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Valerian ( Valeriana officinalis) is a popular medicinal plant in North America and Europe. Its root extract is commonly used as a mild sedative and anxiolytic. Among dozens of chemical constituents (e.g. alkaloids, iridoids, flavonoids, and terpenoids) found in valerian root, valerena-4,7(11)-diene and valerenic acid (C15 sesquiterpenoid) have been suggested as the active ingredients responsible for the sedative effect. However, the biosynthesis of the valerena-4,7(11)-diene hydrocarbon skeleton in valerian remains unknown to date. To identify the responsible terpene synthase, next-generation sequencing (Roche 454 pyrosequencing) was used to generate ∼ 1 million transcript reads from valerian root. From the assembled transcripts, two sesquiterpene synthases were identified ( VoTPS1 and VoTPS2), both of which showed predominant expression patterns in root. Transgenic yeast expressing VoTPS1 and VoTPS2 produced germacrene C/germacrene D and valerena-4,7(11)-diene, respectively, as major terpene products. Purified VoTPS1 and VoTPS2 recombinant enzymes confirmed these activities in vitro, with competent kinetic properties ( Km of ∼ 10 μ m and kcat of 0.01 s−1 for both enzymes). The structure of the valerena-4,7(11)-diene produced from the yeast expressing VoTPS2 was further substantiated by 13C-NMR and GC-MS in comparison with the synthetic standard. This study demonstrates an integrative approach involving next-generation sequencing and metabolically engineered microbes to expand our knowledge of terpenoid diversity in medicinal plants. Database The sequences of cDNAs described in this work are available in the GenBank database under the following accession numbers: , JQ437839; , JQ437840 [ABSTRACT FROM AUTHOR]

The volatile constituents from roots of Valeriana officinalis L. were investigated using GC and GC/MS methods. Valerianae radix samples were obtained from retail pharmacies of different European countries. The roots of 15 V. officinalis samples yielded 0.19-1.16% essential oil on a dry weight basis. The basic oil components among the identified 86 compounds were bornyl acetate (2.9-33.7%), á-fenchene (0-28.3%), valerianol (0.2-18.2%), valerenal (tr-15.6%), isovaleric acid (0-13.1%), camphene (0-11.1%) and valeranone (0.5-10.9%). Bornyl acetate/valerenal chemotype was characteristic for 9 of the 15 samples of valerian roots from different European countries. Some samples did not contain α-fenchene and camphene (Germany, Czech), isovaleric acid (France, Moldova, Russia 2) and valerianic acid (Estonia, Ukraine 1, Scotland, Moldova, Russia 1). Valerian root oil from Estonia was rich in essential oil, bornyl acetate (33.7%), valerianol (16.8%) and valeranone (9.5%). [ABSTRACT FROM AUTHOR]

Abstract: Volvalerenone A (1), a new type of mononorsesquiterpenoid with an unprecedented 5/6/6 tricyclic ring system, was isolated from the roots of Valeriana officinalis, the official species of valerian used in Europe. The structure of volvalerenone A was elucidated based on its spectroscopic and single-crystal X-ray crystallography data. The absolute configuration was assigned by the computational method. A possible biosynthetic pathway of volvalerenone A was also proposed. Preliminary biological studies showed that volvalerenone A had weak inhibitory activity on acetylcholine esterase (AChE), and no enhancing activity on nerve growth factor (NGF)-mediated neurite outgrowth in PC12 cells was observed at 50μM. [Copyright &y& Elsevier]