Effect of atmospheric pressure dielectric barrier discharge plasma on the biological activity of naringin

The biological activity of naringin treated with atmospheric pressure plasma was evaluated to investigate whether exposure to plasma can be used as a method to improve the biological activity of natural materials. Naringin was dissolved in methanol (at 500 ppm) and transferred to a container. A dielectric barrier discharge (DBD) (250 W, 15 kHz, ambient air) was then generated. Treatment with the plasma for 20 min increased the radical-scavenging activity, FRAP value, and the total phenolic compound content of naringin from 1.45% to 38.20%, from 27.78 to 207.78 mu M/g, and from 172.50 to 225.83 ppm, respectively. Moreover, the tyrosinase-inhibition effect of naringin increased from 6.12% to 83.30% upon plasma treatment. Naringin treated with plasma exhibited antimicrobial activity against foodborne pathogens, especially Salmonella Typhimurium; an activity that was absent before plasma treatment. Structural modifications induced in the naringin molecule by plasma might be responsible for improving the biological activity of naringin. (C) 2014 Elsevier Ltd. All rights reserved.