hydrastine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A poisonous white alkaloid, C₂₁H₂₁NO₆, obtained from the root of the goldenseal and formerly used locally to treat inflammation of mucous membranes.

from The Century Dictionary.

• noun An alkaloid found in the root of goldenscal, Hydrastis Canadensis. It is crystalline, odorless, and, on account of its insolubility, nearly tasteless. Also hydrastia.
• noun A medicine used by eclectic physicians, which is a mixture of hydrastine, berberine, and resin. It is not to be confounded with the alkaloid hydrastine.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) An alkaloid, found in the rootstock of the golden seal (Hydrastis Canadensis), and extracted as a bitter, white, crystalline substance. It is used as a tonic and febrifuge.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun organic chemistry A natural alkaloid present in goldenseal.