ABSTRACT:
Omega-3 fatty acids, (eicosapentaenoic_acid (EPA), docosahexaenoic_acid (DHA) from fish oil are known to have numerous benefits in CNS disorders. Studies have indicated protective action of omega-3 fatty acids in various neurodegenerative disorders. With the intention of producing an alternative source to fish EPA, we have microbially synthesized EPA (MEPA) from rice bran oil which was pharmacologically evaluated using scopolamine induced amnesia in rats as animal model for Alzheimer's disease (AD). Animals were divided into 7 groups of six animals each; control treated with vehicle, one with standard Rivastigmine (5 mg/ kg: p.o.): 3 groups with MEPA (5, 10 and 50 mg/kg p.o.) and one with fish oil (1 g/ kg p.o.) for 15 days. On 15" day 90 min after last dose of drug. all animals except control group were treated with scopolamine (1 mg/ kg: s.c.). Each group was evaluated for spatial memory by Morris Water Maze test. Then, blood was withdrawn by retro-orbital puncture and brain was excised using standard procedure. Brain homogenate and serum were analysed for levels of AchE (Acetylcholinesterase), NO (Nitric_oxide) and ACE (Angiotensin converting enzyme). Scopolamine treatment induced amnesia indicated by increase in escape latency. This was significantly reversed with fish oil and rivastigmine and non-significantly with all three doses of MEPA. Fish oil and rivastigmine significantly decreased AchE level but mEPA effects were non-significant in serum and brain homogenate AchE level. Serum NO and ACE levels were inconsistently affected in AD induced rats. Results suggest that MEPA was not effective in treating scopolamine induced amnesia. Rivastigmine itself is an AchE inhibitor hence exerted significant anti-AchE action but mEPA may not have effet on AchE level. As fish oil contains EPA as well as DHA, the CNS related benefits associated with cognitive impairment seen with fish oil may be due to DHA.