Mucunain

The proteolytic enzyme mucunain is a substance in the tissues of certain legumes of the genus Mucuna, especially M. pruriens. In this species the mucunain is found in stiff hairs, or trichomes, covering the bean pods. When the hairs rub off and come in contact with skin they cause severe itching and irritation. The hairs are small enough to be carried airborne by the wind and are painful if they come in contact with the eyes. Walking shoeless on soil where M. pruriens grows can cause irritation in the feet. The hairs have also been consumed as an herbal remedy for intestinal worms, sometimes mixed with honey for easier swallowing. The pod hairs also contain an amount of serotonin, which, when applied to the skin with mucunain, increases the pruritic qualities of the chemical.