The word ‘terpenoid’ is not only limited to rhyming with words such as meteoroid, avoid, and steroid — it also symbolizes organic compounds produced by plants that offer significant medicinal and pharmacological benefits to humans.

In a review paper, U of T scientists explored the vast role that these chemicals play in our everyday lives.

Co-authors Dr. Michael Phillips, an assistant professor at UTM’s Department of Biology; and Matthew Bergman, a graduate student at the same department, discussed the findings of this review with The Varsity.

Relevance of terpenoids

The presence of terpenoids can be found all around us. Vitamin A is an example, along with the chemical that is key to the unique smell of pine.

The review explained that terpenoids can “attract pollinators, repel herbivores, or attract herbivore predators.” This has broad impacts on fields such as agriculture. 

Terpenoids also feature heavily in cannabis. Specialized terpenoids include well-known compounds such as cannabidiol — also known as CBD — and tetrahydrocannabinol — THC. The compounds have been used for their “psychoactive, anxiolytic and anesthetic effects for thousands of years,” according to the co-authors. 

The ability to make these terpenoids evolved as a result of “selective pressures imposed by animals” on plants. A great sense of irony lies in the fact that these chemical compounds, which often serve as plant defence compounds against herbivorous insects, possess “fortuitous uses in medicine.”

The reason that these compounds are biologically active in humans is in part due to the fact that “our proteins are made up of exactly the same amino acids as the plant proteins,” noted Phillips.

Applications of the review

Phillips hopes to use his review “partly as a teaching tool but also [to] summarize the literature that is important for [his] field.”

Bergman also spoke about the implications that his research would have on non-specialists in biology. “There’s a lot of interest right now in medicinal plants and there’s a lot of confusion surrounding what are the active constituents,” he said.

By conducting the review, Bergman hopes to eliminate some of this confusion. This is important because “there’s a connection between [our research] and what [consumers] find in the grocery store,” added Phillips.

The future of terpenoid research

In many cases, terpenoid-based medications could hold promise in health care, “by virtue of the fact of how much common ancestry we share with herbivores that terpenoids evolved to affect,” noted Phillips.

While many terpenoids represent potentially beneficial compounds for humans, the “testing process is painstaking and resource intensive,” according to the review. This process is further obstructed by the fact that “many [terpenoids] are produced in small amounts,” and “only in response to elicitation.”

Additionally, while the amount of plant terpenoids that can be screened for therapeutic applications is still unknown, it likely surpasses over 100,000 variants, according to the co-authors. With a review of terpenoids completed, researchers now have a tool to develop plans for further research in the field of plant biochemistry.