N-Doped Carbon Quantum Dots From Bauhinia purpurea With Anti-Inflammatory and Wound-Healing Properties

Bauhinia purpurea, a widespread and common plant possessing good antioxidant and anti-inflammatory properties, serves as an excellent precursor for green nanomaterial synthesis. Plant-derived carbon quantum dots (CQDs) often retain the therapeutic traits of their source, enhancing biomedical relevance. In this study, B. purpurea-derived nitrogen-doped CQDs (BPN-CQDs) were synthesized via a green microwave-assisted carbonization method. EDX and FTIR analyses verified nitrogen enrichment and surface functionalization. UV-vis spectroscopy revealed peaks at 287, 325, and 370 nm, an absorption edge at 460 nm, and a direct bandgap energy of 3.44 eV. Fluorescence studies showed peak emission near 440 nm upon 320 nm excitation with redshifting at higher wavelengths. TEM and DLS analyses confirmed spherical morphology with a mean size of 3.6 ± 0.2 nm and a multimodal distribution. BPN-CQDs showed anti-arthritic and anti-inflammatory activity in SW982 cells, enhancing wound closure by 30.36% at 500 µg mL^-1 versus 11.43% in controls. They exhibited good biocompatibility (IC₅₀ = 1821 µg mL^-1) and inhibited protein denaturation (IC₅₀ = 546.3 µg mL^-1) and COX-2 activity (IC₅₀ = 470.9 µg mL^-1) dose-dependently. Cytokine levels of interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were significantly reduced. These findings highlight the therapeutic potential of BPN-CQDs in arthritis management through their biocompatibility and combined anti-inflammatory and wound-healing actions.