Studies on “Vitamin P.” I. Topically Applied “Vitamin P”-Like Substances on the Mammalian Capillary Bed. ∗

Abstract

Summary

1. A mammalian capillary bed preparation was modified from the rat meso-appendix mesenteric preparation of Zweifach and Chambers, and used to estimate the relative activities of various topically applied “vitamin P”-like compounds on microscopically visible vasomotor responses of the vessels.

2. Rutin, rutin sodium acid succinate, hesperidin, hesperidin sodium acid succinate, methylated hesperidin chalcone, esculin and adrenochrome were inert in the concentrations used.

3. The sodium acid phthalates of rutin and hesperidin were slightly active vasoconstrictors.

4. The catechins were highly active vasoconstrictors, including d-catechins, epimerized d-catechins, and especially /-epieatechin, in doses as low as 0.0001 or less.

5. Catechin red (catechin tannin or anhydride) was highly toxic, inducing irreversible vasodilatation and stasis.