The genus Cinnamomum

Chemistry of Cinnamon and Cassia 111
C(4)–C(8) bonds. Cinnamtannin A 2 is a pale amorphous powder, with anisaldehydesulphuric
acid reagent it gives an orange-red colouration, characteristic of procyanidins.
On acid catalysed thiolytic degradation A 2 gives ()-epicatechin moiety.
Similar degradation products are obtained in the case of A 3 and A 4 also. From
analytical studies the interflavanoid linkage involved was shown as C (4)-C8
(Morimoto et al. 1986a,b). The chemical nature of cinnamtannin A 2, A 3 and A 4 are
thus shown to be:
A 2-epicatechin – (4 : 8)-epicatechin – (4 : 8)-epicatechin – (4 : 8)epicatechin
(tetrameric); A 3-epicatechin (4 : 8)-epicatechin (4 : 8)-epicatechin
(4 : 8)-epicatechin (4 : 8)-epicatechin (pentameric).
Morimoto et al. (1986b) further characterised procyanidins B-1, B-2, B-5 and B-7 from
C. cassia bark. They also for the first time identified two new procyanidins, procyanidin
B-2–8-C and 6-C--D-glucopyranosides (Fig. 3A.4).
HO
OH
O
1
HO
OH
OH
HO
OH
O
OH
2
OH
OH
OH
O
OH
HO
OH
OH
O
OH
OH
OH
OH
2: n = 0
4: n = 1
OH
OH
O
OH
1 : (–)-epicatechin 2 : procyanidin B2
3 : procyanidin B4 4 : procyanidin C1
Figure 3A.4 Procyanidins from cassia bark (see text for explanation).
3
OH
OH
O
n
OH
OH
OH
OH
OH
OH