Rhodamine B Amide Derivatives with Anticancer Activity and Fluorescence Properties for Potential Theranostic Applications

Abstract

Rhodamine B (RHB) based derivatives are especially known for their dye characteristics. Nevertheless, very limited of such revealed promising in‐vivo and in‐vitro therapeutic potency; besides demonstrating great interest due to their excellent photophysical and structural proficiency. Therefore, novel RHB derivatives with significant biological activity are requisite. Hence, current work presents the contemporary design aspect, synthesis, characterization, and anticancer activity of five new RHB amides attained by reacting RHB specifically with simple small amines being side chains of existing anticancer drugs. Therefore, this strategy resulted in a dual effect i. e. fluorescence property and considerable anticancer activity among achieved RHB amides. Obtained fluorophores exhibited emission wavelength at ∼560 nm, a fluorescence quantum yield Φf=10 to 40 % in aqueous solutions, and showed operational stability in pH 4–10, conditions. Further, a study for in‐vitro cell‐based experiments was carried out, wherein AGS (Human gastric cancer) and B16F10 (Murine melanoma) cells were used to screen the compounds. Hydroxy phenyl piperazine substituted RHB amide showed greater growth inhibition than other compounds with an IC50 value of 1.18 μM and 9.07 μM in AGS and B16F10 cells. Fluorescence imaging was performed for the compounds in AGS cells with DAPI as the counterstain using confocal laser microscopy.