Moreover, a combination of Ab-mediated ROS induction and
excessive Ca2þ influx has been reported to lead to neuronal loss and
cellular apoptosis.6 Given the importance of ROS-related mechanisms
in AD, several studies have used antioxidants, such as
vitamin E7 and Ginkgo biloba (銀杏yín xìng) extract,8 or have
enhanced the activities of enzymes in the antioxidative defence
system, such as superoxide dismutase (SOD), catalase, glutathione
peroxidase (GPx), and glutathione reductase (GR)9 to protect
neuronal cells from the Ab-induced ROS. These studies have shown
that use of antioxidants and activation of the antioxidative defence
system could suppress the neurotoxicity of Ab in in vivo and in vitro
models. Therefore, agents capable of attenuating oxidative stress
may contribute to a superior therapeutic strategy for the treatment
of Ab-induced neurotoxicity and may lead to improved neurological
outcomes in AD.
Centella asiatica (雷公根lei gong gen), a member of the family
Apiaceae (Umbelliferae), has been used as a traditional medicinal
herb in Asia for over 2000 years. A number of medicinal functions
and biological activities have been found in C. asiatica, both in the
whole plant and its extract, including the ethanolic and aqueous
extracts. The major active components of C. asiatica ethanol extract
(CAE) are the triterpenoids, including asiatic acid and asiaticoside.