From traditional remedy to in vitro evidence: phytochemical composition and skin-related pharmacological activity of birch witches' broom (Taphrina betulina).

BACKGROUND

Birch witches' broom is an abnormal plant structure caused by infection of birch trees with the dimorphic fungus Taphrina betulina Rostr., (1883). Although classified as a disease, witches' broom has traditionally been used in folk medicine to treat skin disorders. This suggests that fungal infection may induce metabolic reprogramming in host tissues, leading to the production and accumulation of biologically active secondary metabolites. We hypothesized that infection-driven metabolic changes in witches' broom tissue could generate compounds capable of modulating keratinocyte viability, migration, and inflammatory responses.

METHODS

Aqueous extracts from witches' broom and healthy birch branches were analyzed by UHPLC-DAD-MSn. Biological activity was assessed in vitro using human keratinocytes (HaCaT) and melanoma cells (HTB-140). Cytotoxicity was determined by MTT assay, keratinocyte migration by scratch assay, pro-inflammatory cytokines IL-6/IL-8 by ELISA, and antimicrobial activity by disc diffusion against skin pathogens.

RESULTS

Phytochemical profiling revealed qualitative differences, particularly in flavonoids, phenolic acids, and diarylheptanoids. Cytotoxicity showed concentration-dependent effects. The IC50 values for witches' broom and healthy birch extracts were 260.9 µg/mL and 327.1 µg/mL in HaCaT cells, and 487.5 µg/mL and 453 µg/mL in HTB-140 cells, respectively. Keratinocyte migration was examined using a scratch assay. After 48 h, witches' broom extract inhibited HaCaT cell migration by 99.09% ± 4.71% at the highest tested concentration, compared to 84.33% ± 5.14% inhibition by the healthy birch extract. Witches' broom extract significantly reduced IL-6 secretion in stimulated HaCaT cells, while showing limited effect on IL-8 production. Antimicrobial activity against skin-associated pathogens revealed selective C. acnes inhibition by witches' broom extract.

SUMMARY: This study provides the first direct comparison of their phytochemical composition and skin-related biological activity. The findings suggest that witches' broom contains bioactive compounds influencing cell viability, migration, and inflammation, supporting its potential relevance in dermatological research and ethnopharmacology.