Phytochemical Constituents from the Seeds of Capsella bursa-pastoris and Their Antioxidant Activities.

Phytochemical investigation of 70% EtOH extract of the seeds of Capsella bursa-pastoris led to the isolation of a new cyclobutane organic acid (1), and fourteen known compounds, including two organosulfur compounds (2, 3), two quinonoids (4, 5), five flavonoids (6-10), three sterols (11-13) and two other types (14, 15). The structures of the compounds were elucidated by extensive spectroscopic analyses as well as comparison of their spectroscopic data with those reported in the literature. The antioxidant capacities of all compounds and extractive fractions were evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging test and ferric reducing antioxidant power (FRAP) assay. Then the antioxidative substances were evaluated for their neuroprotective effects against H2O2-induced HT22 cell injury. The results indicated the strong scavenging ability to free radical of the extractive fractions and compounds 1-3, 8-10 and 13, and the ferric reducing antioxidant power of the extractive fractions and compounds 1-3, 8 and 10, which were close to or higher than that of the positive control trolox. The EtOAc fraction, n-BuOH fraction, and compounds 1, 3 and 8 can protect HT-22 cells from oxidative damage.

Simultaneous determination and pharmacokinetics of five rhubarb anthraquinones in dog plasma by HPLC after orally administration the rhubarb extract.

Rhubarb is widely used in the treatment of obstipation, gastrointestinal indigestion and other diseases in China and other Asian countries for thousands of years. Anthraquinones are the major group of polyphenol constituents including aloe-emodin, rhein, emodin, chrysophanol and physcion. In order to evaluate the pharmacokinetics of five rhubarb anthraquinones, a high-performance liquid chromatography with fluorescence detection (HPLC-FLD) method for simultaneous determination of aloe-emodin, rhein, emodin, chrysophanol and physcion in dog plasma was established. Solid phase extraction (SPE) was applied to the extraction and purification of samples. The calibration curves of five anthraquinones showed good linearity with r greater than 0.9925. The average extraction recoveries, examined at three concentration levels, carried from 92.1% to 102.3%, and the accuracies ranged from 87.7% to 102.5% with precision (RSD) <10%. The pharmacokinetic paremeters of five anthraquinones were investigated systematically after orally administration the rhubarb extract. Five anthraquinones were rapidly absorbed and Tmax for aloe-emodin, rhein, emodin, chrysophanol and physcion was at 0.75, 1.50, 0.75, 1.0 and 2.0 h respectively. The Cmax of five anthraquinones was 0.031, 3.39, 0.27, 0.036 and 0.032 µg/mL while the AUC of five anthraquinones was 0.35 ± 0.058, 32.22 ± 8.29, 2.97 ± 0.66, 0.43 ± 0.10 and 0.41 ± 0.12 mg h/L, respectively.