The status of blue-green bile pigments of butterflies,and their phototransformations

Summary Blue-green bile pigments are found in adults or larvae of many species of butterfly. They are reviewed here. In contrast to the presence of biliverdin IX 1 in some insect species, many Lepidoptera contain pterobilin2 (biliverdin IX ), phorcabilin3, and sarpedobilin4, derived from2 by cyclization. Pigments3 and4 are members of a new natural family of heterocyclic systems which can also be obtainedin vitro from2, by irradiation under visible light. This review presents the information so far available about the chemistry and biochemistry of these pigments, together with a discussion about the possible biological significance of their photosensitivity.Acknowledgments. Thanks are due to Prof. D.H.R. Barton, E. Lederer and J. Bergerard, for their interest and for discussions.