Ammar Tahir

Dr. Ammar Tahir

Department of Pharmacognosy, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
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Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 July 2019 in Scientific Reports
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Journal Article
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UGUlrike Grienke
Ulrike Grienke
PFPaul A Foster
Paul A Foster
JZJulia Zwirchmayr
Julia Zwirchmayr
Ammar TahirAmmar Tahir
Ammar Tahir
JRJudith Maria Rollinger
Judith Maria Rollinger
Emmanuel MikrosEmmanuel Mikros
Emmanuel Mikros
Chemometric methods and correlation of spectroscopic or spectrometric data with bioactivity results are known to improve dereplication in classical bio-guided isolation approaches. However, in drug discovery from natural sources the isolation of bioactive constituents from a crude extract containing close structural analogues remains a significant challenge. This study is a 1H NMR-MS workflow named ELINA (Eliciting Nature’s Activities) which is based on statistical heterocovariance analysis (HetCA) of 1H NMR spectra detecting chemical features that are positively (“hot”) or negatively (“cold”) correlated with bioactivity prior to any isolation. ELINA is exemplified in the discovery of steroid sulfatase (STS) inhibiting lanostane triterpenes (LTTs) from a complex extract of the polypore fungus Fomitopsis pinicola.

1 January 2017 in Molecular & Cellular Proteomics
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Journal Article
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BMBesnik Muqaku
Besnik Muqaku
MEMartin Eisinger
Martin Eisinger
SMSamuel M. Meier
Samuel M. Meier
Ammar TahirAmmar Tahir
Ammar Tahir
TPTobias Pukrop
Tobias Pukrop
Christopher GernerChristopher Gerner
Christopher Gerner
Pathophysiologies of cancer-associated syndromes such as cachexia are poorly understood and no routine biomarkers have been established, yet. Using shotgun proteomics, known marker molecules including PMEL, CRP, SAA, and CSPG4 were found deregulated in patients with metastatic melanoma. Targeted analysis of 58 selected proteins with multiple reaction monitoring was applied for independent data verification. In three patients, two of which suffered from cachexia, a tissue damage signature was determined, consisting of nine proteins, PLTP, CD14, TIMP1, S10A8, S10A9, GP1BA, PTPRJ, CD44, and C4A, as well as increased levels of glycine and asparagine, and decreased levels of polyunsaturated phosphatidylcholine concentrations, as determined by targeted metabolomics. Remarkably, these molecules are known to be involved in key processes of cancer cachexia. Based on these results, we propose a model how metastatic melanoma may lead to reprogramming of organ functions via formation of platelet activating factors from long-chain polyunsaturated phosphatidylcholines under oxidative conditions and via systemic induction of intracellular calcium mobilization. Calcium mobilization in platelets was demonstrated to alter levels of several of these marker molecules. Additionally, platelets from melanoma patients proved to be in a rather exhausted state, and platelet-derived eicosanoids implicated in tumor growth were found massively increased in blood from three melanoma patients. Platelets were thus identified as important source of serum protein and lipid alterations in late stage melanoma patients. As a result, the proposed model describes the crosstalk between lipolysis of fat tissue and muscle wasting mediated by oxidative stress, resulting in the metabolic deregulations characteristic for cachexia.

20 January 2017 in Analytical Chemistry
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Journal Article
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Ammar TahirAmmar Tahir
Ammar Tahir
ABAndrea Bileck
Andrea Bileck
BMBesnik Muqaku
Besnik Muqaku
LNLaura Niederstaetter
Laura Niederstaetter
DKDominique Kreutz
Dominique Kreutz
Christopher GernerChristopher Gerner
Christopher Gerner

1 June 2019 in Journal of Chromatography A
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Journal Article
Closed access
PRPetar M. Ristivojević
Petar M. Ristivojević
Ammar TahirAmmar Tahir
Ammar Tahir
FMFabian Malfent
Fabian Malfent
DMDušanka Milojković-Opsenica
Dušanka Milojković-Opsenica
JRJudith Maria Rollinger
Judith Maria Rollinger

23 January 2019 in Metallomics
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Journal Article
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SMSamuel M. Meier-Menches
Samuel M. Meier-Menches
KZKatja Zappe
Katja Zappe
ABAndrea Bileck
Andrea Bileck
DKDominique Kreutz
Dominique Kreutz
Ammar TahirAmmar Tahir
Ammar Tahir
Christopher GernerChristopher Gerner
Christopher Gerner
The target spectrum and cellular effects of a metallo-prodrug can be separated from its activated species by time-dependent shotgun proteomics.

23 July 2020 in Scientific Reports
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Journal Article
Open access
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JZJulia Zwirchmayr
Julia Zwirchmayr
BKBenjamin Kirchweger
Benjamin Kirchweger
Theresa LehnerTheresa Lehner
Theresa Lehner
Ammar TahirAmmar Tahir
Ammar Tahir
DPDagmar Pretsch
Dagmar Pretsch
JRJudith Maria Rollinger
Judith Maria Rollinger
In this study a robust, whole organism screening based onCaenorhabditis elegansis presented for the discovery of natural products (NP) with beneficial effects against obesity and age-related diseases. Several parameters of the elaborated workflow were optimized to be adapted for probing multicomponent mixtures combining knowledge from traditional medicine and NP chemistry by generating optimized small-scale extracts considering scarcity of the natural source, solubility issues, and potential assay interferences. The established miniaturized assay protocol allows for in vivo probing of small amounts of even complex samples (~ 1 mg) to test their ability to increase the nematodes’ survival time and the suppression of fat accumulation assessed by Nile red staining as hall marks of “healthy aging”. The workflow was applied on 24 herbal and fungal materials traditionally used against symptoms of the metabolic syndrome and revealed promising results for the extracts ofGardenia jasminoidesfruits and the sclerotia fromInonotus obliquus. Tested at 100 µg/mL they were able to significantly reduce the Nile red fluorescence and extend the 50% survival rate (DT50) compared to the control groups. This phenotype-directed in vivo approach opens up new horizons for the selection of natural starting materials and the investigation of their active principles as fast drug discovery tool with predictive value for human diseases.