3.4. Effects of mulberry on cognitive ability
As shown in Table 4, the ME contained about 10% phenolic
compounds, and about one third of these phenolic compounds were
anthocyanins. Trolox equivalent antioxidant capacity demonstrated
that the majority of the contents found in phenolic compounds were attributable to the antioxidant capacity of ME. No statistically
significant difference (PN.05) was observed between food intake
profiles from the different animal groups (data not shown).
Furthermore, a locomotion activity test was executed prior to memory
evaluation, and these data suggested that ambulatory activity was
similar between the groups (data not shown). The learning and
recognition examinations were performed at the 11th week of the
study. The results from avoidance trials showed that SAMR1 (Group I)
had significantly superior cognition over SAMP8 (Group II) (Fig. 1).
The passive avoidance time in Group I was significantly (Pb.05) longer
than the time in Group II. Although consumption of blackcurrant or
ME improved the successful avoidance time of SAMP8 mice by Day 3,
only Group V (500 mg/kg body weight, high dose) demonstrated
superior memory compared to the other groups by Day 7. Furthermore, the successful avoidance times of SAMP8 mice supplemented
with mulberry or BE were greater than those of SAMP8 mice with a
normal diet (Fig. 2). These data revealed that SAMR1 mice had better
memories than SAMP8 mice, suggesting that supplementation with
ME helped to counteract the deficits of learning and recognition that
accompany aging.