Abstract

Background: Stroke is the second most common cause of death and major cause of disability worldwide.
Because of the ageing population, the burden will increase greatly during the next 20 years, especially in
developing countries. Antioxidants have been the focus of studies for developing neuroprotective agents to
be used in the therapy for stroke, which is an acute and progressive neurodegenerative disorder. Allium
cepa (Linn.) has been greatly valued, commercially as well as medicinally, since ancient times. A. cepa is

reported to be potent antioxidants and neuroprotective agent. Our previous work demonstrated that pre-
treatment with methanol extract of A. cepa prevents ischemia-reperfusion (I/R) induced cerebral injury.

Objective: The present study was designed to investigate the effect of methanol extract and flavonoid-rich
fraction of outer scales of A. cepa bulbs post-cerebral injury. Materials and methods: Global cerebral
ischemia was induced in mice by bilateral carotid artery occlusion followed by reperfusion. Treatment with
extracts of A. cepa, was carried out for 28 days after I/R. Cerebral infract size was estimated using
triphenyltetrazolium chloride staining. TBARS assay was employed to measure oxidative stress. Morris
water maze was employed to assess memory, and inclined-beam walking test was employed to evaluate
motor coordination. Phytochemical screening tests showed the presence of flavonoids in the bioactive
extract, hence flavonoid-rich fraction was prepared and biological studies were carried out. Results: The
flavonoid-rich fraction of the outer scales of A. cepa demonstrated the most significant reduction in cerebral
damage and oxidative stress. It also ameliorated the damage to memory and motor coordination. This
bioactive fraction found to contain high amount of total phenolics and total flavonoid content. Conclusion:
The standardized flavonoid-rich fraction of the outer scales of allium cepa may be a potential candidate for
the treatment of post-cerebral damage.