Q&A: What does science say about plants as medicine?

HERSHEY, Pa. — Plants have always played an integral role in traditional medicine and healing practices, according to Kent Vrana, Elliot S. Vesell Professor of Pharmacology at Penn State College of Medicine, and they continue to shape health and medicine today.

Vrana, who is also director of the Center for Cannabis and Natural Product Pharmaceutics at Penn State, studies how chemical substances like drugs and medications interact with the body’s systems. For over four decades, he has studied the mechanisms underpinning these interactions — in health and from such diseases as Parkinson’s disease to substance use disorders — with the goal of learning how to improve human health.

In this Q&A, Vrana discussed the relationship between plant science and human health and the growing role of plant-derived solutions in medicine. He also discussed the connection between plant-derived compounds and biomedical research, particularly in light of growing public interest in plant-inspired and natural products.

Q: How are plant-derived compounds influencing human health and medicine today?

Vrana: Plants make these complex molecules that aren’t essential for growth but protect the plant from pests, for example. Some of these compounds, in turn, have properties that have healing benefits in humans. Many modern medications are derived from or are based on these bioactive plant compounds. Some of the most effective anti-cancer agents, like the chemotherapy medication paclitaxel, also known as Taxol, have come from purified plant compounds.

For example, Appalachia is a rich, biodiverse area and is home to many plants that have historically been used for medicinal purposes like “knitbone,” which is also known as comfrey. Knitbone has been used for broken bones, sprains and bruises for a long time. It contains a compound called allantoin, which stimulates tissue regeneration, and rosemarinic acid, which is anti-inflammatory.

Today, there are many medical conditions and diseases for which we don’t have a magic pill or where medication comes with bad side effects. People are hungry for alternatives, which is driving interest in and demand for plant-devised solutions and natural products for health. But there’s not a lot of incentive on the part of pharmaceutical companies to investigate these plant compounds because you can’t patent the plants and generate exclusive revenue from them. Moreover, biomedical research is expensive. So, you often have people making claims about natural products without data or evidence that it’s going to work.

Q: What’s the connection between plant-derived compounds and biomedical research?

Vrana: Just because something is natural or comes from a plant doesn’t mean it’s safe nor does it mean it’s effective. For many medicinal plants, we don’t know what makes them effective, how they interact with other plant compounds or medications or what the risks are and that can be a big problem.

We saw that with cannabis because it interferes with prescription drug metabolism, which can cause all kinds of problems. For example, there are known cases where patients taking the blood thinner Coumadin developed bleeding problems when they started using cannabis because the cannabis interfered with how Coumadin is broken down, resulting in an increased concentration in the body.

The driving force for our research program is to characterize plant compounds — to be able to understand how the compounds work, their benefits and the best way to deliver them — as well as any risks so that we can use these compounds in a more thoughtful and evidence-based manner.

For example, our research has focused on cannabis. In 2019, we opened the Pennsylvania-approved Medical Marijuana Academic and Clinical Research Center at Penn State. We want to understand the medical benefits of cannabinoids — compounds derived from the cannabis plant — as well as potential drug-to-drug interactions, acute toxicity and risk of cannabis use disorder.

There’s a lot of potential in cannabinoids, which we’re investigating to see how they may help with conditions like neuropathic pain and pain associated with bone fractures. CBD is the most well-known but there are others like cannabigerol and cannabichromene that are promising, particularly for pain.

This year, we changed our name to the Center for Cannabis and Natural Product Pharmaceutics. This allows us to expand our work to other medicinal plants in basic and clinical science studies for a wide range of diseases and conditions like pain, osteoarthritis, inflammatory bowel disease, cancer and others.

Q: Why is interdisciplinary training essential for future health innovations?

Vrana: When I started as a research technician, there were only two or three authors on my first published papers. Now, we don’t publish anything that doesn’t have at least half a dozen people. We’re collaborating across disciplines — experts in basic sciences, plant biology and clinical medicine.

That’s because science is a team sport. I love the idea of expanding my horizons and moving into areas that I don’t know about but have colleagues who do. That’s how science moves forward.

For example, Wes Raup-Konsavage, assistant professor in Neuroscience and Experimental Therapeutics at Penn State College of Medicine and I collaborate with Josh Kellogg, associate professor of veterinary and biomedical sciences at Penn State, who is studying ghost pipe, a traditional medicinal plant used for pain management but its biochemistry hasn’t been well-studied.

I couldn't even think about studying ghost pipe without Josh. This plant, extensively used in the past by the Cherokee, only grows in the wild. Josh and his team harvest the plant, extract the resident chemicals and characterize their structures. Wes and our team then test these chemicals for their ability to manage pain.

Q: How could plants shape the next generation of human health solutions?

Vrana: There's no question the public is going to continue to ask for natural products. Will plant and natural product extracts replace pharmaceuticals? Absolutely not. I hope, however, that for some unmet medical needs for which there is no good approach, nature can help us.

Plants have so much potential for drug discovery. Let’s use nature as a laboratory to make compounds and mixtures of compounds.

But we've got to develop an infrastructure and ecosystem in which we are free to explore those compounds in a safe and controlled way and to find out if we can augment what we're doing in the pharmaceutical environment.

We also need to train the next generation of scientists who will be involved in this space. We need to give them the skills needed to extract plant compounds and to characterize and understand their chemistry. We’re exploring developing more training opportunities for students and early-career researchers.