Dynamics Of Total Polyphenols And Flavonoids Concentration Of Alpine Meadow Plants And Their Antioxidant Activity

The present research was conducted from mid-June to mid-September2012in Tianzhu County Jinqiang river in Gansu Province. The main14families of24species included that Salix oritrepha、Hippophae thibetana、Potentilla fruticosa、Spiraea alpina、 Leycesteriarupicosavar,syringantha、Berberis kansuensis、Subseet. Lapponica、Daphne odora、 Astragalus mahoschanicus、Oxytropis ochrocephala、Polygonum viviparum、Rheum palmatum、Ligularia sagitta、Gentiana marophylla、Potentilla anserina、Pedicidaris kansuensis、Caragana jubata、Kobresia capillifolia、Kobresia tibetica、Hedrysarwn multijugum、Thalictrum alpinum、Leontopodium nanum、Aconitum pendulum、Anaphalis lactea were collectted in the middle of every month. The determining were focused on the shoots and leaf of the targeted plants by the Folin-Ciocalteu method and aluminum salt colour reaction. The total antioxidant capacity was estimated by the following methods:ABTS.+, ferric reducing/antioxidant power(FRAP). The correlation of polyphenol contents and antioxidant capacity of alpine plants was analysised.The results showed that:(1) The total phenolic content of the study the plants changed in a different month:and the increasing trend was by month, the total phenolic content of most plants during6to8months there have been an increasing trend, a downward trend in September; simple phenol content of6to8months have an increasing trend, a downward trend in September; tannin content increasing month by month, the lowest in June, the highest in September; flavonoid content increasing month by month, the lowest in June, the highest in July and August,but September has a downward trend.(2) Antioxidant ability in the June to August increasing month by month, the lowest in September. Test sample FRAP value is between4.63and49.58mmol·L-, there are some differences about total antioxidant capacity of24kinds of alpine plants among fruticosa, Salix oritrepha, Spiraea alpina, Tibetan sea buckthorn shrubs and perennial herb Polygonum viviparum five species showed strong antioxidant activity (FRAP>25mmol·L-1). (3) Total polyphenols, flavonoids and total antioxidant capacity in the FRAP method has extremely significant correlation (P<0.01),the relative coefficient reached a value of0.774and0.754,respectively.The analys is about24alpine plants showed that the higher total polyphenols and flavonoids,the stronger total antioxidant capacity was.(4) It is can be seen that all the samples containing phenolic hydroxyl by the phenolic hydroxyl detection reaction,but all the samples containing phenolic hydroxyl, phenolic hydroxyl in different samples have different positions and numbers, resulting that there are some difference in the detection reaction.In addition,it may has some error to judge the blue and green by sensory judgment, and also can not make sure that the samples containing phenolic hydroxyl are much more.