I agree curcumin (ex440, em500nm) but there may be practical issues because water solubility is poor. 5-aminolevulinate and methyl 5-aminolevulinate are well established PPIX prodrugs.
Also quinine has logP 3.4 but is pH dependent so check clogD.
Morin hydrate is a bioflavonoid hydrophobic drug it has ex430, em 535. you can try it and it is affordable from Sigma Aldrich company. you can refer to our article about it in the link https://www.researchgate.net/publication/256377052_Formulation_characterization_and_pharmacokinetics_of_Morin_hydrate_niosomes_prepared_from_various_non-ionic_surfactants
Regards
Article Formulation, characterization and pharmacokinetics of Morin ...