Sadaji Yamada

Identification of vasopressor phospholipid in crude soybean lecithin

The vasopressor phospholipid in crude soybean lecithin was isolated by column chromatography on Sephadex LH-20. It represented 0.1% of crude soybean lecithin. The isolated phospholipid was identified to be lysophosphatidic acid by gas chromatography-mass spectrometry analysis of TMS-deacylated product and acetolysis product. Nuclear magnetic resonance analysis favored the 1-monoacyl isomer over the 2-isomer. By enzymic determination with L-3-glycerophosphate dehydrogenase, the isolated phospholipid was identified as 1-monoacyl-L-3-glycerophosphate. Gas chromatographic examination revealed that it was composed of a large percentage of unsaturated fatty acids, especially linoleic acid. The activity of isolated lysophosphatidic acid was slightly less than that of synthetic 1-linoleoyl-L-3-glycerophosphate.

Separation of lac dye components by high-speed counter-current chromatography.

High-speed counter-current chromatography has been successfully applied to the separation of the lac dye components. A 25-mg quantity of the sample was separated using a two-phase solvent system composed of tert.-butyl methyl ether-n-butanol-acetonitrile-water (2:2:1:5). The fractions were analyzed by high-performance liquid chromatography and electrospray tandem mass spectrometry. The separation yielded 2.6 mg of 97.2% pure laccaic acid C, 9.5 mg of 98.1% pure laccaic acid A, 3.6 mg of 98.2% pure laccaic acid B, and 0.5 mg of a 95.0% pure anthraquinonedicarboxylic acid with a molecular mass of 360.

Rapid determination of carbamate pesticides in food using dual counter-current chromatography directly interfaced with mass spectrometry.

Dual counter-current chromatography (dual CCC)-tandem mass spectrometry (MS/MS) was successfully performed with a newly designed spiral column for dual CCC. The small column capacity required for directly coupling with electrospray MS/MS was accomplished by forming a rectangular spiral groove on a plastic disk and sealing it with a PTFE sheet. This novel dual CCC-MS/MS technique was successfully applied for the rapid determination of methomyl, fenobucarb and carbaryl pesticides in food. A two-phase solvent system of n-hexane-acetonitrile-0.1% formic acid (45:45:10) was suitable for both good dual CCC separation and sufficient ionization of pesticides. Recoveries of these three pesticides from mandarin orange and spinach samples fortified at 0.05 mg/kg were in the range of 93-107% with relative standard deviations of 2.4-3.8%.

High Throughput Analysis of N‐Methyl Carbamate Pesticides in Cereals and Beans by Dual Countercurrent Chromatography and Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry

Abstract We developed a new analytical method for analysis of N‐methyl carbamate pesticides in cereals and beans using dual counter‐current chromatography (dual CCC) and liquid chromatography‐electrospray ionization tandem mass spectrometry (ESI LC/MS/MS). After pesticides were extracted from cereals and beans with ethyl acetate, each extract was cleaned up by dual CCC using a non‐aqueous binary solvent system composed of n‐hexane‐acetonitrile and analyzed by ESI LC/MS/MS with a short column. The average recoveries from cereals and beans fortified at the level of 0.01 ppm ranged from 73.9 to 119.6%, with the coefficients of variation from 0.7 to 6.8%. At the fortified level of 0.5 ppm, the recoveries ranged from 72.1 to 117.1% with coefficients of variation from 0.4 to 9.3%. The present analytical method of N‐methyl carbamate pesticides in cereals and beans is considered to be useful for monitoring the pesticide residues in cereals and beans.

Effect of lysolecithin on the systemic arterial blood pressure of anaesthetized rats

REFERENCES the First International Symposium, Excerpta Medica Foundation, Amsterdam, pp. 179-193 Askew, B. M. (1963) Life Sciences 2: 725-730 Carlsson, A., Lindqvist, M., Magnusson, T. (1957) Nature 180: 1200 Fuller, R. W., Perry, K. W., Snoddy, H. D., Molloy, B. B. (1974) Eur. J. Pharmacol. 28: 233-236 Fuller, R. W., Snoddy, H. D., Perry, K. W., Bymaster, F. P., Wong, D. T. (1978) Blochem. PharmacoJ. 27: 193-198 Ther. 129: 273-289

Isolation of Diosgenin[(25R)‐Spirost‐5‐en‐3β‐o1] from a Lysate of a New Hypotensive Phospholipid Occurring in Bovine Brain

Abstract: Diosgenin[(25R)‐spirost‐5‐en‐3β‐o1] and cholesterol were detected as trimethylsilyl derivatives by gas chromatography‐mass spectrometry in an alkaline lysate of a new hypotensive phospholipid from the lipid fraction of bovine brain. These steroids seemed to be present in the hypotensive phospholipid fraction in some bound forms.

A hypotensive phospholipid from dog peritoneal dialysate.

The hypotensive effects of lysophosphatidylethanolamines have been reported (Turcotte et al 1973, 1975; Antonello et al 1973). Recently, we have described the vaso-activity of L-a-lysophosphatidic acid (l-acylsn-glycero-3-phosphate) (Tokumura et al 1978 a,b,c), and the occurrence of an acute depressor-active factor in the acetone-soluble fraction of bovine brain (Tsukatani et al 1976). We now report the pharmacological and chemical characteristics of a short-lasting hypotensive phospholipid obtained from dog peritoneal dialysate (PD) designated tentatively PD.D-I. Preparation of the hypotensive phospholipid PD.D-I. Dog PD (Martini et al 1967) was lyophilized, extracted with chloroform-methanol @:I, v/v), washed by Folch’s procedure (Folch et al 1957) and the total lipid fraction was obtained (approximately 300 mg litre-’ of PD). The lipids were fractionated on a silicic acid column eluted with chloroform-methanol mixtures of increasing polarity, and the phosphorus content in each fraction was determined (Chalvardjian & Rudnicki 1970). The hypotensive effect of each fraction on carotid arterial blood pressure of the urethane (1.8 g kg-l i.p.)-anaesthetized rat was evaluated by intrafemoralvenous injection of a sample of the eluate after it had been dried and redissolved in 0.9% w/v NaCI. The activity was recovered mainly in the eluate of the chloroform-methano1 (4:6, v/v). The active material was further purified through cellulose, first on Sephadex LH-20 [eluting with chloroform-methanol (1 : I , v/v)J and second on Sephadex LH-20 [eluting with acetoneethanol (1 :1, v/v)] columns and the hypotensive activities and phosphorus contents of fractions were evaluated as described above. Finally, 1.94mg of purified hypotensive factor litre-’ of PD was obtained which corresponded to approximately 0.65% of the total lipid of dog PD; it contained 92pg of phosphorus. The purified material showed a single spot on t.1.c. in three different solvent systems (Table 1). Pharmacological properties of PD.D-I. The doseresponse relationship (Fig. 1) was examined on urethane-anaesthetized rats. In the range tested the depressor-response was dosedependent and no tachyphylaxis or sensitization was observed. The minimum effective dose of PD.D-I was approximately 35.2pg kg-’ of the purified preparation on a weight basis and it contained approximately 0.054 pmol phosphate. PD.D-I elicited depressor responses in all species examined approximately to the same extent, but we observed two types of profiles of duration of responses. In rats and cats the arterial blood pressure fell sharply and returned to preinjection

Spectrophotometric Method for Heme Iron Determination in Foods

A simple and rapid method for the determination of heme iron in foods was investigated. A sample was weighed in a centrifuge tube and the fat in the sample was removed with diethyl ether. The residue was mixed well with 1-2 ml water, and added 10 ml of methyl isobutyl ketone (MIBK) and 5 ml of concentrated hydrochloric acid. The tube was placed in an ultrasonic water bath for 10 min. Five ml of water was added to separate the MIBK layer from the aqueous layer. After shaking for 5 min, the mixture was centrifuged for 5 min at 3000 rpm. Heme iron in the MIBK layer was determined by spectrophotometer at a wavelength of 640 nm. The calibration curve was linear from 2.5 to 15μg Fe/ml. The recoveries of heme iron added to foods were within the range from 80.5% to 90.0%. An interlaboratory study of this method for the determination of heme iron in cookie, liver and meat was conducted in 3 laboratories. The coefficient of variation for each sample was within the range of 6.29-7.15%. This method is simple and useful for the determination of heme iron in foods.