Nepeta

Nepeta is a genus of about 250 species of flowering plants in the family Lamiaceae. The members of this group are known as catnips or catmints due to its famed liking by cats&mdash;nepeta pleasantly stimulates cats' pheromonic receptor. The genus is native to Europe, Asia, and Africa, with the highest species diversity in the Mediterranean region east to mainland China. It is now common in North America as a weed. Most of the species are herbaceous perennial plants, but some are annuals. They have sturdy stems with opposite heart-shaped, green to grayish-green leaves. The flowers are white, blue, pink, or lilac and occur in several clusters toward the tip of the stems. The flowers are tubular shaped and are spotted with tiny purple dots. The scent of the plant has a stimulating effect on cats.

Also, oil isolated from catnip by steam distillation is a repellent against insects, in particular mosquitoes, cockroaches and termites. Research suggests that while in a test tube, distilled nepetalactone, the active ingredient in catnip, repels mosquitoes 10 times more effectively than DEET, the active ingredient in most insect repellents, as a repellant on skin it is not as effective.

Effects on cats
Catnip and catmints are mainly known for their behavioral effects they have on cats, particularly domestic cats. Both true catnip and Faassen's catnip have a sharp, biting taste, while the taste of giant catmint is bland. Approximately two thirds of cats are susceptible to the behavioral effects of catnip, as the phenomenon is hereditary. For example, most cats in Australia are not susceptible to catnip since Australian cats are drawn from a relatively closed genetic pool. The fact that it only elicits such a response in a proportion of cats — and that it is such a dramatic response — suggests that a genetic element is involved that is enriched in domesticated breeds.

When cats sense the bruised leaves or stems of catnip, they may roll over it, paw at it, chew it, lick it, leap about and purr, often salivating copiously. Some cats will also growl and meow. This reaction only lasts for a few minutes before the cat loses interest. It takes up to two hours for the cat to "reset" after which it can come back to the catnip and have the same response as before. Young kittens and older cats are less likely to have a reaction to catnip.

There is some disagreement about the susceptibility of lions and tigers to catnip. Some claim that all lions and tigers are effected by catnip but there are others who state that this is not true.

Catnip contains nepetalactone, a terpene. Nepetalactone can be extracted from catnip using steam distillation. Cats detect it through their olfactory epithelium and not through their vomeronasal organ. At the olfactory epithelium, the nepetalactone is hypothesized to bind to one or more olfactory receptors where it probably mimicks a pheromone, such as the hypothetical feline facial pheromone.

Other plants that also have this effect on cats include valerian (Valeriana officinalis) and plants that contain actinidine or dihydroactinidiolide (Smith, 2005).



Species
Nepeta cataria (Catnip, True Catnip, Catmint or Field Balm) is a 50–100 cm tall herb resembling mint in appearance, with greyish-green leaves; the flowers are white, finely spotted with purple. It has been introduced to many countries, and is now a widespread weed in some areas, including the United States. A lemon-scented cultivar, N. cataria 'Citriodora' looks exactly like true catnip, but has the scent of lemons, and can be used like Lemon balm.

Nepeta grandiflora (Giant Catmint or Caucasus Catmint) is lusher than true catnip, and has dark green leaves and dark blue, almost purple flowers.

Nepeta × faassenii (N. racemosa × N. nepetella; Faassen's Nepeta or Faassen's Catnip) is mostly grown as an ornamental plant. This hybrid is far smaller than either of above, and is almost a ground cover. It has greyish-green leaves and light purple flowers.

Some Dracocephalum, Glechoma and Calamintha species were formerly classified in Nepeta.

Nepeta species are used as food plants by the larvae of some Lepidoptera species including Coleophora albitarsella.




 * Selected species