Effect of extraction condition with two ultrasonic methods on phenolic,flavonoids and DPPH free radical scavenging of Celtis australis extract

Plants are rich source of phenolic compounds (phenolic acids, flavonoids andtannins) that are most important natural antioxidants. In the present study twoultrasonic methods including probe and bath were used for the extraction of phenolicand flavonoid compounds from Celtis australis. The effects of different extraction timeincluding 30, 60 and 90 min (bath method) and 5, 10 and 20 min (probe method) onextraction of phenolic and flavonoid compounds were evaluated and then the ability ofextracts to scavenge DPPH free radical were evaluated using three extraction solvent ofwater, 80% methanol and 70% ethanol. The results showed that in the probe method of ultrasonic, the highest phenolic compound (8.906±0.017 milligrams gallic acid/ g drysample), the flavonoid (3.35±0.056 mg of quercetin/g of dry sample) and DPPHradical scavenging activity (94.723±1.127 mg of quercetin/g of dry sample) and DPPHradical scavenging activity (94.74%) were obtained using 70% ethanol within 20minutes extraction. The minimum extraction of phenolic compounds was obtainedusing water for 5 minutes with 4.315±0.184 milligrams gallic acid/ g dry sample. In theultrasound bath, the highest extraction rate of phenolic compounds (8.816±0.015 mggallic acid equivalent/ g dry sample) was extracted using 70% ethanol for 90 minutes.The ethanol 70-90 minutes with 2.536±0.02 mg of quercetin/ g of dry sample showedthe highest extraction rate of flavonoid compounds between all treatments. Theminimum extraction of phenolic, flavonoid, DPPH radical scavenging activity wasobtained using water -30 minutes (for ultrasonic Bath) and water - 5 minutes (forultrasonic probe). Results showed that two methods of ultrasound had different effecton extraction of bioactive compound from Celtis australis. In each extraction method,the extraction rate of phenolic and flavonoid compounds were solvent-dependent.