Scapaundulin C, a novel labdane diterpenoid isolated from Chinese liverwort Scapania undulate, inhibits acetylcholinesterase activity / 中国天然药物

In the present study, scapaundulin C (1), a new labdane diterpenoid, and four related known compounds scapaundulin A (2), 5α, 8α, 9α-trihydroxy-13E-labden-12-one (3), 5α, 8α-dihydroxy-13E-labden-12-one (4), and (13S)-15-hydroxylabd-8 (17)-en-19-oic acid (5), were isolated from the Chinese liverwort Scapania undulate (L.) Dum., using column chromatography. The structures of these compounds were determined on the basis of 1D- and 2D-NMR analyses. The acetylcholinesterase (AchE) inhibitory activity was evaluated using a bioautographic TLC assay and the cytotoxic activity was evaluated by the MTT method. All the compounds were reported for the first time to exhibit moderate AchE inhibitory activity with minimal inhibitory quantities ranging from 250 to 500 ng. All the compounds were tested for their cytotoxicity against five human tumor cell lines, A549, K562, A2780, Hela, and HT29, and compounds 3 and 4 exhibited moderate inhibitory effects on the growth of A2780 cells.

Isolation and structure identification of grape seed polyphenols and its effects on oxidative damage to cellular DNA / 药学学报

<p><b>AIM</b>To isolate polyphenols from grape seeds and to evaluate their antioxidant effects.</p><p><b>METHODS</b>Pure compounds were isolated by using Diaion HP20, Toyopearl HW40 chromatography repeatedly, as well as semi-preparative RP-HPLC, from ethyl acetate extract of grape seeds. IR, MS, NMR, CD, X-Ray crystal diffraction spectral analysis were used to identify the structures. The antioxidant effects of different type of structures were screened by reducing power and DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) free radical scavenging tests. Then, SCGE (single cell gel-electrophoresis) technique was used to investigate the effects of these potent antioxidant phytochemicals on cellular DNA oxidative damage with mice spleen cells, damage was induced by H2O2.</p><p><b>RESULTS</b>Eleven compounds were obtained including 3 novel structures, viniferones A, B and C. Proanthocyanidin B4, catecin, epicatechin and gallic acid showed strong antioxidant power, and at lower concentration (10 micromol x L(-1), 25 micromol x L(-1)), they can prevent cellular DNA damage, while 150 micromol x L(-1) catechin induced damage by itself.</p><p><b>CONCLUSION</b>Viniferones A, B and C were reported for the first time. That polyphenols investigated were shown to be good cellular DNA oxidative damage-preventing phytochemicals at lower concentration, could be used to explain the nutrient effect of grape seed polyphenols at certain degree. At the same time, higher concentration of polyphenols can induce oxidative damage, suggesting that dose is one factor to determine the nutrient effects.</p>