Current Drug Discovery Technologies - Volume 17, Issue 1, 2020

Cell-based assays are an important part of the drug discovery process and clinical research. One of the main hurdles is to design sufficiently robust assays with adequate signal to noise parameters while maintaining the inherent physiology of the cells and not interfering with the pharmacology of target being investigated. A plethora of assays that assess cell viability (or cell heath in general) are commercially available and can be classified under different categories according to their concepts and principle of reactions. The assays are valuable tools, however, suffer from a large number of limitations. Some of these limitations can be procedural or operational, but others can be critical as those related to a poor concept or the lack of proof of concept of an assay, e.g. those relying on differential permeability of dyes in-and-out of viable versus compromised cell membranes. While the assays can differentiate between dead and live cells, most, if not all, of them can just assess the relative performance of cells rather than providing a clear distinction between healthy and dying cells. The possible impact of relatively high molecular weight dyes, used in most of the assay, on cell viability has not been addressed. More innovative assays are needed, and until better alternatives are developed, setup of current cell-based studies and data interpretation should be made with the limitations in mind. Negative and positive control should be considered whenever feasible. Also, researchers should use more than one orthogonal method for better assessment of cell health.

Objective: Aripiprazole, a synthetic compound, obtained by chemical modification of the structure of quinolinone is considered as an atypical antipsychotic drug. The present review is an attempt to summarize the updated information related to reported chemistry and pharmacology of Aripiprazole. Development: Aripiprazole, under development by Otsuka Pharmaceutical, was approved by the U.S. Food and Drug Administration (USFDA) by the end of 2002 with an aim to treat patients with schizophrenia. This drug got approved by European Commission in February 2013 to treat the patients having severe manic episodes in bipolar I disorder Additionally, it got approval in Japan in January 2006 and in Canada in 2014. Pharmacology: Aripiprazole shows high specificity for dopamine receptor especially D2 and D3, serotonin 5-HT1A and serotonin 5-HT2A receptors, reasonable specificity for dopamine D4, serotonin 5- HT2C and 5-HT7, alpha1-adrenergic and histamine H1 receptors. It also shows moderate specificity for the serotonin reuptake. The major side effects include headache, agitation, akithesia, anxiety, tachycardia, insomnia, postural hypotension, constipation, vomiting, dizziness, nervousness and somnolence. Conclusion: The present article embarks the available information on Aripiprazole with emphasis on its clinical pharmacology, mechanism of action, pharmacokinetics, pharmacodynamics, metabolism and clinical trials.

The anti-infective potentials of the natural products are very well known for centuries and are a part of traditional healing. The foremost therapeutic classes include flavones, isoflavones, flavonols, flavanones, flavanols, proanthocyanidins, anthocyanidins, chalcones, and aurones. The chalcone or 1,3-diphenyl-2E-propene-1-one represents the class of natural products which are comprised of benzylideneacetophenone function; i.e. two aromatic moieties linked together by an α, β-unsaturated carbonyl bridge comprising three-carbons. At present, chalcone is one of the privileged scaffolds that can be synthesized in the laboratory to derive different pharmacologically active compounds. This article is the continued form of the previously published work on anti-infective perspectives of chalcones (highlighted till 2015). The current work emphasizes on the discovery process of the chalcone in the period of 2016 to 2017 on malaria, trypanosomiasis, leishmaniasis, filaria, tuberculosis, netamodes, Human Immunodeficiency Virus (HIV), Tobacco Mosaic Virus (TMV), Severe Acute Respiratory Syndrome (SARS), and miscellaneous conditions. This review comprehensively focuses on the latest progress related with the anti-infective chalcones. The content includes the crucial structural features of chalcone scaffold including structure-activity relationship(s) along with their plausible mechanism of action(s) from the duration Jan 2016 to Dec 2017. This literature will be of prime interest to medicinal chemists in getting ideas and concepts for better rational development of potential anti-infective inhibitors.

The unique nature of microgravity encountered in space provides an opportunity for drug discovery and development that cannot be replicated on Earth. From the production of superior protein crystals to the identification and validation of new drug targets to microarray analyses of transcripts attenuated by microgravity, there are numerous examples which demonstrate the benefit of exploiting the space environment. Moreover, studies conducted on Space Shuttle missions, the International Space Station and other craft have had a direct benefit for drug development programmes such as those directed against reducing bone and muscle loss or increasing bone formation. This review will highlight advances made in both drug discovery and development and offer some future insight into how drug discovery and associated technologies may be further advanced using the microgravity assist.

Objective: The series of 2-(4-Phenylamino)-N-(5-((4-nitrophenoxy)methyl) -1,3,4-oxadiazol- 2-yl)aceta-mide (5a-5e) and substituted N-(5-(Phenoxymethyl)-1,3,4-oxadiazol-2-yl)-2- (phenylamino)acetamide (5f-5i) was designed, synthesized and investigated for Collapsin Response Mediator Protein 1 (CRMP 1) inhibitors as small lung cancer. Design: Design of compounds was determined by literature review and molecular docking studies in iGEMDOCK 2.0. Materials and Methods: Novel 1, 3, 4 Oxadiazole derivatives were synthesized and characterized by melting point, TLC, IR Spectroscopy, Mass spectroscopy and 1H NMR. In vitro biological evaluation was performed on NCI-H2066 cell line for different concentrations 10-1000μM by telomeric repeat amplification protocol assay. The assay of telomerase in cellular extracts was modified from the PCR-based Telomeric-Repeat Amplification Protocol (TRAP), using the oligonucleotides TS and CX. Results: Novel substituted 2-(4-Phenylamino)-N-(5-((4-nitrophenoxy)methyl)-1,3,4-oxadiazol-2- yl) acetamide (5a-5e) and substituted N-(5-(Phenoxymethyl)-1,3,4-oxadiazol-2-yl)-2-(phenylamino) acetamide (5f-5i) were synthesized, and characterized using spectral and analytical data. All compounds have shown considerable % inhibition of Cell Growth with respect to Bevacizumab, but compound 5a and 5f were equipotent with respect to activity as compared to standard Bevacizumab. Conclusion: Amongst the hybrids, p-nitro substituted derivative (5a) and p-chloro substituted (5f) showed the highest activity against human lung cancer cell line NCI-H2066 by TRAP assay.

Background: The aim of this study was to evaluate the efficacy of the herbal tea based on Foeniculum vulgare, on inducing regular bleeding in women with oligomenorrhea and secondary amenorrhea( oligo/amenorrhea). Methods: Forty women aged 18- 40 with oligo/amenorrhea were enrolled in this randomized controlled clinical trial and were allocated to two groups equally. The women in the first group were treated by Fomentex (Foeniculum vulgare / Mentha longifolia / Vitex agnus-castus) herbal tea 11.2 g/day in 2 divided doses for 2 weeks and the second group were treated by medroxy progesterone acetate (MP)10 mg/day for the last 10 days of their menstrual cycles. The intervention was repeated in three cycles of menstruation in both groups. Bleeding pattern was documented by the patient on diary cards. The occurrence (yes/no) of bleeding, the regularity of bleeding pattern, the interval of cycles, the duration of bleeding, the volume of blood flow, the hormonal parameters (total testosterone, free testosterone luteinizing hormone and follicle-stimulating hormone), and the endometrial thickness in sonography before and after the intervention were evaluated and compared as outcomes. Results: The number of women with bleeding during the first cycle was in the Fomentex group and the MP group 83.3% and 94.1% respectively (p = 0.61). The regularity of bleeding did not significantly differ in patients treated with Fomentex from those given MP (66.7% vs. 94.1%; p = 0.088). Mean interval of cycles decreased in both groups after intervention (P<0.001). Mean duration decreased significantly in MP group after the intervention but it was not different in patients treated with Fomentex. The difference between 2 groups was not significant (P=0.705). Volume of blood flow, with regard to Pictorial Blood Assessment Chart (PBAC), increased significantly in MP group after the intervention (P=0.001) and it was not different in patients treated with Fomentex (P=0.757); however, difference between 2 groups was not significant (P=0.063). The percentage of patients with on time menstruation in the next (drug-free) episode, was higher in the Fomentex group compared with the MP group (50% vs. 23.5%; p = 0.105). Secondary outcomes such as dysmenorrhea, acne and hirsutism reduced in the Fomentex group (P≤0.05), while they increased in the MP group (P=0.007). At the end of the treatment, there was a significant decrease in luteinizing hormone, total testosterone and free testosterone in patients taking Fomentex. The decrease of endometrial thickness, was significant in both groups after the intervention (P=0.001), but the difference between 2 groups was not significant (P=0.58). No notable complication or side effect was reported in relation to Fomentex. Conclusion: Fomentex herbal tea is a safe, well-tolerated, and effective choice in inducing bleeding and maintaining regular bleeding in women with oligo/amenorrhea.

Background: Telomerase, a reverse transcriptase, maintains telomere and chromosomes integrity of dividing cells, while it is inactivated in most somatic cells. In tumor cells, telomerase is highly activated, and works in order to maintain the length of telomeres causing immortality, hence it could be considered as a potential marker to tumorigenesis.A series of 1,3,4-oxadiazole derivatives showed significant broad-spectrum anticancer activity against different cell lines, and demonstrated telomerase inhibition. Methods: This series of 24 N-benzylidene-2-((5-(pyridine-4-yl)-1,3,4-oxadiazol-2yl)thio)acetohydrazide derivatives as telomerase inhibitors has been considered to carry out QSAR studies. The endpoint to build QSAR models is determined by the IC50 values for telomerase inhibition, i.e., the concentration (μM) of inhibitor that produces 50% inhibition. These values were converted to pIC50 (- log IC50) values. We used the most common and transparent method, where models are described by clearly expressed mathematical equations: Multiple Linear Regression (MLR) by Ordinary Least Squares (OLS). Results: Validated models with high correlation coefficients were developed. The Multiple Linear Regression (MLR) models, by Ordinary Least Squares (OLS), showed good robustness and predictive capability, according to the Multi-Criteria Decision Making (MCDM = 0.8352), a technique that simultaneously enhances the performances of a certain number of criteria. The descriptors selected for the models, such as electrotopological state (E-state) descriptors, and extended topochemical atom (ETA) descriptors, showed the relevant chemical information contributing to the activity of these compounds. Conclusion: The results obtained in this study make sure about the identification of potential hits as prospective telomerase inhibitors.

Background: Due to the appearance of communicable microbial diseases and the toxicity related with presently used several antimicrobials such as β-lactam antibiotics, tetracyclines, quinolones, macrolides, glycopeptides (vancomycin) etc, demand for new antimicrobial agents has become a great concern in new technologies to improve efficacy and safety. Methods: In search of new antimicrobial agents with higher potency, some N-substituted benzimidazole derivatives (4, 5a-5h & 6) were obtained by chloroacetylation of benzimidazole followed by reaction with different amines, which were characterized by spectroscopic methods. All the target compounds were evaluated for their antibacterial and antifungal activity against microorganisms using two-fold serial dilution method. Results: Among the compounds evaluated, compounds 4 and 5d exhibited potent activity against Bacillus thuringiensis and Candida albicans while showed moderate activity against Escherischia coli when compared to amoxicillin and fluconazole. Compound 5a showed significant activity against tested microorganisms. Conclusion: From the current study, it may be concluded that synthesized compounds are fulfilling in terms of their structural distinctiveness and marked biological properties. These compounds might be encouraged to initiate a new class of antimicrobial agents.

Background: Withania somnifera (family solanaceae) is a well-investigated medicinal plant which is also called Indian ginseng due to its wide spectrum of medicinal properties. The contents and activity of the plant may vary depending on the habitat and part of the plant and the solvent used for extraction. The present study deals with the comparative chemical analysis and in vitro antioxidant activity of methanolic fruits extracts and its subfractions (in ethyl acetate, butanol and water) of W. somnifera collected from two different geographical locations. Methods: In the present study, Withania somnifera fruits were collected from two different geographical locations (Uttarakhand and Rajasthan). The different fruit extracts were prepared and studied for total phenolic contents and total flavone contents. The in vitro antioxidant activity was assessed by DPPH free radical scavenging assay and peroxide scavenging assay. Results: Methanol extract of W. somnifera Uttarakhand and ethyl acetate subfraction of W. somnifera Rajasthan showed the highest amount of Total Phenolic Contents (TPC). In W. somnifera Uttarakhand, ethyl acetate extract showed the highest amount of Total flavonoids while in W. somnifera Rajasthan, methanol extract was found to be the richest in flavonoids. Methanolic extract of W. somnifera Uttarakhand showed the highest free radical scavenging activity while in W. somnifera Rajasthan, the highest antioxidant activity was shown by the methanolic extract followed by butanolic extract, water extract and then ethyl acetate. In the peroxide scavenging assay of antioxidant activity, water extract of W. somnifera Uttarakhand showed the highest activity, while in W. somnifera Rajasthan, ethyl acetate extract showed highest scavenging activity. Conclusion: It was concluded that the geographical location exerts a vital effect on the presence of active constituents and also on the antioxidant potential of W. somnifera.

Background: Human GPR40 receptor, also known as free fatty-acid receptor 1, is a Gprotein- coupled receptor that binds long chain free fatty acids to enhance glucose-dependent insulin secretion. In order to improve the resistance and efficacy, computational tools were applied to a series of 3-aryl-3-ethoxypropanoic acid derivatives. A relationship between the structure and biological activity of these compounds, was derived using a three-dimensional quantitative structure-activity relationship (3D-QSAR) study using CoMFA, CoMSIA and two-dimensional QSAR study using HQSAR methods. Methods: Building the 3D-QSAR models, CoMFA, CoMSIA and HQSAR were performed using Sybyl-X software. The ratio of training to test set was kept 70:30. For the generation of 3D-QSAR model three different alignments were used namely, distill, pharmacophore and docking based alignments. Molecular docking studies were carried out on designed molecules using the same software. Results: Among all the three methods used, Distill alignment was found to be reliable and predictive with good statistical results. The results obtained from CoMFA analysis q2, r2cv and r2 pred were 0.693, 0.69 and 0.992 respectively and in CoMSIA analysis q2, r2cv and r2pred were 0.668, 0.648 and 0.990. Contour maps of CoMFA (lipophilic and electrostatic), CoMSIA (lipophilic, electrostatic, hydrophobic, and donor) and HQSAR (positive & negative contribution) provided significant insights i.e. favoured and disfavoured regions or positive & negative contributing fragments with R1 and R2 substitutions, which gave hints for the modifications required to design new molecules with improved biological activity. Conclusion: 3D-QSAR techniques were applied for the first time on the series 3-aryl-3- ethoxypropanoic acids. All the models (CoMFA, CoMSIA and HQSAR) were found to be satisfactory according to the statistical parameters. Therefore such a methodology, whereby maximum structural information (from ligand and biological target) is explored, gives maximum insights into the plausible protein-ligand interactions and is more likely to provide potential lead candidates has been exemplified from this study.

Background: Pseudomonas aeruginosa is an opportunistic multi-drug resistance pathogen implicated as the causative agent in a high-percentage of nosocomial and community acquired bacterial infections. The gene encoding leucyl-tRNA synthetase (LeuRS) from P. aeruginosa was overexpressed in Escherichia coli and the resulting protein was characterized. Methods: LeuRS was kinetically evaluated and the KM values for interactions with leucine, ATP and tRNA were 6.5, 330, and 3.0 μM, respectively. LeuRS was developed into a screening platform using scintillation proximity assay (SPA) technology and used to screen over 2000 synthetic and natural chemical compounds. Results: The initial screen resulted in the identification of two inhibitory compounds, BT03C09 and BT03E07. IC50s against LeuRS observed for BT03C09 and BT03E07 were 23 and 15 μM, respectively. The minimum inhibitory concentrations (MIC) were determined against nine clinically relevant bacterial strains. In time-kill kinetic analysis, BT03C09 was observed to inhibit bacterial growth in a bacteriostatic manner, while BT03E07 acted as a bactericidal agent. Neither compound competed with leucine or ATP for binding LeuRS. Limited inhibition was observed in aminoacylation assays with the human mitochondrial form of LeuRS, however when tested in cultures of human cell line, BT03C09 was toxic at all concentration whereas BT03E07 only showed toxic effects at elevated concentrations. Conclusion: Two compounds were identified as inhibitors of LeuRS in a screen of over 2000 natural and synthetic compounds. After characterization one compound (BT03E07) exhibited broad spectrum antibacterial activity while maintaining low toxicity against human mitochondrial LeuRS as well as against human cell cultures.