sinapine

from The Century Dictionary.

• noun An organic base, C₁₆H₂₃NO₅, existing as a sulphocyanate in white mustardseed. The free base is quite unstable, and has not been obtained.

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

• noun (Chem.) An alkaloid occuring in the seeds of mustard. It is extracted, in combination with sulphocyanic acid, as a white crystalline substance, having a hot, bitter taste. When sinapine is isolated it is unstable and undergoes decomposition.

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

• noun organic chemistry An alkaloidal amine found in black mustard seeds, considered a choline ester of sinapic acid.