3D-QSAR and scaffold hopping based designing of benzo[d]ox-azol-2(3H)-one and 2-oxazolo[4,5-b]pyridin-2(3H)-one derivatives as selective aldehyde dehydrogenase 1A1 inhibitors: Synthesis and biological evaluation.

Aldehyde dehydrogenase 1 (ALDH1A1), an oxidoreductase class of enzymes, is overexpressed in various types of cancer cell lines and is the major cause of resistance to the Food and Drug Administration (FDA)-approved drug, cyclophosphamide (CP). In cancer conditions, CP undergoes a sequence of biotransformations to form an active metabolite, aldophosphamide, which further biotransforms to its putative cytotoxic metabolite, phosphoramide mustard. However, in resistant cancer conditions, aldophosphamide is converted into its inactive metabolite, carboxyphosphamide, via oxidation with ALDH1A1. Herein, to address the issue of ALDH1A1 mediated CP resistance, we report a series of benzo[d]oxazol-2(3H)-one and 2-oxazolo[4,5-b]pyridin-2(3H)-one derivatives as selective ALDH1A1 inhibitors. These inhibitors were designed using a validated 3D-quantitative structure activity relationship (3D-QSAR) model coupled with scaffold hopping. The 3D-QSAR model was developed using reported indole-2,3-diones based ALDH1A1 inhibitors, which provided field points in terms of electrostatic, van der Waals and hydrophobic potentials required for selectively inhibiting ALDH1A1. The most selective indole-2,3-diones-based compound, that is, cmp 3, was further considered for scaffold hopping. Two top-ranked bioisosteres, that is, benzo[d]oxazol-2(3H)-one and 2-oxazolo[4,5-b]pyridin-2(3H)-one, were selected for designing new inhibitors by considering the field pattern of 3D-QSAR. All designed molecules were mapped perfectly on the 3D-QSAR model and found to be predictive with good inhibitory potency (pIC50 range: 7.5-6.8). Molecular docking was carried out for each designed molecule to identify key interactions that are required for ALDH1A1 inhibition and to authenticate the 3D-QSAR result. The top five inhibitor-ALDH1A1 complexes were also submitted for molecular dynamics simulations to access their stability. In vitro enzyme assays of 21 compounds suggested that these compounds are selective toward ALDH1A1 over the other two isoforms, that is, ALDH2 and ALDH3A1. All the compounds were found to be at least three and two times more selective toward ALDH1A1 over ALDH2 and ALDH3A1, respectively. All the compounds showed an IC50 value in the range of 0.02-0.80 µM, which indicates the potential for these to be developed as adjuvant therapy for CP resistance.

Scientific validation of the antimicrobial and antiproliferative potential of Clerodendrum serratum (L.) Moon, its phytoconstituents and their biosafety by acute oral toxicity study.

The screening of aqueous extract of Clerodendrum serratum revealed its broad-spectrum antimicrobial potential against Gram positive, Gram negative bacteria, and yeast. Optimizing the extraction strategies, revealed 15% concentration of aqueous extract prepared at 40 °C by extracting for 40 min, as optimum parameters and its statistical optimization by Box-Behnken design led to 1.16-1.35 folds enhancement in activity. Organic solvent extraction further improved the activity where methanol proved to be the best organic extractant which was effective against all the 13 pathogens tested with inhibition zone ranging from 14 to 32 mm. Minimum Inhibitory Concentration (MIC) study endorsed the methanolic extract to be the best organic extractant, as it showed the lowest MIC (0.5-10 mg/ml) in comparison to aqueous extract (1-10 mg/ml) as well as Partially Purified Phytoconstituents i.e., flavonoids (1-5 mg/ml), diterpenes (5-10 mg/ml) and cardiac glycosides (5-10 mg/ml). All these were found to be biosafe in both In-vitro (Ames and MTT assay) and In-vivo toxicity studies. Acute oral toxicity testing of flavonoids (2000 mg/ml) on Wistar rats did not reveal any significant change in relative organ weight, biochemical, hematological parameters and organs' architecture in comparison to control. Antiproliferative potential of flavonoids against human cancerous cell lines i.e., HeLa, HCT-15, and U87-MG, further increase the importance of this plant as a promising candidate for drug development. The overall study justified the medicinal importance of this plant.

Formulation of sustained-release microspheres of cefixime with enhanced oral bioavailability and antibacterial potential.

Aim: The present work focused on the development of sustained-release microsphere formulation of cefixime to provide reduction in dosing frequency, improved antibacterial activity and patient compliance. Methodology & results: Microspheres were prepared by modified emulsion solvent evaporation method and evaluated by in vitro and in vivo studies. Optimized formulation (FK-07) was found to have entrapment efficiency of 81.12 ± 0.93% and particle size of 166.82 ± 0.86 µm. FK-07 sustained release up to 24 h as demonstrated by in vitro drug release and in vivo pharmacokinetic study in rats. FK-07 showed approximately twofold increase in bioavailability and twofold decrease in MIC90 value against Escherichia coli, Klebsiella pneumoniae and Salmonella typhi in comparison to marketed formulation. Conclusion: Sustaining the release of cefixime using microspheres enhanced its bioavailability, antibacterial efficacy and will help in reducing its dosing frequency.

Antitumour, acute toxicity and molecular modeling studies of 4-(pyridin-4-yl)-6-(thiophen-2-yl) pyrimidin-2(1H)-one against Ehrlich ascites carcinoma and sarcoma-180.

In an effort to discover an effective and selective antitumour agent, synthesis and anti-cancer potential of 4-(pyridin-4-yl)-6-(thiophen-2-yl) pyrimidin-2(1H)-one (SK-25), which has been reported earlier by us with significant cytotoxicity towards MiaPaCa-2 malignant cells, with an IC50 value of 1.95 µM and was found to instigate apoptosis. In the present study, the antitumour efficacy of SK-25 was investigated on Ehrlich ascites tumour (EAT, solid), Sarcoma 180 (solid) tumour and Ehrlich ascites carcinoma. The compound was found to inhibit tumour development by 94.71% in Ehrlich ascites carcinoma (EAC), 59.06% in Ehrlich tumour (ET, solid) and 45.68% in Sarcoma-180 (solid) at 30 mg/kg dose. Additionally, SK-25 was established to be non-toxic at a maximum tolerated dose of 1000 mg/kg in acute oral toxicity in Swiss-albino mice. Computer-based predictions also show that the compounds could have an interesting DMPK profile since all 51 computed physicochemical parameters fall within the recommended range for 95% of known drugs. The current study provides insight for further investigation of the antitumour potential of the molecule.

4-aryl/heteroaryl-4H-fused Pyrans as Anti-proliferative Agents: Design, Synthesis and Biological Evaluation.

AIMS: The current study is focused on the design and synthesis of 4-aryl/heteroaryl-4H-fused pyrans as anti-proliferative agents. All the synthesized molecules were screened against a panel of human carcinoma cell lines. DESCRIPTION: Significant inhibition was exhibited by the compounds against HCT-116 (Colon) and PC-3 (Prostate) cell lines while A-549 (Lung) cell lines, MiaPaCa-2 (Pancreatic) cell lines and HL-60 (Leukemia Cancer) cell lines were almost resistant to the exposure of the test compounds. Compound FP-(v)n displayed noteworthy cytotoxicity towards HCT-116 malignant cells with the IC50 value of 0.67 µM. It induces apoptosis as revealed by several biological endpoints like apoptotic body formation, through DAPI staining, phase contrast microscopy and mitochondrial membrane potential loss. Moreover FP-(v)n is a potent apoptotic inducer confirmed by cell cycle arrest and ROS generation. The cell phase distribution studies indicate an augment from 4.94 % (control sample) to 39.68 % (sample treated with 1.5 µM compound FP-(v)n) in the apoptotic population. Compound FP-(v)n inhibits the tumor growth in Ehrlich ascites carcinoma (EAC), Ehrlich Tumor (ET, solid) and sarcoma-180 (solid) mice models. Additionally, it was established to be non-toxic at maximum tolerated dose of 1000 mg/kg in acute oral toxicity in Swiss-albino mice. CONCLUSION: The current study provides an insight into anti-cancer potential of FP-(v)n, which might be valuable in the treatment of tumor.

Safe and Effective Delivery of Amphotericin B: A Survey of Patents.

BACKGROUND: Amphotericin B, designated as the gold standard among antifungal drugs is the only fungicidal effective against systemic fungal infections. But this drug has various pitfalls associated with it, to bypass which various techniques have been employed and resulted in a variety of lipid based commercially available formulations, which demolished only few of the shortcomings associated with this drug. Further, improvement in the delivery systems of Amphotericin B is advancing at increasingly frenetic pace, to surmount its research and to exploit its therapeutic potency with least toxicities. METHOD: The patent search on "Amphotericin B for its safe and effective delivery" has been carried out to present assimilated information on the patents of the universally accepted Amphotericin B formulations and technologies. Also, the area of focus was the physicochemical properties of Amphotericin B, their role in formulation development and also nanotechnology based formulations of Amphotericin B. RESULTS: Amphotericin B possesses poor aqueous solubility and systemic toxicity rendering obstacle in its formulation development. The interest of scientists and pharmaceutical industries to make further investments in the development of Amphotericin B formulations is due to rare occurrence of resistance to this drug. To bypass these drawbacks, various techniques have been patented which resulted in a variety of commercially available formulations to overcome the limitations of high cost, limited availability, poor storage stability and poor patient compliance. In lieu to this, scientists have developed and patented many novel drug delivery system based formulations and technologies such as use of novel carriers, modification in process for production and purification of Amphotericin B, formation of salts and complexes etc. to bring in limelight the benefits of this wonder drug. CONCLUSION: The purpose of the article is to present assimilated information regarding patents on Amphotericin B formulations and technologies.

Molecular Remodeling of the Insulin Receptor Pathway by Thiazolidinediones in Type 2 Diabetes Mellitus: A Brief Review.

Type 2 diabetes mellitus (T2DM) is characterized by abnormalities in carbohydrate, lipoprotein and lipid metabolism, leading to hyperglycemia and several other complications. Insulin is the major hormone regulating these facets by eliciting various biological responses through its receptor. Insulin exerts diverse effects on cells by targeting distinct functions such as gene expression, fatty acid synthesis, glucose transport and receptor translocation. Insulin mediates these effects through signaling pathways utilizing adapter molecules like small Gproteins, lipid and tyrosine kinases. The anomalous cell response in diabetic condition is due to altered expression/function of these molecules. Thiazolidinediones (TZD's), a class of oral hypoglycemic drugs, have shown to modify these responses, leading to insulin sensitizing effect(s). The TZD's are not only PPARγ agonists, but substantial insulin sensitizing activity is observed through its direct and indirect targets of the insulin receptor pathway, which contributes to its overall performance. TZD's alter(s) cell response via downstream players, primarily IRS, Akt/PKB, PKC, GLUT4, MEK, ERK and transcription factor PGC1α. Thus, this review will focus on the alteration(s) of these molecules in various cell types in diabetic condition and their regulation by TZD's. The physiological changes that occur at the molecular level in T2DM and their modulation by TZD's will provide insights into the key players involved and the potential drug targets for future drug development. The review further highlights the key markers to be evaluated in screening of any potential anti-diabetic agent, and to standardize therapy for T2DM based upon its modulation of the various signaling pathways.

Naphthoflavones as Antiproliferative Agents: Design, Synthesis and Biological Evaluation.

The present study involves the design and synthesis of naphthoflavones as antiproliferative agents. The strategy presents naphthoflavones as hybrids of naphthyl based chalcones and flavones. A panel of human cancer cell lines were employed for the cytotoxicity studies. DK-13 exhibited significant cytoxicity against MiaPaCa-2 cell lines with IC50 value of 1.93 µM and 5.63 µM against MCF-7 cell lines. The compound DK-13 was found to induce apoptosis evidenced through phase contrast microscopy, DAPI staining, and mitochondrial membrane potential loss. The cell phase distribution studies indicated an increase from 11.26 % (control sample) to 55.19 % (sample treated with 20 µM compound DK-13) in the apoptotic population.

Anti-cancer, pharmacokinetic and biodistribution studies of cremophor el free alternative paclitaxel formulation.

PURPOSE: The aim of the present investigation is to determine the in vivo potential of previously developed and optimized Cremophor EL free paclitaxel (CF-PTX) formulation consisting of soya phosphatidylcholine and biosurfactant sodium deoxycholate. CF-PTX was found to have drug loading of 6 mg/ml similar to Cremophor EL based marketed paclitaxel formulation. In the present study, intracellular uptake, repeated dose 28 days sub-acute toxicity, anti-cancer activity, biodistribution and pharmacokinetic studies were conducted to determine in vivo performance of CF-PTX formulation in comparison to marketed paclitaxel formulation. METHODS: Intracellular uptake of CF-PTX was studied using A549 cells by fluorescence activated cell sorting assay (FACS) and fluorescence microscopy. In vivo anti-cancer activity of CF-PTX was evaluated using Ehrlich ascites carcinoma (EAC) model in mice followed by biodistribution and pharmacokinetic studies. RESULTS: FACS investigation showed that fluorescence marker acridine orange (AO) solution showed only 19.8±1.1% intracellular uptake where as significantly higher uptake was observed in the case of AO loaded CF-PTX formulation (85.4±2.3%). The percentage reduction in tumor volume for CF-PTX (72.5±2.3%) in EAC bearing mice was found to be significantly (p<0.05) higher than marketed formulation (58.6±2.8%) on 14th day of treatment. Pharmacokinetic and biodistribution studies showed sustained plasma concentration of paclitaxel depicted by higher mean residence time (MRT; 18.2±1.8 h) and elimination half life (12.8±0.6 h) with CF-PTX formulation as compared to marketed formulation which showed 4.4±0.2 h MRT and 3.6±0.4 h half life. The results of the present study demonstrated better in vivo performance of CF-PTX and this formulation appears to be a promising carrier for sustained and targeted delivery of paclitaxel.