The effect of different partitions of seaweed Sargassum plagyophylum on depression behavior in mice model of despair

Abstract

Background Seaweeds are a famous traditional food resource in some countries containing different types of secondary metabolites. These marine organisms have shown different biological activities. The aim of this study was to investigate the effects of hexane and methanol extracts of Sargassum plagyophylum on depression. Methods Sargassum plagyophylum was collected from Persian Gulf. The plant was extracted by maceration with methanol-ethyl acetate solvent. The extract was evaporated and partitioned by hexane and methanol solvents. The two partitions were administered i.p. to male mice either a single dose or for 7days. Depression was evaluated by the forced swimming test (FST) which higher immobility time indicates depressive-like behavior. Results The immobility time during FST decreased significantly by all the doses of the hexane partitions (notably 40 mg/kg; 10s +/- 2 vs. 114s +/- 12 control group). However, only the lowest dose (20 mg/kg) of the methanol partition reduced immobility time during FST (23s +/- 8, p<0.001). Following the long term administration both of the partitions reduced the immobility time in FST (hexane 27s +/- 11, methanol 70s +/- 14, p<0.05 vs. control 140s +/- 14). Conclusion The hexane partition showed antidepressant effects not only by long-term administration but also by the single dose during FST. The 7days therapy with methanol partition also induced antidepressant behavior, but only the lowest single dose reduced immobility in FST. The methanol partitions possibly have certain substance that interfered with behavior in the FST. Therefore, S. plagyophylum should be considered for further antidepressant studies.