Table 2 Antioxidant activity evaluated from the DPPH assay, in terms of IC50 and APR values for the prepared carbon Dots compared to other carbon Dots and antioxidant benchmarks reported in the literature.

NAR

0.75

1.33

CDs from glucose functionalized with naringenin (NAR) and cyclodextrine (β-CD )

⁵³

β-CD

0.58

1.72

NAR-β-CD-CQDs

0.39

2.56

NAR-β-CD

0.42

2.38

CD

0.004

250

CDs from tomato juice functionalized with glutathione

⁵⁴

Glutathione-CD

0.014

71.43

CD lemon peel extract

2.24

0.45

CDs from lemon and orange peels and their extracts

⁵⁵

CD orange peel extract

2.36

0.42

CQDs lemon

2.38

0.42

CQDs orange

3.06

0.33

Ascorbic acid

0.26

3.85

Benchmark

⁵⁶

AgNPs

0.70

1.43

Silver nanoparticles

AgNPs

0.66

1.51

Silver nanoparticles

⁵⁷

Vitamin C

0.08

12.99

Benchmark

⁵⁸

CS

> 4.5

--

Chitosan (CS) functionalized with gallic acid (GA)

⁵⁹

CS-GA

2

0.5

GCDs-220

4.51

0.22

gardenia seeds-based carbon dots

⁶⁰

N-, S- and B- functionalized CDs

0.22 (N-CDs)

0.12 (NS-CDs)

4.5 (N-CDs)

8.3 (NS-CDs)

CDs from glucosamine, maleic acid, thiomalic acid, and boric acid

⁵⁰

N-, and O-containing CDs

0.47

2.13

CDs from biomass (chinese herbal medicine Poria cocos)

⁶¹

CD-10

0.99

1.01

This work

CD-20

0.86

1.16

This work

CD-30

0.73

1.37

This work

CD-40

0.60

1.67

This work