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Authentication and quality assessment of Plumeriae Rubrae Flos by UHPLC-QTOF-MS/MS and UHPLC-DAD combined with chemometrics.

BACKGROUND
Plumeriae Rubrae Flos, the dried flowers of Plumeria rubra cv. acutifolia (PRCA), is one of the most important materials of herbal tea in China. Recently, due to the lack of effective quality evaluation standards, it has been found that Plumeria rubra (PR) and Plumeria rubra var. alba (PRVA) were pretended to be PRCA in herbal material markets.


OBJECTIVE
To establish an effective method for comprehensive quality assessment on Plumeriae Rubrae Flos, and distinguishing PRCA from its common adulterants, PR and PRVA.


METHOD
In this study, a method combined application of ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS), UHPLC with a diode array detector (UHPLC-DAD) and chemometrics was developed for qualitative and quantitative analysis of PRCA, PR and PRVA, based on their multiple components.


RESULTS
A total of 26 components were identified by UHPLC-QTOF-MS/MS, including 9 flavonoids, 8 iridoids, 7 phenolic acids and 2 coumarins from PRCA. Quantified fingerprints were established and validated using UHPLC-DAD based on 18 chemical markers in PRCA, PR and PRVA samples. The multivariate statistical analysis of quantitative results demonstrated clear discrimination of PRCA, PR and PRVA, which indicated that isoquercetin, luteolin-3'-O-β-D-glucoside, 15-demethylplumieride P-E-coumarate and 4-O-beta-glucopyranosyl-cis-coumaric acid could be considered as the most obvious characteristic components for distinguishing PRCA from PR and PRVA.


CONCLUSIONS
A combination of quantitative fingerprint and chemometrics analysis provided an effective and reliable strategy for the quality control of PRCA.


HIGHLIGHTS
The current study was prospected to apply a comprehensive quality control method for Plumeriae Rubrae Flos.