Correlation between Polyphenol Contents and Antioxidant Activities in Different Echinacea Purpurea Varieties

Objective:Polyphenols are complex compounds containing multiple phenolic hydroxyl groups.They are widely distributed in plants and have antioxidant activities.Whether the antioxidant activities of the cultivated varieties of Echinacea are similar to or better than those of the wild ones and the relationship between the accumulation of polyphenols and their antioxidant activities are still not clear.Methods:Folin-Ciocalteu method,high performance liquid chromatography(HPLC),2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging assay,ferric ion reducing antioxidant power(FRAP)assay,2,2'-azino-bis(3-ethylbenzothiazoline-6)-sulfonic acid(ABTS)radical scavenging assay,and Fe^(2+)chelating ability assay were used,respectively,to detect the total polyphenols and 5 kinds of caffeic acid derivatives(chicoric acid,caffeic acid,caftaric acid,chlorogenic acid,and 1,5-dicaffeoylquinic acid)in the roots,stems,leaves,and flowers,and the antioxidant activities of 3 varieties of Echinacea:E.purpurea L.,cultivar E.purpurea'Aloha',and E.purpurea'White Swan'.Results:E.purpurea L.had the highest contents of total polyphenols,5 caffeic acid derivatives and antioxidant activities,followed by E.purpurea'White Swan'and E.purpurea'Aloha',respectively.E.purpurea'White Swan'had the strongest ability to remove the DPPH,ABTS·^(+)and free radicals,and to chelate Fe^(2+);E.purpurea L.had the strongest ability to reduce FRAP.The correlation analyses revealed that the contents of total polyphenols and caffeic acid derivatives of E.purpurea L.and E.purpurea'White Swan'were correlated with their antioxidant activities.Conclusion:E.purpurea L.was the most appropriate material for the development of medicinal plants.E.purpurea'White Swan'could be used as a substitute for E.purpurea L.in terms of its antioxidant activity.

Diagnosis and Control of Rabbit Hemorrhagic Disease(RHD)

In this study, chronic-type rabbit hemorrhagic disease occurred in rabbit warrens of Shandong, Liaoning, Beijing and Hebei, which was mainly charac-terized by deaths of young and adult rabbits, longer durationand nerve symptoms, was surveyed by epidemiological investigation, bacterial isolation and incubation, artificial infection test and histopathologieal method to analyze the causes of chronic-type rabbit hemorrhagic disease and put forward the corresponding control measures.

Development of a reverse-transcription loop-mediated isothermal amplification assay to detect avian influenza viruses in clinical specimens

In recent years,the avian influenza has brought not only serious economic loss to the poultry industry in China but also a serious threat to human health because of the avian influenza virus(AIV) gene recombination and reassortment.Until now,traditional RT-PCR,fluorescence RT-PCR and virus isolation identification have been developed and utilized to detect AIV,but these methods require high-level instruments and experimental conditions,not suitable for the rapid detection in field and farms.In order to develop a rapid,sensitive and practical method to detect and identify AIV subtypes,4 specific primers to the conserved region of AIV M gene were designed and a loop-mediated isothermal amplification(RT-LAMP) method was established.Using this method,the M gene of H1–H16 subtypes of AIV were amplified in 30 min with a water bath and all 16 H subtypes of AIV were able to be visually identified in presence of fluorescein,without cross reaction with other susceptible avian viruses.In addition,the detection limit of the common H1,H5,H7,and H9 AIV subtypes with the RT-LAMP method was 0.1 PFU(plaque-forming unit),which was 10 times more sensitive than that using the routine RT-PCR.Further comparative tests found that the positivity rate of RT-LAMP on detecting clinical samples was 4.18%(14/335) comparing with 3.58%(12/335) from real-time RT-PCR.All these results suggested that the RT-LAMP method can specifically detect and identify AIV with high sensitivity and can be considered as a fast,convenient and practical method for the clinic test and epidemiological investigation of AIV.

Histopathological Observation of Parvovirus Infection in Foxes

In this study, histopathological changes in the heart, liver, spleen, lung, kidney, intestine, brain and other organs of foxes died of parvovims infection were observed. According to the results, multiple organs of infected foxes were congested and hemorrhaged with tissue damage, inflammatory cell infiltration and a series of pathological changes, mainly exhibiting hepatic cell cord rupture, liver cell granular degeneration and fatty degeneration, small intestinal mucous mem- brane shedding, intestinal villi necrosis and shedding, severe hemorrhage of lamina pmpria with inflammatory cell infiltration, and severe small intestinal bleeding. This study laid a solid foundation for clinical diagnosis, prevention and treatment of parvovirus infection in foxes.