Natural essential oils as a new therapeutic tool in colorectal cancer

Abstract

Colorectal cancer (CRC) is the third most revalent type of cancer in the world and the second most common cause of cancer death (about 1 million per year). Historically, natural compounds and their structural analogues have contributed to the development of new drugs useful in the treatment of various diseases, including cancer. Essential oils are natural odorous products made up of a complex mixture of low molecular weight compounds with recognized biological and pharmacological properties investigated also for the prevention and treatment of cancer. The aim of this paper is to highlight the possible role of essential oils in CRC, their composition and the preclinical studies involving them. It has been reviewed the preclinical pharmacological studies to determine the experimental models used and the anticancer potential mechanisms of action of natural essential oils in CRC. Searches were performed in the following databases PubMed/Medline, Web of science, TRIP database, Scopus, Google Scholar using appropriate MeSH terms. The results of analyzed studies showed that EOs exhibited a wide range of bioactive effects like cytotoxicity, antiproliferative, and antimetastatic effects on cancer cells through various mechanisms of action. This updated review provides a better quality of scientific evidence for the efficacy of EOs as chemotherapeutic/chemopreventive agents in CRC. Future translational clinical studies are needed to establish the effective dose in humans as well as the most suitable route of administration for maximum bioavailability and efficacy. Given the positive anticancer results obtained from preclinical pharmacological studies, EOs can be considered efficient complementary therapies in chemotherapy in CRC.

Keywords: Anticancer properties; Anticancer therapy; Apoptosis; Colorectal cancer; Cytotoxicity; Natural essential oils.

Fig. 1

Diagram with the most representative anticancer molecular mechanism of natural EOs. Legend: ↑increase, ↓decrease, Nuclear factor erythroid 2-related factor 2 (Nrf2), Reactive oxygen species (ROS), Deoxyribonucleic Acid (DNA), Heat shock proteins (Hsps), Interleukin (IL), Tumor necrosis factor (TNF), Forkhead box P3 (FOXP3)