Objective: To determine the contents of the active components gallic acid

protocatechuic acid

corilagin and ellagic acid in Erodium stephanianum from different collection time and to define the best collection time for this herb. Method: The RP-HPLC method was applied and the separation was performed on an Agilent TC-C18 analytical column(4.6 mm×250 mm

5 μm).The mobile phase was methanol(A)-water containing 0.4%H3PO4(B) with gradient elution mode at the flow rate of 0.8 mL·min-1.The detection was set at 259 nm

and the column temperature was 30 ℃. Result: The liner ranges of gallic acid

protocatechuic acid

corilagin and ellagic acid were 0.492-4.920 g·L-1(r=0.999 3)

0.497-4.970 g·L-1(r=0.999 7)

0.995-9.950 g·L-1(r=0.999 8)

0.989-9.890 g·L-1(r=0.999 7)

respectively. The average recoveries were 100.46%(RSD 2.1%)

99.78%(RSD 1.3%)

100.18%(RSD 1.0%)

100.21%(RSD 1.4%)

respectively. Conclusion: The content of gallic acid and protocatechuic acid

in E. stephanianum increased to the maximum value in late May

the content of corilagin and ellagic acid increased to the maximum value in late June. Four acids active compounds increased to the maximum in late June.