Synthesis of carbon quantum dots from garlic juice and evaluation of their cytotoxic and apoptogenic effects on cancer cells.

Background and purpose: Carbon quantum dots (CQDs) have garnered significant interest in various fields as a burgeoning category of photoluminescent nanomaterials. The current study involved the synthesis of photoluminescent carbon dots through the hydrothermal processing of garlic (Allium sativum L.) juice, serving as a naturally derived carbon source. Experimental approach: The morphology and optical properties of the carbon dots were characterized by TEM, XRD, FT-IR, XPS, UV-Vis, and photoluminescence. The cytotoxic and apoptotic effects of CQDs were evaluated in A549, SKNMC, and H1299 (p53 null) human carcinoma cell lines. Findings/Results: The TEM findings confirmed that carbon dots exhibit a limited variability in their size distribution, characterized by mean diameters of around 16.3 ± 2.7 nm. The peak emission wavelength of carbon dots was observed at 400 nm, accompanied by an excitation peak at 320 nm, and their quantum yield in aqueous solution was measured to be 11.5%. The garlic CQDs were proven to be extremely potent cytotoxic agents, especially against H1299 cells. Apoptosis induction by CQDs was accompanied by an increase in activation of caspase-3 and caspase-9, as well as the disruption of mitochondrial membrane potential in H1299 cells. Conclusion and implications: The apoptotic potential of garlic CQDs was evaluated in the most sensitive cell line, H1299. The apoptogenic effect of garlic CQDs on H1299 cells is important because it has been demonstrated that the loss of p53 is associated with poor clinical prognosis in cancer treatment.