| General
info
· An ancient herb
known since 400 B.C., used by the Greeks to treat bronchial problems,
wound healing and mending of broken bones. The name "Comfrey"
is a corruption of con firma,
the uniting of bones.
· The healing constituent is allantoin. Ingredients may be steeped
or dissolved in hot water; boiling should be avoided as this may cause
the breakdown of allantoin.
Botany
Hardy, leafy perennial.
Thick rhizomes, black outside and white inside, containing a mucilaginous
juice. Leaves are entire, lanceolate to ovate-lanceolate, up to 10 inches
long, deep green and hairy. Flowers are variable in color, blue, yellow
or white, borne on short curved racemes, with five-lobed calyx and five
stamens. Fruits are nutlets.
Distribution
Introduced in the Philippines
in the late 60s; cultivated; propagated by seed.
Toxicity !
• Hepatotoxicity: Since the late
70's, subject of persisting concerns and debate on certain alkaloid
contents that may cause liver damage, veno-occlusive liver disease,
ascites and hepatic fibrosis.
• Advice is given against use of comfrey as salad green or tea.
• In July 2001, the US FDA took steps to stop the marketing of
comfrey as a dietary supplement. (Source)
Parts
utilized
Leaves , flowers
and roots.
Chemical constituents
and properties
· Considered antitussive,
expectorant, haemostatic, vulnerary, homepathy.
• Contains allantoin, between 0.6 to 0.8 % to which is attributed
its wound-healing properties.
• Phenolic acids: rosmarinic, chloogenic, caffeic and lithospermic
acids.
• Contains potentially hepatotoxic compounds: pyrrolizidine alkaloids,
including heliosupine, echimidine, heliosuipine, lycopsamine, symphytine
and cynoglossine. The alkaloid concentration is highest in small, young
leaves. Roots also contain high levels of these compounds.
Uses
Nutrition
Confirmed source of vitamin
B12, although in negligible amounts that would require consumption of
4 pounds of comfrey daily for minimum daily requirement.
Folkloric
· Decoction of leaves used for a variety of illnesses: Asthma,
cough, ulcers, constipation, hypertension.
· Poultice of fresh leaves used for sprains and fractures, inflammatory
swelling, external wounds, sores, athlete's foot, burns, insect bites,
and abscesses.
· Used for excessive menstrual flow, cancer, angina, gums disease
· Juice of leaves used for a variety of skin ailments and wounds
healing; apply three times daily.
· Decoction of tea as a sleep-aid.
· Roots and leaves used for broken bones and wounds.
· In Ayurveda,
used for peptic ulcer.
· In Polish
pharmacopoeia, as Radix symphyti, recommended as expectorant, especially
for children.
Studies
• Antiproliferative: Study of effects of chronic oral treatment
of rats with 10% comfrey ethanolic extract was evaluated in a RHM (resistant
hepatocyte model) showed the treatment reduced cell proliferation.
· Mutagenic Effects: Mutagenic
effects of aqueous extracts of Symphytum officinale L. and of its alkaloidal
fractions – Aqueous solutions of three alkaloid fractions were
studied for antimitotic and mutagenic activity. Results showed mutagenic
activity to be induced by lasiocarpine, by alkaloidal fraction 1 and
by diluted infusions from Radix symphyti. Fraction III had only antimitotic
effect.
• Herbal
Tea Concerns / Pyrrolizidine Alkaloids / Hepatotoxicity: Analysis
of herbal teas made from the leaves of comfrey (Symphytum officinale):
reduction of N-oxides results in order of magnitude increases in the
measurable concentration of pyrrolizidine alkaloids: The concentration
of symphytine and echimidine varied considerably in different tea leaves
preparation. Since alklaoids are known to be hepatotoxic, and because
the concentration of pyrrolizidine alkaloids may be underestimated,
consumption of comfrey herbal teas, in native or packaged forms, is
not advised.
• Roots reported to increase incidence
of liver tumors in rats; other studies suggest it is carcinogenic.
• Proliferative / Antimitotic: Results
indicate crude extract and its proteic fraction stimulate invivo proliferation
of studied neoplastic cells and and antimitotic effect on human T lymphocytes
in vitro stimulated with PHA.
• Non-mutagenic:
Study of the comfrey root fluid extract contained in Kytta-Salbe
(R) f and Kutta Plasma (R) f was not mutagenic in bacterial reverse
mutation assay.
• Safety
Assessment : Study highlighted significant differences in
the reported identification of pyrrolizidine alkaloids from the same
plant species, and demonstrates the inadequacy of some procedures to
include N-oxides in the assessment of pyrrolizidine alkaloid-related
safety of food and herbal products.
Safety
studies
· Probably safe
when used topically on unbroken skin. Use should be limited to 4 to
6 weeks per year at less than 100 mcg of unsaturated pyrrolizidine alkaloids.
However, with toxicity concerns, it is advisable to seek alternatives.
· Avoid oral use. Probably not safe
when taken orally. Potential for liver toxicity.
· Contraindicated in pregnancy and lactation.
Availability
Wildcrafted
Ointments
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