ROSEMARY HAS ANTITUMOR ACTIVITY

Rosemary (Rosmarinus officinalis) is a woody herb with fragrant needle-like leaves. Rosemary is native to the Mediterranean region and possesses a bitter, astringent taste and highly aromatic characteristics that complement a wide variety of foods. Rosemary is a member of the family Lamiaceae, and it contains a number of potentially biologically active compounds, including antioxidants such as carnosic acid and rosmarinic acid. Other bioactive compounds include camphor (up to 20% in dry rosemary leaves), caffeic acid, ursolic acid, betulinic acid, rosmaridiphenol, and rosmanol.

Due to its high antioxidant activity, crude and refined extracts of rosemary are now widely available commercially . While the data are difficult to interpret, when rosemary is added along with other herbs to a balsamic vinegar preparation used in soups and salads, it appears to provide protection again oxidative stress in humans .
Considerable evidence also suggests that rosemary extracts, or its isolated components, can retard chemically induced cancers. For example, topical application of a rosemary extract has been reported to block the initiation and promotion phases of B(a)P- and DMBA-mediated skin tumorigenesis .  Adding rosemary or carnosol has also been shown to retard DMBA-induced mammary cancer in rats ).
Rosemary extracts and the active compounds carnosic acid and rosmarinic acid have been found to inhibit the proliferation of various human cancer cell lines, including NCI-H82 (human, small cell lung carcinoma), DU145 (human prostate carcinoma), Hep-3B (human [black] liver carcinoma), K-562 (human chronic myeloid leukemia), MCF-7 (human breast adenocarcinoma), PC-3 (human prostate adenocarcinoma), and MDA-MB-231 (human breast adenocarcinoma; Carnosol was the most effective in reducing tumor proliferation. Carnosol is also known to induce apoptotic cell death in high-risk pre-B acute lymphoblastic leukemia Overall, these data suggest that carnosol, and possibly other constituents in rosemary, may block the terminal apoptotic events induced by some chemotherapeutic drugs and therefore may decrease the effectiveness of some standard therapies for leukemia.

Sourse
 Herbal Medicine: Biomolecular and Clinical Aspects. by Christine M. Kaefer and John A. Milner (2ndEdition)