抄録
The potent anti-bradykinin activity was found in the beet root ; 4-7 μg of bradykinin was antagonized by the crude beet juice equivalent to 1 g of the root in the assay of contraction of the guinea-pig ileum. This substance was quite stable under heat treatment at 100° for 30 min, and its molecular weight seemed to be around 1000. The bradykinin antagonist was purified as follows : the grated beet roots were lyophilized and then extracted with boiling 99% ethyl alcohol. After removal of the alcohol, the residue was dissolved in water and treated with ether. The aqueous layer was concentrated and applied to a Sephadex G-15 column and a Bio-Gel P-2 column successively. The active fraction obtained by these procedures was developed as a single spot on a silica gel thin-layer chromatogram. The inhibitory effects of this substance were observed on the smooth muscle contraction of guinea-pig, the vasodilatation in dog and the increase in the capillary permeability in rat, all of which were induced by bradykinin. The carrageenin-induced edema in the rat's paw and some of the above biological responses by histamine and 5-hydroxytryptamine were also suppressed distinctly or slightly by the beet antagonist.
