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
