Hydrothermally Derived Green Carbon Dots from Broccoli Water Extracts: Decreased Toxicity, Enhanced Free-Radical Scavenging, and Anti-Inflammatory Performance

Abstract

Biomass carbon dots (CDs) derived from natural plants possess the advantages of low cost, photostability, and excellent biocompatibility, with potential applications in chemical sensing, bioimaging, and nanomedicine. However, the development of biomass CDs with excellent antioxidant activity and good biocompatibility is still a challenge. Herein, we propose a hypothesis for enhancing the antioxidant capacity of biomass CDs based on precursor optimization, extraction solvent, and other conditions with broccoli as the biomass. Compared to broccoli water extracts, broccoli powders, and broccoli organic solvent extracts, CDs derived from broccoli water extracts (BWE-CDs) have outstanding antioxidant properties due to the abundant CC, carbonyl, and amino groups on their surface. After optimization of the preparation condition, the obtained BWE-CDs exhibit excellent free-radical scavenging activity with an EC50 of 68.2 μg/mL for DPPH• and 22.4 μg/mL for ABTS•+. Cytotoxicity and zebrafish embryotoxicity results indicated that BWE-CDs have lower cytotoxicity and better biocompatibility than that of CDs derived from organic solvents. In addition, BWE-CDs effectively scavenged reactive oxygen species (ROS) in A549 cells, 293T cells, and zebrafish, as well as eliminating inflammation in LPS-stimulated zebrafish. Mechanistic studies showed that the anti-inflammatory effect of BWE-CDs was dependent on the direct reaction of CDs with free radicals, the regulation of NO levels, and the upregulation of the expression of SOD and GPX-4. This work indicates that the antioxidant activity of CDs could be enhanced by using solvent extracts of biomass as precursors, and the obtained BWE-CDs exhibit characteristics of greenness, low toxicity, and excellent antioxidant and anti-inflammatory activities, which suggests the potential promising application of BWE-CDs as an antioxidant nanomedicine for inflammatory therapy.

Plant Extract-Derived Carbon Dots as Cosmetic Ingredients

“…The synthetic C-dots remarkably reduced the expression of IL-6 and TNF-α as the concentration of C-dots increased, compared to the control group [41]. C-dots showed a good ability to regulate NO production by significantly reducing NO − 3 in zebrafish after treatment with C-dots for 2 h [41]. In addition, the synthetic C-dots upregulated the expressions of superoxide dismutase (SOD) and glutathione peroxidase (GPX-4), which, in turn, scavenge excessed ROS and reduce inflammation [41].…”

“…In particular, the C-dots can effectively scavenge ROS radicals and downregulate pro-inflammatory mediators (e.g., TNF-α, IL-1α, IL-1β, IL-2, IL-6, IL-8, IL-12, and IFN-γ receptors), which are useful for improving the immune system [10,39,40]. Deng et al (2023) reported the powerful anti-inflammatory activities of C-dots produced from Broccoli water extract using a hydrothermal method (180 • C and 8 h) [41]. The synthetic C-dots remarkably reduced the expression of IL-6 and TNF-α as the concentration of C-dots increased, compared to the control group [41].…”

“…Deng et al (2023) reported the powerful anti-inflammatory activities of C-dots produced from Broccoli water extract using a hydrothermal method (180 • C and 8 h) [41]. The synthetic C-dots remarkably reduced the expression of IL-6 and TNF-α as the concentration of C-dots increased, compared to the control group [41]. C-dots showed a good ability to regulate NO production by significantly reducing NO − 3 in zebrafish after treatment with C-dots for 2 h [41].…”

Graphene and nanocomposites—Imprints on environmentally sustainable production and applications based on ecological aspects

“…Figure 6 shows simplistic routes towards the formation of hydrogels. In green freeze drying and hydrothermal techniques, water solvent was used [58,59] . Then, ammonium bicarbonate was used to form Ndoped graphene hydrogel with density of 0.034 g cm −3 .…”

Green transformation of biomass-derived Indian gooseberry into fluorescent intrinsic nitrogen-functionalized carbon quantum dots for real-time detection of vitamin B2 in the nanomolar range

“…The quantum yield of CQDs derived from biomass waste precursors was found to be higher than that from chemical precursors. 21,22 Kundu et al reported the synthesis of uorescent CQDs using biomass precursor rice husk for selective and sensitive detection of Fe 3+ and uoroquinolones. 23 Monte-Filho et al reported highly uorescent CQDs from lemon and onion juices for determination of ribo-avin in multivitamin/mineral supplements.…”