Isethionic acid (2-Hydroxyethanesulfonic acid) is an organosulfur compound. Isethionic acid is widely distributed in animal species and in a few red algal species. Isethionic acid can be used as an anionic detergent and has anti-settlement activity against Balanus amphitrite[1][2].
[1]. Hellio C, et al. Isethionic acid and floridoside isolated from the red alga, Grateloupia turuturu, inhibit settlement of Balanus amphitrite cyprid larvae. Biofouling. 2004 Jun;20(3):139-45. [2]. Tupker RA, et al. Irritancy ranking of anionic detergents using one-time occlusive, repeated occlusive and repeated open tests. Contact Dermatitis. 1999 Jun;40(6):316-22.