|Leaves and mature fruits in July|
Coriaria myrtifolia, called in English redoul, is a shrub to 2–3 m tall. Myrtifolia means myrtle-like leaves.
The fruit is a fleshy black berry achene slightly similar to a blackberry but toxic. Coriaria myrtifolia has the largest fruits in the genus Coriaria. It is especially dangerous for children, who may eat it if they confuse it with edible berries. Coriaria myrtifolia should be recognized as one of the most neurotoxic plants in the western Mediterranean area.
Geographically, this species is confined to northern Mediterranean coastal Spain and Southern France (from the Gironde to the Alpes Maritimes), penetrating into Italy as far as part of the Apennines. The species reappears in the western Rif and Algeria, and in the Balearic islands it appears only in Ibiza. The oldest known mention of this plant, dating from 932, is in a place name and implies its presence in the County of Manresa, north-west of Barcelona.
In all this range, this plant plays an important role in preventing soil erosion and serves as understory vegetation. It is extraordinarily abundant in the less dense woodlands of the Spanish provinces of Girona and Barcelona (eastern part) at altitudes of 200–600 m., reaching occasionally to 1,000 m.
The Spanish name emborrachacabras (i.e. getting goats drunk) refers to the leaves' intoxicating effect on goats that eat them. The French name is (Corroyère à feuilles de myrte). The Occitan name (rodor) and Catalan name (roldor) derive from Latin Rhus tyrius (Syrian or Tyrian sumac), referring to the leaves' use in the traditional tannery industry.
The Redoul is a shrub with branches greyish square section. The leaves are sessile, mostly opposite but sometimes in groups of three or more, oblong, acuminate, with three ribs. The small greenish flowers, which appear from April to June in racemes, have five reddish highlights styles, five sepals and five petals, with ten stamens. The black fruits are formed of five fleshy carpels, each containing one seed.
Toxic effects are characterized by digestive (nausea, vomiting, abdominal pain), neurological (obnubilation, convulsions and their complications), and respiratory disorders (polypnea, respiratory problems, apnea, short and superficial respiration) together with myositis of the pupils. Treatment of this poisoning is purely symptomatic. In the case of convulsions, rapid resuscitation in an intensive care unit is necessary. Coriamyrtin also has a pharmacological action.
Traditionally, leaves of redoul were intensively collected for their tannin content, for tanning and dyeing purposes. During the medieval period, ecclesiastical institutions and the aristocracy clearly sought to establish some royalties on this resource, the samples are being especially on the distribution and sale of material first. These uses are due to the wealth of Coriaria spp tannin, particularly concentrated in the root and the bark of the stem, but also present in leaves, where they coexist with yellow dyes from the chemical group of flavonoids. These tannins are part of the group of hydrolyzable tannins, such as gall tannins. The chemical composition of redoul thus makes a tanning substance, capable of transforming recently flayed animal skins into leather, which is then rot resistant, flexible and relatively impermeable. These properties allow for its widespread use in many industries. Moreover, the well-known chemical reaction of tannins with iron salts, producing black precipitates, is the basis for the manufacture of some inks used since the Middle Ages, and is also used to dye a variety of textiles black or gray. Until the mid-fourteenth century, the material was the subject of extensive trade between the north of Catalonia and Languedoc.
- "Pericarp anatomy and evolution inCoriaria (Coriariaceae)".
- Pommier, Philip (November 2005). "Editorial". Poisoning by Coriaria myrtifolia Linnaeus: a new case report and review of the literature. 46 (6): 600–603. doi:10.1016/j.toxicon.2005.06.026. Retrieved November 2005. Check date values in:
- « In comitatum Manresa, in terminio de Kastro Rosetorium... », F. Udina Martorell, El Archivo condal de Barcelona en los siglos ix-x. Estudio crítico de sus fondos, Barcelona, 1951, p. 204, § 104.
- "Root Nodules of Coriaria".
- "Fixation of Nitrogen in Coriaria myrtifolia".
- E. SWANSON, EDWARD (August 1936). "pharmacology". THE PHARMACOLOGICAL ACTION OF CORIAMYRTIN. 57 (4): 410–418. Retrieved August 1936. Check date values in:
- Tanaka, Kiyoshi (September 1982). "coriamyrtin". Stereocontrolled total synthesis of (.+-.)-coriamyrtin. 57 (4): 410–418. doi:10.1021/ja00382a047. Retrieved September 1982. Check date values in:
- "[Acute intoxication by redoul (Coriaria myrtifolia L.). Three observations]". Presse Med. 31 (33): 1554–6. October 2002. PMID 12422481.
- Vieitez, Ernesto (Nov–Dec 1950). "PalynologicalObservations". Palynological Observations on Some Spanish Honeys. 77 (6): 495–502. doi:10.1021/ja00382a047. Retrieved Nov–Dec 1950. Check date values in:
- "Le redoul, herbe des tanneurs et des teinturiers. Collecte, commercialisation et utilisations d'une plante sauvage dans l'espace méridional (xiiie-xve siècles)".
- "El sector de la planta ornamental en la Península Ibérica" (PDF).