Volatile constituents ofNepeta glomerulosa Boiss. subsp.carmanica

Herbivory Damage Increased VOCs in Wild Relatives of Murtilla Plants Compared to Their First Offspring

Murtilla (Ugni molinae) is a shrub native to Chile that has undergone an incipient domestication process aimed at increasing its productivity. The reduction in intrinsic chemical defenses due to the domestication process has resulted in a decrease in the plant's ability to defend itself against mechanical or insect damage. In response to this damage, plants release volatile organic compounds (VOCs) as a means of defense. To understand how domestication has impacted the production of VOCs in the first offspring of murtilla, we hypothesized that their levels would be reduced due to the induction of mechanical and herbivore damage. To test this hypothesis, we collected VOCs from four offspring ecotypes and three wild relatives of murtilla. We induced mechanical and herbivore damage in the plants and then enclosed them in a glass chamber, where we captured the VOCs. We identified 12 compounds using GC-MS. Our results showed that wild relative ecotypes had a higher VOC release rate of 624.6 µg/cm²/day. Herbivore damage was the treatment that produced the highest release of VOCs, with 439.3 µg/cm²/day in wild relatives. These findings suggest that herbivory triggers defenses through the emission of VOCs, and that domestication has influenced the production of these compounds in murtilla. Overall, this study contributes to bridging the gap in the incipient domestication history of murtilla and highlights the importance of considering the impact of domestication on a plant's chemical defenses.

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.

Nepetalactone Content and Antibacterial Activity of the Essential Oils from Different Parts of Nepeta persica

The essential oils from the flower, leaf, stem and root of Nepeta persica Boiss., analyzed by GC and GC/MS, were shown to contain 4aβ,7α,7aβ-nepetalactone (58.5%, 62.3%, 66.2% and 27.1%, respectively), and 4aα,7α,7aβ-nepetalactone (33.0%, 28.3%, 24.9% and 7.6%, respectively). The other main component of the flower and stem oils was α-pinene (3.6% and 4.4%) and of the leaf oil β-ocimene (3.6%). In the root oil, other main constituents were α-pinene (40.4%), α-amorphene (5.3%), γ-cadinene (2.9%), and cis-calamenene (2.5%). Nepetalactone was the major component of the flower, leaf and stem oils, which are thus important sources of nepetalactone. Antibacterial activities of the flower, leaf, stem and root oils were evaluated using the microdilution broth method. Inhibitory effects on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Enterococcus faecalis were recorded. The flower, leaf, stem, and root oils had difference activities against the test microorganisms. The antibacterial property of the essential oils might be ascribed to their high content of nepetalactone isomers.

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.

Essential Oil Composition of Two Subspecies of Nepeta Glomerulosa Boiss. from Iran

Essential oil compositions of Nepeta glomerulosa Boiss. subsp. glomerulosa and N. glomerulosa subsp. stapfiana (Bornm. ex Rech. f.) Rech. f., each gathered from two different locations, have been investigated by GC and GC/MS. 1,8-Cineole was the major compound in the oils of both collections of subspecies glomerulosa (27.4%, 30.6%), and was also a major constituent of subspecies stapfiana (14.9%, 17.8%). However, caryophyllene oxide was the predominant compound for both oils of subspecies stapfiana (32.0%, 24.1%). From the chemotaxonomic point of view, the two members of each subspecies comprised a separate group with a considerable distance from the other two, and the morphological differences of these two subspecies were well reflected in their essential oil compositions.