Found in Carica papaya L. and in Vasconcellosia hastata Caruel, Caricaceae. Isoln from papaya leaves: Greshoff, Mededeel. uit's Lands. Plant., Buitenzorg. No. 7, 5 (1890); Rapoport, Baldridge, J. Am. Chem. Soc. 73, 343 (1951). Reportedly causes bradycardia, CNS depression: Kakowski, Arch. Int. Pharm. 15, 84 (1905). Structure and stereochemistry: Govindachari et al., Tetrahedron Lett. 1965, 1907. Absolute configuration: Coke, Rice, J. Org. Chem. 30, 3420 (1965). Review of structural studies: Govindachari, J. Indian Chem. Soc. 45, 945 (1968).