Three new flavonoids from the seeds of Hippophae rhamnoides subsp. sinensis

To study the chemical constituents of the seeds of Hippophae rhamnoides subsp. sinensis, three new flavonoids acylated with one monoterpenic acid, named 3-O-β-D-glucosyl-kaempferol-7-O-{2-O-[2(E)-2,6-dimethyl-6-hydroxy-2,7-octadienoyl]}-α-L-rhamnoside (3), 3-O-β-D-sophorosyl-kaempferol-7-O-{3-O-[2(E)-2,6-dimethyl-6-hydroxy-2,7-octadienoyl]}-α-L-rhamnoside (4), and 3-O-β-D-sophorosyl-kaempferol-7-O-{2-O-[2(E)-2,6-dimethyl-6-hydroxy-2,7-octadienoyl]}-α-L-rhamnoside (5), together with four known compounds, were isolated from the seeds of H. rhamnoides subsp. sinensis. Compounds 1 and 2 are reported for the first time from this genus. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D and 2D NMR and HR-MS, and by comparison with literature data.