Caffeic acid and ferulic acid, which are naturally occurring phenols present in a wide variety of plants, were examined for their ability to react with nitrite in vitro and to inhibit nitrosamine formation in vivo. Their activities were compared with other phenols (butylated hydroxyanisole and Trolox) and with a non-phenolic polyhydroxylated compound, glycerol guaiacolate. In simulated gastric fluid, caffeic acid and ferulic acid reacted rapidly and completely with an equimolar quantity of sodium nitrite. In rats receiving aminopyrine and nitrite, caffeic acid and ferulic acid blocked the elevation of serum N-nitrosodimethylamine (NDMA) levels and the serum glutamic pyruvic transaminase levels associated with hepatotoxicity. Neither phenol had any effect on serum levels of NDMA in rats treated with NDMA. In both the in vitro (reaction with nitrite) and in vivo (inhibition of hepatotoxicity) systems, caffeic acid was more effective than ferulic acid. Butylated hydroxyanisole and Trolox were partially effective, and glycerol guaiacolate was inactive. The results of this study suggest that dietary caffeic acid and ferulic acid may play a role in the body's defense against carcinogenesis by inhibiting the formation of N-nitroso compounds.

Abstract6‐Hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid in thin layer tests in vegetable oils and animal fats has two‐four times the antioxidant activity of butylated hydroxytoluene and butylated hydroxyanisole and is more active than propyl gallate, nordihydroquaiaretic acid, ascorbyl palmitate, and α‐ and γ‐tocopherols. It is also more active than tertiary butylhydroquinone in chicken and pork fats and corn, peanut, sunflower, and safflower oils in thin layer tests. Tertiary butylhydroquinone is slightly more active in corn, soybean, cottonseed, and peanut oils in the active oxygen method, probably due to decomposition of the chroman at 98 C. This decomposition is inhibited by ascorbic acid. The chroman is synergized by ascorbyl palmitate‐thiodipropionate and ascorbic acids. Active oxygen method values of 190 hr are obtained in combination with the latter. A spectrofluorometric assay for 6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid has been developed. The compound is 95–100% stable for 2 months at room temperature and 45 C, and a low level of toxicity is found. The copper and iron breakdown products of the chroman have been determined. A possible relationship between these products, protection of the chroman by ascorbic acid and ethylene diaminetetraacetic acid, and a mechanism of action is presented.

No abstract

No abstract

No abstract