Alnus glutinosa / Zwarte els

Takken
: Jonge takken en knoppen zijn kleverig en kaal. De gesteelde knoppen zijn paarsachtig.
Bladeren: De tot 10 cm lange bladeren zijn vrijwel rond tot omgekeerd eirond, met de grootste breedte in of boven het midden. Ze zijn ongelijk gezaagd en meestal met een wigvormige voet en een afgeronde stompe of iets ingesneden top. Er zijn 5 tot 8 paar zijnerven. Van onderen zijn ze alleen in de nerfoksels behaard.
Bloemen: Mannelijke katjes zijn geel, de vrouwelijke roodbruin. De steel is 1 tot 3 cm. Ze groeien aan dezelfde takken. De bloemen verschijnen eerder dan de bladeren.
Vruchten: De elzenproppen zijn gesteeld, kegelachtig en verhouten. De zaden zijn niet of nauwelijks gevleugeld.


Volgens de Flora Batava Plaat 305 in deel IV
Huishoudelijk Gebruik.
Het hout tot zeer veel werk, vooral van Draaijers dienstig. Het wordt zeer hard onder het water, en is hierom bijzonder tot palen geschikt. Op zulke palen is het grootste gedeelte van Venetiën gebouwd. (Mattuschka) De uitgeholde Stam diende aan de ouden tot schuiten. De knoesten en het wortelhout geven fraai geaderd hout tot inleggen. Het levert ook uitnemend goed brandhout op. Sommigen willen, dat in dit hout zich nimmer weegluizen onthouden. De versch geplukte Bladen weren de vlooijen. Houttuijn. Men kan uit den stam in de Lente een verfrisschend sap winnen, even goed om te gebruiken als van den Berk (Miller). De Schors verwt het garen bruin, en met bluswater der smeden, zwart. Een aftreksel der Vrucht, waarbij koperrood is gevoegd, geeft goede inkt (Mattuschka, Houttuijn). De Bladen worden in Lapland in den Herfst vergaderd en gedroogd tot wintervoeder voor Runderen en Schapen. (Gunner) Al het Vee, behalve Varkens, eten de Bladen (LInn. Pan Suecus). — De Zaden welke men wil inzamelen, moeten in het najaar ingewonnen worden, daar zij later ligt uit de Kegelvrucht vallen. Zij moeten volstrekt op eene belommerde plaats gezaaid worden. (Miller).


Medicinal Uses
Alterative;  Astringent;  Cathartic;  Emetic;  Febrifuge;  Galactogogue;  Haemostatic;  Parasiticide;  Skin;  Tonic;  Vermifuge.

The bark is alterative, astringent, cathartic, febrifuge and tonic. The fresh bark will cause vomiting, so use dried bark for all but emetic purposes. A decoction of the dried bark is used to bathe swellings and inflammations, especially of the mouth and throat. The powdered bark and the leaves have been used as an internal astringent and tonic, whilst the bark has also been used as an internal and external haemostatic against haemorrhage[21]. The dried bark of young twigs are used, or the inner bark of branches 2 - 3 years old. It is harvested in the spring and dried for later use. Boiling the inner bark in vinegar produces a useful wash to treat lice and a range of skin problems such as scabies and scabs. The liquid can also be used as a toothwash. The leaves are astringent, galactogogue and vermifuge. They are used to help reduce breast engorgement in nursing mothers. A decoction of the leaves is used in folk remedies for treating cancer of the breast, duodenum, oesophagus, face, pylorus, pancreas, rectum, throat, tongue, and uterus[269]. The leaves are harvested in the summer and used fresh.

Other Uses
Charcoal;  Dye;  Hedge;  Hedge;  Ink;  Insecticide;  Parasiticide;  Pioneer;  Shelterbelt;  Soil reclamation;  Tannin;  Teeth;  Wood.

Tolerant of clipping and maritime exposure, the alder can be grown in a windbreak or a hedge[75]. The trees are very quick to establish[200] and will grow at a rate of 1 metre or more per year when young[K]. This is an excellent pioneer species for re-establishing woodlands on disused farmland, difficult sites etc. Its fast rate of growth means that it quickly provides sheltered conditions to allow more permanent woodland trees to become established. In addition, bacteria on the roots fix atmospheric nitrogen - whilst this enables the tree to grow well in quite poor soils it also makes some of this nitrogen available to other plants growing nearby. Alder trees also have a heavy leaf canopy and when the leaves fall in the autumn they help to build up the humus content of the soil. Alder seedlings do not compete well in shady woodland conditions and so this species gradually dies out as the other trees become established[K]. Because they tolerate very poor soils and also produce nitrogen nodules on their roots, alders are suitable for use in land reclamation schemes. 
The plants can be used as a source of biomass[269]. According to the phytomass files, annual productivity is estimated at 6 to 9 tonnes per hectare. The tree has yielded 11.8 tonnes per hectare per annum on pulverized fuel ash and annual productivity has been estimated at 8.66 tonnes per hectare, with 5.87 tonnes in wood, bark, and branches, 2.79 tonnes in foliage[269]. Alder has been recommended for consideration for firewood plantations in Tropical highlands where unseasonable cold might destroy the red alder. 

The powdered bark has been used as an ingredient of toothpastes. Sticks of the bark have been chewed as tooth cleaners[9]. An ink and a tawny-red dye are obtained from the bark. A green dye is obtained from the catkins. A pinkish-fawn dye is obtained from the fresh green wood[4, 6, 66]. A yellow dye is obtained from the bark and young shoots. A cinnamon dye is obtained from the shoots if they are harvested in March[4]. If they are dried and powdered then the colour will be a tawny shade[4]. The bark and the fruits contain up to 20% tannin, but they also contain so much dyestuff (imparting a dark red shade) that this limits their usefulness. The leaves are also a good source of tannin[4]. The leaves are clammy and, if spread in a room, are said to catch fleas and flies on their glutinous surface[4, 7]. Wood - very durable in water, elastic, soft, fairly light, easily worked, easily split. It is often used for situations where it has to remain underwater and is also used for furniture, pencils, bowls, woodcuts, clogs etc. It is much valued by cabinet makers. The wood also makes a good charcoal


The wood is much used. When young it is brittle and very easily worked. When more mature it is tinted and veined; in the Highlands of Scotland it is used for making handsome chairs, and is known as Scottish mahogany. It has the quality of long endurance under water, and so is valuable for pumps, troughs, sluices, and particularly for piles, for which purpose it is said to have been used in sixteenth-century Venice and widely in France and Holland. The roots and knots furnish good material for cabinet-makers, and for the clogs of Lancashire mill-towns and the south of Scotland the demand exceeds the supply, and birch has to be used instead. It is also used for cart and spinning wheels, bowls, spoons, wooden heels, herring-barrel staves, etc. On the Continent it is largely used for cigar-boxes, for which its reddish, cedar-like wood is well adapted. After lying in bogs the wood has the colour but not the hardness of ebony. The branches make good charcoal, which is valuable for making gunpowder.

The bark is used by dyers, tanners, leather dressers, and for fishermen's nets.

---Dyeing---The bark is used as a foundation for blacks, with the addition of copperas. Alone, it dyes woollens a reddish colour (Aldine Red). The Laplanders chew it, and dye leathern garments with their saliva. An ounce dried and powdered, boiled in three-quarters of a pint of water with an equal amount of logwood, with solution of copper, tin, and bismuth, 6 grains of each, and 2 drops of iron vitriol, will dye a deep boue de Paris.
Both bark and young shoots dye yellow, and with a little copper as a yellowish-grey, useful in the half-tints and shadows of flesh in tapestry. The shoots cut in March will dye cinnamon, and if dried and powdered a tawny shade. The fresh wood yields a pinkish-fawn dye, and the catkins a green.
The leaves have been used in tanning leather. They are clammy, and if spread in a room are said to catch fleas on their glutinous surface.

---Constituents---The bark and young shoots contain from 16 to 20 per cent of tannic acid, but so much colouring matter that they are not very useful for tanning. This tannin differs from that of galls and oak-bark, and does not yield glucose when acted upon by sulphuric acid, which, it is stated, resolves it into almine red and sugar.

---Medicinal Action and Uses---Tonic and astringent. A decoction of the bark is useful to bathe swellings and inflammations, especially of the throat, and has been known to cure ague.

Peasants on the Alps are reported to be frequently cured of rheumatism by being covered with bags full of the heated leaves.
Horses, cows, sheep and goats are said to eat it, but swine refuse it. Some state that it is bad for horses, as it turns their tongues black.


 Pharmacogn Rev. 2011 Jul-Dec; 5(10): 174–183. Bioactive constituents and medicinal importance of genus Alnus
Sushil Chandra Sati, Nitin Sati,1 and O. P. Satihttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263052/

The genus Alnus has been reviewed for its chemical constituents and biological activities including traditional importance of some common species. The plants of this genus contain terpenoids, flavonoids, diarylheptanoids, phenols, steroids, and tannins. Diarylheptanoids are the dominant constituents within the genus Alnus, few of them exhibited antioxidant effects and inhibitory activity against nuclear factor kappaB activation, nitric oxide and tumor necrosis factor-α production, human umbilical vein endothelial cells, farnesyl protein transferase, cell-mediated low-density lipoprotein oxidation, HIF-1 in AGS cells, and the HIV-1-induced cytopathic effect in MT-4 cells. Some ellagitannines showed hepatoprotective activity even in a dose of 1 mg/kg which is ten-fold smaller compared with the dose of traditional flavonoid-based drugs. The members of genus Alnus are well known for their traditional uses in the treatment of various diseases like cancer, hepatitis, inflammation of uterus, uterine cancer, rheumatism, dysentery, stomachache, diarrhea, fever, etc. The aim of the present review is to summarize the various researches related to the chemistry and pharmacology of genus Alnus.

TRADITIONAL USES OF ALNUS SPECIES

The members of genus Alnus are well known for their traditional medicinal values. These have been used for the treatment of various diseases including cancer and as an alterative, astringent, cathartic, emetic, febrifuge, galactogogue, hemostatic, parasiticide, skin tonic, vermifuge, etc. Alnus japonica is a popular folk medicine in Korea for cancer and hepatitis.[3] The bark of Alnus glutinosa is alterative, astringent, cathartic, febrifuge, tonic, and useful in mouth and throat inflammations, the vinegar extract of inner bark of plant produces a useful wash to treat lice and a range of skin problems such as scabies and scabs.[46] The leaf, roots, and bark of A. nepalensis are used in dysentery, stomach ache, and diarrhea in Indian system of medicine (Ayurveda).[7] A decoction of the root of A. nepalensis is prescribed to treat diarrhea and paste from the leaves is applied on cuts and wounds as a hemostatic.[8] The mixture of leaves of Alnus jorullensis and branches of Polylepis racemosa R. et P is used to treat inflammation of uterus, uterine cancer, and rheumatism.[9] The bark of Alnus hirsuta is used in Korean and Chinese traditional medicine as remedies for fever, hemorrhage, alcoholism, and diarrhea.[10,11] The decoction of A. glutinosa barks is used to treat swelling, inflammation, and rheumatism.[12] It has also been used as an astringent, bitter, emetic, and hemostatic, and for the treatment of sore throat and pharyngitis.[13,14] Contemporary indigenous healers used the bark of Alnus rubra for various medicinal teas.[15,16]

Hepatoprotective activity
Buniatian et al. studied hepatoprotective properties of altan (obtained on the basis of ellagitannines from the cones of black alder A. glutinosa) on the model of acute liver damage induced with tetrachloromethane. It was found that altan exhibits the hepatoprotective activity even in a dose of 1 mg/kg which is ten-fold smaller than the dose of traditional flavonoid-based drugs. Altan limits choleopoiesis disorder, has an anti-inflammatory and membrane stabilizing effect, and recovers physiological antioxidant system.  Buniatian ND, Chikitkina VV, Iakovleva LV. The hepatoprotective action of ellagotannins. Eksp Klin Farmakol. 1998;61:53–5. [PubMed]

Antimicrobial activities
Middleton et al. (2005) tested antibacterial activity of A. glutinosa. The MeOH extract was found to be active against the following eight bacterial species: Citrobacter freundii NCTC 9750, Escherichia coli NCIMB 8110, Escherichia coli NCIMB 4174, Klebsiella aerogenes NCTC 9528, Lactobacillus plantarum NCIMB 6376, Pseudomonas aeruginosa NCTC 6750, Staphylococcus aureus NCTC 10788, and Staphylococcus aureus NCTC 11940 (MRSA), the most potent activity was against E. coli (NCIMB 8110) with an MIC value of 1.25 × 10-1 mg/ml. Despite the high MIC value against MRSA (1.00 mg/ml), this finding could be considered significant, at least qualitatively, because this activity was not due to a purified compound, but due to crude extract.[14] In 1995, Saxena et al. tested the antimicrobial activity of methanol extract of the bark of A. rubra against Gram-positive and Gram-negative bacteria. Diarylheptanoid and its glycoside (oregonin) were identified as the two constituents responsible for this activity.
 Saxena G, Farmer S, Hancok RE, Towers GH. Antimicrobial compounds from Alnus rubra. Int J Pharmacogn. 1995;33:33–6.

General toxicity
n-Hexane, DCM, and MeOH extracts of A. glutinosa were tested for general toxicity using the brine shrimp lethality assay by Middleton et al. in 2005. All three extracts of A. glutinosa showed low levels of toxicity toward brine shrimps (LD50 values were in the range of 1.29 × 10-1 to 8.30 × 10-1 mg/ml). Middleton P, Stewart F, Al-Qahtani S, Egan P, Rourke C, Abdulrahman A, et al. Antioxidant, antibacterial activities and general toxicity of Alnus glutinosa, Fraxinus excelsior and Papaver rhoeas.Iran J Pharm Res. 2005;2:81–6.
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