Rhododenol (Rhododendrol) – induced toxicity appears to happen at higher concentrations and the protective mechanism it triggers

• Not all consumers developed white blotching after applying rhododendrol (rhododenol)-containing products
• All treatment areas didn’t necessarily develop white blotchingThe authors performed cell cultures on normal human melanocytes

• Results
  • high doses (1500micromol and 3000micromol) had a cytotoxic effect
    • apoptosis was observed at 3000micromol (through activation of caspase 3)
  • low doses of 300-900micromol inhibited melanogenesis (downregulation of tyrosinase, Pmel17, MITF, Melan A)
    • low doses activate the autophagy lysosome pathway in melanocytes (LAMP1) (revealed by fuorescence after marking Rhododenol and Bafilycin 1)
    • (electron microscopy showed a reduced number of melanosomes and an increased number of lysosomes)

Explanation: autophagy induction attenuates rhododenol induced cytotoxicity in melanocytes

Comment: this study shows that rhododenol (rhododendrol) toxicity appears to happen at higher doses and non-cytotoxic lysosomal activation is a protective mechanism. This might also explain why progressive repigmentation occurs as another study presented at this meeting suggests (Inoue M. et al.)

Contributors

Dr Christophe Hsu – dermatologist. Geneva, Switzerland

Source of information: Yang L. et al. Rhododendrol activates autophagy-lysosome pathway in melanocytes: a potential mechanism for skin depigmentation disorder aussi . JSID Annual Meeting (Japanese Society of Investigative Dermatology, 日本研究皮膚科学会) 2014 – Osaka, Japan