# Carnosic acid in topical rosemary extract enhances skin repair via TRPA1 activation

## TL;DR

Topical rosemary extract containing carnosic acid helps skin heal faster with less scarring by activating TRPA1 receptors.

## Contribution

The study identifies TRPA1 activation by carnosic acid as a novel mechanism for promoting regenerative skin healing.

## Key findings

- Ethanol-based rosemary extract accelerates wound healing and reduces fibrosis in mice.
- Carnosic acid activates TRPA1 on sensory neurons to enhance tissue regeneration.
- Mice lacking TRPA1 in sensory neurons do not benefit from rosemary extract's effects.

## Abstract

Mammalian skin wounds typically heal with a scar, characterized by fibrotic tissue that disrupts original tissue architecture and function. Therapies that limit fibrosis and promote regenerative healing remain a major unmet clinical need. Rosemary extract, particularly in the form of topical oils and creams, has gained widespread public attention for its purported wound-healing properties. However, its efficacy and mechanism of action remain poorly understood. We show in adult wound healing mouse models that an ethanol-based rosemary extract accelerates the speed of wound healing and mitigates fibrosis. Mechanistically, we identify that carnosic acid, a major bioactive component of rosemary leaves, activates the transient receptor potential ankyrin 1 (TRPA1) nociceptor on cutaneous sensory neurons to enhance tissue regeneration. Mice lacking TRPA1 in sensory neurons do not exhibit these pro-regenerative responses, confirming its role as a critical mediator. Together, these findings suggest that topical rosemary extract may represent an effective and accessible therapeutic approach to improve skin repair outcomes.

Carnosic acid in topical rosemary extracts reduce scar formation in injured skin.