The enantiomeric composition of linalool and linalool oxide in the flowers of kiwifruit (Actinidia) species

Abstract

A survey of linalool enantiomers in kiwifruit (Actinidia) flowers was conducted to determine their potential as sources of these valuable floral fragrances, and revealed a wide range of enantiomeric ratios. While flowers of A. polygama and A. chrysantha contained almost exclusively one enantiomer, most species contained significant amounts of both (R) and (S) isomers. In some species enantiomeric ratios of floral linalool differed between genotypes, full siblings, and in one case clones, and ratios changed from year to year as well as diurnally. Enantioselective biosynthesis of the linalool-derived furanoid and pyranoid linalool oxides was examined in flowers of an A. chrysantha and an A. polygama genotype. The flowers of both species produced almost exclusively (S)-linalool. A. chrysantha flowers incubated with rac-d5-linalool preferentially processed the (S)-isomer through to the linalool oxides. However, the A. polygama flowers were less discriminatory in their use of rac-d5-linalool and processed significant quantities of d5-(R)-linalool as well.

Identification, functional characterization, and regulation of the enzyme responsible for floral (E)-nerolidol biosynthesis in kiwifruit (Actinidia chinensis)

“…6D) also showed that ( S )-( E )-nerolidol was the predominant enantiomer and hence supports the assumption that AcNES1 is likely to be responsible for floral ( S )-( E )-nerolidol biosynthesis in A. chinensis . In contrast to the ( S )-linalool produced by AcNES1, the predominant linalool enantiomer in A. chinensis flowers, as previously shown by Matich et al (2010) was ( R )-linalool.…”

Green tea flavour determinants and their changes over manufacturing processes

“…Additionally, reduced levels in product tea infusions may also result from its conversion to stress-induced linalool oxides, which may be catalysed by CYP76C1 as shown in Arabidopsis (Boachon et al, 2015). Linalool and its derivatives (Matich, Bunn, & Hunt, 2010) with strong floral scents are key contributors for tea floral scent based on OAV analysis, and changes in their abundances most likely altered the tea aromas, as found by Takeo (1981). It would be interesting to understand the biochemistry underlying these manufacture-induced abundance changes of geraniol and linalool.…”

Natural pericosines B and C as enantiomeric mixtures: Direct evidence by chiral HPLC analysis

“…Generally, it is believed that natural products exist as either of two distinct enantiomers to play biologically important roles. However, nature sometimes gives us interesting examples of natural products existing as mixtures of enantiomers 1–7. This is particularly noticeable in marine natural products.…”