α-Cedrene

α-Cedrene is a major sesquiterpene of cedarwood oils (Texan, Virginian, Himalayan).

Skin. A 5 percent patch test on 25 volunteers caused no irritation or sensitization.

Oral. Acute oral LD50 in rats exceeds 5 g/kg; rabbit dermal LD50 exceeds 5 g/kg.

Subchronic. Cedrene significantly induces CYP and ethylmorphine N-demethylase (EMND) by intraperitoneal, oral or inhalation routes. Oral 200 mg/kg/day for three days increased ethylmorphine metabolism by 160 percent and CYP content by 40 percent. This raises a theoretical drug interaction with opioid analgesics.

Reproductive. Acetyl cedrene (related compound) at gavage 25–100 mg/kg/day on gestation days 7–17 gave maternal and developmental NOAELs of 50 and 100 mg/kg/day.

Mutagenicity. Non-mutagenic in Salmonella TA98 and TA100. Moderate cytotoxicity against HL60 leukemia cells (IC50 22.20 μg/mL).

α-Cedrene is the structural carrier of the classical cedarwood note in perfumery. Its CYP induction activity is worth noting, although the clinical impact from practical essential oil exposure is unclear.