Medicinal Chemistry - Volume 12, Issue 5, 2016

Mass spectrometry (LC-MS or LC-MS/MS) appears in all phases of drug discovery and drug development areas. Starting with the screening and identification of a therapeutic agent and further measuring its in vivo and in vitro properties include: absorption, distribution, metabolism, excretion and toxicity (ADMET) and also pharmacokinetic (PK) and pharmacodynamic (PD) quantitative parameters of drug candidate. Mass spectrometry also serves as a necessary tool also to confirm purity and stability of analyzed new chemical entities (NCEs)/new molecular entities (NMEs) as well as for the analysis of degradation products from the synthesis and following on every stages of drug discovery.

Background: Second mitochondrial activator of caspase (Smac) is a short mitochondrial peptide. When released from the mitochondria into the cytoplasm, it binds to inhibitor of apoptotic proteins (IAPs) within the cytoplasm and prevents them from inhibiting apoptosis. Objective: Delivery of external synthetic Smac peptide into the cytoplasm of malignant cells could greatly improve the efficiency of apoptosis-inducing chemotherapeutic agents. Method: In our study different conjugates based on the seven N-terminal amino acids AVPIAQK of Smac (SmacN7) were produced to obtain a cytoplasm-directed Smac variant. SmacN7 and a point mutant (AVPKAQK) were coupled either to rhodamine alone or to both rhodamine and undecylic aldehyde, which is an antagonist of the Lily-of-the-valley fragrance receptor. The fifth conjugate consisted of rhodamine coupled only to undecylic aldehyde, without SmacN7. The uptake of these five conjugates into three different human cell lines was characterized and quantified by confocal laser scanning microscopy and flow cytometry. A caspase apoptosis assay was performed for cells incubated with the five different conjugates after induction of apoptosis. Results: The coupling of undecylic aldehyde to SmacN7 increased the cellular uptake of the correct and mutant conjugates. Conclusion: Caspase 3/7 apoptosis tests after induction of apoptosis with staurosporine or UV irradiation showed that the coupling of SmacN7 with undecylic aldehyde resulted in a greatly increased adjuvant pro-apoptotic effect compared to the separate components and a mutant SmacN7 peptide sequence in the LNCaP prostate carcinoma cells compared to the benign prostate hyperplasia (BPH) cells and the human embryonal kidney (HEK) cells.

The Bcl-2 family includes 26 proteins involved in apoptosis. Cancer cells can develop the ability to avoid apoptosis through the upregulation and/or down regulation of such proteins Bax, Bcl-xL or Mcl-1, especially during chemoresistance progress. These proteins engaged in a network of dynamic interactions that control apoptosis triggering have become attractive therapeutic targets in cancers including melanoma. Among them, the Bax/Bcl-xL interaction appears critical in maintaining mitochondria integrity. Therefore a series of mixed polyphenol-heterocyclic molecules, were rationally designed by molecular docking as Bax/Bcl-xL inhibitors. It has been screened against B16-F10 melanoma cancer cells for a preliminary investigation of their cytotoxicity. All these compounds exhibited a significant cytotoxicity against these cancer cells, in the 0.3-6 μM range. A pyrazole-type molecule, which had a submicromolar IC50 value with an excellent selectivity index (14), is the most promising derivative for further development.

A novel structure of ferrocene derivative 1 was synthesized with cyanuric chloride and ferrocenemethanol as starting materials. The synthesized compound was fully characterized using 1H NMR, 13C NMR, MS and XRD. Subsequently, the in vitro anticancer effect against A549, HCT116 and MCF-7 cell lines was preliminarily evaluated by the MTT method. The result showed that this compound exhibits good cytotoxic effect on A549, HCT116 and MCF-7 cell lines.

S. divinorum is a psychoactive plant that has been consumed as a recreational drug of abuse in the last years. Salvinorin A is its main constituent, and is responsible for the observed psychoactive effects. Both S. divinorum and salvinorin A have become controlled drugs in several countries, but they are not listed in the Schedules of the United Nations Drug Conventions. Regarding the effects of S. divinorum consumption, almost all studies are based on in vivo or on surveys, and there are no studies in vitro on its toxicity. Furthermore, all studies are focused on the acute toxicological effects of the plant. So, it is of utmost importance to further investigate the effects of S. divinorum and salvinorin A, particularly using in vitro models, after prolonged exposures. In this context, the present work evaluated the in vitro toxicity induced by S. divinorum or salvinorin A in six cell lines, through MTT assays and LC50 determination. Overall, results showed that both S. divinorum and salvinorin A are cytotoxic, dose- and time-dependent. Also, Hep G2 and Caco 2 (to a lesser extent) cells showed lower sensitivity to S. divinorum and salvinorin A when compared to the other studied cell lines. To our knowledge, this is the first work focused on the in vitro toxicity of S. divinorum and salvinorin A using a variety of cell lines, which are extensively described in literature and have been widely used in several in vitro studies.

A novel series of iodo-chrysin derivatives with resorcinol as raw materials were synthesized according to Baker-Venkataraman reaction and their inhibitory activities in vitro against thyroid cancer cell lines (SW-579 and TT) were evaluated by the standard methyl thiazole tetrazolium (MTT) method. Biological test results showed that these derivatives possessed stronger anti-thyroid cancer activities than 5-FU. Compound 21 showed the strongest activity against SW-579 cell lines with IC50 value of 3.4μM and compound 10 showed the strongest activity against TT cell lines with IC50 value of 6.2μM, it was better than 5-FU (59.3μ, 18.4μM respectively).

Background: Quinazoline and sulfonamide derivatives are considered to be important classes of drugs due to their wide range of biological activities especially anticancer. Methods: A novel series of sulfonamides incorporating benzo[g] quinazolinemoieties 2-19 and sulfonyl containing benzo[g] quinazolinemoieties 20, 21 were designed and synthesized starting from 4- chlorobenzo[g] quinazoline 1. In-vitro screening as anticancer agents was done for the synthesized compounds. Molecular docking study was also performed to explore the binding interactions of the synthesized compounds within the active site of carbonic anhydrase IX (CA IX), which most commonly expressed in some types of cancer cells. Conclusion: The results indicated that the most potent compounds were 2 and 7 showing effectiveness on more than one cell line.

Background: The genus Hypericum (family Clusiaceae) comprises various species that are used in traditional medicine, such as wound healing, antidepressant, and anticancer agents. Objective: The aim of this study was to evaluate the inhibitory capacity of extracts and fractions from two Hypericum species used in the Brazilian folk medicine (H. brasiliense and H. connatum) against the enzymes prolyl oligopeptidase (POP), dipeptidyl peptidase-IV (DPP-IV), and acetylcholinesterase (AChE), as well as to identify their main active constituents. Methods: Dried aerial parts of H. connatum and H. brasiliense were subjected to extraction with 8:2 methanol-H2O. Each hydroalcoholic extract was fractioned resulting in ethyl acetate and aqueous fractions. The activity of POP, DPP-IV and AChE was determined in vitro in 96-well microplates. Results: The main components identified in the plant extracts were chlorogenic acid (1), quercitrin (2), rutin (3), quercetin (4), and isoquercitrin (5). Hydroalcoholic extracts, ethyl acetate and aqueous fractions showed high POP inhibitory activity with IC50 values of 2.6 to 3.7 μg/mL. AChE and DPP-IV inhibitory effects were very low for all extracts and substances. Conclusion: Chlorogenic acid (1) and quercetin (4) were the main constituent responsible for the activity observed against POP. Parallel artificial membrane permeability assay of ethyl acetate fractions of both species showed that the metabolite that can effectively pass through the lipid membrane is 4, the aglycone form of 2, 3 and 5.

The ability of DNA to capture oligonucleotide molecules in solution is of great importance in genetics, medical diagnostics, and drug discovery. The DNA hybridization event in which the probe, which is usually a single-stranded DNA (ssDNA) covalently immobilized on a functionalized surface, recognizes the complementary target and forms a stable duplex structure that is the basis of highly specific bio recognizing devices. In this computational study, molecular modeling and Quantitative Structure Activity Relationship (QSAR) calculations were utilized at PM3 level in order to evaluate the interaction of aldehyde ssDNA on chitosan-functionalized silicon substrate and the biological activity of the proposed compounds. Molecular modeling of ssDNA 5’-(TTCA) attached on chitosan- functionalized silicon dioxide substrate was carried out. Molecular modeling and QSAR calculations were utilized at MM3 level in order to evaluate the interaction of target DNA on DNA probe on chitosan-functionalized silicon substrate through hydrogen bonding and the biological activity of the proposed compounds.

In view of the emerging clinical indications for Phosphodiesterase 9 inhibitors e.g. treatment of Alzheimer, diabetes, cancer, and the limited number of its selective inhibitors which possess a single chemical scaffolds, a structure-based approach was undertaken to mine the ZINC database by virtual screening to identify novel PDE9 inhibitors. The database, which was never reported to have been used before for discovery of PDE9 inhibitors, was screened against the ligand binding pocket of the PDE9 complex (PDB:4GH6) using molecular docking programs, MOE and AutoDock Vina in PyRx. Three different scoring functions were used to evaluate the docking poses and scores of the compounds, and the compounds were selected through consensus selection, thus reducing the margin of error in docking. The highest scoring compounds were then selected and purchased for in vitro testing as PDE9 inhibitors and cancer growth inhibitory agents. This led to the discovery of three previously unreported potent PDE 9 inhibitory compounds with two unique chemical scaffolds. Consistent with the role of PDE9 in cancer cell growth, the compounds also inhibited the growth of breast tumor cell lines, MCF-7 and MDA-468 at concentrations comparable to those that inhibited PDE9.

A set of 21 thiourea derivatives were prepared through reacting 3-amino-1H-1,2,4-triazole with the commercial aliphatic and aromatic isothiocyanates. The aliphatic isothiocyanate was used as reagent leading to substitution on NH atom of 3-aminotriazole ring, whereas the triazole amino group was substituted when isothiocyanate group was bonded to the Csp2 hybridized atom, e.g. an aryl or C=O fragment. All compounds were evaluated in vitro for the antimicrobial activity. The derivatives 1, 2, 4, 8, 9, 10 and 12 showed the highest inhibition against Gram-positive cocci (S. aureus and S. epidermidis). The observed MIC values were in the range of 4–32 μg/mL. Compounds were also tested for their in vitro antimicrobial activity against the hospital methicillin-resistant strains of S. aureus. The observed MIC values varied from 4 to 64 μg/mL. The products 4 and 10 effectively inhibited the formation of biofilms of the methicillin-resistant and standard strains of S. epidermidis. The compound 10 was found to be more promising with IC50 values of 2–6 μg/mL as compared to the control. Moreover, the cytotoxicity against the MT-4 cells of all studied thioureas was evaluated. The compound 18 was significantly cytotoxic (CC50 = 8 μM).

Two series of novel benzothiazole derivatives conjugated with semicarbazone scaffold were designed and synthesized through a structure-based molecular hybridization strategy. All the target compounds were evaluated for their cytotoxicity in vitro against three cancer cell lines (HT-29, MKN-45 and H460) by standard MTT assay. The pharmacological results indicated that seven compounds (17h-n) exhibited comparable or even better antiproliferative activity in comparison with reference drugs Sorafenib and PAC-1. Particularly, compound 17i displayed remarkable cytotoxicity against tested three cancer cell lines with IC50 values of 0.84, 0.06 and 0.52 μM, which were 4.3-, 36.6-, 4.2-folds more potent than Sorafenib and 1.2-, 13.7-, 6.9-times more active than PAC-1, respectively.