Identification of phenolics and nucleoside derivatives in Gastrodia elata by HPLC-UV-MS.

An HPLC-UV-MS method for simultaneous identification of predominant phenolics and minor nucleoside derivatives in Gastrodia elata was developed, which was based on their UV and MS characteristics summarized through a series of homemade reference standard experiments. Phenolics showed characteristic UV lambda(max) at 267 nm, M + NH(4) base peak in positive mode and M-H base peak in negative mode while nucleosides exhibited UV lambda(max) at 255 nm, M + H, M-H + 2H(2)O or M-H + CH(3)COOH. Phenolics conjugates mainly underwent the consecutive loss of gastrodin residue (-268 U) and the combined loss of H(2)O and CO(2 )from the citric acid unit under negative MS/MS conditions whereas nucleosides simply lost the ribose (-132 U) under positive MS/MS conditions. According to these characteristics, a special pattern under MS/MS conditions and reported compound data for G. elata in the literature, not only 15 phenolics were identified but also 6 nucleoside derivatives were identified. Among these compounds, seven phenolics and three nucleoside derivatives have not been reported yet from G. elata.