Usnic Acid and Its Topical Use-A Concise Review

Area of Science:

• Dermatology
• Oncology
• Pharmacology

Background:

• Usnic acid (UA), a lichen metabolite, has dual therapeutic potential in dermatology.
• Clinical use is hindered by hepatotoxicity and poor solubility.

Purpose of the Study:

• Evaluate topical efficacy, molecular mechanisms, and formulation strategies for UA.
• Focus on UA enantiomers and UA-rich extracts for dermatological and oncological care.

Main Methods:

• Comprehensive literature search (PubMed, Scopus, Google Scholar) of 36 publications.
• Analysis of in vitro studies on anti-melanoma activity and tissue regeneration.
• Review of advanced drug delivery systems for UA topical application.

Main Results:

• Usnic acid induces apoptosis in resistant melanoma cell lines, with (-)-UA overcoming doxorubicin resistance.
• Low UA concentrations promote wound/burn healing by upregulating VEGF and fibroblast activity.
• Advanced formulations (liposomes, nanoemulsions, nanogels) enhance skin permeability and retention.

Conclusions:

• Topical UA demonstrates anti-melanoma and tissue regenerative properties.
• Advanced drug delivery systems mitigate UA toxicity and improve efficacy.
• Bio-functionalized dressings and nano-formulations are crucial for clinical translation.