UPLC-MS analysis and green synthesis of fennel extract-carbon quantum dots: an assessment of antibacterial, anticancer, and antioxidant potentials
摘要
In this study, a novel green synthesis method of phytochemical functionalized carbon quantum dots (CQDs) by sucrose pyrolysis passivated with fennel (Foeniculum vulgare) seed extract is reported. UPLC-MS analysis in dual ESI+/ESI− modes comprehensively revealed bioactive phytochemicals, including trans-anethole derivatives, phenolic glycosides, and sesquiterpenes. Structural improvements were observed in carbon quantum dots functionalized with fennel seed extract (CQDs-F): XRD and FTIR showed the specific interfacial binding processes with fennel extract. TEM confirmed a quasi-spherical morphology in the range of 4.05–6.9 nm. CQDs-F demonstrated notable bioactivity and selective antibacterial efficacy against Gram-negative E. coli, with an inhibition of 23.33 ± 0.58 mm at 1000 µg/ml, which was four times higher than that observed for Gram-positive isolates. The MIC results were in agreement with the results obtained by the well diffusion assay where E. coli which showed the largest inhibition zones for all concentrations tested had the lowest MIC value (62.5 µg/ml) while S. aureus, B. subtilis and P. aeruginosa, which showed no inhibition below 125 µg/ml in the well diffusion assay, showed a MIC of 125 µg/ml by the broth microdilution method. Furthermore, a dose-dependent antioxidant activity was demonstrated with a DPPH IC50 of approximately 12.75 µg/ml in the range 3.9–1000 µg/ml, owing to the synergistic reactive oxygen species-scavenging effects of UPLC-MS-characterized polyphenols. CQDs-F in vitro toxicity was assessed on three cell lines namely human colon carcinoma (Caco-2) and human breast cancer (MCF-7) cells with inhibitory IC50 Vero = 479.8 > Caco-2 = 160.2 > MCF-7 = 134.8 µg/ml. This preliminary study evaluated the antibacterial, antioxidant and anticancer potentials of CQDs-F.