Safety Evaluation of Rhinacanthus nasutus Root Extract Gel Prepared from a Pilot Plant

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Patamaporn Pruksakorn
Chattraporn ๋Jaima
Praw Suppajariyawat
Virat Sumateewatanakul
Kanidsorn Larpardisorn
Chayada Tongkamsen
Warangluk Pimpapai
Archawin Rojanawiwat‡
Pilaslak Akrachalanont


Introduction and objective: Rhinacanthus nasutus (commonly known as thong phan chang in Thai) root extract gel preparation, containing 0.1% rhinacanthin C, is an herbal product that was developed as an effective topical agent for fungal skin infection using knowledge from both scientific research and Thai traditional medicine. However, the safety of a novel herbal preparation should be assessed before it is approved for use in humans. This study aimed to evaluate the safety of R. nasutus root extract gel preparation prepared in a pilot plant.

Methods: Safety study of R. nasutus root extract gel was conducted following the Organisation for Economic Co-operation and Development (OECD) Guidelines, including the bacterial reverse mutation test (Test Guideline 471) and the acute dermal irritation/corrosion test (Test Guideline 404). Skin irritation testing in healthy Thai volunteers was performed using a single patch test.

Results: Topical preparation of R. nasutus root extract was not found to cause any mutations in bacteria, nor did it irritate or corrode the animal skin. Moreover, it did not cause any skin reactions in healthy volunteers during the single patch test.

Discussion: R. nasutus root extract gel preparation, containing 0.1% rhinacanthin C, is categorized as an herbal product derived from research and development beyond traditional knowledge. Thus, the product needs safety and efficacy data from animal models and humans for product registration. In order to study the safety profile of the product according to international standards, the results suggest the R. nasutus root extract gel had non-genotoxic and non-skin corrosive effects, nor did it cause dermal irritation in both animal models and humans.

Conclusion and recommendation: R. nasutus root extract gel preparation is deemed to be safe for humans and we can further proceed to clinical trials for efficacy and safety evaluations in patients with fungal skin infections.

Article Details

Original Articles


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