Final Report on the Safety Assessment of Azulene

Abstract

Azulene is an extract from the volatile oil of several perennial herbs and is detected in tobacco smoke. It functions as a skin conditioning agent in cosmetic formulations, including hair dyes. Azulene is reported to be used in a wide range of cosmetic formulations, but these reported uses are likely to be uses of guaiazulene, a chemically related colorant, because there are currently no suppliers of Azulene to the cosmetics industry. The anti-inflammatory action of Azulene has been demonstrated in several animal studies. Effects at the cellular level are reported to include inhibition of respiration and growth, but no effect on ciliary activity or membrane permeability. Relatively low oral toxicity was seen in acute animal studies. Azulene was not mutagenic in an Ames test, with and without metabolic acfivation. An allergic response to Azulene was noted in one case report. These data were clearly insufficient to support the safety of Azulene in cosmetics. Additional data needed to make a safety assessment include: methods of manufacture and impurities, especially naphthalenes; current concentration of use; skin penetration, if there is significant skin penetration, then both a 28-day dermal toxicity study to assess general skin and systemic toxicity and a reproductive and developmental toxicity study are needed; one genotoxicity study in a mammalian system, if positive, then a 2-year dermal carcinogenesis study using National Toxicology Program methods is needed; skin irritation and sensitization in animals or humans; and ocular toxicity.