Extension of Drosophila Lifespan by Rhodiola rosea Through an Anti-oxidant Independent Mechanism

S.E. Schriner, A. Abrahamyan, M. Holmbeck, A. Pavlov Jr., I.E. Bussel, M. Jafari
Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA

Rhodiola rosea is an adaptogenic plant that can increase the resistance of an organism to physical, mental and environmental stresses. Previously, we found that R. rosea could extend the mean life span of the fruit fly, Drosophila melanogaster, approximately 7%. We evaluated a new formulation of R. rosea (SHR-5) which contains elevated levels of the putative active compounds (rosin, rosarin, and rosavin), and found that it could extend mean life span by 43% (P<0.0001), and maximum life span by 33% when compared to control diet fed flies. The precise mechanism of R. rosea is currently unknown; however, it has been proposed to act as an antioxidant.

In order to test this hypothesis, we evaluated the survival of R. rosea fed and control Drosophila when subjected to three different oxidative stresses: paraquat, H2O2, and iron-nitrilotriacetic acid (Fe-NTA). Supplementation of R. rosea afforded enhanced protection against paraquat in male flies (P=0.011) and had a borderline protection in female flies (P=0.052). Female R. rosea fed flies had an elevated resistance to H2O2 (P<0.002), whereas no protection was observed in males (P=0.61). The opposite result was found with Fe-NTA treatment in which males benefited from R. rosea feeding (P=0.0011) and females did not (P=0.51). We also found no effect of R. rosea feeding on the enzyme activities of catalase, and the cytosolic and mitochondrial superoxide dismutase isoforms, nor did we observe a change in mitochondrial respiratory parameters. The findings that R. rosea does not afford a generalized protection against oxidative insults, does not alter the major antioxidant enzymes, and does not alter mitochondrial respiration, suggest that R. rosea may extend fly life span through an antioxidant independent mechanism.

Keywords: Rhodiola rosea, Drosophila, Lifespan, Anti-oxidants, Oxidative stress