Chemical fingerprint and quantitative analysis of flavonoids for quality control of Sea buckthorn leaves by HPLC and UHPLC-ESI-QTOF-MS

•An HPLC fingerprint method for Sea buckthorn leaf flavonoids was developed.•An UHPLC-ESI-Q/TOF-MS/MS method was established to identify flavonoids.•HCA and PCA were successfully applied to cluster samples.•Origin and collecting time impact the quality of Sea buckthorn leaves.•Monsoon climate may be the main factor. The fruits and leaves of Sea buckthorn (Hippophae rhamnoides L.) have been proved their important medicinal and nutritional values. In this study, a high-performance liquid chromatography (HPLC) fingerprinting method based on the distribution and relative amount of seven flavonoids was established for the food quality evaluation of Sea buckthorn leaves. The chromatographic peaks were identified using UHPLC-UV-ESI-QTOF-MS. The chemometrics procedure was applied to identify more useful chemical markers for improving the quality control standard. The results indicated that the HPLC fingerprint combining similarity evaluation and quantification analysis can be successfully used to assess the quality of Sea buckthorn leaves. Chemometrics analysis shown that the quality has a certain extent differences in recovery regions and harvest time, the best harvest time was May and June which the leaves in growing period. The factors influencing its quality were also suggested based on HCA.