Abstract: The study aimed to compare the phenolic components in Dendrobium officinale stems, leaves and flowers. An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established to determine the phenolic components. The samples were extracted with methanol in water, and the extract was separated on a Wates T3 C18 column by gradient elution. Then, the target compounds were analyzed by positive and negative electrospray ionization under the multiple reaction monitoring (MRM) mode. By employing 18 standard phenolic compounds as references, 15 phenolic compounds were detected in D. officinale samples, including 3,5-dihydroxybenzoic acid, tangeretin, chlorogenic acid, quercetin, rutinum, p-hydroxybenzoic acid, caffeic acid, syringate, kaempferol, vanillic acid, coumalic acid, sinapic acid, ferulic acid, 3-hydrocycinnamic acid, and salicylic acid. The contents of phenolic compounds in different parts of D. officinale were in the descending order of flowers > leaves > stems. Rutin was identified as the most dominant phenolic compound in the three parts There were differences in the major phenolic compounds in them. The major phenolic compounds in D. officinale flowers were rutin, caffeic acid, ferulic acid and p-hydroxybenzoic acid. The contents of rutin and caffeic acid in the leaves were higher than those of other phenolic compounds. The major phenolic compounds in the stems were rutinum, ferulic acid and vanillic acid. The results of this study may provide a scientific reference for the exploitation of phenolic substances in different parts of D. officinale.

Key words: Dendrobium officinale; ultra-high performance liquid chromatography-tandem mass spectrometry; multiple reaction monitoring; phenolic components; detection methods