Antidepressive effect of polyphenols and omega3 fatty acid from pomegranate peel and flax seed in mice exposed to chronic mild stress

In this study polyphenols from pomegranate peel, and n3 fatty acids with polyphenols from flax seed were evaluated for their anti depression properties in mice exposed to chronic mild stress (CMS). A total of 40 mice initially trained to consume 2 percent sucrose solution for 3 weeks were then divided into five groups of eight each. The first group was the normal control, the remaining four groups were exposed to CMS but were force fed with either: 10 mL water per kg bodyweight per day; imipramine (a standard antidepressant) 15 mg kg bodyweight; 30 mg per kg bodyweight polyphenol equivalent extract from pomegranate peel; or 30 mg polyphenols
per kg bodyweight with omega 3 fatty acids present, for 50 days. At the end, blood and brain were analyzed for various biomarkers of depression. The flax seed and imipramine groups had significantly increased sucrose consumption, decreased cortisol (blood), decreased epinephrine and norepinephrine concentration, decreased monoamine oxidase A and B activity, and decreased superoxide dismutase activity. Lipid peroxidation was completely inhibited. In contrast, pomegranate peel extract also completely inhibited lipid peroxidation in the brain, and reduced enzyme activity and hormone concentration but to a lesser extent than flax seed.
Polyphenols from flax seed with omega 3 fatty acids were able to reduce all the CMS effects tested compared to polyphenols from pomegranate peel. (Authors abstract)

Pomegranate peel has been shown to possess good antioxidant activity.  Flaxseed has omega 3 fatty acid and many polyphenolic compounds such as phenolic acids, flavonoids and lignans along with vitamin C and E.  The aim of the present study was to assess whether polyphenols alone, or in combination with omega-3 fatty acid, by scavenging the liberated free radicals in excess under stress,is able to normalize brain function in mice exposed to chronic mild stress (CMS).

Energy and sucrose intake and brain function are interrelated.  A much greater sucrose intake was observed in the flax seed extract and imipramine groups than in the pomegranate peel extract group. It has been shown that conversion of alpha linolenic acid to docosahexaenoic acid supports glucose uptake, thereby stimulating neurons for better cognitive function, indicating reduced oxidative stress.   In addition omega 3 fatty acid may be metabolized faster than oleate or linoleate to ketones, a secondary fuel for brain function. This suggests better energy supplementation from flax seed extract than peel for improved cognitive function.
Flax seed extract significantly decreased cortisol level compared to peel extract, indicating a possible synergistic effect between omega 3 fatty acid and polyphenols, given that both the extracts inhibited lipid peroxidation completely. The overall effect of flax seed extract, having both polyphenols with omega-3 fatty acid, may be considered better in overcoming stress, indicating the importance of omega-3 fatty acid for maintaining cellular integrity and function. Both polyphenol extracts exhibited equal potential, as indicated by complete inhibition of lipid peroxidation. Polyphenols from flax seed with omega-3 fatty acids were able to reduce all CMS effects tested compared to polyphenols from pomegranate peel.(Editors comments)