Green synthesis of gold nanoparticles using quercetin biomolecule from mangrove plant, Ceriops tagal: Assessment of antiproliferative properties, cellular uptake and DFT studies

•A quercetin gold nanoparticles (Qu-AuNPs) were synthesized from Ceriops tagal mangrove plant and characterized by FT-IR, UV, P-XRD, TEM, SEM, and EDX analysis.•The fluorescence property of the Qu-AuNPs was tested by using a fluorescence microscope.•The synthesized Qu-AuNPs exhibited promising anticancer activities against A549 and Hela cell lines.•DFT analyses were performed to ascertain the reducing behaviour of quercetin to act as a reducing agent.