Pyrethrum dermatitis.II. The allergenicity of pyrethrum oleoresin and its cross-reactions with the saline extract of pyrethrum flowers

Tests on sensitised guinea pigs have indicated that crude pyrethrum oleoresin contains two types of allergens. The more potent are compounds with similar allergenic determinants to the allergens present in the 0.9% saline extract of pyrethrum flowers which have been tentatively classified as glycoproteins or glycopeptides with molecular weights distributed between about 60 000 and 200 000. The second class of allergens is the sesquiterpene lactones, principally pyrethrosin but these are of minor importance due to their low concentration in pyrethrum oleoresin. Contrary to a recent report, no allergenic activity was obtained from pyrethrin II.     

Pyrethrum dermatitis I. The allergenic properties of various extracts of pyrethrum flowers

Extracts of pyrethrum flowers were obtained by treatment with various aqueous and organic solvents. These were tested for immediate and delayed hypersensitivity reactions in guinea pigs previously sensitised to pyrethrum by single subcutaneous injection of the ground flowers suspended in Freund's complete adjuvant. Strong reactions were elicited by various aqueous extracts of the flowers; the allergens are of high molecular weight, being non-dialysable. A hexane extract (similar to pyrethrum oleoresin) produced a moderate reaction, but a commercially refined pyrethrum extract proved negative. An extract of the spent flowers with methylene chloride showed irritant effects in unsensitised guinea pigs.     

Über die Prüfung des Forstsaatgutes

European Journal of Forest Research -