Abstract: Seasonal variation of corilagin, geraniin as well as total phenolic contents during the growth period, where were obtained from the whole grass, roots, stems and leaves of Geranium sibiricum Linne, were investigated. The antioxidant capacity (FRAP, DPPH, ABTS) were evaluated to confirm the optimum picking part and stage. Results showed that corilagin (CG), geraniin (GE) and total phenolic contents (TPC) increased dramatically in the vegetative growth period (137.567 3±1.890 7 GAE/g extracts)and decreased gradually during the reproductive growth and withering period (74.7518±1.010 1 GAE/g extracts), while the total flavonoid contents (TF) was high in summer and reached the highest during the withering period. The optimum picking part and time were the whole grass and July, respectively, and the total antioxidant capacity (FRAP) was (12.321 5±0.188 2)mmol/g extracts. Correlation of the data obtained from principal composition analysis (PCA) showed that TPC, CG and GE had high relationship (r>0.753) and they also had high relationship with antioxidant capacity (|r|>0.75).

Key words: G.sibiricum Linne, polyphenol, seasonal variation, antioxidant capacity