ABSTRACT
AIM To investigate the correlations between antioxidant activities and contents of total flavonoids and total phenols of chloroform,ethyl acetate,n-butanol and ethanol extracts from Nervilia fordii (Hance) Schltr..METHODS The contents of total flavonoids and total phenols in four extracts from N.fordii were determined by AlCl3-HAc-NaAc coloration method and Folin-Ciocalteu colorimetric method,respectively.The antioxidant activities of extracts were evaluated by determining scavenging activities of DPPH radical,hydroxyl radical and ABTS radical,together with reducing power.Then the correlations between antioxidant activities and contents of two constituents were analyzed by SPSS17.0 software.RESULTS The antioxidant activities of four extracts from N.fordii all showed dose-effect relationships,that of ethyl acetate extract was the strongest,while that of ethanol extract was the weakest.They had some correlations with the content of total flavonoids (0.604 ＜ r ＜ 0.638) and significant correlations with the content of total phenols (r ＞ 0.977).CONCLUSION Ethyl acetate extract from N.fordii can be used for the development of natural antioxidants,and the content of total phenols is the main factor to influence its antioxidant activity.
ABSTRACT
Objective To optimize the method for total DNA extraction and RAPD analysis of Nervilia fordii (NF),and to study the genetic diversity of different breeds of NF,the substitute of NF and the fake of NF at molecular level.Methods We used low-pH extraction medium with high salt to extract total DNA,and used randomly amplified polymorphic DNAs (RAPD) to select polymorphism primer from 49 random primers.Twenty-two kinds of NF samples were analyzed by RAPD,and classified by SPSS.Genetic diversity were estimated by Shonnon's index and Nei's index.Results A higher puritiy of DNA can be obtained from fresh HF than that from medical materials.We selected 19 polymorphism primers for the cluster analysis of fresh NF and dried medical material.For medical materials of NF,the distance of amplification band of small-leave breed is close to that of middle-size leave breed,but is far away from that of,big-leave breed and Nervilia plicata.For the fresh materials of NF,there breeds of Nervilia fordii can be classified into one kind,the distance of fresh NF band is far from that of Nervilia plicata,Pachyrhizus erosus and the cultured breed,and more far awary from that of Plantago asiatica and Centella asiatica.Shonnon's genetic diversity is 0.463,Nei's genetic diversity is 0.267.Intra-population genetic variation is obvious compared to iner-population genetic variation.The estimated gene flow from Gst (Nm) is 0.94.Conclusion The molecular difference in different breeds of Nervilia Fordii can be used to identify Nervilia Fordii.The genetic diversity of Nervilia fordii is mainly caused by the geography environment.