cis-Parinaric acid is a naturally occurring polyunsaturated fatty acid containing an unusual conjugated (Z,E,E,Z) tetraene. This chromophore provides for a natural fluorescence at 432 nm with an excitation wavelength at 320 nm. cis-Parinaric acid occurs naturally in the seeds of the Makita tree, a tropical rainforest tree indigenous to Fiji. Makita seeds are inedible, and this toxicity may be due at least in part to the unstable conjugated fatty acids, including cis-parinaric acid, contained within the seed. cis-Parinaric acid has been used for the measurement of phospholipase activity, lipase activity, and as an indicator of lipid peroxidation.[1][2][3][4]

Reference:
[1]. Wolf, C., Sagaert, L., and Bereziat, G. A sensitive assay of phospholipase using the fluorescent probe 2-parinaroyllecithin. Biochemical and Biophysical Research Communications 99, 275-283 (1981).
[2]. Beisson, F., Ferté, N., Nari, J., et al. Use of naturally fluorescent triacylglycerols from Parinari glaberrimum to detect low lipase activities from Arabidopsis thaliana seedlings. Journal of Lipid Research 40, 2313-2321 (1999).
[3]. McGuire, S.O., James-Kracke, M.R., Sun, G.Y., et al. An esterification protocol for cis-parinaric acid-determined lipid peroxidation in immune cells. Lipids 32, 219-226 (1997).
[4]. de Hingh, Y.C.M., Meyer, J., Fischer, J.C., et al. Direct measurement of lipid peroxidation in submitochondrial particles. Biochemistry 34, 12755-12760 (1995).