A marsh samphire (Salicornia europaea) extract induces a strictly sex-specific, Tor-signaling-dependent extension of lifespan and exhibits anti-obesogenic properties

Abstract

We have studied the health-promoting properties of the marsh samphire Salicornia europaea by employing the fruit fly Drosophila melanogaster. Supplementing a standard diet with 0.2% of an aqueous extract of this halophilic plant (SEE), which grows in sandy and muddy habitats in intertidal zones, extended the lifespan of two different Drosophila strains by up to a third. This effect was strictly sex-specific and only affected females. When analyzing the body composition, we found that the body fat content of SEE-treated female flies was lower compared to controls. The extract also positively impacted the lifespan of flies fed a high-fat diet but not a high-sugar diet. It is of note in this context that SEE exhibited a lipase-inhibitory activity in vitro. Moreover, SEE counteracted ageing-associated loss of intestinal barrier integrity. The sex-specific lifespan extensions induced by the SEE were entirely dependent on functional Tor signaling in the flies. Tissue-specific silencing of the Tor signalling pathway in different cellular compartments of the intestine reduced, but did not completely abolish, the lifespan-prolonging effect in females. This suggests that other organs also contribute to this effect. In contrast to the observation that Tor signalling is necessary for the life-prolonging effect, Foxo deficiency led to a reduction in the effect, but not to its complete absence. In conclusion, the SEE is a promising candidate for a health-promoting intervention, and we laid the current groundwork for identifying the compounds that mediate this effect in future studies.