Catmint

Cats go wild over it ! Catmint has a powerful effect on cats making them go crazy when they’ve chewed a few leaves. Our cat has only just discovered we grow a number of varieties of catmint (Nepeta spp.) and now sleeps underneath one, a variety called ‘Six Hills Giant’ as if to guard his stash. Another is Nepeta racemosa ‘Walkers’ Low’ which spread eagles itself at the front of the border and must take its chances with the lawn mower. The plant has been investigated for its ability to attract feral cats (Clapperton et al., 1994).

The Nepeta genus (Family: Lamiaceae) provides a wide ranging selection of perennials for the horticulturalist, especially for dryer regions of the garden. The number of species is about 250. The plants originate from around the Mediterranean, much of central and Southern Europe, Near east and central and southern Asia.

A number are cultivated for their catnip oils – the nepetalactones which are associated with folk medicine. The plants are used to treat bacterial infections and will serve as antibacterials, as fungicides and as antivirals. They are also useful insect repellants and some insects also exploit nepetalactones in defensive secretions. 

The species include:

• N. argolica Bory & Chaub.
• Nepeta cataria L.   
• N. x faassenii Bergm. ex Stearn
• N. nepetella L 
• N. nuda L
• N. persica Boiss
• N. sibirica L   .  

The Essential Oils and Aroma of Catmint

The aroma and essential oils have been widely studied, usually taking N. cataria L.   as the species of choice for this. Classic techniques such as steam distillation hydrodistillation, solvent extraction, static headspace and solid phase extraction have been used to isolate the volatiles.

Techniques of gas chromatography (GC) and GC-MS (gas chromatography with mass spectroscopy) have then been employed to help identify the components some of which have used cluster analysis (de Pooter et al., 1988).

If catnip is looked at then the componentry is mainly geranyl acetate, geraniol, citronellol and citronellyl acetate (Baranauskiene et al., 2003), which in sensory terms generate a woody, certainly herbal and almost mint-like aroma but without the higher green notes.

The essential oils include a couple of nepetalactones, 1,8-cineole, E-caryophyllene and cironellyl acetate (Morteza-Semnani and Saeedi, 2004). A very recent paper on oil extraction of N. Cilicia Boiss. Ex Benth. (Formisano et al., 2013) using gas chromatography with GC-mass spectroscopy identified 75 compounds including spathulenol (15%w/w), hexdecanoic acid (14%), δ-cadinene (5.5%) and α-copaene (4.5%).

The major constituents in N. argolica were found to be stereoisomers of nepetalactones (94.5–68.0%). 4aα,7α,7aβ-nepetalactone (Tzakou et al., 2000). Oxygenated sesquiterpenes were found in N. argolica B. & C. (Skaltsa et al., 2000). 

Much of the chemistry of the genus is covered in a review by Formisano et al., (2011).

The nepetalactones have antibacterial properties (D’Antuono and Elementi, 2006) and have been quantified in catmint leaves using reversed phase HPLC coupled with UV and MS detection (Wang et al., 2007).

References

Baranauskiene, R., Venskutonis, R.P., Demyttenaere, J.C., (2003) Sensory and instrumental evaluation of catnip (Nepeta cataria L.) aroma. J. Agric. Food Chem. 51 pp. 3840-3848

Clapperton, B.K., C.T. Eason, R.J. Weston, A.D. Woolhouse, and D. Morgan. (1994) Development and testing of attractants for feral cats, Felis-Catus L. Wildlife Res. 21(4) pp. 389–399.

D’Antuono LF, Elementi S (2006). Facts and perspectives of edible Lamiaceae: flavor and health, industrial exploitation, and the consumer. Int. Symposium on the Labiatae:  Acta Hortic., 723 http://www.actahort.org/books/723/723_2.htm

De Pooter, H. L., Nicolai, B., De Laet, J., De Buyck, L. F., Schamp, N. M., & Goetghebeur, P. (1988). The essential oils of five Nepeta species. A preliminary evaluation of their use in chemotaxonomy by cluster analysis. Flavour and Fragrance Journal, 3(4), pp. 155-159 (Article).

Formisano, C., Rigano, D., Arnold, N.A., Piozzi, F. Senatore, F. (2013) GC and GC–MS analysis of the essential oil of Nepeta cilicica Boiss. ex. Benth. from Lebanon. Nat. Prod. Res. DOI: 10.1080/14786419.2013.805332

Formisano, C., Rigano, D., Senatore, F. (2011) Chemical constituents and biological activities of Nepeta species. Chemistry & Biodiversity 8 pp. 1783-1818

Skaltsa, H. D., Lazari, D. M., Loukis, A. E., & Constantinidis, T. (2000). Essential oil analysis of Nepeta argolica Bory & Chaub. subsp. argolica (Lamiaceae) growing wild in Greece. Flavour and Fragrance Journal, 15(2), pp. 96-99 (Article)

Tzakou, O., Harvala, C., Galati, E. M., & Sanogo, R. (2000). Essential oil composition of Nepeta argolica Bory et Chaub. subsp. argolica. Flavour and Fragrance Journal, 15(2), pp. 115-118 (Article).

Wang, M., Cheng, K-W., Wu, Q., Simon, J.E. (2007) Quantification of nepetalactones in catnip (Nepeta cataria L.) by HPLC coupled with ultraviolet and mass spectrometric detection. Phytochemical Anal. 18(2) pp. 157-160