Symphytum peregrinum Ledeb.
Comfrey, Russian comfrey, Quaker comfrey
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Comfrey, mainly cultivated as green forage, can be used with maize to make
ensilage. Comfrey is difficult to conserve because of the low amounts of
carbohydrates. It is also used as a green vegetable, some cooking it in two
waters and serving it with chives. Only small and medium leaves are used.
They may be boiled or steamed for 2 minutes, and then eaten in salads or with a
sauce. Comfrey is an ingredient in various herbal, pharmaceutical, and
cosmetic preparations such as creams, eyedrops, hair products, lotions, and
ointments (Leung, 1980). It is said to be antiinflammatory. The mucilage is
thought to soften the skin when used in baths. Some organic gardeners
recommend a mixture of comfrey and kudzu leaves for composting.
Plant contains allantoin, used in some face creams, or to cure scours in pigs
and calves, or give a bloom to horses. For humans, it is reported to be good
for asthma, whooping cough, stomach and duodenal ulcers and lung ailments.
Gerard's herbal is quoted in the New Scientist (July 15, 1976, p. 14.) on
multicolored Comfrey, variously known as Abraham, Isaac and Jacob, Pigweed,
Suckers or Church Bells. "The slimie substance of the roote made in a posset
of ale and given to drink against the pain in the backe gotten by any violent
motion such as wrastling or overmuch use of women, doth in foure or five days
perfectly cure the same, although involuntarie flowing of seed in men be gotten
thereby." Comfrey is said to be alterative, astringent, demulcent, emollient,
expectorant, hemostat, nutritive, and vulnerary. The root decoction is used as
a mouthwash or gargle for asthma, bleeding gums, hoarseness, sore throat and
stomatitis. It is also used for arthritis, bronchitis, bloody urine, cough,
dysentery, dysmenorrhea, enterorrhagia, gallstones, gastritis, hematochezia,
hematuria, hemoptysis, internal ulcers, leucorrhea, metrorrhagia, scrofula,
tonsilitis, and ulcers of the kidney. In a vague reference Hutchens (1973)
quotes S. Clymer (1963) "Numerous uncontradicted reports of lung cancer cured
where all other means have failed and in which the sole treatment consisted of
infusion made from the whole green plant and, even in some instances, of
infusion made from the powder of the entire plant." Interestingly, comfrey does
contain b-sitosterol which shows anticancer activity against the Lewis Lung
Carcinoma Adenocarcinoma 755 and Walker Carcinosarcoma 256 tumor systems.
Homeopathically, comfrey is prescribed for abscess, bone cancer, breast,
enlarged glands, eye pain, fracture, gunshot wounds, hernia, menstrual arrest,
sexual abscess, sprains and wounds (Hutchens, 1973). Allantoin, present in
comfrey leaves and roots is said to be a cell proliferant, making the edges of
wounds grow together and healing sores.
Per 100 g, comfrey is said to contain 0.5 mg thiamine, 1.0 mg riboflavin, 5.0
nicotinic acid, 4.2 mg pantothenic acid, 0.07 mg Vit. B12 (rare in vegetarian
diet), 28,000 IU Vit. A, 100 mg Vit. C, 30 mg Vit. E and 0.18 mg allantoin.
So-called Russian comfrey (84.93% water) contains (ZMB) 22.73% CP, 5.39% EE,
4.22% NFE, 21.25% ash, 5.35% silica, 2.02% Ca, and 0.57% P. Based on 16
analyses, prickly comfrey (83.1 to 89.8% H2O) contained (ZMB): 1623%
protein, 1.02.8% EE, 11.918.2% CF, 12.422.1% ash, and 43.249.1% NFE. The
root contains 0.75 to 2.55% allantoin and about 0.3% alkaloids (symphytine,
echimidine), lithospermic acid (said to be antigonadotrophic), 29%
mucopolysaccharide (of glucose and fructose). There is a gum consisting of
L(-)-xylose, L-rhamnose, L-arabinose, D-mannose, and D-glucuronic acid. Also
reported are 2.4% pyrocatechol tannins, 0.65% carotene, glycosides,
isobauerenol, b-sitosterol, stigmasterol, steroidal saponins, triterpenoids,
(e.g. isobanerenol), choline, consolidine, silicic acid, lasiocarpine,
viridiflorine, echinatine, and heliosupine-N-oxide (List and Horhammer,
19691979). According to Morton (1975), "Comfrey (Symphytum officinale
L.) has considerable tannin in the leaves and the infusion of the dried
leaves is very astringent. Comfrey root possesses 2.4% tannin...used in
Germany for tanning leather. The above-ground plant contains the alkaloid
lasiocarpine...consolidine and the N-oxide of heliosupine. Additional
alkaloids have been found in the root... The acid fraction of an aqueous
extract of the plant has shown antigonadotrophic activity in mice." According
to Cancer Treatment Reports (1976; p. 1176), tannin-containing extracts from
several plants produced either sarcomas or liver tumors. Tannic acid is
hepatotoxic and several workers report that tannic acid or tannin extracts from
plants were oncogenic in animals. On p. 1183, lasiocarpine is reported
as an oncogenic compound. Based on these Cancer Treatment Reports, one might
conclude that comfrey contains two oncogenic or tumor-inducing substances.
Perennial, shrubby herb, with powerful mucilaginous roots that go down to a
depth of 22.5 m; basal leaves lush, forming a rosette the first year, 30100
cm long; stem-leaves hairy, petioled, broad pointed, often up to 5 cm in
length, rough-textured, on succulent, grooved stems; inflorescence tall,
terminal cyme, up to 1.3 m tall (to 3 m tall on good rich soils); flowers
magenta-pink, or blue, bell-shaped; plant usually does not set seed.
Several vegetable strains of comfrey are known, the best cvs being 'Webster
Strain' and 'Backing No. 14'. Some horticulture cvs are yellow-variegated or
with yellow-margined leaves. (2n = 36)
Native to the Caucasus, Russia and Persia, where it grows up to 1350 m
elevation. Introduced and cultivated in England, United States, Canada
(British Columbia), Kenya, North Rhodesia, New Zealand, Australia.
Comfrey is suitable for the temperate and subtropical regions. It will grow
and produce where many other forage plants will not. Almost any soil that
allows deep root penetration (to about 2.5 m) will grow comfrey. The crop
needs lots of water, and will stand flooding. Manures and fertilizers,
particularly potash, should be added to the soil. Comfrey will grow in partial
shade. The above-ground foliage will stand 15° of frost for a short time,
and the roots will stand winter temperatures of -40°C. In the Crop
Diversification Matrix, comfrey is reported to range from the Boreal Moist
Forest Life Zone to the Warm Temperate Moist Forest Life Zone, tolerating
annual biotemperature of 615°C, annual precipitation of 511 dm, and pH of
Propagation is mainly by divisions of the crown or root cuttings, started in
nursery beds. Comfrey usually does not produce seed, and plants obtained from
seed are very often inferior. Rooted divisions are planted out in the spring
(or in the autumn) as soon as frost does not endanger the foliage. They should
be planted in rows 1 m each way. The crop should be kept weed free until the
plants are established. After that there is no weed problem. Both mechanical
and manual techniques may be used. Irrigation may be necessary, as the plant
requires a lot of water. Fertilization of the soil is necessary to keep the
fields producing well, the fertilizer being best applied at end of April or
beginning of May, at rate of 400 kg/ha of a 5-20-20 formula. Soil should be
adjusted to pH 6.5.
Plants last about 20 years or so. However, the plants should not be allowed to
flower as they produce less, the amount of protein in the leaves is reduced and
the amount of fiber increased. The leaves should be cut about 5 cm above the
ground, the height adjusted so that neither the crown nor young shoots be
injured. A first cutting can be made some months after planting when the
plants have a good growth. A mowing machine is used. Three or four cuttings
per year are possible with well established healthy plants.
Comfrey has a reported potential of 247 MT/ha of green fodder, but the average
is usually less than that figure, about 237 MT/ha reported from England.
Australia claims up to 250 MT/ha green fodder, with 33% protein based on dry
material. Such biomass would have the energetic equivalent of 30 to 40 barrels
of oil per hectare. According to U.S. Oil Week (Sept. 17, 1979), an Oregon
company, Western Comfrey refines the plant into a 25% protein cattle feed
selling for $210 a ton. It is estimated to produce 22.5 gal alcohol/bushel
with 44% protein cattle feed as a byproduct. Agri-Fuels of Portland put up
$1.5 million to build a distillery to turn out 1 million gallons fuel grade
alcohol along with tons of rich cattle feed.
Figures available suggest that DM Yields would be in the range of 10 to 25
MT/ha/yr and that poor land, such as the types now commonly employed for
rough-grazing, could be used. The ratio of output to input energy for native
perennials is estimated at 410 times higher than in arable crops (Palz and
Chartier, 1980). Actual yields will vary considerably with conditions; soil
depth may prove to be an important parameter. In the absence of definitive
yield information, an average yield of 17.5 MT DM/ha/yr is assumed. In the
absence of experimental energy determinations, a conservative figure of 17.5
GJ/MT is also assumed. The cost of establishing the energy farm is based on a
published figure for comfrey (cost of initial establishment, spread over 10
years, with interest on the outstanding balance at 12% = $461/ha/yr), but may
be considerably less for vigorously spreading species such as Polygonum,
Pteridium, and Urtica. The likely cost is ca $2.00 to $2.50 per GJ.
If the initial planting cost could be halved, it would cost only $1.40 to $1.80
per GJ, at which level these energy sources would be competitive. As feedstock
to anaerobic digestion, perennial crops at $2.25/GJ gross thermal value would
give a feedstock cost of $3.75/GJ of product gas (without transport and
storage) and a probable minimum gas cost of $8.25 per GJ. These figures are
based also on harvesting cost of $75.00/ha (Palz and Chartier, 1980).
Grasshoppers, slugs, cutworms and pyrethrum eelworms have been reported as the
worst pests. Several nematodes also attack comfrey: Meloidogyne hapla, M.
javanica and several species in East Africa. The following fungi have been
found on comfrey: Corticium solani, Pleospora herbarum, Stemphylium
botryosum (leaf spot) and Sclerotium rolfsii.
Complete list of references for Duke, Handbook of Energy Crops
- Hutchens, A.R. 1973. Indian herbalogy of North America. Merco, Ontario,
- Leung, A.Y. 1980. Encyclopedia of common natural ingredients used in food,
drugs, and cosmetics. John Wiley & Sons. New York.
- List, P.H. and Horhammer, L. 19691979. Hager's handbuch der pharmazeutischen
praxis. vols 26. Springer-Verlag, Berlin.
- Morton, J.F. 1975. Is there a safer tea? Morris Arb. Bul. 26(2):2430.
- Palz, W. and Chartier, P. (eds.). 1980. Energy from biomass in Europe. Applied
Science Publishers Ltd., London.
Last update Friday, January 9, 1998 by aw