The preparation of bile acid amides and oxazolines, II, the synthesis of the amides and oxazolines of ursodeoxycholic acid, deoxycholic acid, hyodeoxycholic acid and cholic acid

Bile acid amides and oxazolines were synthesized by a sequence of steps involving the reaction of the free bile acid with formic acid to yield the formyloxy derivative, preparation of the formyloxy acid chloride, condensation of the acid chloride with 2-amino-2-methyl-1-propanol to give the amide and, finally, cyclization of the amide with thionyl chloride to give the oxazoline. The oxazolines were characterized by physical constants, thin layer and gas-liquid chromatography and identified by elemental analysis and gas-liquid chromatography-mass spectrometry. Some of the bile acid oxazoline derivatives alter the activity of bacterial 7-dehydroxylases $\text{in vitro}$, and inhibit the growth of certain anaerobic bacteria in pure culture.     

Effect of naturally occurring triterpenoids glycyrrhizic acid, ursolic acid, oleanolic acid and nomilin on the immune system.

The effect of naturally occurring triterpenoid compounds such as glycyrrhizic acid, ursolic acid, oleanolic acid, and nomilin on the immune system was studied using Balb/c mice. Intraperitoneal treatments with 5 doses of these terpenoid compounds were found to enhance the total white blood cells (WBC) count. In ursolic acid, oleanolic acid and nomilin treated animals the maximum total WBC count was observed on the 6th day, while in glycyrrhizic acid treated animals it was observed only on the 9th day after the drug treatment. In ursolic acid, oleanolic acid and nomilin treated animals the percentage of increase in the total WBC count was to 91.48 +/- 4.6%, 135.75 +/- 6.4% and 117.33 +/- 17.9% respectively. In the glycyrrhizic acid treated animals the total WBC count was increased to 114.9 +/- 18%. Bone marrow cellularity and alpha-esterase positive cells were also enhanced by the treatment with these terpenoids. Treatment with various triterpenoids along with antigen produced an enhancement in the specific antibody titre and the number of plaque forming cells (PFC) in the spleen. Triterpenoids remarkably inhibited delayed type hypersensitivity reaction (DTH). These results indicate the immunomodulatory activity of naturally occurring triterpenoids such as glycyrrhizic acid, ursolic acid, oleanolic acid and nomilin.     

High-performance liquid chromatographic separation of ascorbic acid,erythorbic acid,dehydroascorbic acid,dehydroerythorbic acid,diketogulonic acid,and diketogluconic acid

High-performance liquid chromatography on a Zorbax NH₂ analytical column, with acetonitrile: 0.05 m KH₂PO₄ (75:25, $\text{w}\text{w}$) used as eluant, has allowed the separation, in less than 14 min, of ascorbic acid, erythorbic acid, dehydroascorbic acid, dehydroerythorbic acid, diketogulonic acid, and diketogluconic acid. Ultraviolet monitoring at 268 nm allows ascorbic acid and erythorbic acid to be detected at the 25-ng level, while refractive index detection monitors the elution of all six compounds. Tyrosine is a good internal standard, being well separated from the other compounds and having an adequate ultraviolet absorption at 268 nm. We have found dithiothreitol to be effective in rapidly reducing dehydroascorbic acid to ascorbic acid, providing the basis for indirectly determining dehydroascorbic acid after its reduction. The potential of this high-performance liquid chromatographic procedure for evaluating the levels of these compounds in orange juice and urine is demonstrated.     

Effect of the bacterial DNA gyrase inhibitors, novobiocin, nalidixic acid, and oxolinic acid, on oxidative phosphorylation

When incubated with isolated intact rat liver mitochondria, novobiocin and nalidixic acid act as uncouplers of oxidative phosphorylation; they stimulate oxygen uptake and inhibit ATP synthesis. Novobiocin is about as powerful an uncoupler as is 2,4-dinitrophenol, nalidixic acid is somewhat less powerful, and oxolinic acid exerts no inhibition whatsoever at the concentrations used. The three inhibitors are without effect on oxidative phosphorylation in Escherichia coli nor does novobiocin affect this process in a novobiocin-permeable mutant of yeast. While it would appear that oxolinic acid may be a relatively specific tool for the manipulation of the superhelicity of DNA in complex systems such as mammalian mitochondria and intact mammalian cells, the specificity of each of these inhibitors may depend upon the particular conditions and species used and such experiments require adequate controls on oxidative phosphorylation.     

Study on the extraction, purification and quantification of jasmonic acid, abscisic acid and indole-3-acetic acid in plants

Introduction  – Jasmonic acid (JA), abscisic acid (ABA) and indole‐3‐acetic acid (IAA) are important plant hormones. Plant hormones are difficult to analyse because they occur in small concentrations and other substances in the plant interfere with their detection. Objective  – To develop a new, inexpensive procedure for the rapid extraction and purification of IAA, ABA and JA from various plant species. Methodology  – Samples were prepared by extraction of plant tissues with methanol and ethyl acetate. Then the extracts were further purified and enriched with C₁₈ cartridges. The final extracts were derivatised with diazomethane and then measured by GC‐MS. The results of the new methodology were compared with those of the Creelman and Mullet procedure. Results  – Sequential elution of the assimilates from the C₁₈ cartridges revealed that IAA and ABA eluted in 40% methanol, while JA subsequently eluted in 60% methanol. The new plant hormone extraction and purification procedure produced results that were comparable to those obtained with the Creelman and Mullet's procedure. This new procedure requires only 0.5 g leaf samples to quantify these compounds with high reliability and can simultaneously determine the concentrations of the three plant hormones. Conclusion  – A simple, inexpensive method was developed for determining endogenous IAA, ABA and JA concentrations in plant tissue. Copyright © 2008 John Wiley & Sons, Ltd.     

Action of the antiepileptic drug, valproic acid, on fatty acid oxidation in isolated rat hepatocytes

Valproate at 0.1 to 5 mM strongly inhibited oxidation of 1-(14C)-palmitate in isolated rat hepatocytes. Valproate at the same concentrations markedly decreased ketogenesis from 1 mM oleate. Valproate in a dose up to 5 mM did not significantly affect cellular concentration of ATP but lowered beta-hydroxybutyrate/acetoacetate and lactate/pyruvate ratios which paralleled its effect on ketogenesis. Moreover concomitant acetyl-CoA levels were drastically decreased by valproate. From this it may be concluded that inhibition of fatty acid oxidation by valproate results in reduced production of two carbons units and a drop of NADH/NAD+ ratio in rat hepatocyte. This suggests that valproate seriously interferes with beta-oxidation of physiological long-chain fatty acids.     

Research on the adsorption property of supported ionic liquids for ferulic acid, caffeic acid and salicylic acid

In this paper, the preparation of new supported ionic liquids (SILs) composed of the N-methylimidazolium cation and the quinoline cation is described. They have been confirmed and evaluated by infrared spectroscopy, elemental analysis and thermogravimetric analysis. Six kinds of different SILs included SiO(2)·Im(+)·Cl(-), SiO(2)·Im(+)·BF(4)(-), SiO(2)·Im(+)·PF(6)(-), SiO(2)·Qu(+)·Cl(-), SiO(2)·Qu(+)·BF(4)(-) and SiO(2)·Qu(+)·PF(6)(-). The adsorption characteristics of ferulic acid (FA), caffeic acid (CA) and salicylic acid (SA) on SILs were investigated by static adsorption experiments. It was found that SiO(2)·Qu(+)·Cl(-) had excellent adsorption and desorption capacity to three tested phenolic compounds. The dynamic adsorption characteristics of FA, CA and SA on SiO(2)·Qu(+)·Cl(-) were also studied. The saturated adsorption capacity of FA, CA and SA using SiO(2)·Qu(+)·Cl(-) as adsorbent was 64.6 mg/g, 53.2 mg/g and 72.2 mg/g respectively. Using 70% ethanol as eluent, the saturated desorption efficiencies of FA, CA and SA were 97.2%, 90.3% and 96.5% respectively. Thus, SiO(2)·Qu(+)·Cl(-) had strong adsorption and separation capacity for FA, CA and SA.     

Effect of gibberellic acid, kinetin and naphthylacetic acid on the growth of coconut seedlings

The effects of three growth regulators, namely gibberellic acid (GA₃), kinetin (6-furfuryl-aminopurine) and α-naphthyl-acetic acid (NAA), each at five concentrations (0, 25, 50,10² and 10³ mg/litre) on the growth of coconut seedlings (Cocos nucifera) were examined. GA₃ at 25 mg/litre increased growth in height; higher concentrations had no significant effect. Kinetin at 10² and 10³ mg/litre and NAA at all concentrations reduced height growth compared with the control. No treatment caused a significant increase in total dry weight.     

Structural studies on colanic acid, the common exopolysaccharide found in the Enterobacteriaceae, by partial acid hydrolysis. Oligosaccharides from colanic acid

The exopolysaccharide slime colanic acid has been isolated from representative strains of Escherichia coli, Salmonella typhimurium and Aerobacter cloacae. Analysis showed that each polymer contained glucose, galactose, fucose and glucuronic acid, together with acetate and pyruvate. The molar proportions of these components were 1:1.8:1.9:1:1:1 approximately. On the basis of periodate oxidation of the natural and deacetylated polysaccharide, glucose is proposed as the site of the acetyl groups. The pyruvate is attached to galactose. Three neutral oligosaccharides and ten electrophoretically mobile oligosaccharides were isolated and partially characterized. Four of the fragments were esters of pyruvic acid. Most oligosaccharides were isolated from all three polysaccharide preparations. Three further oligosaccharides were isolated from carboxyl-reduced colanic acid and sodium borotritide was used to label the glucose derived from glucuronic acid in these fragments. One trisaccharide was obtained from periodate-oxidized polysaccharide. On the basis of these oligosaccharides a repeating hexasaccharide unit of the following structure is proposed: [Formula: see text] The significance of this structure in colanic acid biosynthesis is discussed.     

去甲肾上腺素,甘氨酸,γ—氨基丁酸和L—谷氨酸对节段性与下行性...

Noradrenaline (NE), glucine (GLY), gamma-aminobutyric acid (GABA) and L-glutamic acid (L-GLU) were locally applied to the dorsal surface of lumbar spinal cord on anesthetized and immobilized rats and their effects on segmental (SP) and descending (DP) spinal field potentials were examined. Both waves N and P of SP and DP were reduced markedly in amplitudes following local application of NE. A significant decrease in amplitude of wave N and a remarkable increase in wave P in both SP and DP were shown during the application of GLY, GABA and L-GLU. The results suggest that these neurotransmitters may be involved in the generation of waves N and P, particularly affecting the activities of interneurons in the spinal dorsal horn.     

Quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhance the Fenton reaction in phosphate buffer.

Quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhanced the Fenton reaction in phosphate buffer, respectively. The enhancement by quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid of the Fenton reaction may be partly related to their respective actions in the biological systems such as a neurotoxic effect (quinolinic acid), a marked growth-inhibitory action on rice seeding (alpha-picolinic acid and fusaric acid), and an antiseptic (2,6-pyridinedicarboxylic acid). The ultraviolet-visible absorption spectrum of the mixture of alpha-picolinic acid with ferrous ion showed a characteristic visible absorbance band with a lambda(max) at 443 nm, suggesting that alpha-picolinic acid chelate of Fe2+ ion forms in the solution. Similar characteristic visible absorbance band was also observed for the mixture of Fe2+ ion with quinolinic acid (or fusaric acid, or 2,6-pyridinedicarboxylic acid). The chelation seems to be related to the enhancement by quinolinic acid, alpha-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid of the Fenton reaction. alpha-Picolinic acid was reported to be a toxic substance isolated from the culture liquids of blast mould (Piricularia oryzae CAVARA). On the other hand, it has also been known that chlorogenic acid protects rice plants from the blast disease. The chlorogenic acid inhibited the formation of the hydroxyl radical in the reaction mixture of alpha-picolinic acid, FeSO4(NH4)2SO4, and H2O2. Thus the inhibition may be a possible mechanism of the protective action of the chlorogenic acid against the blast disease.