Abstract: The extraction and antibacterial activity of Seabuckthron flavonoids, were investigated. Distilled water and ethanol were chosen as the extraction solvents, ultrasonica was used as an extraction method. The contents of total flavonoids and polyphenol were tested by UV-VIS spectrophotometer. Cylinder plate assay and tube doule dilution were used to test antibacterial activity on 13 genus of ordinary food contaminating microorganisms. The results showed that the flavonoid content of Qinghai Seabuckthorn leaves and its antibacterial activity were significantly better than those of large berry Seabuckthorn leaves from Neimenggu province. Ethanol is better in extraction and antibacterial activity of flavonoids than distilled water, and ultrasonica could enhance the dissolving of compounds with antibacterial activity.

Key words: Seabuckthorn leaf, flavonoid, polyphenol, extraction, antibacterial activity