Discussion
Results of the present investigation strongly suggest an antidiabetic
potential for aloe. In-vivo results show decreased serum
glucose and increased serum insulin levels in aloe-treated rats
compared to diabetic controls (Table 1). In agreement, previous
authors claimed for such antidiabetic effect for aloe extract
on experimental animals. Our in vitro results support this
finding, where aloe was found to increase the rate of insulin
secretion from pancreatic islets (Figs. 4 and 5).
Many explanations were suggested for this antidiabetic effect
of aloe. The first explanation is the potent antioxidant effect
of aloe extract. Aloe is long known to have antioxidant
potential via suppression of free radical formation and
enhancement of cellular thiol status. It is also reported
to stimulate glutathione-S-transferase enzyme activity. Our
results strongly supported the antioxidant potential of aloe,
where it was found to suppress elevated serum MDA levels
and increase blood GSH and SOD levels. Recent approaches
focus on the role of oxidative stress in pancreatic beta cell
damage. That is, oxidative stress is involved as a causative
factor in the pathogenesis of diabetes, and hence antioxidants
like aloe may have a true antidiabetic effect via antioxidant
potential.
The anti-inflammatory potential of aloe may be the second
explanation for its antidiabetic effect. Diabetes may be considered
as an inflammatory disease where inflammation participates
in the progression of diabetes, where tumor necrosis
factor-a was found to decrease peripheral insulin sensitivity.25
Many authors claimed for the anti-inflammatory potential of
aloe due to many of its components like emodin and mannose-
6-phosphate. It was reported that the anti-inflammatory
effect of aloe extract is comparable to that of
hydrocortisone.
Finally, aloe may act as a hypoglycemic agent through potent
inhibition of pancreatic a-amylase activity.29 This action
decreases starch breakdown and offers good postprandial glycemic
control.
These findings are promising for further clinical studies on
aloe extract or extract components in the management of diabetes
mellitus.