During the last decade, essential polyunsaturated fatty acids (PUFAs) such as eicosatetraenoic acid (EPA) and docosahexaenoic acid (DHA) derived from marine sources have been investigated as nonpharmacological dietary supplements to improve different pathological conditions, as well as aging.

The aim of this study was to determine the effects of dietary n-3 PUFA monoacylglycerides (MAG, both EPA and DHA) on the mitochondrial metabolism and oxidative stress of a short-lifespan model, Drosophila melanogaster, sampled at five different ages.

Our results showed that diets supplemented with MAG-EPA and MAG-DHA increased median lifespan by 14.6% and decreased mitochondrial proton leak resulting in an increase of mitochondrial coupling.

The flies fed on MAG-EPA also had higher electron transport system capacity and mitochondrial oxidative capacities. Moreover, both n-3 PUFAs delayed the occurrence of lipid peroxidation but only flies fed the MAG-EPA diet showed maintenance of superoxide dismutase activity during aging.

Nutraceutical compounds

The study, therefore, highlights the potential of n-3 PUFA monoacylglycerides as nutraceutical compounds to delay the onset of senescence by acting directly or indirectly on the mitochondrial metabolism and suggests that Drosophila could be a relevant model for the study of the fundamental mechanisms linking the effects of n-3 PUFAs to aging.

The aim of the current study was to determine the effects of dietary n-3 PUFA supplements on the mitochondrial metabolism and oxidative stress of Drosophila melanogaster sampled at five different ages.

Two different supplements were specifically tested:

1. A 40.08% monoacylglyceride rich oil enriched in DHA (65% w/w), referred to as MAG-DHA;

2. A 40.72% monoacylglyceride rich oil enriched in EPA (82% w/w), referred to as MAG-EPA. These monoacylglyceride rich oils comply with the USP monograph of mono- and diacylglycerides.

Although these compounds are a heterogeneous mixture of mono- and diacylglycerides, they were chosen in our study based on their high contents in monoglycerides (more than 40%).

These compounds have been shown to increase the plasma concentration and bioavailability of both EPA and DHA n-3 PUFAs in rodents compared to other forms and have never been tested in Drosophila.

MDA Levels

MDA levels were measured using the TBARS assay kit from Cayman Chemical. Briefly, the samples were incubated with thiobarbituric acid at high temperature (90–100 °C) and the adducts formed by the reaction were determined fluorimetrically at an excitation wavelength of 530 nm and an emission wavelength of 550 nm against a standard curve of MDA. Results are expressed as nmol of MDA formed per mg of proteins ± s.e.m.