Novel Tetrahydroquinazolinamines as Selective Histamine 3 Receptor Antagonists for the Treatment of Obesity.

The histamine 3 receptor (H3R) is a presynaptic receptor, which modulates several neurotransmitters including histamine and various essential physiological processes, such as feeding, arousal, cognition, and pain. The H3R is considered as a drug target for the treatment of several central nervous system disorders. We have synthesized and identified a novel series of 4-aryl-6-methyl-5,6,7,8-tetrahydroquinazolinamines that act as selective H3R antagonists. Among all the synthesized compounds, in vitro and docking studies suggested that the 4-methoxy-phenyl-substituted tetrahydroquinazolinamine compound 4c has potent and selective H3R antagonist activity (IC50 < 0.04 µM). Compound 4c did not exhibit any activity on the hERG ion channel and pan-assay interference compounds liability. Pharmacokinetic studies showed that 4c crosses the blood brain barrier, and in vivo studies demonstrated that 4c induces anorexia and weight loss in obese, but not in lean mice. These data reveal the therapeutic potential of 4c as an anti-obesity candidate drug via antagonizing the H3R.

Plant and algal chlorophyll synthases function in Synechocystis and interact with the YidC/Alb3 membrane insertase.

In the model cyanobacterium Synechocystis sp. PCC 6803, the terminal enzyme of chlorophyll biosynthesis, chlorophyll synthase (ChlG), forms a complex with high light-inducible proteins, the photosystem II assembly factor Ycf39 and the YidC/Alb3/OxaI membrane insertase, co-ordinating chlorophyll delivery with cotranslational insertion of nascent photosystem polypeptides into the membrane. To gain insight into the ubiquity of this assembly complex in higher photosynthetic organisms, we produced functional foreign chlorophyll synthases in a cyanobacterial host. Synthesis of algal and plant chlorophyll synthases allowed deletion of the otherwise essential native cyanobacterial gene. Analysis of purified protein complexes shows that the interaction with YidC is maintained for both eukaryotic enzymes, indicating that a ChlG-YidC/Alb3 complex may be evolutionarily conserved in algae and plants.

Substituted carbamothioic amine-1-carbothioic thioanhydrides as novel trichomonicidal fungicides: Design, synthesis, and biology.

Sexually transmitted diseases like trichomoniasis along with opportunistic fungal infections like candidiasis are major global health burden in female reproductive health. In this context a novel non-nitroimidazole class of substituted carbamothioic amine-1-carbothioic thioanhydride series was designed, synthesized, evaluated for trichomonacidal and fungicidal activities, and was found to be more active than the standard drug Metronidazole (MTZ). Compounds were trichomonicidal in the MIC ranges of 4.77-294.1 µM and 32.46-735.20 µM against MTZ-susceptible and -resistant strains, respectively. Further, compounds inhibited the growth of at least two out of ten fungal strains tested at MIC of 7.50-240.38 µM. The most active compound (20) of this series was 3.8 and 9.5 fold more active than the MTZ against the two Trichomonas strains tested. Compound 20 also significantly inhibited the sulfhydryl groups present over Trichomonas vaginalis and was found to be more active than the MTZ in vivo. Further, a docking analysis carried out with cysteine proteases supported their thiol inhibiting ability and preliminary pharmacokinetic study has shown good distribution and systemic clearance.

Novel aryl piperazines for alleviation of 'andropause' associated prostatic disorders and depression.

A series of seventeen piperazine derivatives have been synthesized and biologically evaluated for the management of andropause-associated prostatic disorders and depression. Five compounds 16, 19, 20, 21 and 22 significantly inhibited proliferation of androgen-sensitive LNCaP prostatic cell line with EC50 values of 12.4 µM, 15.6 µM, 11.8 µM, 10.4 µM, 12.2 µM respectively and decreased Ca2+ entry through adrenergic-receptor α1A blocking activity. Anti-androgenic behaviour of compound 19 and 22 was evident by decreased luciferase activity. The high EC50 value in AR-negative cells PC3 and DU145 suggested that the cytotoxicity of compounds was due to AR down regulation. Compound 19 reduced the prostate weight of rats by 53.8%. Further, forced-swimming and tail-suspension tests revealed antidepressant-like activity of compound 19, lacking effects on neuromuscular co-ordination. In silico ADMET predictions revealed that the compound 19 had good oral absorption, aqueous solubility, non-hepatotoxic and good affinity for plasma protein binding. Pharmacokinetic and tissue uptake of 19 at 10 mg/kg demonstrated an oral bioavailability of 35.4%. In silico docking studies predicted similar binding pattern of compound 19 on androgen receptor as hydroxyflutamide. Compound 19 appears to be a unique scaffold with promising activities against androgen associated prostatic disorders in males like prostate cancer and BPH and associated depression.

A combination of complexation and self-nanoemulsifying drug delivery system for enhancing oral bioavailability and anticancer efficacy of curcumin.

OBJECTIVE: Curcumin, the golden spice from Indian saffron, has shown chemoprotective action against many types of cancer including breast cancer. However, poor oral bioavailability is the major hurdle in its clinical application. In the recent years, self-nanoemulsifying drug delivery system (SNEDDS) has emerged as a promising tool to improve the oral absorption and enhancing the bioavailability of poorly water-soluble drugs. In this context, complexation with lipid carriers like phospholipid has also shown the tremendous potential to improve the solubility and therapeutic efficacy of certain drugs with poor oral bioavailability. METHODS: In the present investigation, a systematic combination of both the approaches is utilized to prepare the phospholipid complex of curcumin and facilitate its incorporation into SNEDDS. The combined use of both the approaches has been explored for the first time to enhance the oral bioavailability and in turn increase the anticancer activity of curcumin. RESULTS: As evident from the pharmacokinetic studies and in situ single pass intestinal perfusion studies in Sprague-Dawley rats, the optimized SNEDDS of curcumin-phospholipid complex has shown enhanced oral absorption and bioavailability of curcumin. The cytotoxicity study in metastatic breast carcinoma cell line has shown the enhancement of cytotoxic action by 38.7%. The primary tumor growth reduction by 58.9% as compared with the control group in 4T1 tumor-bearing BALB/c mice further supported the theory of enhancement of anticancer activity of curcumin in SNEDDS. CONCLUSION: The developed formulation can be a potential and safe carrier for the oral delivery of curcumin.

Preclinical pharmacokinetics and ADME characterization of a novel anticancer chalcone, cardamonin.

Cardamonin (CRD), a chalconoid obtained from several medicinal plants of Zingiberaceae family, had shown promising potential in cancer prevention and therapy. For further development and better pharmacological elucidation, we performed a series of in vitro and in vivo studies to characterize its preclinical pharmacokinetics. The study samples were analyzed using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high performance liquid chromatography-ultra violet (HPLC-UV) methods. CRD is partially soluble (<10 µM) and possess high permeability (>0.2 × 10-4 cm/sec). It is moderately bound to plasma proteins (<50%). It shows partitioning in red blood cell (RBC) compartment with the partition coefficient between RBCs and plasma (KRBC/P ) of 0.95 at 0 min to 1.39 at 60 min, indicating significant but slow RBC uptake. In mice, CRD is poorly absorbed after oral administration with 18% oral bioavailability. It possesses high clearance, short mean residence time, and high volume of distribution in mice. It exhibited multiple peak phenomena both after oral and intravenous administration and is excreted both as conjugated and unchanged CRD in bile. It is majorly excreted in faeces and negligibly in urine. The preclinical absorption, distribution, metabolism, and excretion data are expected to succour the future clinical investigations of CRD as a promising anticancer agent. Copyright © 2016 John Wiley & Sons, Ltd.

PEGylated chitosan nanoparticles potentiate repurposing of ormeloxifene in breast cancer therapy.

AIM: Development and optimization of ormeloxifene-loaded PEGylated chitosan nanoparticles (CNPs) for enhancing its literature profound therapeutic activity against breast cancer. METHODS: CNPs were prepared by ionotropic gelation method and characterized. RESULTS: Optimized formulation (CNPs10) had average 304 nm particle size with 0.247 polydispersity index and spherical shape with +31 mV surface charge. CNPs10 had 88.37% entrapment efficiency and 20.93% loading efficiency. CNPs10 demonstrated dose-dependent enhancement in cytotoxicity, cellular uptake, apoptosis, disruption of mitochondrial membrane potential and activation of caspase-3 in breast cancer MDA-MB-231 and MCF-7 cells over free ormeloxifene. In vivo studies divulged improved pharmacokinetic parameters, reduced toxicity, suppressed tumor burden and increased survival in CNPs10-treated female Sprague-Dawley rats. CONCLUSION: PEGylated CNPs enhanced anticancer activity of ormeloxifene.

Identification of gallic acid based glycoconjugates as a novel tubulin polymerization inhibitors.

A novel class of gallic acid based glycoconjugates were designed and synthesized as potential anticancer agents. Among all the compounds screened, compound 2a showed potent anticancer activity against breast cancer cells. The latter resulted in tubulin polymerization inhibition and induced G2/M cell cycle arrest, generation of reactive oxygen species, mitochondrial depolarization and subsequent apoptosis in breast cancer cells. In addition, ultraviolet-visible spectroscopy and fluorescence quenching studies of the compound with tubulin confirmed direct interaction of compounds with tubulin. Molecular modeling studies revealed that it binds at the colchicine binding site in tubulin. Further, 2a also exhibited potent in vivo anticancer activity in LA-7 syngeneic rat mammary tumor model. Current data projects its strong candidature to be developed as anticancer agent.

Rapid quantitative analysis of ormeloxifene and its active metabolite, 7-desmethyl ormeloxifene, in rat plasma using liquid chromatography-tandem mass spectrometry.

Ormeloxifene (ORM) is a non-steroidal, selective estrogen receptor modulator used as a once a week oral contraceptive and is intended for long-term clinical use by females. Therefore, a simple, sensitive and rapid LC-MS/MS method was developed and validated for simultaneous quantification of ORM and its active metabolite (7-desmethyl ormeloxifene, 7-DMO) in rat plasma. Also, the method was partially validated in human plasma. Chromatographic separation was achieved on Discovery HS C-18 column (5µm, 50×4.6mm) with mobile phase [acetonitrile: aqueous ammonium acetate (0.01M) buffer (85: 15, %v/v)] at a flow rate of 0.8mL/min. The calibration curve was linear (r≥0.99) for a concentration range of 0.78-100ng/mL for both the analytes. The precision (%RSD; ORM, 1.3 to 13.4; 7-DMO, 3.1 to 15.0) and accuracy (%bias; ORM, -13.8 to 12.5; 7-DMO, -10.6 to 6.8) in both rat and human plasma were within the acceptable limits. The recovery for ORM and 7-DMO was always >79.1% and >72.9%, respectively. Both the analytes were found stable in rat plasma even after 30 days of storage at -80°C and on being subjected to three freeze-thaw cycles. The method has not only short run time (3.5min) but requires a low plasma sample volume (20µL) and is the first reported LC-MS/MS method for simultaneous quantification of the marketed drug known as centchroman (INN: ormeloxifene) and the metabolite 7-DMO in plasma. The method was applied to evaluate drug-drug interaction of ORM with the commonly prescribed antidepressant drug sertraline using serial sampling in rats.

Gender-related pharmacokinetics and bioavailability of a novel anticancer chalcone, cardamonin, in rats determined by liquid chromatography tandem mass spectrometry.

A reversed phase liquid chromatography tandem mass spectrometry method was developed and validated for quantification of cardamonin, a potential anticancer chalcone, in rat serum. Curcumin was used as an internal standard. Following liquid-liquid extraction using n-hexane and ethyl acetate (60:40, v/v), the processed samples were chromatographed on a C18 column using acetonitrile and ammonium acetate buffer (0.01 M, pH 4.5) (85:15, v/v) as mobile phase at a flow rate of 0.6 mL min(-1). Mass spectrometric detection was performed in the negative electrospray ionization mode by multiple reaction monitoring (m/z 269→122 and 367→217 for cardamonin and curcumin, respectively). The method was validated in terms of selectivity, accuracy, precision, sensitivity, reproducibility, dilution integrity and stability. The linearity was established in the range of 1-200 ng mL(-1) (r≥0.999). The recovery of cardamonin from spiked serum was always >90%. The intra- and inter-day precision (%RSD) and accuracy (%bias) were well within the acceptable limits. The method was applied for single oral and intravenous dose pharmacokinetics in male and female Sprague Dawley rats. Following oral dose, cardamonin showed peak serum concentration that occurred at ∼2 h with very low bioavailability in both male (0.6%) and female (4.8%) rats. Cardamonin exhibited a significant gender influence on pharmacokinetics and bioavailability in rats.