Antimicrobial effect of perilla was examined, using microorganisms from air and pure cultures of fungi and bacteria.
Either 0.01% ether-extract of perilla leaves or 10% NaCl allowed considerable growth of microorganisms on usual agar media. However, it was found that in agar media containing more than 5% NaCl, the ether-extract of perilla leaves at a concentration of 0.01% completely inhibited growth of many kinds of microorganisms.
This synergistic antimicrobial effect of perilla and NaCl concentrations may offer a useful tool for preserving some foods without applying any synthetic preservative.