Spatial tissue distribution of polyacetylenes in carrot root

Abstract

The presented results show the usefulness of Raman spectroscopy in the investigation of polyacetylenes in carrot root. The components are measured directly in the plant tissue without any preliminary sample preparation. Compared with the strong polyacetylene signals the spectral impact of the surrounding biological matrix is weak, except for carotenoids, and therefore it does not contribute significantly to the obtained results. Three different Raman mapping techniques applied here have revealed essential information about the investigated compounds. Using point acquisition several spectra have been measured to demonstrate the complex composition of the polyacetylene fraction in carrot root. The molecular structures of falcarinol, falcarindiol and falcarindiol 3-acetate are similar but their Raman spectra exhibit differences demonstrated by the shift of their -C triple bond C- mode. Line mapping performed along the diameter of transversely cut carrot roots has been used to investigate the relative concentration of polyacetylenes and carotenoids. An area map provides detailed information regarding the distribution of both components. It has been found that high accumulation of polyacetylenes is located in the outer section of the root, namely the pericyclic parenchyma, and in the phloem part close to the secondary cambium. The highest concentration of carotenes is seen in the immediate vicinity to polyacetylene conglomerates.

Determination of polyacetylenes in carrot roots (Daucus carota L.) by high‐performance liquid chromatography coupled with diode array detection

“…The carrot peel contained over a ten-fold higher concentration of FaDOH than the corresponding peeled carrots (Table 4, Fig. 3), which is in accordance with the results of several investigations that found FaDOH to be mainly present in the peel and outer layers of the carrot root [12,35,36]. Also FaDOAc was more abundantly present in the carrot peel than in the peeled carrot indicating a similar distribution pattern as FaDOH in the carrot root.…”

Biosynthesis and function of polyacetylenes and allied natural products

“…maritimus had predominantly 4C. Falcarindiol was distributed uniformly through the phloem [467,468]. HPLC analysis of P. quinquefolium root showed that the total content of panaxydol and falcarinol is inversely correlated with root diameter [469].…”

Identification and quantification of valuable plant substances by IR and Raman spectroscopy

“…Baranska et al have shown that by using Raman spectroscopy it is possible to distinguish the main polyacetylenes occurring in carrot as well as in ginseng roots. Carrot polyacetylenes possess a similar molecular structure with two adjacent triple bonds substituted with one -OH group (falcarinol) and two -OH groups (falcarindiol) and show their characteristic -CBBC-mode in the Raman spectrum at 2258 and 2252 cm À1 , respectively [61,62]. In ginseng roots, beside falcarinol, its epoxy derivative (panaxydol) occurs in higher amounts, and can be characterized by the strong Raman signal at 2260 cm À1 [63].…”

“…Raman mapping technique, which has been successfully applied for spatial investigation of polyacetylenes in carrot [61,62] and ginseng roots [63], provides detailed information concerning their individual distribution.…”