Fluorescence and phosphorescence of adrenolutin.

Adrenolutin 3,5,6-trihydroxy-1-methylindole is an intermediate in the metabolism of adrenaline and in the formation of adrenochromo-melanins. Excitation and emission spectra, quantum yield of the adrenolutin fluorescence in water, D2O, ethanol, methanol, acetone and aqueous phosphate buffer at different pH at 293K temperature are reported. Dependence of the quantum yield of adrenolutin on its concentration are measured. Lifetimes of 0.1 mM adrenolutin in water and ethanol are 32.0 +/- 0.2 ns and 9.2 +/- 0.2 ns respectively. Also fluorescence and phosphorescence spectra of adrenolutin in methanol at 110K are obtained. Degrees of polarization and angles between the dipoles for the three main bands absorption of adrenolutin from measurements at 103K are calculated. Adrenolutin may be classified as one of the most strongly fluorescing metabolites. Broad excitation spectrum and high quantum yields make this compound a potential effective acceptor of excitation energy.