laburnine

from The Century Dictionary.

• noun A poisonous alkaloid found together with cytisin in the seeds of the common laburnum, to which their medicinal properties are partly due.

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

• noun (Chem.) A poisonous alkaloid found in the unripe seeds of the laburnum.

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

• noun organic chemistry A poisonous alkaloid found in the unripe seeds of the laburnum.