Allergic contact dermatitis testing of resin of Dipterocarpus alatus Roxb. ex G. Don on human skin in healthy volunteers

Abstract

Resin of Dipterocarpus alatus Roxb.ex G. Don or Yang Na (RYN) is a natural extract that has potential to be used in many cosmetic products. However, its safety data is not yet sufficient. The purpose of this study was to investigate whether unprocessed RYN from Dipterocarpus alatus Roxb.ex G. Don can potentially cause allergic contact dermatitis on human skin. Material and Method: This clinical study was conducted by using Patch test in thirty healthy volunteers both males and females, aged 18 years and over. The tested compound was prepared in petrolatum at the concentrations of 5%, 10%, 20% and 40% and filled in Patch test chambers. Pure petrolatum and 2% sodium dodecyl sulfate (SDS) was used as a negative control and a positive control, respectively. The Patch test chambers were applied on the backs of the subjects and results were evaluated at 4 and 24 hours following the exposure. Results: Results showed that, at 4 hours after the application, no irritation was observed for RYN, negative and positive controls when determined by using International Contact Dermatitis Research Group (ICDRG). At 24 hours after the application, 2% SDS, a positive control, caused mild irritation on all subjects’ backs with the ICDRG score at 1.6 ± 1.03. But all concentrations of RYN exhibited no irritation. Conclusion: Overall results from this study showed that RYN was considered safe for human skin at the concentration up to 40%. RYN can then be potentially used for development of RYN-containing cosmetic products.