There is no known effective regimen for this rare malignancy. Several case reports describe treatment regimens involving surgical resection with adjuvant chemotherapy or radiation treatment; however, survival rates are exceedingly low. The presence of disseminated metastases, present in many patients at diagnosis, precludes surgical resection, and in most cases no treatment is able to be offered due to the critical nature of the neonate.Over the past few decades, the fruit fly Drosophila melanogaster, nematode Caenorhabditis elegans, and budding yeast Saccharomyces cerevisiae have been extensively used for lifespan studies because of their relatively short lifecycles and, especially, the ease of producing knockouts of specific genes. In addition to genetic manipulations, these organisms are also used in the search for anti-aging medicinal preparations. For instance, studies on S. cerevisiae disclosed anti-aging properties of resveratrol, a plant-derived compound, well established by its presence in some types of wine. Drosophila has also been checked for anti-aging properties of resveratrol, as well as 4-phenylbutyrate, caffeine, curcumin, statin, Rhodiola rosea and Rosa damascena, blueberry extract and many other preparations. Changes in diet composition,strawberry gutter system namely dietary and caloric restriction, were also found to extend fruit fly lifespan. Several molecular mechanisms have been proposed for dietary or drug-mediated longevity enhancement. In particular, FOXO , TOR and AMPK signaling pathways are believed to be involved in lifespan-prolonging effects of many treatments, as determined by experiments conducted on fruit fly model.
These pathways are now extensively investigated in many aspects, and many interconnections between them have already been reported. One of the common features of all these signaling pathways is their relation to the stress resistance of organisms. Notably, in many cases, an extended lifespan is accompanied by an increased stress resistance of survivors who have consumed food supplemented with an anti-aging medication. Moreover, one of these life-prolonging preparations, Rhodiola rosea, is a well-known adaptogenic herb. This plant is widely used in folk medicine among Ukrainians living in the Carpathian Mountains, as well as among people in other regions of Eurasia, including Finland, Russia, and China. Preparations from rhizome-like roots of this plant are shown to have cardioprotective, antidepressant, anticancer, antihyperglycemic, antinarcotic, and other beneficial activities. Multiple studies reported that R. rosea extract can enhance resistance to heat stress, heavy metals, and redox-cycling agents. Experiments on the adaptogenic properties of R. rosea have been conducted in animal models, including rats, mollusks, and worms. Recent studies in Drosophila melanogaster have shown that R. rosea can also be used as an anti-aging pharmacological agent. The intriguing relationship between aging and stress resistance is increasingly mentioned in contemporary gerontology. Moreover, it was shown that many adaptogens have antiaging properties; conversely, many anti-aging preparations were found to increase adaptive capabilities.
It has also been hypothesized that stressed plants can synthesize stress-signaling molecules, which increase stress resistance of herbivorous species. In this study, we pursued several goals. Particularly, we wished to reproduce and confirm previous results independently, running experiments in Ukraine on a fruit fly line, caught from nature, and using freshly prepared unprocessed R. rosea rhizome. In some cases, especially for the newly discovered preparations, repeated tests in different laboratories are thought to be useful prior to the search for a molecular mechanism. We also tried to validate adaptogenic properties of our rhizome preparations by checking the resistance of flies fed R. rosea to potential oxidative stress, exerted by menadione, and heat stress. Along with mobility and fecundity, stress resistance can also be examined as an estimate of ‘life quality’. It is noteworthy that not all life-extending medications can improve health span, and this may not be acceptable in the medical sense. Thus, checking health span indices would be important for recognition of an anti-aging remedy with minimum negative side effects. Here, we present data on the life-long stress resistance of fruit flies fed a diet supplemented with R. rosea rhizome powder. Our last goal was to define optimal dietary conditions for the anti-aging effect of R. rosea. This effect can be modulated by different factors, and diet is thought to be one of the most critical. Recent studies have shown that the median lifespan of a population depends not only on the total caloric value of the diet but also on the dietary composition, especially the protein-to-carbohydrate ratio.
If diet modulates the effect of anti-aging pharmacological intervention, the maximum life-prolonging effect may be seen only for some certain dietary conditions, whereas others might not be so favorable. The same is true for health-promoting effects. The dietary response could also provide some implications for the primary molecular targets of R. rosea bio-active compounds, among which salidroside, rosavins, and p-tyrosol are the most studied. In this work, we show how dietary composition may affect life extension and food intake with R. rosea supplement.Previously, it was found that R. rosea increased lifespan in fruit flies. These studies were performed at the University of California in Irvine using R. rosea powder manufactured and processed in China, and a Drosophila melanogaster line, caught in nature and kept for a long time at the laboratory conditions. In Ukraine, Rhodiola rosea, called ‘golden root’, is a famous medicinal herb known to increase working capacity, stamina, and health in general. The plant grows predominantly in mountainous areas around 1000 m above mean sea level. In the Carpathian Mountains, R. rosea is relatively accessible, and the fresh roots can be collected. Virtually every year, research teams from medical universities in the West Ukraine publish their results on multiple health benefits provided by administration of R. rosea extract in local journals. Here we tried to reproduce experiments conducted previously using freshly prepared roots of R. rosea and a wild D. melanogaster line collected in western Ukraine. We have found that supplementation of fruit fly food, containing 5% yeast and 5% sucrose, with 5.0 mg/ml and 10.0 mg/ml of R. rosea rhizome extended the median lifespan of flies of both sexes by 14% to 17% . The same concentrations of R. rosea rhizome increased maximum lifespan of the females by between 3% and 6%. No significant effects on maximum lifespan were observed in males fed with food supplemented by R. rosea in mentioned concentrations. Notably, females and males fed diet supplemented with 2.5 mg/ml and 30.0 mg/ml rhizome had, respectively, a 6% and 15% lower maximum lifespan, compared with the control. Moreover, 30.0 mg/ml of R. rosea decreased median lifespan by 9% to 12% , demonstrating possible toxic effects of the rhizome at the higher concentrations.In previous studies, flies were fed diets containing yeast paste mixed with bio-active compounds from R. rosea, as either rhizome powder [7] or standardized rhizome extract. The lifespan-extending concentration of R. rosea powder, which did not lead to a significant decrease in fecundity, was 60 mg/ml powder. When the extract was used, its active concentration was 25 mg of the extract per 1 ml yeast paste; however, 125 mg/ml extract exhibited a maximum effect. In these experiments,grow strawberry in containers amounts of R. rosea powder mixed into fly food were several times smaller, while the highest concentration, 30.0 mg/ml, shortened lifespan. Nevertheless, it is now possible to say that R. rosea definitely increases the median lifespan of fruit fly cohorts, regardless of the preparation type, supplementation method, basic diet, or fruit fly line. The maximum increase in mean lifespan, shown in previous studies, was around 30%. In this study, an increase of up to 17% was obtained for the diet with 5% and 5% sucrose, with 10.0 mg of R. rosea rhizome powder per 1 ml of food. The differences in the lifespan-prolonging effects obtained in previous studies and this one can be related to differences in the method of R. rosea supplementation and diet.
In particular, the research team in UCI used banana-molasses food, which contains a different set of vitamins and other essential micro-nutrients than the plain yeast-and-sucrose food used in the current experiments. It is possible that R. rosea might prolong lifespan even further in combination with vitamins and other bio-active substances. Moreover, consumption of yeast paste by fruit flies could be less than consumption of ordinary food containing carbohydrates. This could also be the cause of the reductions in fruit fly fecundity with R. rosea preparation found in previous studies. It is known that ingestion of yeast influences the amount of eggs laid by female fruit flies. When yeast and R. rosea preparation are combined in one supplement, the preparation might affect consumption of the whole supplement, and even at the level of food choice. In this study, we have suggested that R. rosea might influence food consumption and in this way regulate lifespan.Food intake was assessed in 6- and 16-day-old females by the amount of food dye, erioglaucine, ingested within 15 min intervals. Six-day-old flies kept on Rhodiola supplemented food did not show significant difference in food consumption as compared with control flies , while 16-day-old individuals fed food supplemented by 5.0 mg/ml Rhodiola rhizome consumed 1.4-, 1.8-, and 3.1-fold less food than controls on diets containing 5%, 10%, and 15% yeast and sucrose, respectively. However, addition of 30.0 mg/ml of Rhodiola supplement led to a halving in ingestion of the food containing 5% yeast and 5% sucrose. Alternatively, feeding was quantified by counting the flies sitting on the food surface directly, as described in. The percentage of flies on the surface of the media with their proboscis extended and touching the food was significantly lower when food was supplemented with 5.0 mg/ml Rhodiola . Thus, a reduced intake of yeast paste in previous studies could be the reason for reduced fecundity, despite it having been shown previously that the influence of R. rosea on yeast consumption is not significant. It was shown that feeding behavior of D. melanogaster is regulated by many mechanisms, including the TOR pathway and its target S6 kinase, the insulin signaling pathway, and developmental hormones. It was recently shown that feeding behavior of D. melanogaster larvae could be regulated by S6 kinase, the downstream target of TOR and phosphoinositide-dependent kinases. Larvae with up-regulated S6K consumed less food. However, a decrease in food consumption, conferred by R. rosea preparation, implies activation of S6 kinase,and, hence, activated TOR kinase. In turn, S6 kinase may inhibit the insulin signaling pathway by phosphorylation of insulin receptor substrate, thus promoting activity of transcriptional factor FOXO. It was found that DAF-16, the FOXO homolog in C. elegans, might be involved in the life-prolonging effect of R. rosea preparations. There are also other regulators of food intake; one of these is the juvenile hormone-binding protein Takeout. It is known that Takeout mutation results in the increased food ingestion. However, Takeout has been shown to regulate feeding time, rather than ingestion rate. Food intake in D. melanogaster is also regulated by bio-genic amines, particularly by serotonin or octopamine. Increased serotonin concentration is considered a satiety signal and inhibits food consumption in insects. It was also suggested that serotonin and octopamine might regulate insulin secretion by insulin-producing cells in Drosophila brain, thus potentially influencing the insulin signaling pathway. This explanation seems plausible, since R. rosea rhizome contains many compounds, such as kaempferol, found as inhibitors of monoamine oxidase, an enzyme catalyzing oxidation of bio-genic amines. Moreover, it was shown that R. rosea preparations are able to inhibit monoamine oxidas. On the other hand, some monoamine oxidase inhibitors, as well as some monoamines themselves, were shown to extend lifespan. Notably, our data have shown that R. rosea does not extend lifespan as much as the mth or chico mutations, or other compounds, for example, 4-phenylbutyrate. In this case, it would be interesting to know which age stratum of individuals would benefit most from the R. rosea treatment. Pursuing the latter goal, we have analyzed Gompertz equation parameters as the next step.In our understanding, the estimates A and α are not related precisely to the aging process itself, and tell us nothing about the rate of physiological changes in an individual. Nevertheless, these parameters could be examined as a good quantitative representation of the most susceptible age stratum in the cohort. For instance, a high A value would indicate accelerated dying among young individuals, while a high α would indicate quick dying in a group of older individuals, which, in our case, constitutes more than 90% of the whole cohort at the time of its half-life. Thus, in this case, we could suppose that the action of R. rosea might depend on the physiological state of the organism, accelerating the death of the least robust organisms, supporting survival of the organisms with a moderate robustness, and not influencing the most robust individuals. This approach partly explains why R. rosea supports survival of ‘young’ female Drosophila, suggesting that they are more resistant to environmental perturbations than males of the same age.