Fingerprint and difference analysis of flavonoids of Hippophae plants grown on the Tibetan plateau

Plant genus Hippophae contains a variety of bioactive substances and has high nutritional and medicinal value. To help the classification of Hippophae plants and ensure its quality, a high-performance liquid chromatography-diode array detector (HPLC-DAD) fingerprinting method was established based on the distribution and relative contents of flavonoids. Chemometrics analysis were used to analyze and compare the differences of Hippophae samples. Differences were observed among Hippophae varieties, and different plants within the same variety showed good similarity. Chemometrics analysis showed that 16 samples of Hippophae fruit and 40 samples of Hippophae leaf were divided into three groups. Four flavonoids were identified in fruit (isorhamnetin-3-O-glucoside-7-O-rhamnoside, rutin, isorhamnetin-3-O-rutinoside, and isorhamnetin) and five were identified in leaf (quercetin-7-O-glucoside, isorhamnetin-3-O-glucoside-7-O-rhamnoside, rutin, guaijaverin, and kaempferol-3-O-rutinoside). The highest flavonoid content in fruit was observed in Hippophae rhamnoides ssp. yunnanensis (average 3.651 mg/g). In leaf, Hippophae neurocarpa had the highest flavonoid content (average 13.303 mg/g) and a higher flavonoid content was observed in male plants (average 8.348 mg/g) than in female plants (average 7.273 mg/g). Correlation was observed between flavonoid content and climate factors. HPLC fingerprinting combined with chemometric analysis and quantitative analysis can provide a good foundation for subsequent production and processing.