plants are rich source of phenolic compounds (phenolic acids, flavonoids and tannins) that are most important natural antioxidants. in the present study two ultrasonic methods including probe and bath were used for the extraction of phenolic and flavonoid compounds from celtis australis. the effects of different extraction time including 30, 60 and 90 min (bath method) and 5, 10 and 20 min (pro...