Biology Reference
In-Depth Information
Figure 3.8 Chemical structures for amylase inhibitors, compounds 57-59, 5-caffeoyl
quinic acid, and 4,5-dicaffeoyl quinic acid.
using DNSA assay to be 10 times (EC
50
of
2.0
m
M) stronger than aca-
rbose (EC
50
of 19
m
M). Such a high activity is quite rarely seen in poly-
phenolic compounds and warrants further investigation particularly on
its inhibition mechanism and selectivity when these compounds are chal-
lenged with complex food matrix. Myricetin is a strong radical scavenger
and thus the stability of
is also a concern. The authors reported
that quercetin had comparable EC
50
(17
m
M) as that of acarbose (19
m
M).
Using the turbidity assay we developed in our lab, we could not detect any
inhibition activity of quercetin against pancreatic
a
-amylase using acarbose
as the reference standard (Huang et al., unpublished results). Therefore, it
needs to be verified if the EC
50
reported is method dependent to rule out
9
and
10
