Dual targeted 2-Benzylideneindanone pendant hydroxamic acid group exhibits selective HDAC6 inhibition along with tubulin stabilization effect.

Abnormal epigenetics has been recognised as an early event in tumour progression and aberrant acetylation of lysine in particular has been understood in tumorigenesis. Therefore, it has become an attractive target for anticancer drug development. However, HDAC inhibitors have limited success due to toxicity and drug resistance concerns. Present study deals with design and synthesis of bivalent indanone based HDAC6 and antitubulin ligands as anticancer agents. Two of the analogues 9 and 21 exhibited potent antiproliferative activities (IC50, 0.36-3.27 µM) and high potency against HDAC 6 enzyme. Compound 21 showed high selectivity against HDAC 6 while 9 exhibited low selectivity. Both the compounds also showed microtubule stabilization effects and moderate anti-inflammatory effect. Dual targeted anticancer agents with concomitant anti-inflammatory effects will be more attractive clinical candidates in future.

Synthesis, Molecular Docking, and 2D-QSAR Modeling of Quinoxaline Derivatives as Potent Anticancer Agents against Triple-negative Breast Cancer.

BACKGROUND: Breast carcinomas aka triple-negative breast cancers (TNBC) are one of the most complex and aggressive forms of cancers in females. Recently, studies have shown that these carcinomas are resistant to hormone-targeted therapies, which makes it a priority to search for effective and potential anticancer drugs. The present study aimed to synthesize and develop the 2Dquantitative structural activity relationship model (QSAR) of quinoxaline derivatives as a potential anticancer agent. METHODS: Quinoxaline derivatives were designed and synthesized (8a-8i and 9a-9d) and the 2DQSAR model against TNBC was developed using VLife MDS v4.4. The anticancer activity was investigated against the TNBC MDA-MB-231 cell line using an MTT cytotoxicity assay. Molecular docking studies along with the estimation of ADMET parameters were done using Discovery Studio. The most potent compound was docked against the ß-tubulin protein target (PDB: 4O2B), using the Autodock Vina v0.8 program. RESULTS: Eleven derivatives of quinoxaline were designed and synthesized (8a-8i and 9a-9d) and a 2D-QSAR model was developed against the TNBC MDA-MB231 cell line. The regression coefficient values for the training set were (r2) 0.78 and (q2) 0.71. Further, external test set regression (pred_r2) was 0.68. Five molecular descriptors viz., energy dispersive (Epsilon3), protein-coding gene (T_T_C_6), molecular force field (MMFF_6), most hydrophobic hydrophilic distance (XA), and Zcomp Dipole were identified. After ADMET, the best analog 8a showed the best activity against the TNBC cell line. The best-predicted hit '8a' was found to bind within the active site of the ß- tubulin protein target. CONCLUSION: The newly synthesized quinoxaline compounds could serve as potent leads for the development of novel anti-cancer agents against TNBC.

Plant isoquinoline alkaloids: Advances in the chemistry and biology of berberine.

Alkaloids are one of the most important classes of plant bioactives. Among these isoquinoline alkaloids possess varied structures and exhibit numerous biological activities. Basically these are biosynthetically produced via phenylpropanoid pathway. However, occasionally some mixed pathways may also occur to provide structural divergence. Among the various biological activities anticancer, antidiabetic, antiinflammatory, and antimicrobial are important. A few notable bioactive isoquinoline alkaloids are antidiabetic berberine, anti-tussive codeine, analgesic morphine, and muscle relaxant papaverine etc. Berberine is one of the most discussed bioactives from this class possessing broad-spectrum pharmacological activities. Present review aims at recent updates of isoquinoline alkaloids with major emphasis on berberine, its detailed chemistry, important biological activities, structure activity relationship and implementation in future research.

Microtubule associated proteins as targets for anticancer drug development.

The dynamic equilibrium of tubulin-microtubule is an essential aspect of cell survivality. Modulation of this dynamics has become an important target for the cancer drug development. Tubulin exists in the alpha-beta dimer form which polymerizes to form microtubule and further depolymerizes back to tubulin dimer. The microtubule plays an essential role in mitosis and cell multiplication. Antitubulin drugs disturb the microtubule dynamics which is essentially required for DNA segregation and cell division during mitosis so killing the cancerous cells. Microtubule Associated Proteins (MAPs) interact with cellular cytoskeletal microtubules. MAPs bind to the either polymerized or depolymerized tubulin dimers within the cell and mostly causing stabilization of microtubules. Some of the tubulin binding drugs are in clinical use and others in clinical trial. MAPs inhibitors are also in clinical trial. Post-translational modification of lysine-40 either in histone or in alpha tubulin has an important role in gene expression and is balanced between histone deacetylases (HDACs) and histone acetyltransferases (HATs). HDAC inhibitors have the anticancer properties to form a drug for the treatment of cancer. They act by inducing cell cycle arrest and cell death. Some of the HDAC inhibitors are approved to be used as anticancer drug while others are under different phases of clinical trial. The present review updates on various MAPs, their role in cancer progression, MAPs inhibitors and their future prospects.

3-Arylindanones and related compounds as antiproliferative agents against colorectal cancer.

Diverse benzylidene indanones and their derivatives were synthesized as anticancer agents. Two of the analogues, that is 7 and 22, exhibited significant antiproliferative activity against several human cancer cell lines. Both the compounds possessed antimitotic activity and induced apoptosis in DLD1 colorectal adenocarcinoma cells through activation of caspase pathways. In cell cycle analysis, both the compounds induced predominantly G2/M phase arrest in DLD1 cells. Molecular docking studies revealed that compound 7 occupies colchicine binding pocket of ß-tubulin. Both the compounds were safe in acute oral toxicity in rodents. Both the compounds are further being optimized for better efficacy.

Synthesis of thymol-based pyrazolines: An effort to perceive novel potent-antimalarials.

A series of thymol based substituted pyrazolines and chalcones was synthesized and evaluated for antimalarial activity, using in-vitro and in-vivo malaria models. All the target compounds (5a-k and 6a-j) were found to be active against human malaria parasite strain Plasmodium falciparum NF54. Among all, compounds 5e and 5f of chalcone series and 6c and 6f of pyrazoline series exhibited prominent antimalarial activity with IC50 less than 3 and 2 µM respectively, while other pyrazolines also significantly inhibited the P. falciparum with IC50 less than 10 µM. The designed pharmacophores were found to be effective against P. falciparum. Compound 6f was found to be able to retard malaria progression in mice. This was evident through decreased parasitemia, increased mean survival time and hemoglobin content in the treated animals. Moreover, 6f was observed as an inhibitor of heme polymerization pathway of the malaria parasite. It also inhibited free heme degradation, which could be possibly responsible for higher reactive oxygen species (ROS) in parasite, thus inhibiting the rapid proliferation of the parasite. In addition to this, compound 6f was found to be non-toxic with a good selectivity index. Based on these observations, the compound 6f could be taken up for further antimalarial lead optimization studies.

Gallic acid-based indanone derivative interacts synergistically with tetracycline by inhibiting efflux pump in multidrug resistant E. coli.

The purpose of the present study was to study the synergy potential of gallic acid-based derivatives in combination with conventional antibiotics using multidrug resistant cultures of Escherichia coli. Gallic acid-based derivatives significantly reduced the MIC of tetracycline against multidrug resistant clinical isolate of E. coli. The best representative, 3-(3',4,'5'-trimethoxyphenyl)-4,5,6-trimethoxyindanone-1, an indanone derivative of gallic acid, was observed to inhibit ethidium bromide efflux and ATPase which was also supported by in silico docking. This derivative extended the post-antibiotic effect and decreased the mutation prevention concentration of tetracycline. This derivative in combination with TET was able to reduce the concentration of TNFα up to 18-fold in Swiss albino mice. This derivative was nontoxic and well tolerated up to 300 mg/kg dose in subacute oral toxicity study in mice. This is the first report of gallic acid-based indanone derivative as drug resistance reversal agent acting through ATP-dependent efflux pump inhibition.

Syntheses of lipophilic chalcones and their conformationally restricted analogues as antitubercular agents.

Lipophilic chalcones and their conformationally restricted analogues were synthesized and evaluated for their antitubercular efficacy against Mycobacterium tuberculosis H37Rv strain. Compounds 16, 24, 25a and 25c were found to be active MIC at 60, 30, 3.5 and 7.5 µg-mL(-1). In vitro cytotoxicity of compounds 16, 24, 25a, 25c and 26 in non-cancerous human epithelial kidney cell line (HEK-293) showed that most active compound 25a was approximately 2.85 times selective towards tubercular versus healthy cells whereas compound 24 was found to be 16 times selective.

Antiproliferative and antioxidant activities of Juglans regia fruit extracts.

CONTEXT: Cancer chemopreventive action of walnut [Juglans regia L. (Juglandaceae)] has been explored. OBJECTIVE: This study evaluated antiproliferative and antioxidant activities of walnut. MATERIALS AND METHODS: Various fractions of walnut extract have been screened for antiproliferative activity against human cancer cell lines using the MTT assay. All these fractions have also been evaluated for total phenolic content, antioxidant activity, and reducing power capacity. RESULTS AND DISCUSSION: Chloroform and ethyl acetate fractions exhibited a high level of antiproliferation against HepG-2, liver cancer cell line (IC(50) = 9 and 15 µg/mL, respectively). CONCLUSION: Exhibiting high phenolic content, antioxidant activity, and potent antiproliferative activity, walnut may act as a cancer chemopreventive agent.

Synergistic anticandidal activity of pure polyphenol curcumin I in combination with azoles and polyenes generates reactive oxygen species leading to apoptosis.

We have shown previously that pure polyphenol curcumin I (CUR-I) shows antifungal activity against Candida species. By employing the chequerboard method, filter disc and time-kill assays, in the present study we demonstrate that CUR-I at non-antifungal concentration interacts synergistically with azoles and polyenes. For this, pure polyphenol CUR-I was tested for synergy with five azole and two polyene drugs - fluconazole (FLC), miconazole, ketoconazole (KTC), itraconazole (ITR), voriconazole (VRC), nystatin (NYS) and amphotericin B (AMB) - against 21 clinical isolates of Candida albicans with reduced antifungal sensitivity, as well as a drug-sensitive laboratory strain. Notably, there was a 10-35-fold drop in the MIC(80) values of the drugs when CUR-I was used in combination with azoles and polyenes, with fractional inhibitory concentration index (FICI) values ranging between 0.09 and 0.5. Interestingly, the synergistic effect of CUR-I with FLC and AMB was associated with the accumulation of reactive oxygen species, which could be reversed by the addition of an antioxidant such as ascorbic acid. Furthermore, the combination of CUR-I and FLC/AMB triggered apoptosis that could also be reversed by ascorbic acid. We provide the first evidence that pure CUR-I in combination with azoles and polyenes represents a novel therapeutic strategy to improve the activity of common antifungals.

Design and synthesis of C-ring lactone- and lactam-based podophyllotoxin analogues as anticancer agents.

A series of novel podophyllotoxin (PDT) analogues was synthesized in which the lactone moiety was shifted to C ring. Some of the derivatives were also synthesized with modified A ring. Analogues 23 and 25 exhibited potent in vitro cytotoxicity against colon cancer (CaCO(2)) cell line. p-Demethylated E-ring analogues exhibited better potency than the corresponding methylated analogues. These analogues showed toxicity comparable to PDT against human erythrocytes albeit at much higher concentrations (100 microg/ml) than their cytotoxicity values.

A promising anticancer and antimalarial component from the leaves of Bidens pilosa.

Bidens pilosa is used in folk medicine for various applications due to the presence of polyacetylenes, flavonoids, terpenoids, phenylpropanoids and others. Bioactivity-guided fractionation of different extracts of B. pilosa leaf showed potential in vitro anticancer and antimalarial activity and led to the identification of a potential marker compound, phenyl-1,3,5-heptatriyne. Erythrocyte osmotic fragility experiments revealed the various extracts as well as the marker component's toxicity profiles on normal blood cells.

Plant-based anticancer molecules: a chemical and biological profile of some important leads.

A number of natural products, with diverse chemical structures, have been isolated as anticancer agents. Several potential lead molecules such as camptothecin, vincristine, vinblastine, taxol, podophyllotoxin, combretastatins, etc. have been isolated from plants and many of them have been modified to yield better analogues for activity, toxicity or solubility. Several successful molecules like topotecan, irinotecan, taxotere, etoposide, teniposide, etc. also have emerged as drugs upon modification of these natural leads and many more are yet to come. In this review, the authors have focused on four important anticancer leads, that is, camptothecin, taxol, combretastatin A-4 and podophyllotoxin. Their chemistry, structure and activity relationships, biological activities, modes of action, analogue synthesis and future prospects have been discussed.

Amide derivatives of 9,11-seco-estra-1,3,5(10)-trien-11-oic acid as modified orally active estrogen agonists with moderate antagonistic activity.

Synthesis of amide derivatives of 9,11-seco-estra-1,3,5(10)-trien-11-oic acid containing alkyl and aromatic amine residues has been carried out with an aim to prepare orally active estrogen antagonists. Modification of the estradiol molecule in the form of C-seco-amide derivatives has led to their high oral absorption. Compounds 7 an n-propyl amide, 8 an n-butyl amide, and 16 a p-anisidyl amide of C-seco-estrane showed significant estrogen antagonistic activity (>20%), while, the majority of compounds possessed high estrogen agonistic activity on oral administration at 10mg/kg dose in rats.