The antioxidant activity of Stachys maritima was determined via initial tests, yielding a DPPH IC50 value of 0.114 ± 0.001 mg/mL, indicative of its ability to neutralize free radicals and mitigate oxidative stress. Moreover, the plant extract demonstrated a significant iron chelation capacity comparable to EDTA (IC50: 5.98 ± 0.10 mg/mL). Analysis of the extract revealed high levels of flavonols, flavonoids, phenolic compounds, proanthocyanidins, and tannins, notably totaling 1039.48 ± 6.53 mg GAE/g and 276.21 ± 4.38 mg CAE/g, respectively, contributing to its robust antioxidant potential. ST-CQDs, nanoscale carbon structures, have garnered interest in biomedicine for their antioxidant properties. Confirmatory analyses showed their high antioxidant activity with DPPH IC50 value of 0.69 ± 0.03 mg/mL and iron chelation capacity of 3.86 ± 0.41 mg/mL. Antimicrobial tests revealed S. maritima efficacy against various pathogens, while ST-CQDs showed no effect. High peak areas in analyses suggest specific compounds' presence, notably certain fatty acids, highlighting their crucial role in composition understanding. Notably, 9,12,15-Octadecatrienoic acid's importance is underscored. These findings provide a significant basis for further exploring TNF development's molecular mechanisms.