Mentha requienii Bentham is a small plant found only on the island of Montecristo, Sardinia, Corsica and on the islands of Caprera and Maddalena; a subspecies of M. requienii has also been identified in Capriaia, where it is called “bistaminata” due to some differences in color compared to the original species, in particular a reduction in the number of stamens and corolla lobes. In Capraia, moreover, on the banks of the Laghetto or Stagnone, the only natural reservoir in the Tuscan Archipelago, Roman mint or poleggio or pulegio (M. pulegium L.) grows, which is also found in the humid areas of Montecristo; also in Montecristo, in the beds of the small watercourses of Cala Maestra, wild mint (M. rotundifolia L.) is found. Roman mint is also found on the island of Giglio, especially on Poggio della Pagana or Poggio Terneti.
Biological form
H-scap (Hemicrypt ta scaposa)
Chorotype
Cultivated (M. x piperita L.)
Botanical characteristics (Mentha x piperita L.)
There are more than 600 varieties of this perennial and rustic herbaceous plant with different scents. It is so vigorous that it spontaneously crosses, giving life to new varieties. The vitality of mint is such that it even makes it a weed. Depending on the species to which it belongs, a mint plant can be from a few dozen centimeters to almost a meter tall, or have a creeping habit.
The upright varieties should be pruned often to keep the tufts compact and renew growth, the creeping ones are perfectly suited to the formation of fragrant lawns. The mint leaves are oval, more rarely round, green, but also variegated with cream or purple edges, always deeply veined. The small flowers, mauve or lilac in color, are gathered in apical spikes and bloom in summer. The best known species, because they are the most aromatic, are spearmint and peppermint.
In particular, true peppermint ( Mentha piperita L. ) is a natural hybrid between M. viridis L. ( green peppermint ) and M. aquatica L. This has a stoloniferous rhizome and erect, red-purple ( black peppermint ) or green ( white peppermint ) scapes, tetragonal and branched. The leaves are opposite, briefly petiolated, oval and lanceolate, glabrous, irregularly serrated at the edge, with mauve-colored veins, like the stems, and covered with a light, bright green down. The flowers, which emerge at the apex of the stems, are gathered in conical terminal spikes, which flower from the bottom upwards. During the summer it produces small flowers, white, pink or purple in color. The tetrachene is made up of four smooth cocci. Being a hybrid, it is sterile and propagates only by vegetative means. This is the most fragrant mint with a strong and penetrating flavour, a small quantity is enough to flavour dishes.
Spearmint ( M. spicata L. ) , also called sweet mint, has purple flowers, rounded, hairless leaves of a bright green-grey colour and a very fragrant appearance.
Cultivation (Mentha x piperita L.)
Mint is a herbaceous crop that can be renewed for several years, although it is preferable to have a duration of no more than two years due to the difficulty of controlling weeds. It has a notable tendency to produce suckers, which makes inter-row work difficult; a technique used in the USA involves, at the end of the first year, in autumn, burying the plants with superficial ploughing so as to have a lawn with less stolon formation in the following year. For these problems, some recommend annual cultivation, since, even if the costs of planting increase, it is possible to reduce the high use of manpower by mechanising the uprooting of stolons and subsequent transplanting. Soil preparation involves ploughing 30-35 cm and possibly burying a good amount of manure, followed by preparing the seedbed. The crop is particularly demanding in potassium and nitrogen; at the time of planting, phospho-potassium fertilization is recommended with 100-120 kg/ha of P2O5, and 150-200 kg/ha of N , to be administered partly at sowing and partly as a top dressing after the first mowing. Planting can be carried out in autumn/late winter, using stolons of about 15 cm or with already formed seedlings of 5-10 cm in late spring; the use of stolons, however, ensures greater rooting. The depth of burial of the stolons is 10 cm while the optimal distances are 40-50 cm inter la and 10-15 cm inter la, in order to obtain an investment of 15-20 plants/m2. In case of dry summer, it is important to intervene with frequent irrigations, sometimes necessary after the first cut to promote a rapid recovery and guarantee a good second cut. In the early stages of cultivation it is good to keep the weeds under control and implement mechanical weeding inter la as far as possible; among the most problematic weeds there is Artemisia verlotorum, which has stolons similar to those of mint and therefore easily confused at the time of planting. A remedy for a more effective control in new plants is propagation by means of leafy seedlings. The balsamic time for harvesting varies according to the destination of the production: for herbal medicine before flowering while for distillation, in full bloom..
Plant organs used
The tops and leaves are used.
Chemical composition and active ingredients
Peppermint oil contains approximately 85 substances; the main component is menthol (50-60{65f2e28177c94f2951789cdb189ff701d60484d918a169e513d16f7e82a02d40}), followed by menthone (5-30{65f2e28177c94f2951789cdb189ff701d60484d918a169e513d16f7e82a02d40}), esters (5-10{65f2e28177c94f2951789cdb189ff701d60484d918a169e513d16f7e82a02d40}), small quantities of cineole and other terpenes.
Properties and uses
Medicinal uses
Peppermint oil, obtained by distilling the freshly picked tops of peppermint, reduces the contraction of several spasmogenic substances, such as acetylcholine, histamine, serotonin and substance P; this oil acts by relaxing the gastrointestinal smooth muscles and inhibits the excitability of the enteric nerves. For these reasons it can be used for colic of the upper gastrointestinal tract, of the biliary tract and for irritable bowel syndrome (IBS).
The essential oil also has decongestant and balsamic properties and is used in inhalation preparations and balsamic drops.
Veterinary uses
The decoction prepared with the leaves is used to rub the fur of animals for anti-parasitic purposes.
Food uses
The fresh or dried leaves are used to flavor various dishes, including risottos, salads and fruit salads; they are even added to tea to give a delicate and characteristic flavor.
