, 5f and 5l exhibited promising antimicrobial activity against the tested organisms of which compound 4b proved to be the most active.     

Synthesis and biological evaluation of novel flavanone derivatives as potential antipsychotic agents

In this study, a series of novel flavanone derivatives were designed and synthesized, and the antipsychotic activities of the target compounds were evaluated in vitro and in vivo. The results showed that synthesized compounds 7a – 7g decreased the activity of dopamine D₂ receptors in HEK293 cells co‐transfected with D₂ receptor/G protein α16a, with IC₅₀ values of 0.051–0.35 μm . Compounds 7a – 7g inhibited the over‐production of nitric oxide stimulated by lipopolysaccharide/interferon‐γ in BV‐2 microglial cells. In mice, intragastric administration of 7d , 7e , and 7g reversed the increase in locomotor activity induced by MK‐801 (an antagonist of NMDA receptors) and decreased the hyperactivity of climbing behavior induced by apomorphine (a dopamine receptor agonist). These results suggest that some of the novel flavanone derivatives have potential antipsychotic effects and may be useful in the treatment of schizophrenia.     

Synthesis and evaluation of some novel benzothiazole derivatives as potential anticancer and antimicrobial agents

Intensive efforts are underway worldwide to develop anticancer and antimicrobial agents. Therefore, a novel series of pyrido[2,1-b]benzo [d]thiazole and 2-(benzo [d] thiazol-2-ylamino)pyrimidine derivatives was synthesized. The synthesized compounds were evaluated for their anticancer activity. Among the tested compounds, compounds 3a, 3b, and 7 exhibited more cytotoxic action than the control drug doxorubicin (CAS 23214-92-8; IC50: 52 microg/ml). Compound 7 was the most potent cytotoxic, with an IC50 of 42.55 pg/ ml, while compounds 3a and 3b induced high cytotoxic action with IC50 values of 50.15 pg/ml and 50.45 pg/ml, respectively. Moreover, the synthesized compounds were screened for their antibacterial and antifungal activities. Compound 6 exhibited moderate antifungal activity against C. albicans with a minimum inhibitory concentration of 125 pg/ml.     

Synthesis and biological evaluation of novel 4,5-dihydropyrazole derivatives as potent anticancer and antimicrobial agents

A focused library of 4,5-dihydropyrazole dervivatives (4, 5, 6, 7a–h, 8, 9a–g, and 10a–g) were synthesized from novel 5-(2,6-difluorophenyl)-3-phenyl-4,5-dihydropyrazole-1-carbothioamide 4. The synthesized compounds were characterized using elemental analysis and spectral data (IR, mass spectra, ¹H and ¹³C NMR) and evaluated for antimicrobial activity by broth dilution method and in vitro anticancer activity. Among the synthesized compounds 7a, 9c, 9g, and 10d exhibit broad spectrum antimicrobial activity against tested microbial strains. The in vitro cancer results ascertain 7a, 9c, and 10d are most potent molecules in comparison to reference standard cisplatin.     

Synthesis and biological evaluation of some novel 1,4-dihydropyridines as potential antitubercular agents

Recent studies showed that 1,4-dihydropyridine-3,5-dicarbamoyl derivatives with lipophilic groups have significant antitubercular activity. In this study, we have synthesized new derivatives of 1,4-dihydropyridines bearing carbmethoxy and carbethoxy group at C-3 and C-5 of the 1,4-dihydropyridine ring. In addition, 1H-pyrazole ring is substituted at C-4 position. These analogues were synthesized by multi-component Hantzsch reaction. The in vitro antitubercular activity of compounds against Mycobacterium tuberculosis H(37) Rv was evaluated. The lowest minimum inhibitory concentration value, 0.02 μg/mL and SI > 500, was found for dimethyl 1,4-dihydro-4-(3-(4-nitrophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethylpyridine-3,5-dicarboxylate 3f, diethyl 1,4-dihydro-4-(3-(4-fluorophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethylpyridine-3,5-dicarboxylate 4c and diethyl 1,4-dihydro-4-(3-(4-bromophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethyl pyridine-3,5-dicarboxylate 4e, making them more potent than first-line antitubercular drug isoniazid. In addition, these compounds exhibited relatively low cytotoxicity.     

Synthesis and biological evaluation of novel resveratrol-oxadiazole hybrid heterocycles as potential antiproliferative agents

A novel class of resveratrol-oxadiazole hybrid compounds was synthesized to screen for their in vitro antiproliferative activity against three human cancer cell lines. All the compounds showed superior antiproliferative activity than the reference compound resveratrol. The most promising active compounds in this series were 1g, 2g, 1c, 2c, 2i and 1a (GI₅₀ < 0.1 µM), endowed with excellent antiproliferative activity. Thus, we believe that resveratrol-oxadiazole hybrid compounds may possibly be used as a good leads for the development of new antiproliferative agents. Structures of newly synthesized compounds were confirmed by NMR and IR spectral data.     

Synthesis of benzothiazole derivatives and their biological evaluation as anticancer agents

This article describes the synthesis and the biological evaluation of two sets of benzothiazole derivatives bearing at C-2 an arylamide (1a–e, 2a–e) or an arylurea (3a–d, 4a–d) moiety. Five compounds (3d and 4a–d) were selected and screened by the National Cancer Institute for the in vitro primary anticancer assay against a panel of 60 human tumor cell lines. Compounds 4a and 4c showed interesting anticancer activities, more marked for compound 4c. All compounds were also submitted to a preliminary in vitro assay as potential inhibitors of the ubiquitin-activating enzyme (E1), but they lacked significant activity.     

Synthesis and biological evaluation of some 2,4,5-trisubstituted thiazole derivatives as potential antimicrobial and anticancer agents

We report on the synthesis and biological evaluation of two series of 2,4,5-polysubstituted thiazoles comprising the acid hydrazide functionality and some derived pharmacophores known to contribute to various chemotherapeutic activities. All newly synthesized compounds were subjected to in-vitro antibacterial and antifungal screening. Of the compounds tested, 13 derivatives displayed inhibitory effect on the growth of three Gram-positive strains while they lack activity against Gram-negative bacteria. Moreover, four compounds were able to exert antifungal activity against C. albicans. Potential antibacterial and antifungal activities were linked to the thiosemicarbazide function 6a-f and those substituted with both the thioureido and thiosemicarbazide moieties 12a-f. Compounds 6f and 12f (R = 4-F-C(6)H(4)) could be considered as the most active members in this investigation with a broad spectrum of antibacterial activity against three types of Gram-positive bacteria, together with an appreciable antifungal activity against C. albicans. Compounds 6d, 6f, and 12f were twice as active as ampicillin against B. subtilis. The best antifungal activity was shown by compound 6d 50% less active than clotrimazole. 17 compounds were selected and tested for their preliminary in-vitro anticancer activity according to the current one-dose protocol of the NCI. Three cell lines, non-small cell lung cancer Hop-92, ovarian cancer IGROV1, and melanoma SK-MEL-2, exhibited some sensitivity against most of the tested compounds. Compound 12f proved to be the most active anticancer member with a broad spectrum of activity against most of the tested subpanel tumor cell lines. Consequently, 12f was carried over to be tested in the five-dose assay.     

Constrained derivatives of stylostatin 1. 1. Synthesis and biological evaluation as potential anticancer agents

Hydroxyaminolactams have been used as constrained surrogates of the Ser-Leu dipeptide in the synthesis of analogues of the cycloheptapeptide stylostatin 1 (2). The rate of cyclization through formation of the Ile-Pro amide bond allowed us to prove that the valerolactams used induced a turn in the linear precursor. Ring closure at the Pro-Phe amide bond was much quicker and provided access to larger amounts of the target structures, with high purity. The conformation of psi-stylostatin 4 was compared to that of native stylostatin 1 using NMR analysis. The ability of three psi-stylostatins and the native stylostatin 1 to inhibit growth of cancer cell lines was tested. None of the compounds showed activity below 1 microM. A possible relationship between the decrease in activity and the presence of the piperidone Ser-Leu surrogate is considered.     

Synthesis, biological evaluation and molecular docking studies of 1,3-benzoxazine derivatives as potential anticancer agents

A series of 6 and/or 8-substituted derivatives of 1,3-benzoxazines, having flavone moiety at 3-position, have been synthesized. For synthesis of the compounds, 6 or/and 8-substituted saliscylaldehydes were reacted with aminoflavone followed by reduction, and CHCl₃/HCHO promoted cyclization to give corresponding aminoflavone precursors which provided the desired 1,3-benzoxazine skeleton. Cytotoxic effects of the synthesized compounds were investigated in vitro against human breast cancer (MCF-7) cell lines. Among the compounds tested, methyl (3f and 6f), methoxy (3h, 3i, and 6h), and chloro (3d) derivatives were found to be most potent with IC₅₀ values of 14.3, 14.9, 17.1, 8.03, 12.1, and 12.03 μM, respectively. Molecular docking studies of most active compounds of the series revealed that they bind to a narrow hydrophobic pocket of the N-terminal chain in the ATP binding site of EGFR.     

Synthesis,biological evaluation,and molecular docking studies of pyrazolyl-acylhydrazone derivatives as novel anticancer agents

A series of pyrazolyl-acylhydrazone derivatives (1e–20e) have been designed and synthesized and their biologic activities were also evaluated for telomerase inhibition and tumor cell antiproliferation. Among all the compounds, 12e showed the most potent activity in vitro, which inhibited the growth of MCF-7 and B16-F10 cell lines with IC₅₀ values of 0.57 ± 0.03 and 0.49 ± 0.07 μM, respectively. Compound 12e also exhibited significant telomerase inhibitory activity (IC₅₀ = 1.9 ± 0.43 μM). The result of flow cytometry demonstrated that compound 12e induced cell apoptosis. Docking simulation was performed to insert compound 12e into the crystal structure of telomerase at ATP binding site to determine the probable binding model. Based on the preliminary results, compound 12e with potent inhibitory activity in tumor growth may be a potential anticancer agent.     

新型鬼臼毒素衍生物的合成及抗肿瘤活性研究

目的通过对鬼臼毒素进行结构改造,寻找高效低毒的抗肿瘤先导化合物。方法运用拼合原理,将川芎嗪和天冬氨酸等结构片段引入鬼臼毒素结构中,通过1 H-NMR、13 C-NMR和HRMS确证结构;采用四甲基偶氮唑蓝(MTT)法评价化合物对人肺癌细胞A549、人肝癌细胞HepG2和人乳腺癌细胞MCF-7的活性及对人正常肝细胞L-02的毒性,并采用4′,6-二脒基-2-苯基吲哚(DAPI)染色法观察优势化合物对细胞核形态的影响。结果得到3个新型鬼臼毒素衍生物,其中化合物P-02(IC 50=0.1998±0.08μmol·L^-1)对A549的抑制作用与阳性药阿霉素相当(IC 50=0.1881±0.06μmol·L^-1),较依托泊苷(IC 50=8.55±0.43μmol·L^-1)提高了40倍;该化合物对L-02的毒性(IC 50=0.6701±0.176μmol·L^-1)明显小于阿霉素(IC 50=0.04684±0.02μmol·L^-1);DAPI染色结果表明,化合物P-02通过诱发A549细胞核碎裂产生细胞毒性。结论与临床化疗药物依托泊苷和阿霉素相比,将川芎嗪和氨基酸片段引入鬼臼毒素后可增强抗肿瘤活性,降低毒性,为新型鬼臼毒素类先导化合物的发现提供了参考。     

Synthesis and biological evaluation of novel benzo[c]acridine‐diones as potential anticancer agents and tubulin polymerization inhibitors

A new series of novel benzo[c]acridine‐diones possessing pharmacophoric elements of antitubulins with central dihydropyridine bridge were designed and synthesized as potential anticancer agents and tubulin polymerization inhibitors. The cytotoxic activity of the synthesized compounds was evaluated against eight cancer cell lines including MCF‐7, A2780, HeLa, HepG2, DU145, A549, PC3, and LNCAP cancer cells and normal cells human umbilical vein endothelial cell (HUVEC) through 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide (MTT) assay, wherein β‐lapachone and combretastatin A‐4 were used as positive controls. Some of our compounds ( 4c and 4g ) showed significant cytotoxic activity on cancer cells with IC₅₀ values in the range of 5.23–24.32 μM. None of the synthesized compounds showed significant cytotoxicity on normal HUVEC cells. Among all investigated derivatives, compound 4g showed promising greater antiproliferative activity against all tested cancer cells with the highest sensitivity observed for the PC3 cell line. Results from the flow cytometry analysis of PC3 and MCF‐7 cancer cells treated with 4g showed an induced cell‐cycle arrest at G2/M, and therefore induced apoptosis which occurred at low concentration of test compound, whereas annexin V‐FITC/propidium iodide staining assay in the aforementioned cancer cell lines treated with 4g showed that 4g can cause necrosis in PC3 and MCF‐7 cancer cells at higher concentration. Compound 4g proved to be an inhibitor of tubulin polymerization in a mode similar to that of colchicine and in a dose‐dependent manner. Molecular docking studies of 4g into the colchicine‐binding site of tubulin exhibited a possible mode of interaction between this compound and tubulin.     

Proteasome inhibitors as potential novel anticancer agents

Ubiquitin/proteasome-dependent proteolysis plays an essential role in degrading regulatory proteins and thereby controlling processes of cell proliferation and cell death (apoptosis). Most recent experiments using cell cultures and mouse models have demonstrated that proteasome inhibitors induce cancer cell apoptosis and therefore inhibit tumor growth. The proteasome inhibitors have the following unique features: (i) greater apoptosis-inducing potency when tested in various human tumor cell lines than current anticancer drugs; (ii) ability to selectively target transformed and tumor, but not normal, human cells; and (iii) ability to overcome tumor cell resistance to cytotoxic therapies. We suggest that proteasome inhibitors have potential use as novel anticancer agents.     

Synthesis and biological evaluation of novel imidazopyrimidin‐3‐amines as anticancer agents

Groebke–Blackburn–Bienayme reaction has been utilized for the synthesis of new imidazo[1,2‐a]pyrimidine derivatives as novel anticancer agents. The cytotoxic activities of compounds were evaluated against human cancer cell lines including MCF‐7, T‐47D, and MDA‐MB‐231, compared with etoposide as the standard drug. Among the tested compounds, hydroxy‐ and/or methoxy‐phenyl derivatives ( 6a–c and 6k ) with IC₅₀ values of 6.72–14.36 μm were more potent than etoposide against all cell lines. The acridine orange/ethidium bromide double staining and DNA fragmentation studies demonstrated that the cytotoxic effect of 3‐hydroxy‐4‐methoxyphenyl derivative 6c is associated with apoptosis in cancer cells.