Developing an Isoflavone-derived Fluorescent Probe for Monitoring Cytochrome P450 1A1 and Imaging in Living Colorectal Cancer Cells.

In this work, a fluorescent probe, ISOF-CYP, derived from the typical isoflavone formonetin was developed for monitoring the cytochrome P450 1A1 (CYP1A1) level and imaging in living colorectal cancer cells. Under the excitation at 370 nm, ISOF-CYP acted as the specific substrate of CYP1A1 to report the notable fluorescence signal at 495 nm. During the investigations on the testing conditions, ISOF-CYP exhibited the beneficial performances including a rapid response within 20 min, a high and stable intensity in pH 6.0–9.0, 35–40 ℃. The fluorescence intensity of ISOF-CYP exhibited a dose-dependent enhancement along with the increase of the CYP1A1 level. The detection limit was determined as 0.095 nM from the linear regression. ISOF-CYP selectively detected CYP1A1 among the competing and accompanying analytes. With low cytotoxicity, ISOF-CYP achieved imaging the CYP1A1 level in living colorectal cancer cells. The imaging covered the situations affected by the reported drug, anesthetic protection, and combination strategy. This work inspired a typical natural product modification strategy for the pre-clinical diagnosis and therapeutical management.