Western Coltsfoot Constituents: "The sesquiterpene petasin and related esters, saponins, and mucilage in the leaves; resins and volatile oils in the roots, the young leaves can contain a small amount of pyrrolizidine alkaloids, but these are nearly absent from mature leaves. The roots seem to be lacking these liver damaging substances, and the small amounts found in the immature leaves, (and perhaps the flowering stalks), are less toxic than they are in the senecio type alkaloids." Ref. B p.255.. |