Gentiana kochiana Perr. et Song. (Gentianaceae), a plant used in the traditional medicine of Tuscany (Italy) as antihypertensive remedy, exerts a vasodilator action on in vitro aortic rings that is probably linked to the blocking of the ryanodine-sensitive Ca++ channels.
METHODS AND RESULTS:
In the present study, three known xanthones were isolated from the crude methanolic extract of the roots: gentiacaulein, gentiakochianin, and Swertiaperennin. The first two showed a vasorelaxing activity in rat aortic preparations, pre-contracted by 3 microM norepinephrine (pIC50 = 5.00 +/- 0.032 for gentiacaulein, pIC50 = 4.95 +/- 0.068 for gentiakochianin), 20 mM KCl (pIC50 = 4.90 +/- 0.15 for gentiacaulein; 4.59 +/- 0.069 for gentiakochianin), or 5 mM caffeine; on the contrary, in the same conditions, Swertiaperennin did not show any vasodilator effect. CONCLUSIONS: In conclusion, gentiacaulein and gentiakochianin seem to be the compounds responsible for the vasorelaxing properties of the crude extract of Gentiana kochiana roots. |