Salicylic acid is a derivative of a carboxylic acid, composed of a phenolic ring and a carboxylic group. The simultaneous presence of an acid function (given by the carboxyl group) and a phenolic one, gives this molecule remarkable antirheumatic, as well as anti-inflammatory and anti-inflammatory properties .
Willow extracts are used since ancient times for their healing properties. At the end of the nineteenth century numerous researches on willow extracts lead to synthesis in the laboratory, by acetylation of salicylic acid, of aspirin; the pharmaceutical product owes its name to Spirea sp., another plant from which salicylic acid is derived.
Where is the salicylic acid
Salicylic acid is contained in various plants such as Salix alba L. and Filipendula ulmaria (L.) Maxim. also known by the synonym of Spirea ulmaria L.
The willow is an arboreal plant that can reach 9-10 m in height and in some cases exceed 25 m; the stem is very large, but short, and has a very large and oval-shaped crown below which there are hanging branches. The latter, very often, tend to reach the ground too. The elongated leaves are spirally arranged, bright green, tending to gray on the lower page. Willow is a dioecious plant with male and female inflorescences carried by different trees.
Willow has been used since ancient times for its therapeutic properties. In the I sec. BC Pliny the Elder attributed to the leaves the property of containing sexual intemperance. In the 12th century Hildegard von Bingen used flowers and leaves to combat insomnia, menstrual pain and spasms. Mattioli, a Renaissance physician, used the leaves against insomnia, as a painkiller and to promote healing.
The queen of the meadows or olmaria is a perennial herbaceous plant, 60 to 150 cm tall and grows in damp and marshy environments. The leaves are pinnate dark green on the upper pages and silver on the lower one. The rigid and erect stems support whitish inflorescences with small and very fragrant flowers.
Other plants that contain salicylates are Gaultheria procumbens L., a shrub native to Nor America; Viola tricolor L., also known as pansy; Fragaria vesca L., or wild strawberry and birch, Betula alba L ..
You can learn more about the properties and contraindications of spirea
Properties of salicylic acid
All the properties of willow known since ancient times can be traced back to its active ingredient, salicylic acid.
A glucoside, salicin, is extracted from the bark of the willow. Once assumed, it is metabolised by the intestinal flora into saligenin and the liver into salicylic acid. Because of these transformations, the time to reach the therapeutic index and the duration of the same are superior compared to synthetic salicylates.
Despite the therapeutic dose is rarely achieved with herbal willow extracts and with the recommended doses, willow is useful for antirheumatic and anti-inflammatory action. The use is recommended in case of osteo-articular inflammation, myalgia and neuralgia .
Willow extracts are present in various herbal preparations also for the febrifugal and anti-fever action .
For external use willow extracts are used, for example, in the treatment of acne as anti-inflammatory and healing .
Contraindications of salicylic acid
Willow extracts are contraindicated in case of allergy to salicylates and people allergic to aspirin should avoid its use.
In addition, extracts can cause problems in the stomach such as nausea, irritation, vomiting and gastrointestinal haemorrhage. This toxicity is to be considered minor in the case of intake of willow salicylates compared to aspirin, due to the lower concentration of salicylates in herbal preparations.
Finally, to avoid the simultaneous intake of willow extracts with synthetic or herbal drugs, antiplatelet agents and anticoagulants for possible interactions.