Ro, Dae-KyunPyle, Bryan Wilkinson2012-07-192012-11-132012-07-192012http://hdl.handle.net/11023/129Valeriana officinalis (valerian) is a popular medicinal plant in North America and Europe. Its root extract is commonly used as a mild sedative and anxiolytic. Valerenic acid, a C15 sesquiterpenoid, has been suggested as the active ingredient responsible for the sedative effect. Recently, medical uses of valerenic acid as anti-depressant and anti-inflammatory drugs were suggested due to its affinity for the γ-aminobutyric acid type A (GABAA) receptor as an agonist and its inhibition of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway, respectively. Despite its importance, biochemistry of valerenic acid in valerian remains unknown. To identify the first committed enzymatic step in valerenic acid biosynthesis, next-generation sequencing (Roche 454 titanium) was used to generate ~1 million transcript reads from valerian root. Subsequently, three cDNAs for sesquiterpene synthases (VoTPS1/2/3) were identified and their corresponding recombinant enzymes were purified. Three recombinant enzymes efficiently catalyze the synthesis of valerena-4,7(11)-diene, germacrene C/D, and drimenol, respectively, based on the spectral match in the mass spectrometry library. Additional structural analyses using GC-MS and 13C-NMR spectrometry in comparison to a semi-synthesized standard confirmed the chemical identity of valerena-4,7(11)-diene. This is the first report of valerena-4,7(11)-diene and drimenol synthases, and the biosynthetic mechanisms of these two products from the substrate, farnesyl diphosphate, were proposed.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.BiochemistryValeriana officinalisvalerenic acidvalerena-4,7(11)-dienemaster thesis10.11575/PRISM/26983