β-Ionone

β-Ionone is the major ionone isomer occurring in osmanthus and boronia absolutes. Its safety profile is similar to α-ionone.

Skin. Patch tests on 25 volunteers with undiluted ionone caused no irritation, and at 8 percent no sensitization. In 100 consecutive dermatitis patients, no reactions occurred at 1 percent.

Oral. Acute oral LD50 in mice is 2.0 to 5.33 g/kg.

Subchronic. The 90-day NOAEL is 10 mg/kg. In a 12-week study, NOAEL 11.4 mg/kg.

Reproductive. A 1,000 mg/kg dose caused many resorptions in rats. However, at 250 to 750 mg/kg it attenuated cyclophosphamide-induced embryolethality. A single 480 mg/kg dose in pregnant hamsters caused no toxicity.

Mutagenicity and cancer. Not mutagenic in the Ames test, inhibits mutagenicity caused by cyclophosphamide and aflatoxin B1. Significant anticancer activity against melanoma and breast cancer.

β-Ionone metabolism involves oxidation, reduction and glucuronide conjugation. β-Ionone is a relatively potent inhibitor of rat liver microsomal pentoxy resorufin O-depentilase in vitro, suggesting it might alter the biotransformation of drugs and toxic substances. It induces CYP1A and CYP2B.

β-Ionone is the main constituent for the deep violet-raspberry aroma of osmanthus and boronia, two of the most precious floral absolutes in perfumery.