Production of phytosterols by mature Digitalis purpurea L. plants.

The relative rates of production by mature Digitalis purpurea plants of cholesterol, campesterol, stigmasterol and sitosterol isolated from the glycoside and lipid fractions of the plant extract, were estimated. Plants were exposed to an atmosphere of (14)CO2 in a growth chamber and the radioactivity of the individual sterols assessed at intervals over 25 days on a gas-liquid radio chemical chromatography (GLRC). Incorporation of (14)CO2 occurred within 12 hours into both fractions of the extract. The 5-ene sterols were produced at a similar rate over a period of 25 days but the lipid fraction was about 100% more radioactive than the glycoside fraction.