Volatile constituents of Scutellaria rubicunda Hornem subsp. linnaeana (Caruel) Rech. (Lamiaceae) endemic in Sicily

The genus Scutellaria comprises about 350 species of herbs or subshrubs and rarely shrubs, some of which are used for their antitumor [1] or anti-feedant properties [2]. The essential oils of some Scutellaria species were also investigated and showed antimicrobial and antifungal activities [3, 4]. Scutellaria rubicunda Hornem. subsp. linnaeana (Caruel) Rech. is a herbaceous, endemic species growing wild in the central part of Sicily in the Parco delle Madonie. An earlier phytochemical study revealed that aerial parts contained Scutecyprol B and Scutalbin C, active against five species of lepidopteran larvae [5]. No reports on the essential oil of S. rubicunda subsp. linnaeana has been found in the literature so far. Therefore we report on the chemical composition of the essential oil of this plant. Flowering aerial parts were collected at Piano Battaglia, 1600 m s/l, 80 km south of Palermo (Italy) in July 2005. The oil was isolated by hydrodistillation [6]. The GC and GC/MS analyses evidenced 31 compounds, accounting for 92.7% of the oil that consisted mainly of terpenoids. The oxygenated monoterpenes (44.5%) represented the main fraction with linalool (27.8%) as dominant component. Other representative compounds were α-terpineol (6.7%) and nerol (4.2%). Sesquiterpenes (39.0%) were composed of caryophyllene (28.7%), caryophyllene oxide (4.2%) and α -cedrol (2.3%) as main components.

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