Increased attention has been given to induction of phase II
enzymes as an important mechanism for chemoprevention against
carcinogenesis, but there appear to be fewer studies on the correlation
between antioxidant enzymes and ageing. In the present study, we
examined antioxidant enzyme activity and oxidative status in the liver
and brain to evaluate the antioxidant capacity of spontaneously
ageing mice. As shown inTable 3, not all parameters followed the
same trend; however, antioxidant enzyme expression in Group I
(SAMR1 control) was greater than that in Group II (SAMP8 control).
Additionally, administration of ME could be observed to reverse
antioxidant enzymes expression. Furthermore, the measured levels of
isoprotane, a derivative of lipid oxidation, suggested that consumption of ME also reduced oxidative stress-induced lipid oxidation.
These phenomena may help to explain the relationship between the
antioxidant content in ME and its observed physiological effects. As
shown inTable 4, mulberry and BE were both rich in phenolics, and
anthocyanin contents were approximately 30 and 260 mg/g in the
respective extracts, with TEAC values showing that mulberry and
blackcurrant have potential antioxidant capacities. We further
examined the phytochemicals in ME using HPLC-DAD (diode array
detector) and found that kuromanin (cyaniding-3-O-glucoside) and
oenin (malvidin-3-O-glucoside) were two of the major anthocyanin
component in ME, and that blackcurrant was rich in delphinidin-3-Orutinoside (data not shown). The abundant antioxidants found in
these fruits might explain their antioxidant capacities against free
radical-induced cellular damage and may also promote an increase in
the expression of antioxidant enzymes. It has been previously shown
that dietary supplementation with antioxidants may augment the
decreased antioxidant capacity commonly seen in SAMP8 mice[14],
and it is important that the signaling mechanism responsible for this
observation be examined in greater detail