2,3,4,5-Tetrachloro-6-(3-hydroxy-2,4,5,7-tetraiodo-6-oxo-xanthen-9-yl)benzoic acid
Rose bengal is a pink stain derived as an analogue of fluorescein. Its disodium salt in ophthalmic solutions has been used as a diagnostic agent in suspected damage to conjunctival and corneal cells. It is also used in laboratory settings, including the preparation of Foraminifera for microscopic analysis and suppression of bacterial growth in several microbiological media. A direct cytotoxic effect of Rose bengal on microorganisms and cancer cells has been observed, questioning its potential antitumor actions via intralesional injections. The clinical applications of rose bengal as injectable formulation under the name PV-10 in melanoma, breast cancer and skin conditions such as eczema and psoriasis are being investigated in clinical trials.