helleborein

from The Century Dictionary.

• noun A colorless glucoside, C₂₆H₄₄O₁₅, the most important constituent of black and green hellebore-roots (Helleborus niger, H. viridis, and H. fœtidus). It crystallizes in nodules which carbonize at 280° C., has a sweet taste, and is poisonous. Helleborin, C₃₆H₄₂O₆ (?), occurs with it. It is a powerful intestinal irritant and is used in veterinary medicine.

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

• noun (Chem.) A poisonous glucoside accompanying helleborin in several species of hellebore, and extracted as a white crystalline substance with a bittersweet taste. It has a strong action on the heart, resembling digitalin.

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

• noun Alternative form of helleborin.