Gentiana lutea L. subsp. aurantiaca M. Lainz is an endemic medicinal plant from the Iberian Peninsula. Easily recognizable by the orange/reddish colour of its flowers, several other differences as regards habitat, genetics and concentration in bitter compounds have been reported when comparing subspecies aurantiaca with other G. lutea subspecies.
The present study evaluates the variability in the concentration of the main bitter compounds (secoiridoid glycosides): amarogentin, gentiopicroside, sweroside and swertiamarin, between the cortex and vascular tissues of gentian roots. Methanolic extracts from both tissues obtained from complete root systems of G. lutea subsp. aurantiaca wild collected in the Cantabrian Mountains (Spain) have been analysed by HPLC chromatography.
Obtained results show how the concentration of all analysed compounds is significantly higher in the cortex than in the vascular tissues, but as it can be observed in the Table 1, the difference is much higher as regards the amarogentin. As known, with age the relative amounts of cortex and vascular tissues vary, and with it also the concentration of analysed compounds in the roots. These results underline the necessity of quality control measurements to ensure products with homogeneous characteristics and also suggest that the selection of optimal roots would increase the yield in secoiridoid glycosides.
Tab. 1: Secoiridoid glycosides (mg g of root dry weight) in the cortex/vascular tissues in the roots of wild collected G. lutea L. subsp. aurantiaca. Different letters for every bitter compound are significantly different (p ≤0.05) according to Student's T test.
|
|
Cortex
mg/g
|
Vascular tissues
mg/g
|
Variation
%
|
|
Gentiopicroside
|
7.187 a
|
5.381 b
|
33.6
|
|
Amarogentin
|
0.088 a
|
0.024 b
|
261.5
|
|
Sweroside
|
0.174 a
|
0.108 b
|
61.7
|
|
Swertiamarin
|
0.370 a
|
0.309 b
|
19.8
|
[1] Gonzalez-Lopez O. Polanco C. Gyorgy Z. Pedryc A. Casquero PA. Journal of Molecular Sciences 2014: 10052 – 10066
[2] Gonzalez-Lopez O. Carro G. Aiello N. Scartezzini F. Casquero PA. Planta Medica 2014; 80: 1489 – 1490
