CHANGES IN THE LEVEL OF BIOACTIVE COMPOUNDS IN PAULOWNIA TOMENTOSA FRUITS

摘要

Thejlavonoid and phenylpropanoid glycoside contents of paulownia tomentosa Steud. fruits have been investigated in ElOH extracts obtained during the growing season. Using an HPLC-DAD system, we identified and quantified six C-geranyl flavanones: 3'-O-melhyl-5''-hydroxydiplacone (1), 3-O-melhyl-5'-O-melhyldiplacone (2), 3'-O-methyldiplacol (3), 3-O-melhyldiplacone (4), mimulone (5) and diplacone (6), and two phenylpropanoid glycosides acteoside (1) and isoacleoside (8). The levels of the Jlavonoids varied from minimums of 0.002-0.02% to maximums of 0.064-0.315% depending upon the individual jlavonoid. The concentrations of the jlavonoids increased during the 6-month period of the experiment in contrast to a decrease in the concentrations of the phenylpropanoid glycosides. The concentration of 8 was relatively low, fluctuating between 0.003 and 0.189%, whereas the concentration of 7 was the highest of all of the compounds investigated at 1.4%. The quantity of phenylpropanoid glycosides declined until June and then scarcely changed. Our data suggested that early summer was the appropriate lime for harvesting P. tomentosa/fruits if one is interested in the phenylpropanoid glycosides and autumn the best for the flavonoids. Our findings can be useful for obtaining the highest concentration of bioaclive compounds of P. tomentosa fruits thai can ensure a more effective study of the medicinal properties of these compounds and eventually a preparation of more efficient synthetic derivates. We have also examined the influence of the climatological condition on the total content of phenolic compounds.