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Chemical and Biological Tests with the Toxic Substance of Poison Ivy (Urushiol) and Its Absorption by Amberlite Ion Exchange Resins1

1955; Elsevier BV; Volume: 25; Issue: 1 Linguagem: Inglês

10.1038/jid.1955.89

1523-1747

Francis M. Thurmon, Bertha Ottenstein, Maurice Bessman,

Allelopathy and phytotoxic interactions

Urushiol is a mixture of three closely related derivatives of catechol which differ only in the position of the double bonds in their side chains (1, 2).It is considered the main skin irritant of the poison ivy plant (Rhus toxicodendron).In these experiments it was desirable to have a method for the quantitative estimation of urushiol.Advantage was taken of the phenolie nature of this compound for the development of a colorimetric procedure.This procedure was based on the well knowu Folin-Cioealteau method for the determination of phenols.In the Folin method the color produced from the reaction of a phenolic compound with a phosphotungstic acid reagent is read photometrically.Because of the water insolubility of urushiol a modification was introduced.t Values expressed as gammas of phenol based on a curve plotted for standard solutions of phenol in water are plotted in Figure 2.This curve was used as a standard norm for the determination of phenolic values of urushiol dilutions.Since urushiol is a derivative of cateehol and thus has two pheuolic residues per molecule, it would be expected to exist partially in ionic form in aqueous solution.Because of this ionization it was decided to determine whether ion exchange resins could effectively remove urushiol from solutions.For the in vitro experiments 0.1 % solutions of urushiol were used.They were prepared from 0.1 ml.urushiolt dissolved in 5 ml.95 % ethanol.Then 1 ml 1.5 N-KOH was added and the solution made up to 100 ml. with water.Ten ml. of these solutions were stirred mechanically for 15 minutes with 1 gram amounts