Scientists from MIPT recently managed to extend the lifespan of drosophila flies and nematodes by adding to their diet carotenoids – substances contained in large amounts in brown algae and orange fruits and vegetables, for example carrots – so say the researchers in an article accepted for publication by the journal Pharmacological Research.
Experiments in recent years on flies, worms and fish have demonstrated that their life expectancy is significantly increased if their cells are switched into an “energy saving” regime so that they are forced to actively resist stress caused by both internal and external factors. One of the more effective ways of doing this is to seek natural or synthetic substances that are capable of enhancing the resistance of the cells.
In particular, scientists have long been interested in carotenoids, pigments that are naturally produced in plants. Animal and humans are unable to process these substances, but it is known that they can reduce the risk of a number of serious illnesses and can also increase life expectancy. Previous research has shown that carotenoids have properties that are anti-gene mutation, anti-inflammatory and anti-carcinogenic and are capable of preventing the development of obesity and diabetes, circulation illnesses and osteoporosis.
However, several clinical researches have shown that beta-carotene increases the risk of lung cancer in smokers. So far, the scientists do not have specific data about the mechanisms that the carotenoids use. The Moskalev group at MIPT has researched the effects of two substances from the carotenoid group - the orange plant pigment beta-carotene and fucoxanthin found in algae – on the drosophila fly (Drosophila melanogaster) and the nematode (Caenorhabditis elegans).
During the experiment, half of the subjects were fed normal feed, and the remainder was given a special mix containing either a beta-carotene or a fucoxanthin solution. Observations of the lifespan of several hundred flies and nematodes demonstrated that consumption of either of the substances extended the life of the flies by 30%, while the worms reacted favourably only to the fucoxanthin. Adding a brown algae extract to the ration of the nematode increased average life expectancy by 14%.
The scientists suggest that beta-carotene does not react because of the low solubility of this substance, that is, the worms simply do not absorb it. Moreover, the carotenoids extend the life of female flies to a greater extent. Another difference is in that the pigments protect the females from oxidants, while this effect was not observed among the males. “The fucoxanthin successfully increased the median life expectancy of the drosophila by 14 days for the males and from 14-21 days for the females (data from three repeat experiments combined). The median life expectancy of nematodes increased by 3-5 days. Beta-carotene extended the median life expectancy of drosophila by 8–15 days for the males and from 7-16 days for the males,’” commented the researchers.
The reason for this “gender inequality” in the opinion of Moskalev and his colleagues is that the females eats more food, which means more pigment is absorbed by the organism. All of the positive effects, suggest the biologists, are related to the fact that beta-carotene and fucoxanthin do not just protect the DNA from harm, but also force the cells to be more reactive to stress and are more economical in their use of energy and other substances. During the experiment, the scientists followed the activity of a number of genes that may be related to “longevity” and have discovered what activates those genes that are responsible for the lifespan of humans. In particular, carotenoids increase the expression of genes that are involved in stress response (dSir2, JNK, p53, Gadd45, Keap1, CncC), are responsible for the neutralization of free radicals (Sod1, GclC), for the restoration of DNA (Mus210, Mei-9, Spn-B), and for the coding of heat-shock proteins (Hsp70).
The scientists hope that further research on the activity of these pigments in animals can help us understand whether these discovered effects will work in humans. “We still have more years of experiments to go, but in the future we will be able to create new geroprotectors and substances for enhancing life expectancy based on carotenoids,” says Moskalev.