Furbellow (Brown Algae) Extract Increases Lifespan in Drosophila by Interfering with TOR-Signaling

Abstract

Algal products are well known for their health promoting effects. Nonetheless, an in depth understanding of the underlying molecular mechanisms is still only fragmentary. Here, we show that aqueous furbelow extracts (brown algae, Saccorhiza polyschides) lengthen the life of both sexes of the fruit fly Drosophila melanogaster substantially, if used as nutritional additives to conventional food. This life prolonging effect became even more pronounced in the presence of stressors, such as high-fat dieting of living under drought conditions. Application of the extracts did not change food intake, excretion, or other major physiological parameters. Nevertheless, effects on the intestinal microbiota were observed, leading to an increased species richness, which is usually associated with healthy conditions. Lifespan extension was not observed in target of rapamycin (TOR)-deficient animals, implying that functional TOR signaling is necessary to unfold the positive effects of brown algae extract (BAE) on this important trait. The lack of life lengthening in animals with deregulated TOR signaling exclusively targeted to body fat showed that this major energy storage organ is instrumental for transmitting these effects. In addition, expression of Imaginal morphogenesis protein-Late 2 (Imp-L2), an effective inhibitor of insulin signaling implies that BAE exerts their positive effects through interaction with the tightly interwoven TOR- and insulin-signaling systems, although insulin levels were not directly affected by this intervention.

An aqueous extract of the brown alga Eisenia bicyclis extends lifespan in a sex-specific manner by interfering with the Tor-FoxO axis

“…This means that only females showed this positive effect and males were not affected. This is different from a recent study employing extracts from another brown alga, namely of the furbelow Saccorhiza polyschides, where both sexes showed similar lifespan extensions, although the degree of lifespan-extension was substantially smaller [22]. Such sex-specific effects have been shown more frequently.…”

“…The extracts in question were those of Eisenia bicyclis, of the brown alga Saccorhiza polyschides, and of the picklegrass (Salicornia spec.). The EBE is in the center of the current study and the Saccorhiza polyschides extract has been characterized in detail to exert lifeand/or health-span extension in flies and mice [22,23]. The Salicornia extract on the other hand is of marine origin, but not an algae and serves as a control.…”

Phenotyping of Drosophila Melanogaster—A Nutritional Perspective

“…Due to the abovementioned high degree of functional and/or evolutionary conservation of the nutritional physiology and the key pathways of energy metabolism, D. melanogaster is recognized as a screenable model for anti-obesity agents [ 264 , 265 , 266 , 267 ]. Although published in an unchronological order, the aqueous extract of the brown algae Saccorhiza polyschides was first identified for mitigating the delirious effects of HFD in D. melanogaster [ 267 ] before it was found to counteract diet-induced obesity in mice [ 268 ]. In a recent study, a hydroethanolic extract of Lampaya medicinalis was tested for anti-adipogenic effects in D. melanogaster and HepG2 hepatocytes, preventing HFD-induced TAG accumulation and an accompanied inflammatory response in both systems.…”

The Role of Gut Microbiota in Aging and Aging Related Neurodegenerative Disorders: Insights from Drosophila Model

“…Among the dominant microbes in the gut, the abundance of Gluconobacter increases from 28.99% to 69.18% while Lactobacillus and Acetobacter are much lower. Aqueous furbelow extracts (brown algae, Saccorhiza polyschides ) could also increase species richness of microbiota and extend the lifespan, especially in high-fat and drought diet [ 36 ]. Glucomannan hydrolysates (GMH) are derived from the root of the Amorphophallus konjac plant.…”

“…Although research into antiaging intervention has been progressing rapidly, it should be noted that several studies only demonstrate alteration of diversity and/or abundance of microbiota in parallel with lifespan extension after treatment [ 34 , 35 , 36 , 37 , 38 ]. Further experiments using axenic culture, antibiotics treatment and reintroduction of microbial populations should be performed to clarify whether the antiaging effects of these therapeutic methods rely on targeting microbiota.…”