From The Collaborative International Dictionary of English v.0.48 :
Wrightine \Wright"ine\, n. (Chem.)
A rare alkaloid found in the bark of an East Indian
apocynaceous tree ({Wrightia antidysenterica), and extracted
as a bitter white crystalline substance. It was formerly used
as a remedy for diarrh[oe]a. Called also conessine, and
neriine.
[1913 Webster]