Optimized extraction, odor modulation, and antioxidant and antimicrobial activities of blue essential oil from Artemisia umbrosa

Artemisia umbrosa (Besser) Turcz. ex-Verl. (Asteraceae) produces a rare blue essential oil rich in chamazulene, but its industrial application is hindered by low extraction efficiency and undesirable pungent odors. In this study, an integrated strategy combining ultrasound-assisted hydrodistillation (UAH) optimization and post-extraction odor modulation was developed to obtain a high-quality, color-stable blue essential oil with preserved bioactivity. Extraction parameters were optimized using a Box–Behnken response surface design, with optimal conditions identified as a material-to-liquid ratio of 1:13, an extraction time of 3 h 20 min, and 2% NaCl. Sensory quality was subsequently improved by silica gel adsorption (2 g, 60 °C, 60 min), which effectively reduced pungent odors without compromising blue coloration or chamazulene stability. GC–MS analysis identified 36 volatile constituents, with chamazulene accounting for 50.68% of the total composition. The blue essential oil exhibited strong antioxidant activity, with IC 50 values of 8.71 μL mL −1 (DPPH) and 8.86 μL mL −1 (ABTS), outperforming Artemisia argyi H. Lév. & Vaniot yellow essential oil. Pronounced antimicrobial activity was observed against Staphylococcus aureus (MIC/MBC 21.16/25.94 μL mL −1 ) and Escherichia coli (25.94/30.64 μL mL −1 ), and these activities were retained after deodorization. Stability tests indicated that chamazulene is sensitive to heat, light, and oxidative conditions. Overall, this study provides a practical and scalable approach for producing deodorized, chamazulene-rich blue essential oil, supporting its potential application in natural preservation and cosmetic formulations.