1,2,3-Trithiane-5-carboxylic acid, a first contact allergen from Asparagus officinalis (Liliaceae)

image Although hundreds of cases of allergic contact dermatitis caused by asparagus have been described in the literature, the responsible allergens are still unknown. image Fresh asparagus shoots were purchased in early April. Juice and ether extracts were prepared and stored in a deep freezer until chemical investigations and patch tests could be performed. Known constituents were obtained from investigators who have isolated asparagus components. image Asparagus-sensitive patients were patch tested with the juice or fresh parts of asparagus and four constituents. One of the compounds was synthesized to get greater amounts for experimental sensitization in guinea pigs. image All patients gave positive results with the fresh asparagus and 1,2,3-trithiane-5-carboxylic acid, one of its constituents. Experimental sensitization showed that asparagus has a weak to moderate sensitizing capacity. 1,2,3-Trithiane-5-carboxylic acid showed a similar sensitizing power in the experiments. 1,2,3-Trithiane-5-carboxylic acid is a plant growth inhibitor occurring in asparagus mainly in the early phase of the season. image For the first time, a sulfur-containing growth inhibitor could be determined as a contact sensitizer in an edible plant. A second sensitizing constituent was detected, of which the structure could not yet be elucidated completely.