EGb induces SOD and CK activity and obviously that
of the GPX and GR enzymes of the GSH-regenerating
system in this region.(c) This leads to the scavenging and
detoxification of ROS as well as an increased lipid peroxide
decomposition, particularly high in the temporal cortex
of old animals (17).
As this region shows the lowest cerebral blood flow
compared to other brain regions (6), MDA, a decomposition
product of lipid peroxides, could not be extracted
during the short-term exposition to hypoxia.
Our hypothesis that there is an elevated decomposition
of lipid peroxides by GPX has been confirmed by results
reported in the literature. Mizuno et al. (35) and MartinezRomero
et al. (20) observed an increased basal GPX activity
in the temporal cortex, the hippocampus, and the
cerebral cortex of the aging brain. An induction of GPX
by EGb or its ingredients - quercetine and flavonoids - was
found by Singh et al. and Nagata et al. (36, 37). Sastre
(23) reported that EGb protects the mitochondrial GSH
against age-associated oxidation. Martinez-Romero et
al. (20) also found an elevation in GPX in the cerebral cortex
of old rats after hypoxia.