Enhanced biological activities of gamma-irradiated persimmon leaf extract

The aim of this study was to compare the anti-oxidative and anti-inflammatory activities of gamma-irradiated persimmon leaf extract (gple) with those of non-irradiated persimmon leaf extract (ple). ethanolic extract of persimmon leaf was exposed to gamma irradiation at a dose of 10 kgy. after gamma irradiation,the color of the extract changed from dark brown to light brown. the anti-oxidative and anti-inflammatory activities of gple and ple were assessed from: total polyphenol and total flavonoid contents; 2,2-diphenyl-1-picrylhydrazyl (dpph) assay; 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (abts) assay,and levels of pro-inflammatory mediators such as nitric oxide (no),prostaglandin e2 (pge2),tumor necrosis factor alpha (tnf-α) and interleukin-6 (il-6). the total polyphenol contents of gple and ple were determined to be 224.44±1.54 and 197.33±5.81 mg gallic acid equivalents (gae)/g,respectively,and the total flavonoid contents of gple and ple were 206.27±1.15 and 167.60±2.00 mg quercetin equivalents (que)/g,respectively. the anti-oxidant activities of gple and ple as measured by dpph assays were 338.33±30.19 êg/ml (ic50) and 388.68±8.45 êg/ml (ic50),respectively,and those measured by abts assays were 510.49±15.12 êg/ml (ic50) and 731.30±10.63 êg/ml (ic50),respectively. ic50 is the inhibitor concentration that reduces the response by 50%. gple strongly inhibited the production of no,pge2 and il-6 compared with ple in lipopolysaccharide-stimulated raw264.7 macrophages. furthermore,gple significantly inhibited the production of tnf-α and il-6 cytokines compared with ple in phorbol 12-myristate 13-acetate (pma) plus a23187-stimulated hmc-1 human mast cells. these results indicate that gamma irradiation of ple can enhance its anti-oxidative and anti-inflammatory activities through elevation of the phenolic contents. therefore,gamma-irradiated ple has potential for use in the food and cosmetic industries. © 2017 the author.