Isolation, spectral characterization and biological activity of fractions of the flavonoid-containing Gratiola officinalis L. extract
The extract of G. officinalis was separated by five major fractions and the antitumor activity of hydrophobic fractions has been established. For the most active fractions spectral investigations of the main component were performed using UV-Vis electronic spectra, circular dichroism (CD), Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. On the basis of spectral characteristics, it was demonstrated that the main components of the fractions 4 and 5 of G. officinalis providing its biological activity, highly likely, are of flavonoid nature. Based on the NMR data we propose the structure of the aglycon moiety of the main component from fraction 4 as 4,2,5-trihydroxychalcone. The fraction 5 is the most active, the antitumor effect of which is implemented through cytotoxic, cytostatic, apoptotic and autophagosomal activity in respect to human kidney cancer tumor cells.