Garlic is an herb plant containing bioactive compounds such as phenolic compounds and allicin which possess antioxidant and antibacterial activities. Previous works reported that conventional extraction of these compounds by solvent extraction resulted in low level of yield and long extraction time that might cause degradation of the extracted compounds. Thus, this research aimed at studying ultrasonic-assisted extraction of phenolic compounds and allicin for growth inhibition of Escherichia coli at amplitude of 30% 60% and 90% for different extraction times. The results showed that yield of phenolic compounds and allicin using ultrasonic-assisted extraction was 2 times as high as that conventional extraction with shorter extraction time. Moreover, the condition of ultrasonic-assisted extraction at amplitude of 60% for 40 min was recommended for phenolic and allicin extraction with the highest yield of phenolic compounds and allicin about 351.48 ? 45.11 mg gallic acid/ml of extract and 63.16 ? 5.09 mg/ml. The results was also observed that average of inhibition zone using ultrasonic-assisted extraction did not significantly different when compared with 0.1% W/V chemical preservative (sodium benzoate).
Keywords: Antimicrobial, Allicin, Extraction, Garlic, Ultrasonic