Chem. Also -ina. [f. QUIN-A + -OID + -INE5.] A brownish-black, resinous substance, consisting of amorphous alkaloids, obtained as a by-product in preparing salts of quinia. b. Animal quinoidine, an alkaloid substance resembling quinine found in animal tissues.
1845. Penny Cycl., Suppl. I. 350/1. Quinoidina, the name given by Sertuerner to a third alkali, contained in yellow and red bark.
1853. L. Pasteur, in Pharmac. Jrnl., XIII. 375. Quinoidine … is always a product of transformation of the cinchona alkalies.
1857. Miller, Elem. Chem., III. 273.
1867. Proc. Royal Soc., XV. 92. This fluorescent substance … has a very close optical and chemical resemblance to quinine … we have therefore called it ‘animal quinoidine.’
