Xanthone compounds in shoot cultures of Gentianella bulgarica

Shoot cultures of Gentianella bulgarica established from seedling epicotyls were maintained on MS medium supplemented with BA 0.2 mg l(-1) + NAA 0.1 mg l(-1). Cultures were prone to precocious flowering requiring the use of small shoot buds for multiplication purposes. The contents of three xanthone compounds identified as DGL, BGL, and DMB, in different plant material were determined by HPLC. The analysis revealed that the production of xanthones was affected by different concentrations of BA in medium. Shoot cultures grown at higher BA concentrations contained more DGL than material grown in nature. The concentrations of other two xanthones were lower in shoot cultures than in plants from nature. The radical scavenging activity of plant extracts and xanthones was investigated by DPPH test. Samples from plants grown in nature showed the highest activity (IC(50) = 0.26 mg ml(-1)), while the extracts of shoot cultures grown in media with higher concentrations of BA showed moderate activities (IC(50) from 1.6 to 4.4 mg ml(-1))