FRANGULA ALNUS: CHARACTERISTICS, HABITAT AND PROPERTIES - BIOLOGY - 2025

Frangula alnus is the scientific name to designate the plant with common names arraclán, frangula, hazelnut, among others. It is a small deciduous tree or shrub, with characteristic branches that are apparently stained.

The Frangula alnus is a plant that reaches between 3 to 6 meters in height; It grows in humid areas of acidic and neutral soils in Europe, North Africa, Asia and exists as an introduced species in North America, where it is considered an exotic, alien and invasive species.

Figure 1. Detail of the Frangula alnus plant showing the leaves, young (red) and mature (black) fruits and lenticels on branches. Source: Sten Porse, from Wikimedia Commons

characteristics

Frangula alnus is a plant with a shrubby habit, upright branches, that does not have thorns. It blooms in the intermediate period between the end of spring and the beginning of summer, from April to July.

Stem

The stem is bare, the branches are presented in alternate pairs at acute angles (less than 90 ^or) with respect to the main stem. The bark of the stem is distinguished by having protrusions that look like spots from a distance, called lenticels.

Lenticels are small structures, elongated or circular, observable with the naked eye, that are present as protrusions on stems, trunks and branches of some plant species.

These protrusions have a “lenticular hole” that serves as a substitute for stomata for gas exchange and the entry of oxygen required for cellular respiration.

The stem bark is green on young shoots and turns gray-brown over time.

Leaves

The leaves are bright green on the upper surface, oval in shape, alternately arranged, have petioles and stipules that detach.

They have between 7 to 11 pairs of secondary nerves, well marked, that arch towards the leaf apex and have ribs that stand out in relief on the underside. The blade is 2 to 7 cm and has an entire border. In the fall the leaves turn yellow and red.

Flower

It has small pink or light green flowers, pentamers (5 petals) and 5 triangular-shaped sepals and greenish color. Each petal wraps around a stamen.

They are hermaphroditic flowers (bisexual, that is, both sexes appear in the same flower). They have umbelliform inflorescences, in small cymes located in the axils of the leaves.

Fruit

The fruits are drupe type, spherical in shape, measuring 6 to 10 mm; They have a greenish color initially, then a red color and when they mature they turn brown. Finally, they turn almost black.

Habitat

The Frangula alnus species lives in soils with a high percentage of humidity and silica.

Distribution

Figure 2. Distribution of the Frangula alnus plant. Source: Giovanni Caudullo, via Wikimedia Commons

The Frangula alnus shrub is widely distributed in Europe, Asia, and in northern Africa.

In Spain the species is widely dispersed in humid forests and riverside forests, with particularly acidic soils. It is very common especially in the northern and northern half of the Iberian Peninsula.

In southern Spain it is found in the mountainous areas of the Iberian system, the Toledo mountains, the Central system, the Sierra de Cazorla and other mountain areas. It is also found in the coastal areas of Huelva and Cádiz.

In Canada and the United States, the plant is not native, but an invasive one with a high adaptive potential; it easily colonizes new habitats and is considered a species that threatens forests and native biodiversity, inhibiting the regeneration of endemic trees.

There are studies of the plant as an invasive species in the United States that report that it produces alterations in the properties and functions of the soil, generating higher mineralization rates and altering the nitrogen cycle (its leaves have high nitrogen content).

It is also reported to negatively impact the communities of native soil microorganisms.

Medicinal properties

Frangula alnus is popularly used as a purgative and cholagogue.

Cholagogues are pharmaceuticals or plant extracts that have the pharmacological property of stimulating the release of bile from the gallbladder; This action is frequently accompanied by another effect, which is to accelerate intestinal transit as purgative.

There are studies from extracts prepared with the bark of the plant that report an effective antioxidant activity and powerful antimicrobial activity. It is recommended for use as a preservative additive in the food and pharmaceutical industry, as a natural antioxidant and antimicrobial agent.

In the book Europe's medicinal and aromatic plants: their use, trade and conservation, (Lange 1998), this plant is cited within the list of the 24 most widely used plant species in Spain.

The baetic subspecies of Frangula alnus is considered vulnerable in the Red List of the Spanish Vascular Flora (2000) and in the Andalusian Catalog of threatened species (Decree 104/1994, BOJA of July 14, 1994).

Toxicity

The effects of Frangula alnus are said to be powerful and can last for several days. The fresh plant is extremely purgative and also causes nausea and vomiting.

In popular use for the treatment of constipation, extreme caution is advised, as its cytotoxic and genotoxic activity has been demonstrated.

Chemical composition

Phytochemical studies of Frangula alnus have reported in its composition the chemical compounds frangulin, glucofrangulin, fisciona, emodin, chrysophanic acid, chrysophanol, among others.

It has flavonoids, tannins and various phenols. Today, it is considered a new source of anthraquinone derivatives.

Other common names

The Frangula alnus is designated by many common names according to the particular inhabitants of a locality. Below is a list of some common names by which this plant is popularly designated.

Black alder, alno bacciferous, frangula alno, ácere, azare, baciferous, arraclan, arraclanera, arraclán, myrtle, hazelnut, hazelnut, wild hazelnut, biondo, cavicuerna, poplar, purple durillo, franguilla, frangula, frangula, gedeondoan, frond gediondo, geriondo, smelly, jediondo, ollacarana, hard stick, pudio, rabiacana, rabiacano, rabiacán, salguera, salguera del Bierzo, salguera del Vierzo, sanapudio black, sanguine, sanguine, sanguine, sangueño, sanguino, sanguiño, sangüeño, oilakaran, zumalakar.

Synonymy

There are other scientific names to designate this plant species, according to the denomination that different botanical taxonomists have assigned it:

Frangula atlantica Grubov

Frangula frangula H. Karst.

Frangula nigra Samp.

Frangula pentapetala Gilib.

Frangula vulgaris Hill

Frangula dodonei Ard.

Girtanneria frangula Neck

Rhamnus frangula L.

Rhamnus sanguino Ortega

Rhamnus baetica Willk. & Reverchon

Subspecies and varieties

Frangula alnus f. angustifolia WRFranz

Frangula alnus var. elliptica Meinhardt

Frangula alnus subsp. Gancev saxatilis

Frangula alnus subsp. sphagnicola APKhokhr.

References

1. Brkanaca, R., Gerićb, M., Gajskib, G., Vujčića, V., Garaj-Vrhovacb, V., Kremerc, D. and Domijanc, A. (2015). Toxicity and antioxidant capacity of Frangula alnus bark and its active component emodin. Regulatory Toxicology and Pharmacology. 73 (3): 923-929. doi: 10.1016 / j.yrtph.2015.09.025
2. Cunard, C. and Lee, T. (2009). Is patience a virtue? Succession, light, and the death of invasive glossy buckthorn (Frangula alnus). Biological invasions. 11 (3): 577–586.
3. De Kort, H., Mergeay, J., Jacquemyn, H., and Honnay, O. (2016). Transatlantic invasion routes and adaptive potential in North American populations of the invasive glossy buckthorn, Frangula alnus. Annals of 118 (6): 1089–1099. doi: 10.1093 / aob / mcw157
4. KremeraI, D., Kosaleca, M., Locatellib, F., Epifanob, S., Genoveseb, G., Carluccib, M. and Končića, K. (2012). Anthraquinone profiles, antioxidant and antimicrobial properties of Frangula rupestris (Scop.) Schur and Frangula alnus Bark. Food Chemistry. 131 (4): 1174-1180. doi: 10.1016 / j.foodchem.2011.09.094
5. Lee, TD and Thompson, JH (2012). Effects of logging history on invasion of eastern white pine forests by exotic glossy buckthorn (Frangula alnus Mill.). Forest Ecology and Management. 265 (1): 201-210. doi: 10.1016 / j.foreco.2011.10.035