Rosemary is more than just a fragrant herb used in cooking; it has a long history in traditional medicine. This has prompted scientists to investigate its potential health benefits, particularly in cancer research. This article explores the scientific findings regarding rosemary and its compounds in relation to cancer.
Active Compounds in Rosemary
Rosemary contains numerous bioactive compounds, but three polyphenolic compounds are of particular interest in cancer research: carnosic acid, carnosol, and rosmarinic acid. These substances are primarily responsible for the herb’s antioxidant properties. Carnosic acid and carnosol are diterpenes, a type of chemical compound found in plants, while rosmarinic acid is another type of polyphenol present in rosemary and other plants.
These compounds have been the focus of many studies because of their biological activities. Carnosic acid, for example, is known for its ability to scavenge harmful free radicals in the body. Carnosol is structurally similar to carnosic acid and also exhibits antioxidant effects. Rosmarinic acid has been studied for its anti-inflammatory and anticarcinogenic potential.
Scientists have isolated these compounds from rosemary to study their effects more closely. The concentration of these active compounds can vary depending on how the rosemary is prepared, with extracts often containing much higher levels than the fresh or dried herb.
The Scientific Evidence
The majority of research on rosemary and cancer has been conducted in laboratory settings using cancer cells grown in test tubes. These in vitro studies have shown that rosemary extracts and its isolated compounds can inhibit the growth of various cancer cell lines. For instance, research shows carnosic acid and carnosol can induce cell death in colon, prostate, breast, lung, leukemia, and liver cancer cells.
Animal studies, or in vivo research, have also provided some findings. In studies involving mice, rosemary extract and its compounds have been shown to slow the growth of tumors. For example, carnosic acid has been studied in animal models for its effects on skin and breast cancers by giving animals high concentrations of the purified compounds.
Despite promising results from lab and animal studies, there is a significant lack of large-scale human clinical trials, and results from preclinical research do not always translate to humans. Therefore, there is currently not enough scientific evidence to support the use of rosemary or its extracts as a treatment for cancer in humans.
Potential Mechanisms of Action
Scientists have identified several ways that rosemary’s active compounds may combat cancer cells, based on laboratory and animal research.
- Antioxidant effect: Compounds like carnosic acid can neutralize free radicals, which are unstable molecules that can damage DNA and potentially lead to cancer. By reducing this oxidative stress, rosemary’s compounds may help protect cells from cancerous changes.
- Anti-inflammatory properties: Chronic inflammation is linked to an increased risk of developing cancer, and rosmarinic acid, in particular, has been shown to interfere with inflammatory pathways. By reducing inflammation, these compounds could create a less favorable environment for cancer cells to thrive.
- Inducing apoptosis: Cancer cells are known for their ability to evade this natural process of programmed cell death, allowing them to multiply uncontrollably. Studies have shown that carnosic acid and carnosol can trigger apoptosis in cancer cells, effectively causing them to self-destruct.
- Inhibition of angiogenesis: Tumors need a blood supply to grow and spread, a process called angiogenesis. By cutting off this supply, their growth can be halted, and some research suggests that rosemary’s compounds can interfere with the signals that create new blood vessels to feed a tumor.
Practical and Safety Considerations
Using rosemary as a culinary herb is generally safe and different from using highly concentrated rosemary supplements or essential oils. Adding rosemary to food does not provide the high doses of active compounds used in research studies, and these concentrated forms carry a higher risk of side effects.
High doses of rosemary extract can cause stomach irritation, kidney problems, and other adverse effects. Rosemary supplements may also interact with certain medications, such as blood thinners, by affecting how they work in the body.
Anyone considering using rosemary supplements, particularly those undergoing cancer treatment, should first consult with their oncologist or another healthcare provider. Self-treating with any supplement as a replacement for conventional cancer therapies is not recommended and can be dangerous.