7 research outputs found

    DNDI-6174 is a preclinical candidate for visceral leishmaniasis that targets the cytochrome bc1.

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    New drugs for visceral leishmaniasis that are safe, low cost, and adapted to the field are urgently required. Despite concerted efforts over the last several years, the number of new chemical entities that are suitable for clinical development for the treatment of Leishmania remains low. Here, we describe the discovery and preclinical development of DNDI-6174, an inhibitor of Leishmania cytochrome bc1 complex activity that originated from a phenotypically identified pyrrolopyrimidine series. This compound fulfills all target candidate profile criteria required for progression into preclinical development. In addition to good metabolic stability and pharmacokinetic properties, DNDI-6174 demonstrates potent in vitro activity against a variety of Leishmania species and can reduce parasite burden in animal models of infection, with the potential to approach sterile cure. No major flags were identified in preliminary safety studies, including an exploratory 14-day toxicology study in the rat. DNDI-6174 is a cytochrome bc1 complex inhibitor with acceptable development properties to enter preclinical development for visceral leishmaniasis

    Are supplements supplemented? Evaluating the composition of complementary and alternative medicines using mass spectrometry and metabolomics

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    The complementary and alternative medicines (CAM) industry is worth over US$110 billion globally. Products are available to consumers with little medical advice; with many assuming that such products are ‘natural’ and therefore safe. However, with adulterated, contaminated and fraudulent products reported on overseas markets, consumers may be placing their health at risk. Previous studies into product content have reported undeclared plant materials, ingredient substitution, adulteration and contamination. However, no large-scale, independent audit of CAM has been undertaken to demonstrate these problems in Australia. This study aimed to investigate the content and quality of CAM products on the Australian market. 135 products were analysed using a combination of next-generation DNA sequencing and liquid chromatography-mass spectrometry. Nearly 50% of products tested had contamination issues, in terms of DNA, chemical composition or both. 5% of the samples contained undeclared pharmaceuticals. Increasing reports of adulteration with novel drug analogues led to the development of a high-throughput untargeted method for pharmacovigilance. Rapid direct sample analysis coupled to mass spectrometry was used to screen products, this time for hundreds of compounds in minutes with minimal sample preparation. The data correlated well with previous analyses, with the added benefit of detected additional compounds including phytochemicals and vitamins. Finally, metabolomics was used to assess the compositional diversity of finished herbal products on the market and how they compare to standard reference materials. The analysis iii showed that, despite all products stating the same ingredients, there was a clear difference in biochemical profile between products and also the reference materials. The combined techniques and analyses used in this project provide an audit and quality control toolkit which will allow for stronger regulation of CAM products. The data collected has shown that such regulation is needed to improve product quality and to protect consumer safety

    Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine (TCM)

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    Globally, there has been an increase in the use of herbal remedies including traditional Chinese medicine (TCM). There is a perception that products are natural, safe and effectively regulated, however, regulatory agencies are hampered by a lack of a toolkit to audit ingredient lists, adulterants and constituent active compounds. Here, for the first time, a multidisciplinary approach to assessing the molecular content of 26 TCMs is described. Next generation DNA sequencing is combined with toxicological and heavy metal screening by separation techniques and mass spectrometry (MS) to provide a comprehensive audit. Genetic analysis revealed that 50% of samples contained DNA of undeclared plant or animal taxa, including an endangered species of Panthera (snow leopard). In 50% of the TCMs, an undeclared pharmaceutical agent was detected including warfarin, dexamethasone, diclofenac, cyproheptadine and paracetamol. Mass spectrometry revealed heavy metals including arsenic, lead and cadmium, one with a level of arsenic >10 times the acceptable limit. The study showed 92% of the TCMs examined were found to have some form of contamination and/or substitution. This study demonstrates that a combination of molecular methodologies can provide an effective means by which to audit complementary and alternative medicines

    Lead optimization of a pyrrole-based dihydroorotate dehydrogenase inhibitor series for the treatment of malaria

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    Malaria puts at risk nearly half the world's population and causes high mortality in sub-Saharan Africa, while drug resistance threatens current therapies. The pyrimidine biosynthetic enzyme dihydroorotate dehydrogenase (DHODH) is a validated target for malaria treatment based on our finding that triazolopyrimidine DSM265 (; 1; ) showed efficacy in clinical studies. Herein, we describe optimization of a pyrrole-based series identified using a target-based DHODH screen. Compounds with nanomolar potency versus; Plasmodium; DHODH and; Plasmodium; parasites were identified with good pharmacological properties. X-ray studies showed that the pyrroles bind an alternative enzyme conformation from; 1; leading to improved species selectivity versus mammalian enzymes and equivalent activity on; Plasmodium falciparum; and; Plasmodium vivax; DHODH. The best lead DSM502 (; 37; ) showed; in vivo; efficacy at similar levels of blood exposure to; 1; , although metabolic stability was reduced. Overall, the pyrrole-based DHODH inhibitors provide an attractive alternative scaffold for the development of new antimalarial compounds

    The application of metabolomics for herbal medicine pharmacovigilance: a case study on ginseng

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    Herbal medicines are growing in popularity, use and commercial value; however, there remain problems with the quality and consequently safety of these products. Adulterated, contaminated and fraudulent products are often found on the market, a risk compounded by the fact that these products are available to consumers with little or no medical advice. Current regulations and quality control methods are lacking in their ability to combat these serious problems. Metabolomics is a biochemical profiling tool that may help address these issues if applied to quality control of both raw ingredients and final products. Using the example of the popular herbal medicine, ginseng, this essay offers an overview of the potential use of metabolomics for quality control in herbal medicines and also highlights where more research is needed
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