Abstract:

In the present study, we aimed to detect and quantify cyclo-dopa amides in Portulaca oleracea L. Together with four known ones (oleracein A–D), we further identified eight new cyclo-dopa amides, named oleracein H–O, using an HPLC-DAD combined with an improved HPLC-ESI-MS/MS method. A standardized HPLC fingerprint of cyclo-dopa amides was generated for the first time through analyzing 11 batches of P. oleracea. Simultaneously, the contents of two major amides, oleracein A (OA) and oleracein B (OB), and the total amides (TID) were determined. Our results showed that the contents of OA and OB of P. oleracea ranged from 35.00 to 151.93 mg/kg and from 40.00 to 150.44 mg/kg, respectively. Moreover, TID ranged from 314.16 to 928.60 mg/kg (calculated by OA), or from 475.83 to 1393.00 mg/kg (calculated by OB). Taken together, our newly developed method could be used for the quality assessment and quality control of this herb.

Key words: Portulaca oleracea L., Cyclo-dopa amide, Detection and quantification