This study investigated the antioxidant activities, and antimicrobial activity in vitro of an 80% ethanol extract from garlic, daikon, leek, ginger, onion, and green onion, which are widely-used ingredients in Korean food that contain sulfur. The total polyphenol content in ginger and leek extracts showed a high value (233.63±4.59 and 220.98±10.56 mg/g GAE) and onions, leeks, garlic, and daikon followed by with 69. 07±1.42, 68.83±2.11, 19.41±0.40, 19.05±03.32 mg/g GAE, respectively. DPPH radical scavenging activity was highest with ginger extracts (1.57±0.15 mg/mL as IC50) followed in order of decreasing activity by leeks, onions, daikon, green onions, and garlic. The results of ABTS radical scavenging activity and FRAP value showed higher antioxidant activity in extracts from ginger and leek. The order of vegetables with most to least prevalent ABTS radical scavenging activity was green onions, onions, garlic, and finally daikon. From greatest to least FRAP value, the relevant vegetables were green onions, onions, daikon, and garlic (p<0.05). Ginger extracts showed promise against seven strains of microbes: Bacillus cereus, Bacillus subtillis, Staphylococcus aureus, Lactobacillus plantarum, Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa. Garlic extracts (5 mg/disc) showed strong antimicrobial activity against B. cereus (22.3 mm) and E. coli (24.3 mm). Extracts of both onion and green onion showed antimicrobial activity against only E. coli (12.7 and 10.3 mm) and B. cereus (12.0 and 12.5 mm) at 10 mg/disc, and the inhibition zone diameter from extracts of garlic and leeks were 18.0 mm and 10.4 mm vs. L. plantarum at 10 mg/disc. This study showed positive antioxidant activities for ginger and leeks, and positive antimicrobial activities for leeks and garlic. These sulfur-containing vegetables are widely used in Korean food. Leeks especially could serve as a functional food preservative.
