Effect Of Dendrobium Officinale Polysaccharides On The Lifespan Of Caenorhabditis Elegans And Its Mechanism

In this paper, we studied the effects of Polysaccharides from Dendrobium officinale on the Caenorhabditis elegans'lifespan, in terms of tolerance and health expectancy. The extraction process polysaccharide was water extraction and ethanol precipitation. Being model organism, three strains of nematode named as CB1370 (daf-2(el370) III),CF1038 (daf-16(mu86) I) and TJ365(DAF-16::GFP), respectively, were exploited to probe the possible mechanism of action of dendrobium polysaccharide. The results showed that the polysaccharide yield is 17.66%, and the content is 91.35% of the crude polysaccharide;The lifespan of C.elegans was significantly extended, and the stress tolerance was markedly enhanced than control group. The most noticeable is the enhancing in the heat stress resistance. At the same time, the healthspan of C.elegans was lengthened under heat stress and oxidative stress. The results demonstrated that the polysaccharide possibly extended the lifespan of C.elegans by enhancing its stress tolerance; The polysaccharide could not extend the lifespan of the CB1370, CF1038 nematode strains, but it could apparently extend the life span of wild-type N2 nematodes strain, which implying that the polysaccharide could extend the lifespan of C.elegans possibly via DAF-2 and DAF-16 gene or the insulin signaling pathway; In subcellular localization assay of DAF-16, the polysaccharide could notably strengthen the capability of transportation and expression of DAF-16 under the condition of 35?, then promote the stress tolerance of TJ365, which indicated that the polysaccharide finally acted on the downstream genes DAF-16 of insulin signaling pathway. Through real-time quantitative PCR assay, we found that the polysaccharide upregulated the DAF-16 and HSP-16.2 genes, which implying that increasing the stress tolerance by improving the expression ability of DAF-16 could affect the lifespan of C.elegans. In conclusion, polysaccharide from D. officinale could extend the lifespan of C.elegans by promoting the stress tolerance through insulin signaling pathway downstream genes DAF-16.