Screening, fingerprinting, and identification of phenolic antioxidants in Persicaria chinensis (L.) H. Gross by liquid chromatography - electrochemical detection and liquid chromatography - tandem mass spectrometry.

Persicaria chinensis (L.) H. Gross (P.

Separation, identification, and fingerprinting of antioxidant components in persimmon (Diospyros kaki) leaves by offline two-dimensional liquid chromatography with electrochemical detection and tandem mass spectrometry.

In this work, the antioxidant components in persimmon (Diospyros kaki) leaves were separated by offline two-dimensional liquid chromatography-electrochemical detection (LC×LC-ECD) and identified by LC-tandem mass spectrometry (LC-MS/MS). A total of 33 antioxidants, mainly proanthocyanidins, and glycosides of kaempferol and quercetin, were identified. The antioxidant assays demonstrated that the fractions collected from the first-dimension LC (D-LC) possessed considerable radical scavenging capabilities, with correlation coefficients of peak area versus radical scavenging capability of 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) being 0.

Evaluation of the phytochemicals and antioxidant activity of Lophatherum gracile Brongn based on chemical fingerprinting by HPLC with electrochemical detection.

A combinative method using high-performance liquid chromatography-electrochemical detection for fingerprinting and quantitative analysis was developed and successfully applied for the quality evaluation of Lophatherum gracile Brongn leaves collected from 21 geographical locations in China. In the fingerprint analysis, 18 common peaks were observed among the 21 samples, and 10 peaks were identified. Simultaneous quantification of the 10 components was conducted to interpret the variations in these compounds among the L.

Two new 19-hydroxy bufadienolides with cytotoxic activity from the skins of .

Two new 19-hydroxy bufadienolides, named bufohydrolide A () and bufohydrolide B (), and four known analogs () were isolated from the aqueous extracts of the skins of . Their structures were established by spectral data analyses, such as UV, IR, 1 D/2D NMR and mass spectra. Compounds were evaluated for their cytotoxic activity against SMMC-7721, HT-29 and A549 cells.