Evaluation of the antidepressant- and anxiolytic-like effects of a hydrophilic extract from the green seaweed Ulva sp. in rats

Violle N, Rozan P, Demais H, Nyvall Collen P, Bisson JF. - 2018, Nutr Neurosci, 21:248-256.

OBJECTIVES: The green seaweed Ulva sp. contains a large amount of ulvans, a family of sulphated polysaccharides. The present study was designed to investigate in rats the antidepressant- and anxiolytic-like effects of a hydrophilic extract of Ulva sp. (MSP) containing about 45% of ulvans.

METHODS: After a 14-day administration of MSP at doses of 10, 20 and 40 mg/kg/day, 48 and 60 male adult Wistar rats were respectively tested in the elevated plus-maze (EPM) and the forced swimming test (FST). In the FST, MSP effects were compared to the reference antidepressant drug imipramine (IMI) (10 mg/kg/day). Acute and sub-chronic toxicities of the extract were also assessed in male and female rats following OECD guidelines.

RESULTS: MSP treatment did not modify anxiety-related behaviour in the EPM. In contrast, MSP induced a dose-dependent reduction of immobility behaviour in the FST. At the highest tested dose of 40 mg/kg, MSP displayed a significant antidepressant-like effect similar to IMI. MSP did not modify the exploratory behaviour of rats in the open field test and did not produce any toxic effect.

DISCUSSION: MSP may potentially represent a good adjunct or alternative to existing antidepressant therapeutics. Further studies are necessary to confirm the mechanism of action of MSP and its modulation of brain functioning.

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