Leu*co"ma*ine (l&usl;*kō"m&adot;*&ibreve;n or - ēn), n. [Leuco- + -maine, as in ptomaine.] (Physiol. Chem.) An animal base or alkaloid, appearing in the tissue during life; hence, a vital alkaloid, as distinguished from a ptomaine or cadaveric poison.