ascaridole

Ascaridole is a naturally occurring monoterpene endoperoxide and a research compound found as a degradation product of α-terpinene in essential oils, most notably tea tree oil. It is not an approved pharmaceutical drug but has been studied as a contact allergen responsible for allergic contact dermatitis associated with tea tree oil exposure. Research conducted at the University Medical Center Groningen (Universitair Medisch Centrum Groningen) investigated ascaridole's sensitizing potential through clinical patch test studies at concentrations of 1%, 2%, and 5% in petrolatum. The compound's biological target involves the innate immune system, specifically dendritic cell (DC) activation — a hallmark of chemical skin sensitizers — with upregulation of costimulatory molecules such as CD86, CD80, CD40, and CD54. Ascaridole is classified as a small molecule (natural product/monoterpene). It has no brand name, as it is a research/investigational compound. The diseases studied in relation to ascaridole are contact allergy and allergic contact dermatitis. Studies suggest that 2% is the optimal patch test concentration, and that ascaridole may be the primary contact allergen in oxidized tea tree oil.