Ethanol extracts of Panax notoginseng increase lifespan and protect against oxidative stress in Caenorhabditis elegans via the insulin/IGF-1 signaling pathway

Abstract

Panax notoginseng (Burk.) F.H. Chen (PN) has been widely used as an edible and medicinal resource in China, with PN powder being used in dosage form. The present study aimed to investigate the optimal powder size of PN and evaluate its anti-ageing effect in Caenorhabditis elegans. Firstly, four PN powders of different sizes were prepared and their extracts were obtained. These extracts improved the lifespan of Caenorhabditis elegans, with FPE having the greatest effect. Moreover, FPE increased the activity of antioxidant enzymes and reduced the accumulation of reactive oxygen species. FPE also decreased the lipofuscin level and the carbonylated protein content. At the same time, FPE affected the mRNA expression levels of sod-3, hsp-16.2, daf-2, and daf-16 involved in the insulin/IGF-1 signaling pathway, as detected by RT-PCR. Furthermore, the upregulation of SOD-3::GFP and HSP-16.2::GFP following addition of FPE was quantitated using fluorescence. Daf-2 and daf-16 mutants were used for the survival assay, and no life span extension was observed. These observations not only revealed that fine powder is the optimal particle size for PN, but also validated that the anti-ageing effects of PN are mediated by the insulin/IGF-1 signaling pathway.

Keywords

• Panax notoginseng
• Powder
• Caenorhabditis elegans
• Anti-ageing
• Insulin/IGF-1 signaling pathway