A common ingredient in traditional medicine goes under the microscope

Thanks to its warming, spicy flavour, ginger (Zingiber officinale) has been a commonly-used flavouring agent in food and drink for millennia. Its use as a herbal medicine to treat a variety of ailments – including colds, migraines, and nausea – is likely to be just as ancient. In recent years, there’s been a growing interest in ginger’s potential use in clinical settings. A new paper published in Carbon [DOI: 10.1016/j.carbon.2023.03.039] suggests that the spice could accelerate the process of wound healing though its anti-inflammatory properties.

The study, carried out by Chinese researchers, looked specifically at carbon dots derived from ginger (GCDs). The team started with dried ginger slices that were ground into a powder, sonicated in ultrapure water and processed in a microwave synthesizer at 180 °C. After cooling, the solution was filtered, dialyzed, and placed in a freeze-dryer, to produce the final carbon dot powder. No additional reagents or surface passivation agents were used in the process. The dots were then characterised using a range of techniques, including high-resolution TEM, x-ray diffraction and ultraviolet–visible spectroscopy. The GCDs were found to fluorescence blue, with a wavelength of 430 nm, and to have good dispersibility and stability.

Human umbilical vein endothelial (HUVEC) cells and mouse monocyte-macrophage leukemia (RAW.264.7) cells were used for in vitro studies of the dots. These cells were incubated with the GCDs at varying concentrations, and the cell viability measured in comparison with unaltered (control) cells. Even at high concentrations of 1 g.mL-1, the researcher found no significant increase in cytotoxicity, which they say “…clearly indicate that the prepared GCDs have good biosafety and the potential to promoting cell growth.”

An inflammatory model was fabricated with lipopolysaccharide-induced RAW264.7 cells to investigate the anti-inflammatory properties of the GCDs. Cells that contained GCDs showed significantly lower levels of pro-inflammatory mediators than the control cells. At concentrations of 200 μg.mL-1, the inhibition rates of four of these factors (TNF-α, IL-1β, IL-6, and nitric oxide) were 51.6 %, 81.7 %, 86.0 %, and 58.7 %, respectively. The researchers also found that the presence of GCDs enhanced the migration capacity of HUVEC cells at all concentrations – cell scratches closed faster when the dots were present than in the controls, e.g., when cells were cultured at 200 μg.mL-1 for 24 h, the cell scratch closure rate was 42.5 % compared with 20.4 % in the control samples.

The authors say that this anti-inflammatory behaviour results from the GCDs’ ability to effectively block the TLR4/NF-κB inflammatory trigger pathway by reducing the expression of the protein, and by minimising the damage caused by inflammatory mediators. They write, “We considered that this may be due to the fact that GCDs, as nanoparticles, have an ultra-small size that makes it easier for them to penetrate cell membranes and nuclear membranes and be taken up by cells. And we also think that the GCDs has abundant groups, hydrogen bonds can be formed with TLR4 to help them closely bind.”

In addition, they carried out an in vivo wound healing experiment out on a group of 25 anesthetized rats, with full-thickness skin wounds 1×1 cm2 in diameter on each of their backs. Over a period of two weeks, the extent of the wounds were studied, and at all stages, the wounds treated with GCDs (at a concentration 200 μg.mL-1) were seen to heal at a faster rate. On the 14th day, the authors say “…wounds in the GCDs-treated group were basically closed, and the wound healing rate was 97.1%. The control group still exhibited obvious scab formation.”

They conclude “As far as we know, this study [is the first to demonstrate] the efficient anti-inflammatory effect of ginger-derived CD…. The results showed that the GCDs effectively promote wound healing and reduce inflammation, making them a highly promising material for topical wound application.”


Jianting Li, Wenjuan Fu, Xiangying Zhang, Qijia Zhang, Dandan Ma, Yuting Wang, Wenhui Qian, Dong Zhu. “Green preparation of ginger-derived carbon dots accelerates wound healing,” Carbon In Press (2023). DOI: 10.1016/j.carbon.2023.03.039