Antioxidant and radical scavenging activities of chamazulene

Essential oils (EOs) of chamomile contain several bioactive compounds, including monoterpenes, sesquiterpenes, triterpenes and fatty acids. Hydrodistillation of chamomile EO induces the formation of chamazulene, a bioactive compound. Chamazulene was isolated from the EO by column chromatography. The total antioxidant capacity confirmed a higher antioxidant activity of chamazulene (IC₅₀ = 6.4 μg mL^− 1) than of ascorbic acid (IC₅₀ = 12.8 μg mL^− 1), α-tocopherol (IC₅₀ = 20.5 μg mL^− 1) and of butylated hydroxytoluene (BHT) (IC₅₀ = 30.8 μg mL^− 1). Chamazulene was unable to react with DPPH√. However, when chamazulene was assayed with ABTS√, a strong and significantly (P < 0.05) higher free radical scavenging activity was observed (IC₅₀ = 3.7 μg mL^− 1), with respect to BHT (IC₅₀ = 6.2 μg mL^− 1) and α-tocopherol (IC₅₀ = 11.5 μg mL^− 1). The results of this work show that chamazulene is an important factor for the antioxidant power of chamomile oil.