Inhibitory activity for chitin synthase II from Saccharomyces cerevisiae by tannins and related compounds.

In the course of search for potent inhibitors of chitin synthase II from natural resources, seven tannins and related compounds were isolated from the aerial part of Euphorbia pekinensis and identified as gallic acid (1), methyl gallate (2), 3-O-galloyl-(-)-shikimic acid (3), corilagin (4), geraniin (5), quercetin-3-O-(2"-O-galloyl)-beta-D-glucoside (6), and kaempferol-3-O-(2"-O-galloyl)-beta-D-glucoside (7). These and nine related compounds, (-)-quinic acid (8), (-)-shikimic acid (9), ellagic acid (10), kaempferol (11), quercetin (12), quercitrin (13), rutin (14), quercetin-3-O-(2"-O-galloyl)-beta-D-rutinoside (15) and 1,3,4,6-tetra-O-galloyl-beta-D-glucose (16), were evaluated for the inhibitory activity against chitin synthase II and III. They inhibited chitin synthase II with IC(50) values of 18-206 microM, except for two organic acids, (-)-quinic acid (8) and (-)-shikimic acid (9). Among them, 3-O-galloyl-(-)-shikimic acid (3) was the most potent inhibitor against chitin synthase II of Saccharomyces cerevisiae with an IC(50) value of 18 microM. The inhibition appears to be selective for chitin synthase II, as they did not appreciably inhibit chitin synthase III.

Low-density lipoprotein-antioxidant constituents of Saururus chinensis.

A new diarylbutane lignan, saururin A (1), and a known 8-O-4'-type neolignan, machilin D (2), were isolated from a total methanol extract of the underground parts of Saururus chinensis. The structures of 1 and 2 were elucidated by spectroscopic data analysis. Compounds 1, 2, and virolin (3) (the methyl ether of 2) exhibited significant low-density lipoprotein (LDL)-antioxidant activity in the thiobarbituric acid-reactive substance (TBARS) assay with IC(50) values of 8.5, 2.9, and 4.3 microM, respectively.

Tamoxifen inhibits GH3 cell growth in culture via enhancement of apoptosis.

OBJECTIVE: To investigate the antitumor effects of tamoxifen on pituitary tumor GH3 cells, which lack receptors for dopamine. METHODS: GH3 cells were treated with tamoxifen (10(-7) mol/L), bromocriptine (10(-8) mol/L), or a combination of tamoxifen and bromocriptine in serum-free media. The cell number, bromodeoxyuridine (BrdU) labeling ratio, and apoptotic ratio were assessed. Prolactin (PRL) expression was examined using immunocytochemistry and Western blot analysis. RESULTS: After tamoxifen treatment for 4 days, the cell number decreased to 53.0% of that of untreated control cells. The percentage of PRL-immunoreactive GH3 cells decreased to 2.9%, versus 8.6% of untreated control cells, which was compatible with the results of Western blot analysis for PRL. Apoptosis increased to approximately three times that of untreated control cells at Day 2 of treatment, whereas no significant change was shown in BrdU incorporation. These effects by tamoxifen were not observed in the simultaneous treatment with 17beta-estradiol. Bromocriptine did not change the cell number, BrdU incorporation, the apoptotic ratio, or the percentage of PRL-positive cells, and it was also shown that tamoxifen did not change the sensitivity of GH3 cells to bromocriptine treatment. CONCLUSION: Tamoxifen, an antiestrogen, exerts its antitumor effect on GH3 cells in two ways: by suppression of cell growth and by causing a decrease in PRL. Apoptosis seems to contribute to the inhibition of GH3 cell growth.

Lathyrus saponin, a new trisaccharide glycoside from Lathyrus japonicus.

A new triterpenoid saponin, named Lathyrus saponin (3), was isolated from the whole plant of Lathyrus japonicus Willd. together with two known saponins, azukisaponins II (1) and V (2). as their methyl esters. The structure of 3 was determined to be soyasapogenol B 3-0-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D-glu curonopyranoside on the basis of physicochemical and spectroscopic methods.

Effect of hippocampectomy on sleep patterns in cats.

The study was planned to see if the hippocampus has an influence on fast wave sleep (FWS) as well as on slow wave sleep (SWS). From 8 male cats EEG, EMG and EOG were recorded for 24 h, first under normal conditions, secondly after cortical damage to the dorsal marginal portion of posterior ectosylvian gyrus, and thirdly following hippocampectomy done through the cortical damage. From the records, SWS, FWS and the sleep state (defined as a sequence of SWS or SWS-FWS phases between two successive waking states) were measured in terms of their occurrence, the mean duration and the total time they occupied in the day, night and 24 h. In addition, sleep sequences were classified according to the number of constituent sleep phases. Cortical damage did not affect SWS, FWS, or sleep state with regard to their occurrence, the mean duration, and the total time they occupied in 24 h. Nor did it affect the proportion of short and long sequences. The circadian variation of sleep was clearly retained. Hippocampectomy significantly reduced the total time occupied by sleep state, SWS and FWS, increased the occurrence of sleep state and SWS phase against decreased incidence of FWS phase, and reduced the mean duration of sleep state and SWS phase. Hippocampectomy also significantly increased the occurrence of sleep sequences with only one SWS phase at the cost of sequences with alternating SWS and FWS phases. Following hippocampectomy, the circadian variation of sleep was not only retained, but actually exagerated. The hippocampus in inferred to facilitate the FWS as well as the SWS phase of sleep.