>Anybody have something to say about comfrey?
I think that comfrey is not an herbal material which should be used
internally. It is well established that many varieties of comfrey have
small but real amounts of pyrrolizidine alkaloids, many of which are
insidious liver toxins. The most damning evidence is the two papers by
Hirono et al., which showed that both the purified major alkaloids of
Symphytum AND the crude plant material produced a similar effect. AHPA ( I
believe) has a position that comfrey should not be sold for internal use.
(1) Furuya, T.; Araki, K. Studies on Constituents of Crude Drugs. I.
Alkaloids of Symphytum officinale Linn. Chem. Pharm. Bull 1968, 16, 2512-2516.
(2) Hirono, I.; Haga, M.; Fujii, M.; Matsuura, S.; Matsubara, N.; Nakayama,
M.; Furuya, T.; Hikichi, M.; Takanashi, H.; Uchida, E.; Hosaka, S.; Ueno, I.
Induction of Hepatic Tumors in Rats by Senkirkine and Symphytine. J. Natl.
Cancer Inst. 1979, 63, 469-472.
(3) Hirono, I.; Mori, H.; Haga, M. Carcinogenic Activity of Symphytum
officinale. J. Natl. Cancer Inst. 1978, 61, 865-869.
(4) Mattocks, A.R. Toxic Pyrrolizidine Alkaloids in Comfrey. Lancet 1980,
(5) Debska, W.; Owczarska, A.; Madalinska, R. Investigations of Radix
Symphyti for Losiocarpine Content. Herba Polonica 1980, 26, 47-52.
John A. Beutler, Ph.D.
Laboratory of Drug Discovery Research & Development
Developmental Therapeutics Program
National Cancer Institute
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