Biotransformation of Cardenolides by Plant Cell Cultures¹

Abstract

A culture of Daucus carota cell line Ca68, previously shown to specifically hydroxylate digitoxigenin at the C-5 position, has been shown also to convert gitoxigenin and oleandrigenin to their corresponding 5β-hydroxy derivatives. These two products have not been identified previously. 5β-Hydroxygitoxigenin has been identified by physico-chemical methods and data on its mass spectrum and ¹³C-NMR spectrum are reported. 5β-Hydroxyoleandrigenin was identified from its high resolution mass spectrum. Addition of gitoxigenin at 72 hrs after inoculation resulted in a two fold increase in the rate of bioconversion compared to addition at 0 hr. The results are discussed in relation to other biotransformation reactions and with respect to improving the yields of plant products and the formation of novel compounds.

Key Word Index

Daucus carota - Apiaceae (Umbelliferae) - Plant Cell Cultures - Bioconversion - Cardenolides - 5β-Hydroxylation - Gitoxigenin - Oleandrigenin