The present invention relates to a composition for inhibiting cellular senescence comprising quercetin-3-O-β-D-glucuronide (Q3GA) as an active ingredient, and provides a composition for inhibiting cellular senescence of fibroblasts or umbilical vein endothelial cells induced by adriamycin or replicative senescence of fibroblasts or umbilical vein endothelial cells. Specifically, the quercetin-3-O-β-D-glucuronide (Q3GA) is characterized by being isolated from Polygoni avicularis herba extract. The composition may be usefully used for treating aging-related diseases, for example, skin aging, rheumatoid arthritis, osteoarthritis, hepatitis, chronically damaged skin tissue, arteriosclerosis, prostatic hyperplasia and liver cancer, by inhibiting a cellular senescence process of human fibroblasts and umbilical vein endothelial cells.
