High performance liquid chromatographic study of influence of saccharose and poly(ethylene glycol) on production of hypericin and hyperforin by Hypericum perforatum L.
The influence of saccharose and poly(ethylene glycol) present in the cultivation medium on production of hypericin and hyperforin by Hypericum perforatum L. was evaluated in in vitro experiments. Hypericin and hyperform were isolated by modified Soxhlet extraction with 80% ethanol and determined by HPLC with UV-Vis detection at 592 and 292 mn in less than 4 min. Calibration graphs were linear in the concentration interval 20-200 ng per injection (5 mu l) with correlation coefficients R-2>0.999. Limits of detection (for the 3 S/N criterion) were 90 and 270 pg per injection for both hypericin and hyperforin. Addition of saccharose (10, 20 and 30 g dm(-3)) or PEG (1.25-5 g dm(-3)) to cultivation medium increased the production of both substances in plant tissues. Synthesis of both substances in most experimental plants was the same or lower at higher contents of PEG. Concentrations of hypericin and hyperforin in plants were of the order 100 and 10(3) mu g g(-1), respectively. Morphological changes induced by saccharose and poly(ethylene glycol) were also observed and described.