ROS-driven, p53-mediated apoptosis in HepG2 cells induced by Blumea eriantha carbon quantum dots

Carbon quantum dots (CQDs), owing to their small size, special surface functionalities, and remarkable fluorescence properties, have gained significant attention from researchers in the biomedical field. In the present work, CQDs were synthesized from Blumea eriantha DC extract using green approach via microwave-assisted technique. The synthesized Blumea eriantha DC-Carbon quantum dots (BEDC-CQDs) were characterized using various spectroscopic techniques to confirm their formation. Strong absorption peaks at 279.46 nm and 325.41 nm are attributed to the excitation of π and n electrons of C=C and C=O groups, respectively, indicating the formation of CQDs. HepG2 cells were treated with varying concentrations of BEDC-CQDs and gauged via MTT assay, flow cytometry, and western blot analysis. Apoptosis, ROS generation, and expression of p53 and MDM2 proteins were evaluated to determine the cytotoxic mechanism. BEDC-CQDs exhibited bright light blue fluorescence under UV irradiation, with PLQY 18.90%. XRD peaks reveal the nano-crystalline nature of the BEDC-CQDs. HR-TEM analysis revealed spherical particles ranging in size from 2.19 to 8.95 nm. The MTT assay of BEDC-CQDs on HepG2 cells demonstrated substantial cell cytotoxicity at a concentration of 50 μgmL⁻¹, with an IC₅₀ value of 40.86 μgmL⁻¹. Flow cytometry results indicated that BEDC-CQDs induced apoptosis in HepG2 cells and significantly increased intracellular ROS levels. Western blot analysis further disclosed that the expression of p53 and MDM2 were increased by 6.282- and 3.836-fold, respectively, in BEDC-CQD treated HepG2 cells compared to the control. These observations suggest that the synthesized BEDC-CQDs could serve as a viable therapeutic agent against hepatocellular carcinoma and support further exploration of similar nanohybrids with other bioactive compounds.