Volatile Constituents ofNepeta heliotropifoliaLam

Composition of the Essential Oils and Antibacterial Activities of Hymenocrater yazdianus, Stachys obtusicrena and Nepeta asterotricha Three Labiatae Herbs Growing Wild in Iran

Water-distilled essential oils from leaves of Hymenocrater yazdianus Rech.f., flowers of Stachys obtusicrena Boiss., and stems and flowers of Nepeta asterotricha Rech.f, which are endemic to Iran, were analyzed by GC and GC/MS. Fifty-five components of the leaf oil of H. yazdianus were characterized, representing 95.1% of the total components detected. The major constituents were identified as 1,8-cineole (17.6%), β-caryophyllene (13.9%), α-pinene (10.6%) and caryophyllene oxide (10.4%). Germacrene-D (37.5%) and α-bisabolol (23.5%) were the main components among the twenty constituents characterized in the flower oil of S. obtusicrena, representing 90.8% of the total components detected. Thirty-five compounds representing 93.0% of the stem oil of N. asterotrica were identified among which terpinen-4-ol (22.8%) and γ-terpinene (14.1%) were the major ones. The flower oil of the species was characterized by higher amounts of terpinen-4-ol (24.8%), 4aα, 7aβ-nepetalactone (18.2%) and 1,8-cineole (11.6%) among the thirty-three components comprising 98.5% of the total oil detected.

The antibacterial activity of the stem, leaf and flower oils of Hymenocrater yazdianus, Stachys obtusicrena and Nepeta asterotricha against seven Gram-positive and Gram-negative bacteria were determined using the MIC method. The growth inhibitory zone (mm) was also measured.

Antibacterial Activity and Composition of the Essential Oil of Nepeta Menthoides from Iran

The antibacterial activity and chemical composition of the essential oil obtained from the aerial flowering parts of Nepeta menthoides were analyzed by GC and GC-MS. Twenty-nine compounds representing 97.6% of the total oil were identified. Oxygenated monoterpenes (71.9%) were the principal fraction of the oil with 1,8-cineole (33.8%) and 4aα-7α-7aα-nepetalactone (23.2%) as the main constituents. The antibacterial activity of the oil and its two main constituents were tested against seven bacteria. High activity of the oil and its two main constituents was demonstrated against all the tested bacteria with MIC values in the range of 1.8 - 7.2, 0.9 - 7.2 and 1.8 - 15 mg/mL, respectively.