Monograph
Comfrey - Symphytum officinale L.
Boraginaceae
Date: February 18, 2014 Posted by: Dafydd Monks
Common Names
Comfrey, Knitbone, Boneset, Knitback, Consound, Blackwort,
Bruisewort, Slippery Root, Gum Plant, Ass Ear. Llysiau'r cwlwm (Welsh)
Reinweld (German), Grande consoude (French).
Description
A strongly robust
branching perennial with many long (~25 cm)
tongue shaped leaves emerging from a substantial fleshy rootstock,
comfrey grows up to 120cm in height. It is a hairy plant: the leaves,
and especially the stems are roughly hairy; these hairs may be
irritant. The leaves are decurrently ‘winged’, blending into the stem;
these wings are visible as far down the stem as the next leaf junction.
This winging can clearly be seen in the illustration above. The leaves
decrease in size the further up the stem they grow, and the stems
terminate in one-sided clusters of drooping flowers, either creamy
white to yellow, or purple, growing on short stalks. The flowers have
long pointed calyx teeth, and have bell-shaped corollas. Symphytum
officinale is frequently found in damp places such as ditches and
riverbanks, and is common in England, Wales and Lowland Scotland, but
is rare in the highlands of Scotland and almost absent from Ireland.
Parts Used
Foliage; traditionally also the Rhizome.
Collection and Processing
Foliage: Mature leaves should be collected
throughout the
summer, avoiding the early leaves which are high in Pyrrolizidine
Alkaloids
Rhizomes: The rhizomes and roots should be unearthed
and dried in the
autumn after the plant has died down. It is at this point that the
Allantoin and Inulin levels are highest.
Constituents
Foliage: Mucilage, tannin, allantoin,
Pyrrolizidine Alkaloide
including symphytine, echinidine. Vitamin B12
Rhizomes: around 29%
mucilage (polysaccharides of fructose and glucose), phytosterols,
triterpenoid (isobauerenol), phenolic compounds (including caffeic,
chlorogenic and lithospermic acids), tannin, asparagine, pyrrolizidine
alkaloids (including symphytine, cynoglossine, consolidine), inulin,
silicic acid.
Actions
Foliage: Demulcent, anti-inflammatory,
vulnerary,
antirheumatic, antihaemorrhagic.
Rhizomes: Demulcent, vulnerary, antihaemorrhagic,
cell-proliferant,
astringent, expectorant.
Indications
Foliage: Topically; applied, and most known as an ointment or
poultice for sprains, strains and bruising. Internally; Arthritis,
Rheumatic Pain, Gastric Ulcers
Rhizomes: Topically; applied and most known as an ointment for sprains,
fractures, strains, herniae and ulceration.
Therapeutics
Symphytum is well known for its impressive tissue-healing
actions: it is a wound healer, specifically effective in encouraging
wounds and ulcers which will not ‘knit’ back together to form
granulation tissue and close. This action has a down-side however; care
must be taken to ensure that infected wounds do not ‘scab over’ before
the infection has been removed. Failure to do this can result in the
formation of abscesses. Another area in which Symphytum demonstrates a
considerable action to improve tissue integrity is in broken bones,
sprained ligaments and arthritis: Symphytum has been shown to increase
the density of remodelled bone, and to improve the osseointegration of
metal implants into bone tissue, even when low doses are administered.
These attributes have been linked to the presence of Allantoin which is
a cell proliferating agent.
The tissue healing actions of Allantoin lead to Symphytum (both foliage
and rhizomes) being used to treat gastric ulcers of the stomach and
duodenum, however internal use is questioned by the presence of
Pyrrolizidine Alkaloids which are stated to be hepatotoxic.
Dosage
Foliage:
GSL Schedule 1 (Unrestricted).
Fluid Extract: 1:1, 25% alcohol. 2 - 8ml daily.
Rhizomes:
GSL Schedule 2 (External Use Only)
2 – 4 g by decoction
Fluid Extract: 1:1, 25% alcohol. 2- 4 ml daily.
Ointment: 5 – 20% Dried Herb or dried root by weight. Commission E
suggest that daily applied dosage should not exceed 100 mcg of
pyrrolizidine alkaloids with a 1,2-unsaturated necine structure
(including N-oxides).
Further Reading