Background: The incidence of delirium is high in older patients undergoing cardiovascular surgery with cardiopulmonary bypass (CPB). Intraoperative tissue hypoperfusion and re-reperfusion injury, which generate reactive oxygen species (ROS), are suggested to induce delirium. Ascorbic acid is an excellent antioxidant and may reduce organ damage by inhibiting the production of ROS. This prospective observational study aimed to measure pre- and postoperative plasma ascorbic acid levels and examine their association with delirium. Methods: Patients older than 70 years of age scheduled for elective cardiovascular surgery using CPB were enrolled. From September 2020 to December 2021, we enrolled 100 patients, and the data of 98 patients were analyzed. Results: In total, 31 patients developed delirium, while 67 did not. Preoperative plasma ascorbic acid levels did not differ between the non-delirium and delirium groups (6.0 ± 2.2 vs. 5.5 ± 2.4 µg/mL, p = 0.3). Postoperative plasma ascorbic acid levels were significantly different between the groups (2.8 [2.3–3.5] vs. 2.3 [1.6–3.3] µg/mL, p = 0.037). Conclusions: In patients who undergo cardiovascular surgery with CPB, lower postoperative plasma ascorbic acid levels may be associated with the development of delirium.

The protecting effect of (−)-epicatechin (EC), (−)-epicatechin gallate (ECg), (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCg) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) on the DNA strand scission induced in tritiated water was analyzed. The scission with the hydroxyl radical produced by the decomposition of water molecules was decreased by the addition of above reagents. Protective effect of EGCg, EC and DMPO was dependent on their concentrations, but that of ECg and EGC was independent. Therefore, it was considered that certain amounts of ECg, EGC molecules might locate around DNA molecules, interacting with DNA.