High cytotoxicity of betulin towards fish and murine fibroblasts: Is betulin safe for nonneoplastic cells?

Betulin, a natural pentacyclic triterpene with the lupane structure that is present in significant amounts in the outer bark of birch, is known for its broad array of biological and pharmacological properties. Betulin has attracted attention as a potential, natural-origin antimicrobial substance. The literature describes it as selectively toxic to neoplastic cells but safe for normal cells.