Antioxidant and antimicrobial activities of commercial rice wine extracts of Taiwanese Allium fistulosum

The antioxidant and antibacterial activities of commercial rice wine extracts obtained from different plant parts of Allium fistulosum were assayed. The results showed that commercial rice wine extracts of A. fistulosum contained 28.3-95.9 μL/mL allicin and exhibited significant antioxidant and antibacterial activities. The DPPH radical scavenging capacity ranged from 90.2% to 52.1%, and the IC50 value ranged from 14.6 to 26.0 μg/mL. The total phenolic content of wine extracts was 56.4-198.9 mg GAE/g extracts. The TEAC assay of extracts ranged from 6.2 to 15.5 mmol/g extracts. Antibacterial activities were tested against 4 bacteria by using agar disc diffusion and tube dilution tests. All extracts exhibited antibacterial activities against gram-positive bacteria, such as Bacillus subtilis and Staphylococcus aureus, and gram-negative bacteria, such as Escherichia coli and Pseudomonas aeruginosa. Thus, A. fistulosum wine extracts could be used as natural and functional additives in cooking foods.