Carbon quantum dots amplify beneficial effects of EGCG against neural injuries by NLRP3 inflammasome after intracerebral hemorrhage.

Neuroinflammation plays an indispensable role in neural damages after ICH, responsible for the induced high mortality and poor prognosis. NLRP3 inflammasome, which is known mediated by ROS, has been widely documented to aggravate brain injuries. Therefore, suppressing neural injuries by ROS/NLRP3 pathway may be beneficial in treating ICH. As the major catechin found in green tea, epigallocatechin-3-gallate (EGCG) shows excellent anti-oxidative and anti-inflammatory effects. In this study, EGCG-carbon quantum dots (EGCG-CQDs) were successfully fabricated based on EGCG by hydrothermal synthesis method. EGCG-CQDs exhibited an excellent aqueous solubility, and emerged more abundant phenolic oxygens as well as oxygen-rich functional groups. Importantly, EGCG-CQDs showed superior free radical scavenging activity by DPPH and ABTS assays in vitro than EGCG. In vivo, a significant antioxidative activity was presented by EGCG-CQDs rather than EGCG. Furthermore, the upregulated NLRP3 and the induced inflammatory cascades (NF-κB, Caspase-1 and GSDMD) in ICH were attenuated by EGCG-CQDs. Inflammatory factor productions were also decreased by EGCG-CQDs, such as IL-1β, IL-18, IL-6 and TNF-α. Finally, the disturbed neural viability, disordered cytomorphology, and neurological deficits were significantly improved by EGCG-CQDs rather than EGCG. Therefore, CQDs might be an effective form to amplify the efficacy and bioavailability of EGCG, exerting considerable effects on treating ICH by suppressing ROS/NLRP3.