Abstract: This research aims to establish an UPLC method for the determination of crocin I and crocin II in Gardenia jasminoides var.grandiflora, and study on content variations of crocin I,crocin II and gardenoside in G.jasminoides var.grandiflora with different harvesting times.The extract from 80% methanol ultrasonic extraction was used to determine the contents of crocinⅠand crocinⅡby UPLC-DAD.System suitability conditions were as follows:column:Agilent Pro120 EC C18 (50 mm×4.6 mm,2.7 μm),mobile phase:water(A)-acetonitrile (B) with gradient elution mode (0-5 min,5%-20%B;5-17 min,20%-27%B),column temperature:15 ℃,flow speech:0.8 mL/min,detection wavelength:440 nm.The content of gardenoside was determined by the method of content determination of G.jasminoides from Chinese Pharmacopoeia (2015 edition).The methodological studies showed that the linear ranges were 49.5560-955.6000 ng (r=0.9995) for crocin I,5.9045-1180.9000 ng (r=0.9997) for crocin II.The average recoveries of crocin I and crocin II were 98.17% and 99.67% (n=9),respectively.It was proved that the method for the determination of crocin I and crocin II was simple,stable,reproducible and well separated.With prolonging of harvesting time,the contents of crocin I and crocin II increased gradually.However,the content of gardenoside decreased firstly and then increased gradually to a balance value.The study provided experimental basis for determining the optimal harvesting time of G.jasminoides var.grandiflora fruits.

Key words: Gardenia jasminoides var.grandiflora, crocin I, crocin II, gardenoside, UPLC-DAD, assay