α-Irone

α-Irone is the principal constituent for the characteristic aroma of orris (iris rhizome) oil. The compound is among the most expensive perfumery materials.

Skin. A 10 percent patch test on 25 volunteers produced neither irritation nor sensitization. At the same concentration, it produced reactions in 5 of 1,606 consecutive dermatitis patients, a 0.3 percent rate.

Oral. Acute oral LD50 in rats exceeds 5 g/kg, in mice 7.4 g/kg. Acute dermal LD50 in rabbits exceeds 5 g/kg.

Subchronic. A 90-day dietary study in rats at 5.2 to 5.9 mg/kg/day showed no significant adverse effects.

Cancer. Twenty-four ip injections totaling up to 9.6 g/kg over 24 weeks did not increase primary lung tumor incidence in mice.

α-Irone, particularly the (Z)-isomer, is the constituent determining the value of orris oil from years-aged iris rhizome. Orris is among the most expensive perfumery materials on the market.