3, 7-dihydroxy-2, 4-dimethoxyphenanthrene protects against UVB-induced skin hyperpigmentation via antioxidant and anti-melanogenic mechanisms.

BACKGROUND

Excessive reactive oxygen species (ROS) produced by UVB radiation can disrupt the normal redox balance, leading to oxidative cellular damage as well as triggering melanin synthesis by melanocytes. Currently, natural active substances are emphasized in UV protection research. This study explored the protective effect of 3, 7-dihydroxy-2, 4-dimethoxyphenanthrene (DDP), a bioactive compound from Dendrobium lindleyi Stendel, against UVB-induced skin hyperpigmentation and examined its specific mechanism.

METHODS

To evaluate the anti- melanogenic and antioxidant activities of DDP in vitro, molecular docking was used to predict the binding conformation of DDP to tyrosinase (TYR) and melanocortin 1 receptor (MC1R). Subsequently, CCK8 and cell live/dead staining were used to screen the safe concentration range. B16-F10 cells were treated with different doses of DDP before UVB light irradiation and before α-melanocyte-stimulating hormone (α-MSH) induction, and the evaluation of cells included determination of melanin content, Western blotting analysis, TYR activity assay, ROS assay, DPPH• and ABTS•+ radical scavenging assays. A brown guinea pig model was used to further evaluate the protective effect of DDP on UVB-induced skin pigmentation in vivo, and compared with commercial skin care products.

RESULTS

In the present study, Molecular docking showed that DDP binds to TYR and MC1R better than Kojic Acid. DDP was found to possess excellent anti-melanogenic and antioxidant activities in vitro. DDP was effective in alleviating skin melanin accumulation induced by UVB irradiation without inflammatory side effects.

CONCLUSIONS

DDP protects against UVB-induced skin hyperpigmentation via antioxidant and anti-melanogenic mechanisms.