Skin lesions due to okra (Hibiscus esculentus L.): proteolytic activity and allergenicity of okra.

The present report describes experimental studies on the proteolytic activity of the secretion on the surface of okra pods and the allergenicity of okra components, to clarify the etiology of skin lesions due to okra. Proteolytic activity was detected on the surface of immature okra pods and seemed to be sufficient to cause the skin lesions. Further, in vivo, intradermal injection of the enzyme solution prepared from immature okra pods led to increased capillary permeability in guinea pigs, in contrast to heated preparations. The fraction purified by preparative paper chromatography from an ethyl acetate extract of okra pods showed moderate allergenicity in the guinea pig maximization test. The present experimental evidence supports our suggestions from previous surveys that the proteolytic enzyme of okra may be responsible for development of skin lesions, and that allergic contact dermatitis may also play a part in addition to irritant contact dermatitis.