Headspace Volatiles ofScutellaria californicaA. Gray Flowers

Volatile constituents of California skullcap (Scutellaria californica A. Gray) flowers were isolated by solid-phase microextraction (SPME) and analyzed by GC and GC/MS. A total of 52 constituents were identified (constituting 90.8% of the total area), 12 of which were tentatively identified. β-Caryophyllene (56.6%), germacrene D (6.9%), methyl 2-methylbutyrate (4.9%), β-bourbonene (4.5%), α-humulene (2.8%), methyl butyrate (2.7%), and α-copaene (1.5%) were the major constituents of the flower volatiles. Due to their low odor thresholds (measured in water) and fruity aroma, methyl 2-methylbutyrate (4.9%; odor threshold = 0.1 ppb) and ethyl 2-methylbutyrate (0.7%; odor threshold = 0.007 ppb) were considered to be important contributors to the characteristic sweet, apple-like odor of these flowers. Key Word Index: Scutellaria californica Lamiaceaeheadspace volatilesβ-caryophylleneodor threshold