Carvone is basically a terpenoid that is found in several essential oils. This phytochemical is the key constituent of spearmint oil. It also occurs naturally in spearmint, caraway seeds, and ginger grass in addition to dill seeds. When stored at room temperature, carvone is in liquid state and has a pleasing smell. This naturally occurring chemical is often used in the form of a flavoring agent, especially in chewing gums and liqueurs. It is also added to perfumes and soaps to enhance their scent. Carvone has often been used in medicines, spices and perfumes over several centuries.
This monoterpene hydrocarbon is found in elevated amounts in spearmint, caraway and dill seeds. Carvone is a member of the terpenoid family. This chemical is found in a liquid state and its color varies from light yellow to being colorless. Carvone is soluble in alcohol, chloroform, ether, propylene glycol and various mineral oils.
Carvone is a phytochemical belonging to the category of compounds known as terpenes. Plants usually produce this chemical with the aim of attracting helpful insects. For instance, some plants produce this chemical and emit it when they are assailed by caterpillars. The terpenes released by these plants draw parasitic wasps, which not only exterminate the caterpillars, but also destroy their eggs. Subsequently, the bodies of the caterpillars are consumed by the emergent wasp larvae.
There are two mirror images of carvone - R-(-)-carvone plus S-(-)-carvone. The smell of these two varieties of carvone are distinctly different and even squirrel monkey are able to identify them.
While the smell of R-(-)-carvone is similar to that of spearmint leaves, the smell of S-(+)-carvone bears resemblance to that of caraway seeds. People have been using both these varieties of carvone since ancient times. In Rome, people have been using them for therapeutic purposes.
In 1877, German chemist Franz Varrentrapp was the first to isolate the pure variety of carvone. Soon after the discovery of the pure form of this compound, Schweitzer named it carvol. In present times, large quantities of carvone is isolated from caraway seeds (about 60% to 70%), the oil extracted from dill seeds (about 40% to 60%) and the spearmint oil (about 50% to 80%). In addition, this natural compound is also present in significant quantities in the oil extracted from mandarin orange peel.
R-(-)-carvone is hauled out from the leaves of spearmint plant, which is considered to be an excellent source of this terpenoid. In addition, R-(-)-carvone, which has a number of commercial uses, is found in ginger grass oil, peppermint oil and kuromoji oil.
Essential oil obtained from many other mint species also contain significant amounts of R-(-)-carvone. Most prominent among them is spearmint essential oil, which contains anything between 50% and 80% of this compound. Hence, spearmint is the major source of this plant compound and is widely used to produce R-(-)-carvone.
On the other hand, S-(+)-carvone forms the main component (roughly 60% to 70%) of the oil extracted from caraway seed (called Carum carvi). This variety of carvone is produced on large scale every year, about 10 tons annually. This compound is also found in dill seed oil (about 40% to 60%). In dill seed oil it is extracted from Anethum graveolens.
Nevertheless, most of the commercially used R-(-)-carvone is derived by synthesizing R-(+)-limonene. The isomer of R-(-)-carvone is also found in kuromoji oil. There are some oils, such as ginger grass oil, which enclose a blend of both these varieties of carvone. Some natural oils like peppermint oil enclose trace amounts of this terpenoid.
Several studies undertaken to analyze the biological properties of carvone have stated that this terpenoid is an antiviral, diuretic, decongestant and has tonic properties. Apparently, this plant compound has a potent anti-tumour effect. Findings of a study undertaken by scientists at the United States National Cancer Institute on rodents have suggested this.
Aside from their use in the food industry, carvones are also employed in aromatherapy. Similar to various other essential oils, carvone is also widely employed in air fresheners, as they have a pleasing fragrance. Moreover, this phytochemical possesses many medicinal properties and, hence, is an ideal choice for treating specific health conditions.
Precisely speaking, carvone is a key element of the oil hauled out from caraway seeds, which contain large percentage of this chemical - almost 99 percent. It works as a relaxant, thereby clearing the respiratory tract, alleviating stress and emotional exhaustion. Since it also works like an expectorant, carvone helps in treating bronchitis, coughs and bronchial asthma.
Carvone is also effective in treating sore throats and laryngitis. It works by rinsing out the toxic substances in the respiratory tract, thereby facilitating speedy recovery. At the same time, carvone also helps in unwinding the digestive system. It is also effective for curing flatulence, gastric spasms, and stomach colic. Moreover, this phytochemical is also effective in treating nervous digestion. Carvone is also employed for clearing the urinary tract.
People identified the benefits offered by carvone several thousand years back and have been using in food since then. The famed Spearmint Gum of Wrigley employs natural spearmint oil, which is extracted from Mentha spicata. In fact, Life Savers, which also has a spearmint flavour, uses spearmint oil. Moreover, carvone extracted from caraway and dill too has been utilized by the food industry since long. The popular European beverage Kummel is also produced by blending caraway extract and alcohol.
Agricultural use: Aside from carvone's use in the food industry and aromatherapy, it is widely used in some regions of the world for agricultural purposes. In the Netherlands, farmers use carvone to stop stored potatoes from sprouting.
Some time back, scientists undertook a study to identify carvone's anti-fungal activity on potato tubers as well as various other plant diseases. In addition, the study aimed at exploring the suppression of potato sprouts.
The findings hinted that during the two in-vitro trials undertaken during the course of the study scientists detected that carvone had anti-fungal activity against various species of fungi. Consequently, carvone has been assigned the trade name "talent", which works in the form of an anti-fungal agent and suppresses potato tubers from sprouting in the Netherlands.
Moreover, the extract from carvone was found to be a very effective mosquito repellent. Currently the United States Environmental Protection Agency is reviewing the potency of carvone as well as its safety in the form of a pesticide.