An investigation into the origins of salicylic acid in man

Sensitive, accurate and reliable methods to determine the concentrations of salicylic and salicyluric acids in urine and of salicylates in foodstuffs were developed in order to assess the extent of people's exposure to salicylates. These methods involved extraction of acidified aqueous phases with ethyl acetate, high pressure liquid chromatography with systems of stepwise gradient elution, and electrochemical quantification. Urine from a group of vegetarians who had not taken salicylate drugs contained more of these acids than urine from people with an unrestricted diet. However, the highest amounts of salicylic acid and salicyluric acid were excreted by people who took low doses of aspirin regularly. Blood from a group of rural Indians contained the highest concentration of salicylic acid. By examining the blood of normal and "germ-free" rats it was concluded tentatively that the metabolic activity of the gut micro flora did not contribute to the amounts of salicylic acid in serum. Several potential precursors of salicylic acid were investigated as possible dietary sources of salicylates and it was concluded that chorismic acid and benzoic acid might be precursors of salicylic acid in serum. It was established that food produced from plants cultivated "conventionally" contained less salicylic acid than food produced from plants cultivated under "organic" conditions. Very high contents of salicylates were present in several of the spices that are used in large quantities in Indian cookery. The evidence presented in this work indicated strongly that people from a rural part of India, who live on highly spiced, principally vegetarian foods, were exposed to salicylic acid to a much greater extent than any of the other groups of people investigated who had not taken salicylate drugs and it is suggested that this extensive exposure might have contributed significantly to the very low incidence of colorectal cancer in this population.Sensitive, accurate and reliable methods to determine the concentrations of salicylic and salicyluric acids in urine and of salicylates in foodstuffs were developed in order to assess the extent of people's exposure to salicylates. These methods involved extraction of acidified aqueous phases with ethyl acetate, high pressure liquid chromatography with systems of stepwise gradient elution, and electrochemical quantification. Urine from a group of vegetarians who had not taken salicylate drugs contained more of these acids than urine from people with an unrestricted diet. However, the highest amounts of salicylic acid and salicyluric acid were excreted by people who took low doses of aspirin regularly. Blood from a group of rural Indians contained the highest concentration of salicylic acid. By examining the blood of normal and "germ-free" rats it was concluded tentatively that the metabolic activity of the gut micro flora did not contribute to the amounts of salicylic acid in serum. Several potential precursors of salicylic acid were investigated as possible dietary sources of salicylates and it was concluded that chorismic acid and benzoic acid might be precursors of salicylic acid in serum. It was established that food produced from plants cultivated "conventionally" contained less salicylic acid than food produced from plants cultivated under "organic" conditions. Very high contents of salicylates were present in several of the spices that are used in large quantities in Indian cookery. The evidence presented in this work indicated strongly that people from a rural part of India, who live on highly spiced, principally vegetarian foods, were exposed to salicylic acid to a much greater extent than any of the other groups of people investigated who had not taken salicylate drugs and it is suggested that this extensive exposure might have contributed significantly to the very low incidence of colorectal cancer in this population