Recently, rosemary extracts standardized to diterpenes (e.g. carnosic acid and carnosol) have been approved
by the European Union (EU) and given a GRAS (Generally Recognized as Safe) status in the United
States by the Food and Drug Administration (FDA). Incorporation of rosemary into our food system and
through dietary selection (e.g. Mediterranean Diet) has increased the likelihood of exposure to diterpenes
in rosemary. In consideration of this, a more thorough understanding of rosemary diterpenes is needed
to understand its potential for a positive impact on human health. Three agents in particular have received
the most attention that includes carnosic acid, carnosol, and rosmanol with promising results of
anti-cancer activity. These studies have provided evidence of diterpenes to modulate deregulated signaling
pathways in different solid and blood cancers. Rosemary extracts and the phytochemicals therein
appear to be well tolerated in different animal models as evidenced by the extensive studies performed
for approval by the EU and the FDA as an antioxidant food preservative. This mini-review reports on the
pre-clinical studies performed with carnosic acid, carnosol, and rosmanol describing their mechanism
of action in different cancers.