Wakeman—Pigments of Flowering Plants. 
823 
Plnloretin. 
CH 
CH 
HOC 
HC 
| c ”C-CH 2 — ch 2 ~ 
COH 
CH 
COH 
CH 
Phloretin occurs as the glucoside phloridzin in several species 
of Rosaceae, especially in the leaf buds and the bark of Pirns 
mains, 1 the apple tree. Phloridzin was discovered in 1835 by 
De Koninck 2 and Stas in the bark of the apple tree. Later 
Stas, 3 1839, made an extended study of phloridzin and recog¬ 
nized its glucosidal character, isolating glucose and phloretin. 
Further studies of phloretin and of phloridzin were made by 
Rennie, 4 Schiff, 5 Hesse, 6 and Fischer, 7 also by Schunck and 
Marchlewski. 8 In 1894 Michael 9 found that phloretin upon 
hydrolysis yields phloroglucin and phloritinic acid. The latter 
was at the time believed to be p-hydroxy-hydrotropic acid. 
CH CH 
CH CH 
CH 
Later Bougult 10 found phloretinic acid to be identical with 
p-hydroeumaric acid. 
CH CH 
CH CH * 
p-Hydroxycumarlc add 
1 Jr. Prakt. Chem., 98, p. 205; C. r, 139, p. 294. 
2 Ann., 15, p. 75, 258. 
3 Ann., 30, p. 200. 
4 Jr. Chem. Soc., 49, p. 860; 51, p. 636. 
6 Ann., 172, p. 357; 229; p. 374; B., 2, p. 743; 14, p. 303. 
8 Ann., 176, p. 288. 
7 Ber., 21, p. 288. 
8 Ber., 26, p. 942. 
8 Ber., 27, p. 2686. 
