Antioxidative constituents of Rosmarinus officinalis and Salvia officinalis. III. Stability of phenolic diterpenes of rosemary extracts under thermal stress as required for technological processes.

The concentration of phenolic diterpenes in commercially available extracts of Rosmarinus officinalis (rosemary) determined by HPLC with electrochemical detection ranged from 2.8 to 22.5%. Antioxidant activity of extracts under simultaneous storage and thermal stress depended directly on the concentration of phenolic diterpenes. Differences in rates of degradation of individual phenolic diterpenes at different temperatures were obtained.