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.

Anticancer Effects of Five Biflavonoids from Ginkgo Biloba L. Male Flowers In Vitro.

Ginkgo biloba L., an ancient dioecious gymnosperm, is now cultivated worldwide for landscaping and medical purposes. A novel biflavonoid-amentoflavone 7''-O-ß-D-glucopyranoside (1)-and four known biflavonoids were isolated and identified from the male flowers of Ginkgo. The anti-proliferative activities of five biflavonoids were evaluated on different cancer lines. Bilobetin (3) and isoginkgetin (4) exhibited better anti-proliferative activities on different cancer lines. Their effects were found to be cell-specific and in a dose and time dependent manner for the most sensitive HeLa cells. The significant morphological changes validated their anticancer effects in a dose-dependent manner. They were capable of arresting the G2/M phase of the cell cycle, inducing the apoptosis of HeLa cells dose-dependently and activating the proapoptotic protein Bax and the executor caspase-3. Bilobetin (3) could also inhibit the antiapoptotic protein Bcl-2. These might be the mechanism underlying their anti-proliferation. In short, bilobetin (3) and isoginkgetin (4) might be the early lead compounds for new anticancer agents.