COMFREY
Source: Symphytum officinaleL.;Symphy-
tum uplandicumNym.; S. asperum
Lepechin. (Family Boraginaceae).
Common/vernacular names:Common com-
frey, Russian comfrey (S. uplandicum),
prickly comfrey (S.asperum), and blackwort.
GENERAL DESCRIPTION
Perennial herbs with branching stems and
thick root. Parts used are the dried rhizome
and root; also the leaves.
Common comfrey (S.officinale) is an erect,
stout, often branched perennial, to 1 m; leaves
broadly lance shaped; middle and upper ones
sessile, but at point of insertion extend down-
ward on stalk; stalk distinctly winged; flowers
variable from white or cream, yellowish to
rose, pink, or light to dark violet; anther about
as wide as filament; petal lobes recurved;
calyx segments distinctly lanceolate; nutlets
smooth; occurs in moist grasslands and riv-
erbanks most of Europe, is rare in extreme
south, naturalized alien in northern Europe;
eastern North America.
Russiancomfrey(S.uplandicum),ahybrid
ofS.officinaleandS.asperum,robustperennial,
1–2 m. Intermediate between parents. Leaves
narrow winged on the main stalk, ending be-
tweeninternodes;flowersdarkviolettoblue,or
pinkishtopink-blue.NativetonorthernEurope,
mostly persisted after cultivation.
Prickly comfrey, (S.asperum), stems not
winged, upper leaves on short stalks; flowers
rosetobluish;antherssignificantlyshorterthan
filaments;from SouthwestAsia; naturalizedin
Europe, and the eastern United States (rare).
CHEMICAL COMPOSITION
S.officinaleroot contains 0.75–2.55% allan-
toin;1–3about 0.3% alkaloids, including the
pyrrolizidine alkaloids symphytine, echimi-
dine, heliosupine, viridiflorine, echinatine,
7-acetyllycopsamine, 7-angelylretronecine
viridiflorate, lasiocarpine, and acetylechimi-
dine;3–5 the presence of lasiocarpine is
questioned;^6 lithospermic acid;^7 29% muco-
polysaccharide that is composed of glucose
and fructose;^8 a gum consisting of L()-
xylose,L-rhamnose,L-arabinose,D-mannose,
andD-glucuronic acid;^9 pyrocatechol tannins
(2.4%); 0.63% carotene; glycosides, sugars;
isobauerenol,b-sitosterol, and stigmasterol;
steroidal saponins; triterpenoids; rosmarinic
acid, and others.1,4,10,11
S.asperumcontains the pyrrolizidine alka-
loids asperumine, echinatine, heliosupine, 7-
acetyllycopsamine, and acetylechimidine.^5
S.uplandicumcontains symphytine, sym-
landine, echimidine; 7-acetyllycopsamine,
7-angelylintermidine, uplandicine, lycopsa-
mine, and intermedine.^5
Leaves also contain substantial quantities
of allantoin,2,3alkaloids (ca. 0.15%),^12 and
possibly other similar constituents as the root.PHARMACOLOGY AND BIOLOGICAL
ACTIVITIESAllantoin is reported to have healing proper-
ties (MARTINDALE).
An aqueous extract of comfrey containing
lithospermic acid and other common plant
acids has been reported to exhibit antigonado-
tropic activity in mice,^13 though lithospermic
acid itself has no such activity unless oxidized
by a plant phenol oxidase preparation.^7
Comfrey is reported to have anti-inflamma-
tory properties.^14 It is also considered to have
many beneficial properties, including astrin-
gent, demulcent, emollient, hemostatic, and
expectorant properties, among others.
Anti-inflammatory efficacy has been con-
firmed, correlating clinical and analytic data
of topical comfrey products by measuring
redness and pain sensitivityin vivo, to the
allantoin and rosmarinic acid fractions of
preparations.^10TOXICOLOGYThe root and leaves of S. officinalehave
been found to be carcinogenic in rats.^15Comfrey 225