Stinging hairs

Main actives The fresh leaves and stems are rich in vitamins A and C and iron. They also contain histamine, serotonin, acetylcholine and formic acid in the stinging hairs. The dried herb contains Flavonoids (0.7-1.8%) including rutin and iso-quercitrin, silicic acid (1-5%), a trace of volatile oil and potassium and nitrate ions. 

Mechanical protection is provided by thorns, spikes, trichomes, glandular hairs, and stinging hairs (which are often supported by defense... 

Several plants produce compounds which are identical to animal neurotransmitters, such as acetylcholine and histamine in stinging hairs of Urtica, or serotonin and dopamine in several other species (Tables 3-9). That these compounds can serve as receptor agonists is apparent. Furthermore, quite a number of alkaloids are known whose structures share obvious structural elements with endogenous neurotransmitters (compare neurotransmitters in scheme I with alkaloids in II) and could thus function as structural analogues. If the three dimensional structure of the corresponding receptor or protein were known, the methodology of molecular modeling could be employed. This approach was not in the... 

Formic acid—HCO,OH—46—occurs in the acid secretion of red ants, in the stinging hairs of certain insects, in the blood, urine, bile, perspiration, and muscular fluid of man, in the stinging-nettle, and in the leaves of trees of the pine family. It is produced in a number of reactions by the oxidation of many organic substances sugar, starch, flbrin, gelatin, albumin, etc. by the action of potash upon chloroform and kindred bodies by the action of mineral acids in hydrocyanic acid during the fermentation of diabetic urine by the direct union of carbon mon-... 

Fu, H.Y., S.J. Chen, R.F. Chen, et al. 2006. Identification of oxalic acid and tartaric acid as major persistent pain-inducing toxins in the stinging hairs of the nettle, Urtica thunbergiana. Ann. Bot. 98(l) 57-65. 

Stinging hairs >KryHHe bojiockh Two-horned /IBypOXHH... 

Histamine (11) and serotonin (3) are found in the stinging hairs of several species such as Cnidoscolus texams (Eu-phorbiaceae), Mucuna pruriens (Fabaceae), and Urtica di-oica (Urticaceae), as well as vegetative materials of Cnidoscolus urens, and fruits of the banana, Musa sapentium (Lookadoo and Pollard, 1991 Seigler and Bloomfield, unpublished data Smith, 1980). 

Figure 7.5. Photomicrograph of the stinging hair of nettle. [Her (1) by permission of Cornell University Press.]. -i .

Without silica, nettles do not develop the ability to sting. Barber and Shone (112b) described experiments in which the nettle Urticaria dioica was grown in a culture solution nominally free of silica. The leaves showed little stinging ability. Then a solution of silica was added to the culture medium and in 2 weeks the stinging hairs... 

Description. Members of the l/rfrca species are perennials that reproduce from seeds and spread from undeigiomd rootstocks therefore, they tend to cx cur in contiguoiE patches. The plants may grow as tall as 1.5 meters, and the opposite leaves and stems are covered with stinging hairs that release acetylcholine (ACh), histamine, serotonin, and formic acid. 

Herbaceous perennial up to 30-150 cm, monoecious or dioecious, stems four angled leaves and stems with stinging hairs leaves opposite, ovate to cordate oblong-lanceolate, serrate flowers green, in axillary panicles June to September found in waste places, moist thickets, fields, pastures most of North America and Europe. ... 

Fresh plants sting on contact, due to amines in bladder-like base of stinging hairs. Upon contact, the hair tip breaks off, injecting the amines and folic acid into the skin. Burning sensation may last for up to 1 h (foster and CARAS). 

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