Anticancer Activities of Phenolic Compounds in Medicinal Plants, Herbs and Spices

Epidemiological studies show that diets rich in fruits and vegetables are associated with a lower risk of chronic diseases, such as coronary heart disease and cancer.  Growing numbers of researches have suggested that these health benefits may be related to phytochemical constituents, such as carotenoids, glucosinolates, and phenolic compounds.  This presentation will review the anticancer activity of phenolic compounds in medicinal plants, herbs and spices.  Phenolic compounds are the most ubiquitous plant secondary metabolites, with more than 8000 compounds that have been identified. The major types of phenolics are phenolic acids and flavonoids such as rosmarinic acid and quercetin.  Carcinogenesis is a very complicated process, which is generally divided into the stages of initiation, promotion, and progression.  Evidence has shown that polyphenols can impact all three carcinogenesis stages.  Phenolic compounds can work as antioxidants to scavenge free radicals which may cause damage to DNA and lipids.  They can also switch on genes that can eliminate carcinogens.  Phenolic compounds can suppress cancer by regulation of the cell cycle, inhibition of cell proliferation, induction of apoptosis (programmed cell death), and regulation of Phase I and II detoxification enzyme systems.  Phenolics can also have anti-angiogenesis activity, and thereby inhibit the third stage: progression (expansion and migration of clonal cancer cells into uncontrolled or multiple tumors).  Herbs contain numerous bioactive ingredients with multiple biological activities.  Scientists generally believe that it is the mixture of phytochemicals, rather than a single compound, that is responsible for the health benefits of culinary and medicinal herbs.  Anticancer activity assessed using an in vitro colon cancer assay will be shown for extracts from five herb species: thyme (Thymus vulgaris), sage (Salvia officinalis), rosemary (Rosmarinus officinalis), peppermint (Mentha piperita), and spearmint (Mentha spicata).