In this review, I wish to summarize studies on sialic acid-N-acetylneuraminic acid (Neu 5Ac), N-glycoloylneuraminic acid (Neu 5Gc), 3-deoxy-D-glycero-D-galacto-nonulopyranosonic acid (KDN), and their alkyl, acyl, dehydro and deoxy derivatives. Our working strategy is"cell component derivatives of sialic acid which have a good shape and good balance between hydrophilicity and hydrophobicity, would elicit various kinds of physiological activities."Preparation and physiological activities of sialic acid derivatives, and a new method of stereochemistry determination are reported. Several derivatives show remarkable physiological activities for novel medicines in the XXI century. A generic name'GLYCOLIPOID'is proposed for such compounds.
In order to clarify the mechanism of topoisomerase II mediated DNA cleavage activity caused by intercalators (9-anilinoacridines), antitumor activities against murine P388 and calf thymus DNA topoisomerase II mediated DNA cleavage activities of compounds m-AMSA, A4P73, A3P56, and A3P166 have been studied. A4P73 was found to have potent antitumor and DNA cleavage activities.
Glucuronoxylomannan (AC) from the fruiting bodies of Tremella fuciformis exhibited a significant dose-dependent hypoglycemic activity in normal mice and also showed a significant activity in streptozotocin-induced diabetic mice, by intraperitoneal (i.p.) administration. The activities of AC-derivatives such as a product of AC which side chains had been removed were lower than that of native AC. AC raised the plasma insulin level in normal mice. Administration of AC to normal mice significantly increased the activities of hepatic hexokinase and glucose-6-phosphate dehydrogenase, but it decreased that of hepatic glucose-6-phosphatase. Furthermore, AC reduced the glycogen content in the liver, increased the total lipid in epididymal adipose tissue, and lowered the plasma cholesterol level. The foregoing results indicated that the hypoglycemic activity of AC in normal mice was at least responsible for the increase of insulin secretion and for the acceleration of glucose metabolism. Single oral administration at a dose of 50-300 mg/kg of AC did not affect the plasma glucose level in normal mice, but continuous oral administrations of the AC solution (0.75 g/l) instead of water for a long time was found to be effective on the plasma glucose level in both experiments of the mice injected once i.p. with streptozotocin (170 mg/kg) at 0 d of AC administration and streptozotocin-induced diabetic mice.
In order to establish a rapid and accurate in vitro drug assay method, we have applied the avidin D-biotin complex enzyme-linked immunosorbent assay using 5-bromodeoxyuridine (BrdU-ELISA) in the microplate cultures. To study the rat gastric cell proliferation, BrdU was treated with the cultured cells, and then, the rate of the uptake of BrdU into the cells was measured using an anti-BrdU antibody. Prostaglandin E2 (PGE2) (0.01, 0.1 and 1 μM), cimetidine (1, 3 and 10 μM) and omeprazole (3 and 10 μM) were shown to induce the significant proliferation of rat gastric cultured cells. Indomethacin (IND) (0.1, 0.25 and 0.5 mM) caused a dose-dependent inhibition of the proliferation of the cultured cells proliferation. The result obtained by the BrdU-ELISA method was more reproducible than that by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay method. PGE2 (0.01, 0.1 and 1 μM), cimetidine (1, 3 and 10 μM), omeprazole (1, 3 and 10 μM), cetraxate (3, 10 and 30 μM) and famotidine (30 μM), but not sofalcone and NC-1300-O-3, have been shown to protect significantly rat gastric cultured cells against IND-induced damage in vitro. From these results, it might be suggested that this BrdU-ELISA method is useful for investigating the effect of drugs on the proliferation of rat gastric cultured cells.
The effects of the temperature on the micellar formation and on the micellar structure of poly (ethylene oxide)/poly (propylene oxide)/poly (ethylene oxide) triblock copolymer, pluronic L-64, were investigated in terms of surface tension, fluorometric analysis, static and dynamic light scattering measurements. Two clear discontinuities corresponding to the cmcI and cmcII were found in the relationship between the surface tension and L-64 concentration. The cmcI was little affected by the temperature, but the cmcII was greatly influenced. Furthermore, the numbers of micelle aggregation, micellar sizes and micellar shapes varied greatly with changing in the temperature and L-64 concentration.
The inhibitory effects of various synthetic oligosaccharides (1-8) on anti-lipid IV antiserum binding activity were examined by ELISA (enzyme linked immunosorbent assay). Compound 8, containing an epitope GlcA-4Meβ1-4Fuc of lipid IV, inhibited but precursers (1-5) of lipid IV did not inhibit the binding activity. In addition to the nonreducing end disaccharide derivative (6) having a methyl group at position 4 of glucuronic acid, its analogous compound (7) having no methyl groups was synthesized and their inhibition activities were compared. Moreover, the inhibitory effects of compounds (1-5) were examined using each antiserum.
The fruit body of a Basidiomycete Agaricus blazei, Jun-17 (Himematsutake) was extracted with hexane and chloroform-methanol (2 : 1, v/v), and the antimutagenic effect of the extracts was examined using an Ames/Salmonella/microsome assay. Both extracts of Agaricus inhibited the mutagenicity of benzo [a] pyrene (B [a] P). The hexane extract was purified by silica gel column chromatography and high performance liquid chromatography (HPLC), and linoleic acid was isolated as a main substance having antimutagenic activity. Fr. IIa, IIb, IIc and IIb, which reduced the number of His+ revertant colonies induced by B [a] P, were separated from the chloroform-methanol extract by silica gel column chromatography and HPLC. An antimutagenic substance in Fr. IIa was linoleic acid. From Fr. IIb, a bactericidal, not antimutagenic, substance was isolated and identified as 13-hydroxy cis-9, trans-11-octadecadienoic acid (13ZE-LOH). Antimutagenic substances in Fr. IIc and IId were not purified. The possible source and mechanism of formation of 13ZE-LOH are discussed.
A simple and reproducible high performance liquid chromatographic (HPLC) method using an internal standard (I.S.) was developed for the determination of an anticancer drug, paclitaxel, in biological fluids. The sample preparation involves a solid-phase extraction step. HPLC was performed on an ODS column using acetonitrile-2 mM phosphoric acid (45 : 55) as a mobile phase with detection at 227 nm. A linear relationship was obtained in the range of 0.02-2.0 μg/ml in the rat plasma and urine. Since the recovery of the drug was as high as that of I.S. (>96%), a standard curve generated from the solution of the drug with I.S. in the mobile phase could be used for determination. The method could be applicable for human and dog plasma as well as rat plasma, and the intra- and interday coefficients of variation at 0.05, 2.0 and 10.0 μg/ml were less than 7%. This method is useful for pharmacokinetic studies of paclitaxel.