AbstractIn this study, three semisynthetic betulonic acid-based compounds, 20(29)-dihydrolup-2-en[2,3-d]isoxazol-28-oic acid, 1-betulonoylpyrrolidine, and lupa-2,20(29)-dieno[2,3-b]pyrazin-28-oic acid, were studied in biotransformation experiments using Nicotiana tabacum and Catharanthus roseus cell suspension cultures. Biotransformation was performed using cyclodextrin to aid dissolving poorly water-soluble substrates. Several new derivatives were found, consisting of oxidized and glycosylated (pentose- and hexose-conjugated) products.