Originally posted February 2nd, 2022.
Scientists from Purdue University are studying a number of herbs from the Mediterranean region that are thought to suppress tumor development. The scientists mapped the herbs’ molecular biosynthetic pathway and are attempting to reproduce the compounds in the lab. Joseph Mercola reports on his blog, Mercola.com:
Plant scientists from Purdue University in West Lafayette, Indiana, took the next step in discovering how compounds found in Mediterranean spices, including thyme and oregano, may be developed into pharmaceutical products that could help suppress tumor development.
The research was published in December 2021 in the Proceedings of the National Academy of Sciences.1 The researchers looked at the monoterpene alcohols found in thyme, oregano and other herbs in the Lamiaceae family.
Most members of the family are annual or perennial herbs with fragrant volatile oils. Other herbs in the family include rosemary, basil, catnip and sage.2 According to the American Cancer Society,3 experts estimated 1.9 million new cases in 2021 and 608,570 deaths in the same year.
Many of the risk factors for cancer are modifiable.4 This means that you have control over your exposure to risk factors that may increase your potential for cancer. Risk factors for cancer include a poor diet, physical inactivity, drinking alcohol, excess body weight and cigarette smoke.
Researchers in the featured study were interested in identifying the compounds and determining the biosynthesis in thyme, oregano and other herbs in the Lamiaceae family that may have an impact on suppressing tumor growth. The research follows past studies5 that have demonstrated herbs and spices play a role in the prevention and treatment of cancer.
Plant Scientists Found a Recipe for Herbal Compound
The distinctive flavors in oregano and thyme are from thymol, carvacrol and thymohydroquinone. Thymol is the primary extract from thyme.6 The herb is often used in tea to treat colds and coughs, valued for the secrolytic, antispasmodic and antibacterial properties. Oregano has higher levels of carvacrol. The compounds are closely related and produced in the plant through multiple stages.
Scientists were intrigued by the anticancer properties of thymohydroquinone. In a collaborative effort with two other universities7 they were able to determine how the precursors, thymol and carvacrol, were formed.
The researchers determined that these findings alter past data of how scientists had believed thymol and carvacrol are formed.8 The study also identified the enzymes involved in the production of the monoterpenes, which may provide further research targets for metabolically engineering terpenes considered high value in plants.9
Having determined the pathway used to create these compounds, scientists now believe they can selectively breed plants to produce higher amounts, or they may incorporate production into other microorganisms, like yeast. Using this method to harvest the compounds would require fermentation. To pursue the next step, the team secured a $5 million grant from the National Science Foundation.10
In other research, scientists have found that the overall incidence of cancer is lower in countries eating Mediterranean diets, which they believe correlates with reduced risk. Some identified aspects of the diet that reduce risk are a higher consumption of fruits and vegetables and lower consumption of processed meat.11
The scientists from Purdue University sought to identify the compounds in the Mediterranean herbs that could suppress tumor development and determine how they might be used in pharmaceutical drug treatments. The study was designed to map the molecular biosynthetic pathway, or “recipe,” and identify the steps that might be needed to reproduce the compounds in the lab.
To identify the pathway, the researchers used RNA sequencing and screened more than 80,000 genes from the plant samples. They determined genes the plants used to produce thymohydroquinone, and from this and past research, they identified the molecular map. One of the researchers, Natalia Dudareva from the department of chemistry, commented in a press release:12
“These plants contain important compounds, but the amount is very low and extraction won’t be enough. By understanding how these compounds are formed, we open a path to engineering plants with higher levels of them or to synthesizing the compounds in microorganisms for medical use.
It is an amazing time for plant science right now. We have tools that are faster, cheaper, and provide much more insight. It is like looking inside the cell; it is almost unbelievable.”
Herbs Suppress Tumor Growth and Development
Herbal medicine has played an important role in nearly every area of the world. It was practiced in ancient cultures and has seen a resurgence in popularity in Western culture. Natural products isolated from herbs used in Chinese medicine have also demonstrated apoptosis, angiogenesis suppression and retarded metastasis.
One paper13 reviewed the therapeutic potential of compounds isolated from these herbs, including flavonoids, terpenes and quinones. One of the terpenes, artemisinin, which is derived from sweet wormwood, was found to have excellent anticancer potential.
More recently, this compound has shown some efficacy against SARS-CoV-2, the virus that causes COVID-19.14 Chinese herbal medicines have also been used to alleviate the side effects of chemotherapy. One Cochrane review of the literature15 found that despite the low quality of the study, the results suggested that decoctions of Huangqi, aka astragalus, could decrease the side effects of chemotherapy.
Two papers were published in 202116,17 that evaluated the effect of carvacrol and thymol against cancer cells. In one literature review18 of studies published from 2003 to 2021, the results revealed that both carvacrol and thymol have antitumor and antiproliferative activity.
A second paper19 evaluated the effect of carvacrol and thymol against acute myeloid leukemia and found a combination of the compounds induced tumor cell death with low toxicity to normal cells.
Another lab study published in 2020,20 found that thymol and carvacrol induced apoptosis in ovarian cancer cells in a time- and dose-dependent manner. The combination of monoterpenes also demonstrated antiproliferative properties. The cell line used in this lab study was more sensitive to thymol than to carvacrol.
In addition to suppression of tumor cell growth or development, the anti-inflammatory effects of monoterpenes may also help reduce the risks from cancer. Inflammation has been linked to the progression of cancer cells, so targeting chronic inflammation may be an effective strategy for prevention and treatment.21
One paper published in the Frontiers in Pharmacology,22 detailed the pharmacological features of thymol, including anti-inflammatory, antispasmodic, free radical scavenging, and antitumor, and antifungal properties.