Green synthesis of fluorescent carbon nanodots from sage leaves for selective anticancer activity on 2D liver cancer cells and 3D multicellular tumor spheroids

N-Doped Carbon Nanodots as Temperature Sensors and Fluorescent Probes for the Detection of Tinidazole in Milk

In this study, nitrogen-doped carbon nanodots (N-CDs) with temperature and fluorescence sensing were prepared via hydrothermal method using L-lysine and ethylenediamine as precursors. The synthesized N-CDs exhibited spherical morphology with sizes ranging from 2.8 to 5.2 nm, with an average diameter of 4.03 nm. Maximum fluorescence emission was observed at 390 nm upon excitation at 320 nm, with the excitation spectrum closely overlapping the absorption spectrum of tinidazole (TNZ). In the temperature range of 20 ~ 50 °C, the fluorescence intensity of N-CDs decreased linearly with the increase of temperature. TNZ was detected based on inner filter effect (IFE) using N-CDs as a fluorescent probe. The fluorescence quenching degree had a good linear correlation with the TNZ concentration in the range of 1~100 µM (r = 0.9970), and the detection limit was 0.362 µM. In addition, the detection limits of other nitroimidazole antibiotics, including metronidazole (MNZ), Ornidazole (OMZ) and Seknidazole (SNZ), were 0.324 µM, 0.345 µM and 0.341 µM, respectively. Importantly, this method exhibits minimal interference from ions present in milk and has been validated in real milk samples, with recovery rates ranging from 92.56 to 107.27%. These results highlight the method's strong potential for application in food analysis.

Exploration of isoxazole analogs: Synthesis, COX inhibition, anticancer screening, 3D multicellular tumor spheroids, and molecular modeling

In this study, a new series of Isoxazole-carboxamide derivatives were synthesized and characterized via HRMS, 1H-, 13CAPT-NMR, and MicroED. The findings revealed that nearly all of the synthesized derivatives exhibited potent inhibitory activities against both COX enzymes, with IC50 values ranging from 4.1 nM to 3.87 μM. Specifically, MYM1 demonstrated the highest efficacy among the compounds tested against the COX-1, displaying an IC50 value of 4.1 nM. The results showed that 5 compounds possess high COX-2 isozyme inhibitory effects with IC50 value in range 0.24-1.30 μM with COX-2 selectivity indexes (2.51-6.13), among these compounds MYM4 has the lowest IC50 value against COX-2, with selectivity index around 4. Intriguingly, this compound displayed significant antiproliferative effects against CaCo-2, Hep3B, and HeLa cancer cell lines, with IC50 values of 10.22, 4.84, and 1.57 μM, respectively, which was nearly comparable to that of doxorubicin. Compound MYM4 showed low cytotoxic activities on normal cell lines LX-2 and Hek293t with IC50 values 20.01 and 216.97 μM respectively, with safer values than doxorubicin. Furthermore, compound MYM4 was able to induce the apoptosis, suppress the colonization of both HeLa and HepG2 cells. Additionally, the induction of Reactive oxygen species (ROS) production could be the mechanism underlying the apoptotic effect and the cytotoxic activity of the compound. In the 3D multicellular tumor spheroid model, results revealed that MYM4 compound hampered the spheroid formation capacity of Hep3B and HeLa cancer cells. Moreover, the molecular docking of MYM4 compound revealed a high affinity for the COX2 enzyme, with energy scores (S) -7.45 kcal/mol, which were comparable to celecoxib (S) -8.40 kcal/mol. Collectively, these findings position MYM4 as a promising pharmacological candidate as COX inhibitor and anticancer agent.