Cycloastragenol (TA-65), a small-triterpenoid purified from the root of an Asian medicinal herb, has currently received particular attention for its potential to regulate transcription of telomerase. TA-65 is capable to increase average telomere length and to decrease the percentage of critically short telomeres and DNA damage in MEFs that harbor critically short telomeres. The effects on telomerase appear to be in common with other triterpenoid saponins (ie, ginsenosides RG1 and Rg3). These compounds at concentrations from 1 to 20 μM were reported to protect against IL-1β-, H2O2-, and tert-butylhydroperoxide-induced senescence in human chondrocytes, endothelial progenitor cells and fibroblasts, respectively.
