Essential oils are of great significance in the essential oil industry. Over 600 kinds of aroma chemicals are found in nature, and they are generally obtained by steam distillation or extracting with organic solvents. As the second generation of fragrance raw materials, most of them possess better safety than synthetic ones.
It has become more and more evident that essential oils also possess some biological functions other than the traditional uses of fragrance materials in food, pharmaceutics, and cosmetics. This review article mainly focuses on the antiviral, antitumor, antimicrobial, insecticidal activities of essential oils or its active components so as to provide references for further study.
Effects of essential oils on the immune system
There is no question that the human innate immune system and adaptive immune system work together to protect human body from invading pathogens. It also plays an important role in cancer and allergic diseases and so on. However, chronic inflammation can cause tissue damage and lead to various disease states including cardiovascular disease, cancer, and autoimmune disorders.
Lymphocytes are one of the main components of white blood cells, which make up about 20% of total leukocyte count in humans. There are two major types of lymphocytes: B lymphocytes (B cells) and T lymphocytes (T cells). The former produces antibodies to fight against antigens while the latter coordinates the body’s immune responses.
Now, more and more studies indicate that essential oils not only act as antibacterial agents but also possess an inhibitory effect on suppressor T cells. They do this by affecting the secretion of cytokines (including interleukin IL-2, IL-4, IL-10, and interferon-γ). Studies have found that essential oils can enhance the activity of macrophages.
The role of essential oil in cancer treatment
A large number of studies proved that essential oils exhibit antitumor effects by inhibiting cell growth and inducing apoptosis in tumor cells through various mechanisms including activation of casp.