Microwave synthesis of carbon dot from asparagus racemosus for Ag+ ion sensing, anti-oxidant and cytotoxicity studies

In this study, we provide a single-step, environmentally friendly microwave method for producing water-soluble, monodisperse carbon dots (CDs) using the natural herb Asparagus racemosus root as a carbon precursor. These CDs were characterised structurally and morphologically using TEM, XRD, and FTIR techniques. TEM measurements of the newly created CDs showed that they were ranged in size of 2 to 10 nm. By using FTIR spectroscopy, the functional groups -OH and COOH on the exterior of the CDs was proved. The potential of the synthesized carbon dots was used to sense Ag+ ion in an aqueous media. Here, we provide a colorimetric carbon dot (CD) probe for detecting the Ag+ ion in water visually. Moreover, antioxidant characteristics were assessed using the DPPH method, and their cytotoxicity was studied upon A549 cell-lines. Results from the DPPH assay revealed that CDs at higher concentrations had greater antioxidant capacity than the standard L-ascorbic acid and the MTT assay reveals the cytotoxic properties by increasing the rate of cell death as the concentration of CDs increases. There is a rise in cytotoxic activity, or 95% cell inhibition, at a dose of 500 µg/mL anti-cancerous and antioxidant effects may be favourably correlated. KEY WORDS: Antioxidant activity, Free radical scavenging, Lung cancer cell line Bull. Chem. Soc. Ethiop. 2025, 39(5), 907-920. DOI: https://dx.doi.org/10.4314/bcse.v39i5.8