the effect of chitosan on antioxidant activity and some secondary metabolites of mentha piperita l.

plants are almost reach sources of phenolic compounds such as flavonoids which are the most importantnatural antioxidants. antioxidant compounds are essential for protecting human body against oxidativestress. however use elicitors could increase the antioxidant activity of plant. the purpose of this studywas to evaluate the effects of chitosan on the content of phenolic and flavonoid compounds and alsoantioxidant activity mentha piperita l.in this study, firstly the mentha piperita l. were grown up for 6-weekperiod at greenhouse conditions and then were treated with 50-100 μm of chitosan, then total phenolic andflavonoid contents were determined using spectrophotometry and finally antioxidant activities of extractswere evaluated with 2,2-diphenyl-1-picryl hydrazyl (dpph) method and the results were analyzed withexcel software and variance analysis testing method with spss software. the results showed the contentof phenolic compounds in the methanol extract based on sample mg of gallic acid /g for control withwater, 50μm and 100μm treatments respectively were 146.8,233.1,339.1. meanwhile the total volumeof flavonoid content of the methanol extract per mg of rutin/g respectively were 9.88,12.11,14.06 andconcentration of the said extracts respectively were 196.3,147.7,128.62. in regard to the above resultsit can be concluded that due to having phenolic and flavonoid contents, mentha piperita l showed thatantioxidant activity could be stimulated upon chitosan treatment moreover, antioxidant activity increasedby increasing chitosan treatment content. therefore, this method can be used to increase antioxidant effectof plant as a natural antioxidant and all the phenolic and flavonoid contents.