The present study showed lignans could also inhibit AR protein
expression and the efficacy was similar to that of epalrestat.
Recently, it has been reported that the inhibitory effect of total lignans
from fructus arctii on aldose reductase is similar compared
to AR inhibitor epalrestat (Xu et al., 2010). This is consistent with
our findings. Moreover, lignans displayed a long-term effect of lowering
MBP. Although lignans were not comparable to captopril in
lowering MBP, they were as obvious as captopril in reversing vascular
remodeling in SHR. The findings also indicated that AR played
an influential role in the processes of hypertensive vascular remodeling.
Furthermore, AR inhibitor has been used to prevent and treat
chronic complications in diabetes. Many diabetics are subject to
hypertension. Lignans are effective fractions extracted from Eucommia
ulmoides, which has been proven to be safe and effective in
inhibiting AR and lowering blood pressure. Therefore, Eucommia
ulmoides lignans may have a great potential to treat patients subject
to both diabetes and hypertension at the same time. In addition,
we also found that both lignans and epalrestat had no effect on HR.
Captopril could reduce heart rate after being administered for 4
weeks, however, the effect of reducing heart rate became weaker
after 8 weeks. It may be related to drug tolerance.