Exploring rosemary extract and wound healing

Jiayi Pang, a rising third-year student from Little Neck, New York, has spent the summer studying the therapeutic effect of rosemary extract on wound healing.

It all started with TikTok she says. "It's a funny origin story. Basically, my mentor, Emmanuel Rapp, was concerned about his hair loss. We saw these TikToks of people using rosemary water and oil to regrow their hair." The before and after pictures showed a dramatic difference, Pang says, and she and Rapp, a Ph.D. candidate in cell and molecular biology, decided to put these TikToks up for a scientific challenge to see if it was accurate.

"We were a little skeptical," Rapp says, "but historically plants have been used to treat ailments and diseases."

Pang's project is based out of the Thomas Leung Research Groupin the Department of Dermatology & Institute for Regenerative Medicine. The Leung Lab specializes in skin wound healing, Rapp says, so it made sense to test skin regeneration alongside hair regrowth.

The group created an ethanol-based rosemary plant extract from which they created a rosemary cream.

Several experiments using rosemary cream, among other rosemary-based treatments, debunked the widespread belief that rosemary promotes hair growth.

However, the team also applied the cream to small mouse ear punctures and, to their surprise, noticed that the rosemary group healed significantly faster and better than the control group. "We saw that rubbing this ethanol-based extract of rosemary on the ears of the mice led to almost near full wound closure," Rapp says.

"From then on, we continued this project trying to figure out what aspect of rosemary causes the healing," Pang says.

The team is in the process of figuring out the cellular and molecular mechanisms of rosemary-induced wound repair. Pang and Rapp hypothesize that the pathway rosemary uses to promote wound healing is through the TRPA1 channel, based on the lab's previous research. "If you activate TRPA1, you promote wound closure," Rapp says.

Pang is currently testing different extraction methods and solvent variants to see their effect on wound healing. Extracting the rosemary plant in solvents of differing polarities allows Pang to assess which is most effective with the hope of eventually identifying the active compound.

Pang, who is majoring in cell and molecular biology, has always been interested in medicine, science, and research, she says, but most of her practical, hands-on experience in high school was curtailed because of the COVID-19 pandemic. Coming to Penn, she says, she wanted to learn wet lab skills and practice conducting experiments using the scientific method.

Pang has been working on the rosemary extract experiments since the fall of 2023. She was able to continue the work this summer with the support of a College Alumni Society Undergraduate Research Grant and a Frances Velay Fellowship through the Center for Undergraduate Research and Fellowships.

Pang hopes these experiments will advance scientific knowledge of plant extracts and wound healing, she says. "If that leads to wound healing treatments where we can use natural resources like rosemary, I think that would be really impactful and pretty cool."