1H NMR-based metabolomic approach combined with multivariate statistical analysis was used to evaluate the quality of 21 Farfarae Flos (FF) samples from different growth regions. Principal component analysis showed that wild and cultivated FF could be separated clearly, suggesting a big chemical difference existed between them. Supervised PLS-DA analysis indicated that the wild samples showed higher levels of secondary metabolites, such as bauer-7-ene-3β, 16α-diol, chlorogenic acid, rutin, 7-(3'-ethylcrotonoyloxy)-1α-(2'-methyl-butyryloxy)-3, 14-dehydro-Z-notonipetranone (EMDNT), tussilagone, β-sitosterol and sitosterone. This is consistent with traditional experience that the quality of wild samples are better than that of cultivated ones. The content of pyrrolizidine alkaloids senkirkine also differed greatly among samples from different habitats. The Pearson correlation analysis showed that senkirkine is positively correlated with 4, 5-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, 3,4-O-dicaffeoylquinic acid, rutin, kampferol analogues, to a statistically significant extent. The correlation between the toxic compounds and the bioactive components in FF should be further studied.

Objective To investigate the adverse effect of different doses of high power microwave(HPM) irradiation on oxidative stress in the brain of Wistar rats in order to contribute to establishing an animal model to evaluate protective agents which will be used for protection against microwave radiation.Methods Eighty male Wistar rats were randomly divided into 16 groups according to factor analysis.The average power density was 0,10,30 and 100 mW/cm2 and the sampling time was 6 h,1,3 and 7 d .The duration of exposure was 6 minutes for each radiation group.After exposure, the rats were sacrificed at each sampling time.Colorimetric method was used to measure the content of malondialdehyde(MDA) and protein carbonyl, the activity of GSH-px, SOD and CAT.Results The content of MDA and protein carbonyl of each radiation group was increased with the radiation dose, but decreased with the sampling time prolonged.The activity of superoxide dismutast(SOD),glutathion peroxidase(GSH-px) and catalase(CAT) in each radiation group was decreased with the radiation dose increased, and with the sampling time prolonged, but increased later.Conclusion Microwave radiation can cause oxidative stress in rats brain, as shown by the oxidative damage of lipid and protein and the decrease in the activity of antioxidant enzymes.Besides, the effect also depends on the radiation dose and sampling time.