ABSTRACT
OBJECTIVE To comprehensively screen the optimal steaming time of salt-steaming Morinda officinalis （SSMO） based on Q-markers and anti-oxidative activities， and to establish characteristic quality standard of the decoction pieces. METHODS The contents of six Q-markers （1-kestose， nystose， 1F-fructofuranosylnystose， inulotriose， inulotetraose and inulopentaose） in SSMO at different steaming time were determined by HPLC-ELSD method simultaneously. The activity of sample extracts to scavenge 4 kinds of oxidative free radical and their iron reduction abilities were determined by visible UV spectrophotometer. The optimal steaming time of SSMO was screened by gray relevance degree and entropy weight technique for order preference by similarity to an ideal solution （TOPSIS）-fusion model method. The contents of six Q-markers in 10 batches of SSMO prepared at the optimal steaming time were determined. HPLC-ELSD fingerprints of SSMO decoction pieces were established. RESULTS The results showed that the contents of six Q-markers were the highest when SSMO was steamed for 3-5 h； and the ability of scavenging DPPH·， ABTS·， PTIO·， ·OH and iron reduction ability was the best at 5 h. There were 20 common peaks in the fingerprints for 10 batches of samples， and the similarities were higher than 0.990. A total of 9 chromatographic peaks were identified， which were D-fructose （peak 1）， D（+）-glucose （peak 2）， sucrose （peak 3）， 1-kestose （peak 4）， nystose （peak 5）， 1F-fructofuranosylnystose （peak 6）， inulotriose （peak X2）， inulotetraose （peak X3） and inulopentaose （peak X4）. Average contents of six Q-markers were 4.17%， 5.54%， 6.60%， 2.89%， 2.62% and 2.13%， respectively. CONCLUSIONS The optimal steaming time of SSMO is 5 h； the contents of six Q-markers are primarily determined on the basis of dry product， which are no less than 3.03%， 4.11%， 4.87%， 2.15%， 1.96% and 1.58%， respectively. The ratio of Inulin-/Inulo oligosaccharides content is no more than 2.5.