assesment of different dna extraction methods in medicinal plants

medicinal plants have high importance in medicine and pharmacogonosy because of their secondary metabolites. essential oils, antioxidants and flavonoids are the major compounds of many medicinal plants. these compounds especially antioxidants can increase oxidation of dna in response to wounds. nowadays, progresses in biotechnology such as molecular markers were used for phylogenetic relationships, construction of linkage maps and decreasing the repeated plants in gene bank. most of these methods need high dna quality and purity. different methods for dna extraction have been improved. in most cases three hints are considered including quality, quickness of extraction and its quantity. medicinal plants need to improve methods to prevent dna oxidation because of their phenolic compounds. in this study, four dna extraction methods were compared in thyme, spearmint, peppermint, horsemint and some yarrow species. these methods include murry and thompson, prittila et al, dellaporta et al and komatsuda et al method using blender.  the results showed that the combination of prittila et al and murry and thompson methods using two steps buffer and using mixed of 2- mercaptoethanol and polyvinylpyrrolidone (pvp) can decrease dna oxidation and improve dna amount. the lowest amount of dna and the quickest method was komatsuda et al procedure. in the studied plants, the highest and the lowest oxidation were observed in yarrow and spearmint, respectively.