Development of a Fluorescent Assay to Search New Drugs Using Stable tdTomato-Leishmania, and the Selection of Galangin as a Candidate With Anti-Leishmanial Activity

Antimonials continue to be considered the first-line treatment for leishmaniases, but its use entails a wide range of side effects and serious reactions. The search of new drugs requires the development of methods more sensitive and faster than the conventional ones. We developed and validated a fluorescence assay based in the expression of tdTomato protein by Leishmania, and we applied this method to evaluate the activity in vitro of flavonoids and reference drugs. The pIR1SAT/tdTomato was constructed and integrated into the genome of Leishmania (Leishmania) amazonensis. Parasites were selected with nourseothricin (NTC). The relation of L. amaz/tc3 fluorescence and the number of parasites was determined; then the growth in vitro and infectivity in BALB/c mice was characterized. To validate the fluorescence assay, the efficacy of miltefosine and meglumine antimoniate was compared with the conventional methods. After that, the method was used to assess in vitro the activity of flavonoids; and the mechanism of action of the most active compound was evaluated by transmission electron microscopy and ELISA. A linear correlation was observed between the emission of fluorescence of L. amaz/tc3 and the number of parasites (r2 = 0.98), and the fluorescence was stable in the absence of NTC. No differences were observed in terms of infectivity between L. amaz/tc3 and wild strain. The efficacy of miltefosine and meglumine antimoniate determined by the fluorescence assay and the microscopic test showed no differences, however, in vivo the fluorescence assay was more sensitive than limiting dilution assay. Screening assay revealed that the flavonoid galangin (GAL) was the most active compound with IC50 values of 53.09 µM and 20.59 µM in promastigotes and intracellular amastigotes, respectively. Furthermore, GAL induced mitochondrial swelling, lipid inclusion bodies and vacuolization in promastigotes; and up-modulated the production of IL-12 p70 in infected macrophages. The fluorescence assay is a useful tool to assess the anti-leishmanial activity of new compounds. However, the assay has some limitations in the macrophage-amastigote model that might be related with an interfere of flavanol aglycones with the fluorescence readout of tdTomato. Finally, GAL is a promising candidate for the development of new treatment against the leishmaniasis.

Download Full-text

Foeniculum vulgareMill: A Review of Its Botany, Phytochemistry, Pharmacology, Contemporary Application, and Toxicology

BioMed Research International ◽

10.1155/2014/842674 ◽

2014 ◽

Vol 2014 ◽

pp. 1-32 ◽

Cited By ~ 90

Author(s):

Shamkant B. Badgujar ◽

Vainav V. Patel ◽

Atmaram H. Bandivdekar

Keyword(s):

Traditional Medicine ◽

Scientific Evidence ◽

New Drugs ◽

Future Research ◽

Foeniculum Vulgare ◽

Wide Range ◽

Research Findings ◽

Valuable Compounds

Foeniculum vulgareMill commonly called fennel has been used in traditional medicine for a wide range of ailments related to digestive, endocrine, reproductive, and respiratory systems. Additionally, it is also used as a galactagogue agent for lactating mothers. The review aims to gather the fragmented information available in the literature regarding morphology, ethnomedicinal applications, phytochemistry, pharmacology, and toxicology ofFoeniculum vulgare. It also compiles available scientific evidence for the ethnobotanical claims and to identify gaps required to be filled by future research. Findings based on their traditional uses and scientific evaluation indicates thatFoeniculum vulgareremains to be the most widely used herbal plant. It has been used for more than forty types of disorders. Phytochemical studies have shown the presence of numerous valuable compounds, such as volatile compounds, flavonoids, phenolic compounds, fatty acids, and amino acids. Compiled data indicate their efficacy in severalin vitroandin vivopharmacological properties such as antimicrobial, antiviral, anti-inflammatory, antimutagenic, antinociceptive, antipyretic, antispasmodic, antithrombotic, apoptotic, cardiovascular, chemomodulatory, antitumor, hepatoprotective, hypoglycemic, hypolipidemic, and memory enhancing property.Foeniculum vulgarehas emerged as a good source of traditional medicine and it provides a noteworthy basis in pharmaceutical biology for the development/formulation of new drugs and future clinical uses.

Download Full-text

Semi-automated high-throughput substrate screening assay for nucleoside kinases

10.33774/chemrxiv-2021-k0w7q ◽

2021 ◽

Author(s):

Katja Hellendahl ◽

Maryke Fehlau ◽

Sebastian Hans ◽

Peter Neubauer ◽

Anke Kurreck

Keyword(s):

High Throughput ◽

Viral Infections ◽

Screening Assay ◽

Liquid Handling ◽

Wide Range ◽

High Throughput Assay ◽

Liquid Handling Robot

Nucleoside kinases (NKs) are key enzymes involved in the in vivo phosphorylation of nucleoside analogues used as drugs to treat cancer or viral infections. Having different specificities, the characterization of NKs is essential for drug design and the production of nucleotide analogues in an in vitro enzymatic process. Therefore, a fast and reliable substrate screening assay for NKs is of great importance. Here, we report the validation of a well-known luciferase-based assay for the detection of NK activity in 96-well plate format. The assay was semi-automated using a liquid handling robot. A good linearity was demonstrated (r² >0.98) in the range of 0 to 500 µM ATP, and it was shown that also alternative phosphate donors like dATP or CTP were accepted by the luciferase. The developed high-throughput assay revealed comparable results to HPLC analysis. The assay was exemplary used for the comparison of the substrate spectra of four nucleoside kinases using 20 (8 natural and 12 modified) substrates. The screening results correlated well with literature data and, additionally, previously unknown substrates were identified for three of the NKs studied. Our results demonstrate that the developed semi-automated high-throughput assay is suitable to identify best performing NKs for a wide range of substrates.

Download Full-text

Antimalarial activity of traditional Kampo medicine Coptis Rhizome extract and its major active compounds

10.21203/rs.2.19890/v3 ◽

2020 ◽

Author(s):

Awet Alem Teklemichael ◽

Shusaku Mizukami ◽

Kazufumi Toume ◽

Farhana Mosaddeque ◽

Mohamed Gomaa Kamel ◽

...

Keyword(s):

Herbal Medicine ◽

Active Compound ◽

Antimalarial Activity ◽

New Drugs ◽

Herbal Extract ◽

Herbal Extracts ◽

Vitro Assay ◽

Malaria Model

Abstract Background: The herbal medicine has been a rich source of new drugs exemplified by quinine and artemisinin. In this study, examined a variety of Japanese traditional herbal medicine (Kampo) for their potential antimalarial activities. Methods: We designed a comprehensive screening to identify novel antimalarial drugs from a library of Kampo herbal extracts (n = 120) and related compounds (n=96). The antimalarial activity was initially evaluated in vitro against chloroquine/mefloquine-sensitive (3D7) and -resistant (Dd2) strains of Plasmodium falciparum . The cytotoxicity was also evaluated using primary Adult Mouse Brain cells. After being selected through the first in vitro assay, positive extracts and compounds were examined for possible in vivo antimalarial activity. Results: Out of 120 herbal extracts, Coptis Rhizome showed the highest antimalarial activity (IC 50 1.9 µg/mL of 3D7 and 4.85 µg/mL of Dd2) with a high selectivity index (SI) > 263 (3D7) and > 103 (Dd2). Three major chlorinated compounds (coptisine, berberine, and palmatine) related to Coptis Rhizome also showed antimalarial activities with IC 50 1.1, 2.6, and 6.0 µM (against 3D7) and 3.1, 6.3, and 11.8 µM (against Dd2), respectively. Among them, coptisine chloride exhibited the highest antimalarial activity (IC 50 1.1 µM against 3D7 and 3.1 µM against Dd2) with SI of 37.8 and 13.2, respectively. . Finally, the herbal extract of Coptis Rhizome and its major active compound coptisine chloride exhibited significant antimalarial activity in mice infected with P. yoelii 17X strain with respect to its activity on parasite suppression consistently from day 3 to day 7 post-challenge. The effect ranged from 50.38 to 72.13% (P <.05) for Coptis Rhizome and from 81 to 89% (P <.01) for coptisine chloride. Conclusion: Coptis Rhizome and its major active compound coptisine chloride showed promising antimalarial activity against chloroquine-sensitive (3D7) and -resistant (Dd2) strains in vitro as well as in vivo mouse malaria model. Thus Kampo herbal medicine is a potential natural resource for novel antipathogenic agents.

Download Full-text

Evolution of Antibacterial Drug Screening Methods: Current Prospects for Mycobacteria

Microorganisms ◽

10.3390/microorganisms9122562 ◽

2021 ◽

Vol 9 (12) ◽

pp. 2562

Author(s):

Clara M. Bento ◽

Maria Salomé Gomes ◽

Tânia Silva

Keyword(s):

Rapid Development ◽

Drug Susceptibility Testing ◽

New Drugs ◽

Host Cells ◽

Screening Methods ◽

Antibacterial Drug ◽

Efficient Treatment ◽

Wide Range

The increasing resistance of infectious agents to available drugs urges the continuous and rapid development of new and more efficient treatment options. This process, in turn, requires accurate and high-throughput techniques for antimicrobials’ testing. Conventional methods of drug susceptibility testing (DST) are reliable and standardized by competent entities and have been thoroughly applied to a wide range of microorganisms. However, they require much manual work and time, especially in the case of slow-growing organisms, such as mycobacteria. Aiming at a better prediction of the clinical efficacy of new drugs, in vitro infection models have evolved to closely mimic the environment that microorganisms experience inside the host. Automated methods allow in vitro DST on a big scale, and they can integrate models that recreate the interactions that the bacteria establish with host cells in vivo. Nonetheless, they are expensive and require a high level of expertise, which makes them still not applicable to routine laboratory work. In this review, we discuss conventional DST methods and how they should be used as a first screen to select active compounds. We also highlight their limitations and how they can be overcome by more complex and sophisticated in vitro models that reflect the dynamics present in the host during infection. Special attention is given to mycobacteria, which are simultaneously difficult to treat and especially challenging to study in the context of DST.

Download Full-text

Diphenylpyrazole-Derived Compounds Increase Survival Time of Mice after Prion Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00151-11 ◽

2011 ◽

Vol 55 (10) ◽

pp. 4774-4781 ◽

Cited By ~ 8

Author(s):

Fabienne Leidel ◽

Martin Eiden ◽

Markus Geissen ◽

Hans A. Kretzschmar ◽

Armin Giese ◽

...

Keyword(s):

High Throughput Screening ◽

Natural Infection ◽

New Drugs ◽

Transmissible Spongiform Encephalopathies ◽

Spongiform Encephalopathy ◽

Variant Form ◽

Screening Assay ◽

High Throughput Screening Assay

ABSTRACTTransmissible spongiform encephalopathies (TSEs) represent a group of fatal neurodegenerative disorders that can be transmitted by natural infection or inoculation. TSEs include scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and Creutzfeldt-Jakob disease (CJD) in humans. The emergence of a variant form of CJD (vCJD), which has been associated with BSE, produced strong pressure to search for effective treatments with new drugs. Up to now, however, TSEs have proved incurable, although many efforts have been made bothin vitroandin vivoto search for potent therapeutic and prophylactic compounds. For this purpose, we analyzed a compound library consisting of 10,000 compounds with a cell-based high-throughput screening assay dealing with scrapie-infected scrapie mouse brain and ScN2A cells and identified a new class of inhibitors consisting of 3,5-diphenylpyrazole (DPP) derivatives. The most effective DPP derivative showed half-maximal inhibition of PrPScformation at concentrations (IC50) of 0.6 and 1.2 μM, respectively. This compound was subsequently subjected to a number of animal experiments using scrapie-infected wild-type C57BL/6 and transgenic Tga20 mice. The DPP derivative induced a significant increase of incubation time both in therapeutic and prophylactic experiments. The onset of the prion disease was delayed by 37 days after intraperitoneal and 42 days after oral application, respectively. In summary, we demonstrate a highin vitroefficiency of DPP derivatives against prion infections that was substantiatedin vivofor one of these compounds. These results indicate that the novel class of DPP compounds should comprise excellent candidates for future therapeutic studies.

Download Full-text

The application of omics-based human liver platforms for investigating the mechanism of drug-induced hepatotoxicity in vitro

Archives of Toxicology ◽

10.1007/s00204-019-02585-5 ◽

2019 ◽

Vol 93 (11) ◽

pp. 3067-3098 ◽

Cited By ~ 3

Author(s):

Jian Jiang ◽

Charlie D. Pieterman ◽

Gökhan Ertaylan ◽

Ralf L. M. Peeters ◽

Theo M. C. M. de Kok

Keyword(s):

Human Liver ◽

Drug Hypersensitivity ◽

New Drugs ◽

Animal Testing ◽

Drug Induced ◽

Human Liver Cell ◽

Wide Range ◽

Bioinformatic Approaches

Abstract Drug-induced liver injury (DILI) complicates safety assessment for new drugs and poses major threats to both patient health and drug development in the pharmaceutical industry. A number of human liver cell-based in vitro models combined with toxicogenomics methods have been developed as an alternative to animal testing for studying human DILI mechanisms. In this review, we discuss the in vitro human liver systems and their applications in omics-based drug-induced hepatotoxicity studies. We furthermore present bioinformatic approaches that are useful for analyzing toxicogenomic data generated from these models and discuss their current and potential contributions to the understanding of mechanisms of DILI. Human pluripotent stem cells, carrying donor-specific genetic information, hold great potential for advancing the study of individual-specific toxicological responses. When co-cultured with other liver-derived non-parenchymal cells in a microfluidic device, the resulting dynamic platform enables us to study immune-mediated drug hypersensitivity and accelerates personalized drug toxicology studies. A flexible microfluidic platform would also support the assembly of a more advanced organs-on-a-chip device, further bridging gap between in vitro and in vivo conditions. The standard transcriptomic analysis of these cell systems can be complemented with causality-inferring approaches to improve the understanding of DILI mechanisms. These approaches involve statistical techniques capable of elucidating regulatory interactions in parts of these mechanisms. The use of more elaborated human liver models, in harmony with causality-inferring bioinformatic approaches will pave the way for establishing a powerful methodology to systematically assess DILI mechanisms across a wide range of conditions.

Download Full-text

Antimalarial activity of traditional Kampo medicine Coptis Rhizome extract and its major active compounds

10.21203/rs.2.19890/v2 ◽

2020 ◽

Author(s):

Awet Alem Teklemichael ◽

Shusaku Mizukami ◽

Kazufumi Toume ◽

Farhana Mosaddeque ◽

Mohamed Gomaa Kamel ◽

...

Keyword(s):

Herbal Medicine ◽

Active Compound ◽

Antimalarial Activity ◽

New Drugs ◽

Herbal Extract ◽

Herbal Extracts ◽

Related Compounds ◽

Malaria Model

Abstract Background: The herbal medicine has been a rich source of new drugs exemplified by quinine and artemisinin. In this study, examined a variety of Japanese traditional herbal medicine (Kampo) for their potential antimalarial activities.Methods: We designed a comprehensive screening to identify novel antimalarial drugs from a library of Kampo herbal extracts (n = 120) and related compounds (n=96). The antimalarial activity was initially evaluated in vitro against chloroquine/mefloquine-sensitive (3D7) and -resistant (Dd2) strains of Plasmodium falciparum. The cytotoxicity was also evaluated using primary Adult Mouse Brain cells. After being selected through the first in vitro assay, positive extracts and compounds were examined for possible in vivo antimalarial activity.Results: Out of 120 herbal extracts, Coptis Rhizome showed the highest antimalarial activity (IC50 1.9 µg/mL of 3D7 and 4.85 µg/mL of Dd2) with a high selectivity index (SI) > 263 (3D7) and > 103 (Dd2). Three major chlorinated compounds (coptisine, berberine, and palmatine) related to Coptis Rhizome also showed antimalarial activities with IC50 1.1, 2.6, and 6.0 µM (against 3D7) and 3.1, 6.3, and 11.8 µM (against Dd2), respectively. Among them, coptisine chloride exhibited the highest antimalarial activity (IC50 1.1 µM against 3D7 and 3.1 µM against Dd2) with SI of 37.8 and 13.2, respectively. . Finally, the herbal extract of Coptis Rhizome and its major active compound coptisine chloride exhibited significant antimalarial activity in mice infected with P. yoelii 17X strain with respect to its activity on parasite suppression consistently from day 3 to day 7 post-challenge. The effect ranged from 50.38 to 72.13% (P <.05) for Coptis Rhizome and from 81 to 89% (P <.01) for coptisine chloride.Conclusion: Coptis Rhizome and its major active compound coptisine chloride showed promising antimalarial activity against chloroquine-sensitive (3D7) and -resistant (Dd2) strains in vitro as well as in vivo mouse malaria model. Thus Kampo herbal medicine is a potential natural resource for novel antipathogenic agents.

Download Full-text

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

Nuklearmedizin ◽

10.1055/s-0038-1629552 ◽

1991 ◽

Vol 30 (01) ◽

pp. 35-39 ◽

Cited By ~ 1

Author(s):

H. S. Durak ◽

M. Kitapgi ◽

B. E. Caner ◽

R. Senekowitsch ◽

M. T. Ercan

Keyword(s):

Soft Tissue ◽

Room Temperature ◽

Normal Subjects ◽

Left Testis ◽

Wide Range ◽

Activity Ratios ◽

The Right ◽

Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

Download Full-text

Natural Anti-inflammatory compounds as Drug candidates in Alzheimer’s disease

Current Medicinal Chemistry ◽

10.2174/0929867327666200730213215 ◽

2020 ◽

Vol 27 ◽

Author(s):

Reyaz Hassan Mir ◽

Abdul Jalil Shah ◽

Roohi Mohi-ud-din ◽

Faheem Hyder Potoo ◽

Mohd. Akbar Dar ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Natural Products ◽

Protective Action ◽

New Drugs ◽

Huperzine A ◽

Brain Disorder ◽

Anti Inflammatory

: Alzheimer's disease (AD) is a chronic neurodegenerative brain disorder characterized by memory impairment, dementia, oxidative stress in elderly people. Currently, only a few drugs are available in the market with various adverse effects. So to develop new drugs with protective action against the disease, research is turning to the identification of plant products as a remedy. Natural compounds with anti-inflammatory activity could be good candidates for developing effective therapeutic strategies. Phytochemicals including Curcumin, Resveratrol, Quercetin, Huperzine-A, Rosmarinic acid, genistein, obovatol, and Oxyresvertarol were reported molecules for the treatment of AD. Several alkaloids such as galantamine, oridonin, glaucocalyxin B, tetrandrine, berberine, anatabine have been shown anti-inflammatory effects in AD models in vitro as well as in-vivo. In conclusion, natural products from plants represent interesting candidates for the treatment of AD. This review highlights the potential of specific compounds from natural products along with their synthetic derivatives to counteract AD in the CNS.

Download Full-text

Antimicrobial peptides for the treatment of pulmonary tuberculosis, allies or foes?

Current Pharmaceutical Design ◽

10.2174/1381612824666180327162357 ◽

2018 ◽

Vol 24 (10) ◽

pp. 1138-1147

Author(s):

Bruno Rivas-Santiago ◽

Flor Torres-Juarez

Keyword(s):

Pulmonary Tuberculosis ◽

Antimicrobial Peptides ◽

Experimental Models ◽

New Drugs ◽

World Health ◽

Public Health Issue ◽

Health Organization ◽

Drug Resistant Strains

Tuberculosis is an ancient disease that has become a serious public health issue in recent years, although increasing incidence has been controlled, deaths caused by Mycobacterium tuberculosis have been accentuated due to the emerging of multi-drug resistant strains and the comorbidity with diabetes mellitus and HIV. This situation is threatening the goals of World Health Organization (WHO) to eradicate tuberculosis in 2035. WHO has called for the creation of new drugs as an alternative for the treatment of pulmonary tuberculosis, among the plausible molecules that can be used are the Antimicrobial Peptides (AMPs). These peptides have demonstrated remarkable efficacy to kill mycobacteria in vitro and in vivo in experimental models, nevertheless, these peptides not only have antimicrobial activity but also have a wide variety of functions such as angiogenesis, wound healing, immunomodulation and other well-described roles into the human physiology. Therapeutic strategies for tuberculosis using AMPs must be well thought prior to their clinical use; evaluating comorbidities, family history and risk factors to other diseases, since the wide function of AMPs, they could lead to collateral undesirable effects.

Download Full-text