Helmut Viernstein

Prof. Helmut Viernstein


Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

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

Representative Publications

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10 October 2017 in Nutrients
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Journal Article
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Wantida ChaiyanaWantida Chaiyana
Wantida Chaiyana
CPChanun Punyoyai
Chanun Punyoyai
SSSuvimol Somwongin
Suvimol Somwongin
PLPimporn Leelapornpisid
Pimporn Leelapornpisid
KIKornkanok Ingkaninan
Kornkanok Ingkaninan
MMMonika Mueller
Monika Mueller
This study aims to investigate the biological activities related to hair loss of Equisetum debile extracts, including 5α-reductase inhibition, interleukin-6 (IL-6) secretion reduction, and anti-oxidation. E. debile extracts were obtained by maceration in various solvents. Crude extract (CE) was obtained by maceration in 95% ethanol. Chlorophyll-free extract (CF) was the CE which of the chlorophyll has been removed by electrocoagulation. Hexane extract (HE), ethyl acetate extract (EA), and ethanolic extract (ET) were fraction extracts obtained from maceration in hexane, ethyl acetate, and 95% ethanol, respectively. The extracts were investigated for inhibitory activity against 5α-reductase and IL-6 secretion. Total phenolic contents (TPC) were investigated and antioxidant activities were determined by means of 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2′-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The inhibition of lipid peroxidation was determined by the ferric thiocyanate method. The cytotoxicity of the extracts on dermal papilla cells and irritation test by hen's egg test chorioallantoic membrane assay were also investigated. All extracts could inhibit 5α-reductase and decrease IL-6 secretion in lipopolysaccharide-stimulated macrophage. The antioxidant activity of E. debile extracts was directly related to their TPC. ET which contained the highest TPC (68.8 ± 6.7 mg GA/g) showed the highest equivalent concentration (EC1) of 289.1 ± 26.4 mM FeSO4/g, TEAC of 156.6 ± 34.6 mM Trolox/g, and 20.0 ± 6.0% DPPH inhibition. However, EA exhibited the highest inhibition against lipid peroxidation (57.2 ± 0.4%). In addition, EA showed no cytotoxicity on dermal papilla cell line and no irritation on chorioallantoic membrane of hen’s eggs. In conclusion, EA was suggested as the most attractive ingredients for functional food and nutraceuticals because of the high inhibitory activity against 5α-reductase, IL-6 secretion, and lipid peroxidation inhibition.

1 January 2007 in BMC Molecular Biology
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STStefan Toegel
Stefan Toegel
WHWenwen Huang
Wenwen Huang
CPClaudia Piana
Claudia Piana
FUFrank M Unger
Frank M Unger
MWMichael Wirth
Michael Wirth
Helmut ViernsteinHelmut Viernstein
Helmut Viernstein
Chondroprotective agents (CPA) such as glucosamine, curcumin and diacerein represent potential remedies for the management of osteoarthritis and several studies have been performed on their effects in-vitro and in-vivo. For the investigation of chondroprotective action on chondrocyte gene expression, quantitative real-time RT-PCR is the method of choice. However, validation of applied normalization strategies represents a crucial and sometimes neglected step in the analysis process. Therefore, the present study aimed to determine the expression stability of common reference genes (ACTB, Beta actin; GAPDH, Glyceraldehyde-3-phosphate; B2M, Beta-2-microglobulin; HPRT1, Hypoxanthine phosphoribosyl-transferase I; SDHA, Succinate dehydrogenase complex, subunit A; YWHAZ, Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide) under the influence of glucosamine, curcumin and diacerein in the IL-1β-stimulated C-28/I2 chondrocyte model, using the geNorm software tool.



18 October 2016 in Scientia Pharmaceutica
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SCSuporn Charumanee
Suporn Charumanee
SOSiriporn Okonogi
Siriporn Okonogi
JSJakkapan Sirithunyalug
Jakkapan Sirithunyalug
PWPeter Wolschann
Peter Wolschann
Helmut ViernsteinHelmut Viernstein
Helmut Viernstein
The aim of the study was to investigate the solubility of piroxicam (Prx) depending on the inclusion complexation with various cyclodextrins (CDs) and on ethanol as a co-solvent. The phase-solubility method was applied to determine drug solubility in binary and ternary systems. The results showed that in systems consisting of the drug dissolved in ethanol–water mixtures, the drug solubility increased exponentially with a rising concentration of ethanol. The phase solubility measurements of the drug in aqueous solutions of CDs, β-CD and γ-CD exhibited diagrams of AL-type, whereas 2,6-dimethyl-β-CD revealed AP-type. The destabilizing effect of ethanol as a co-solvent was observed for all complexes regardless of the CD type, as a consequence of it the lowering of the complex formation constants. In systems with a higher concentration of ethanol, the drug solubility was increased in opposition to the decreasing complex formation constants. According to this study, the type of CDs played a more important role on the solubility of Prx, and the use of ethanol as a co-solvent exhibited no synergistic effect on the improvement of Prx solubility. The Prx solubility was increased again due to the better solubility in ethanol.

25 October 2009 in Powder Technology
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Closed access
SBSharareh Salar Behzadi
Sharareh Salar Behzadi
CPChakguy Prakasvudhisarn
Chakguy Prakasvudhisarn
JKJohanna Klocker
Johanna Klocker
PWPeter Wolschann
Peter Wolschann
Helmut ViernsteinHelmut Viernstein
Helmut Viernstein