Analysis of volatile oil from Nepeta glomerata Montbret et Aucher ex Bentham from Lebanon

Abstract

Nepeta L., one of the largest genera of Lamiaceae, consists of about 300 species, many of which are pleasantly aromatic, rich in essential oils and of potential economic interest. Several Nepeta species are used in folk medicine as diuretic, diaphoretic, antitussive, antispasmodic, anti-asthmatic, febrifuge, emmenagogue and sedative agents [1]. Nepeta glomerata Montbret et Aucher ex Bentham, catmint, has an aromatic, characteristic odour, which bears a certain resemblance to that of Mint. In this communication we report the study of the essential oil of this plant extracted by hydrodistillation using a Clevenger-type apparatus according to the method recommended in the European Pharmacopoeia [2]. For our study, aerial parts of N. glomerata were collected at the full flowering stage in August 2007 near the Ainnete village, Makmel mountain (1650/1850 a. s.l.), Lebanon. Makmel Mountain is considered as the East's Plateau and Lebanon's water reservoir. The essential oil was analysed by GC and CG/MS: peak identification was accomplished by comparison of their mass spectra with NIST 02 and Wiley 275 libraries and with those reported in literature, as well as by comparison of their retention indices with literature values. Results showed that volatile constituents of N. glomerata consist above all of monoterpenes (41.1%) and sesquiterpenes (28.7%), with a prevalence of oxygenated monoterpenes (22.1%) and oxygenated sesquiterpenes (15.2%). alpha-Pinene (13.4%), spathulenol (8.6%) and carvacrol (5.4%) are the main compounds of the oil.