Determination of the carnosic acid content in wild and cultivated Rosmarinus officinalis

The concentration of carnosic acid in a representative selection of leaves from wild and cultivated populations of Rosmarinus officinalis was determined by reversed-phase HPLC following extraction with supercritical carbon dioxide. Different sources of variability including season, genetics, leaf age, and growing origin (wild or cultivated) were considered. Variability in the carnosic acid content among rosemary leaves appears to be largely due to seasonal and environmental factors, in addition to their individual origin(genetics). The results reveal excellent correlation (r = 0.93) between the carnosic acid concentration and photoperiod. The results presented can be used to improve the selection of raw materials for the extraction of carnosic acid from rosemary.