Potent vasorelaxant analogs from chemical modification and biotransformation of isosteviol

Isosteviol (1) has been reported to exhibit moderate vasorelaxant activity. In order to enhance the bioactivity of this compound, chemical modification of 1 to the dihydro analog, ent-16β-hydroxybeyeran-19-oic acid (2), was undertaken. Compound 2 was then converted to the corresponding acetate deriv...

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Bibliographic Details
Main Authors: Orawan Wonganan, Chainarong Tocharus, Chonticha Puedsing, Sureeporn Homvisasevongsa, Oratai Sukcharoen, Apichart Suksamrarn
Format: Journal
Published: 2018
Online Access:https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84875987038&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/48038
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Institution: Chiang Mai University
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Summary:Isosteviol (1) has been reported to exhibit moderate vasorelaxant activity. In order to enhance the bioactivity of this compound, chemical modification of 1 to the dihydro analog, ent-16β-hydroxybeyeran-19-oic acid (2), was undertaken. Compound 2 was then converted to the corresponding acetate derivative, ent-16β-acetoxybeyeran-19-oic acid (3). Biotransformation of compounds 1-3 by the fungus Cunninghamella echinulata NRRL 1386 was investigated and the metabolites 4-9 were obtained. The substrates and their metabolites were subjected to in vitro rat aorta relaxant activity evaluation. The metabolite 4, ent-7α-hydroxy-16-ketobeyeran-19-oic acid, exhibited the most highly potent activity, with EC 50 of 3.46 nM, whereas the parent compound 1 showed relatively low activity (EC 50 57.41 nM). A 17-fold increase in vasorelaxant activity of the analog 4 relative to compound 1 is of particular significant. Compound 4 exerted vasorelaxant activity at particularly low concentration and the vasorelaxant profile reached maximum at relatively low concentration, especially when compared with acetylcholine, the positive control. © 2012 Elsevier Masson SAS. All rights reserved.