Metabolism of derivatives of toluene. 4. Cresols

Abstract

A procedure is described for the identification of phenolic compounds by paper chromatography. 2. Examples are given of the use of the method in metabolic studies. 3. All the theoretically possible oandp-hydroxylation products have now been identified in rabbit urine after administration of the o-, m-and phydroxybenzoic acids and amides. 4. It has been shown that both salicylic acid and m-hydroxybenzoic acid are conjugated with glycine in the rabbit. The authors thanks are due to Dr R. Consden for his advice in preliminary discussions on the technique of paper chromatography. We are indebted to the Royal Society for a Government Grant which defrayed part of the cost of this work. Some micro-analyses were carried out by Drs Weiler and Strauss, Oxford.

The fate of certain organic acids and amides in the rabbit. 10. The application of paper chromatography to metabolic studies of hydroxybenzoic acids and amides

“…Lederer, 1949). We did not detect 3:4-dihydroxytoluene, which we have shown to be a metabolite of p-cresol (Bray, Thorpe & White, 1950). It has already been mentioned that we have not yet found a solvent mixture suitable for the detection of phenol and cresols.…”

Scientific Opinion on Flavouring Group Evaluation 22, Revision 1 (FGE.22Rev1): Ring‐substituted phenolic substances from chemical groups 21 and 25

“…Despite the fact that 2-and 3-methylphenols are considerably less cytotoxic than the p-isomer, also with 2-and 3-methylphenol some decrease of hepato-cellular GSH has been observed, which could indicate the involvement of an epoxide in the metabolism towards 2,5-dihydroxytoluene (Bray et al, 1950a;Thompson et al, 1994). Further, from the data by Thompson et al, (1994), the involvement of a quinone-hydroquinone redox cycle in hepatocellular GSH depletion by 2-and 3-methylphenol cannot be excluded.…”

“…Total urinary recoveries ranged from 84 -96 % of the dose (Bray et al, 1950b). Based on another study by the same research group (Bray et al, 1950a), it is likely that these amounts were excreted within 24 hours after dosing.…”

“…the parent cresols and the dihydroxytoluenes) were excreted mainly as the glucuronic acid (60-72 % of the dose) and sulphate conjugates (10-15 % of the dose) within 24 hours. p-Hydroxybenzoic acid was excreted as an unidentified conjugate and as free acid (Bray et al, 1950a).…”

Opinion of the Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to Flavouring Group Evaluation 22 (FGE.22): Ring‐substituted phenolic substances from chemical groups 21 and 25 (Commission Regulation (EC) No 1565/2000 of 18 July 2000)

“…Total urinary recoveries ranged from 84 -96 % of the dose (Bray et al, 1950b). Based on another study by the same research group (Bray et al, 1950a), it is likely that these amounts were excreted within 24 h after dosing.…”