Honokiol Improves Acne-like Lesions in a Rabbit Ear Model by Alleviating Hyperkeratosis and Sebum Secretion

The prevalence of acne vulgaris is high, but the topical retinoids used as the foundation of treatment have teratogenic and photosensitivity properties. Previous studies have suggested that honokiol, a small-molecule compound extracted from Magnolia officinalis, could effectively inhibit Cutibacterium acnes (C acnes) and inflammation in vitro. However, the effect in vivo is unclear. The rabbit ear acne model that we created showed obvious comedones and hyperkeratosis. These lesions were repeatedly measured and recorded by dermatoscopy (ultraviolet light). Compared with the control group, topical 2.5% honokiol cream obviously improved the comedones and hyperkeratosis and effectively reduced sebum secretion, as shown by Oil Red O staining. The effects were equivalent to those of adapalene gel without local side effects. We added honokiol's other functions to acne treatment in addition to antiinflammation, but further studies are needed.