Download the Free Unbound MEDLINE PubMed App to your smartphone or tablet.
Available for iPhone, iPad, iPod touch, and Android.
D-Phenylalanine derivative [keywords]
- N-Amino acid linoleoyl conjugates: anti-inflammatory activities. [Journal Article, Research Support, N.I.H., Extramural]
- Bioorg Med Chem Lett 2012 Jan 15; 22(2):872-5.
Several N-linked amino acid-linoleic acid conjugates were studied for their potential as anti inflammatory agents. The parent molecule, N-linoleoylglycine was tested in an in vivo model, the mouse peritonitis assay where it showed activity in reducing leukocyte migration at doses as low as 0.3mg/kg when administered by mouth in safflower oil. Harvested peritoneal cells produced elevated levels of the inflammation-resolving eicosanoid 15-deoxy-Δ(13,14)-PGJ(2). These results are similar to those obtained in earlier studies with N-arachidonoylglycine. An in vitro model using mouse macrophage RAW cells was used to evaluate a small group of structural analogs for their ability to stimulate 15-deoxy-Δ(13,14)-PGJ(2) production. The d-alanine derivative was the most active while the d-phenylalanine showed almost no response. A high degree of stereo specificity was observed comparing the d and l alanine isomers; the latter being the less active. It was concluded that linoleic acid conjugates could provide suitable templates in a drug discovery program leading to novel agents for promoting the resolution of chronic inflammation.
- Simultaneous analysis of aspartame and its hydrolysis products of Coca-Cola Zero by on-line postcolumn derivation fluorescence detection and ultraviolet detection coupled two-dimensional high-performance liquid chromatography. [Journal Article, Research Support, Non-U.S. Gov't]
- J Chromatogr A 2011 May 20; 1218(20):2976-83.
An innovative two-dimensional high-performance liquid chromatography system was developed for the simultaneous analysis of aspartame and its hydrolysis products of Coca-Cola Zero. A C8 reversed-phase chromatographic column with ultraviolet detection was used as the first dimension for the determination of aspartame, and a ligand-exchange chromatographic column with on-line postcolumn derivation fluorescence detection was employed as the second dimension for the analysis of amino acid enantiomers. The fluorimetric derivative reagent of amino acid enantiomers was o-phthaldialdehyde. The hydrolysis of aspartame in Coca-Cola Zero was induced by electric-heating or microwave heating. Aspartame was quantified by the matrix matched external standard calibration curve with a linear concentration range of 0-50 μg mL(-1) (r(2)=0.9984). The limit of detection (LOD) and the limit of quantification (LOQ) were 1.3 μg mL(-1) and 4.3 μg mL(-1), respectively. The amino acid enantiomers was analyzed by the matrix matched internal standard calibration method (D-leucine as the internal standard) with a linear concentration range of 0-10 μg mL(-1) (r(2)=0.9988-0.9997). The LODs and LOQs for L- and D-aspartic acid and L- and D-phenylalanine were 0.16-0.17 μg mL(-1) and 0.52-0.55 μg mL(-1), respectively, that was 12-13 times more sensitive than ultraviolet detection. The overall analysis accuracy for aspartame and amino acid enantiomers was 90.2-99.2% and 90.4-96.2%, respectively. The overall analysis precision for aspartame and amino acid enantiomers was 0.1-1.7% and 0.5-6.7%, respectively. Generally, the extent of aspartame hydrolysis increases with the increase of electro-thermal temperature, microwave power, and the duration of hydrolysis time. D-aspartic acid and D-phenylalanine can be observed with the electro-thermal racemization at the hydrolysis temperature 120°C for 1 day and only D-aspartic acid can be observed at the hydrolysis temperature 90°C for 2 and 3 days. For the microwave induced hydrolysis, only L-aspartic acid was detected at the power 560 W for 1 min and 320 W for 3 min.
- Evaluation of readily accessible azoles as mimics of the aromatic ring of D-phenylalanine in the turn region of gramicidin S. [Journal Article, Research Support, Non-U.S. Gov't]
- ChemMedChem 2011 May 2; 6(5):840-7.
The influence of replacing the d-phenylalanine residue with substituted and unsubstituted azoles on the structure and biological activity of the antibiotic gramicidin S was investigated against a representative panel of Gram-positive and Gram-negative bacteria strains. Substituted triazole derivatives, obtained using a convergent synthetic strategy, are as active as gramicidin S, provided that any substituent on the triazole moiety is not too large. The unsubstituted triazole derivative was biologically less active than the parent natural product, gramicidin S. In general for the triazole series, the hemolytic activity could be correlated with the antibacterial activity, that is, the higher the antibacterial activity, the higher the toxicity towards blood cells. Interestingly, its imidazole counterpart showed high antibacterial activity, combined with significantly diminished hemolytic activity.
- Immobilization of molecularly imprinted polymer nanoparticles in electrospun poly(vinyl alcohol) nanofibers. [Journal Article, Research Support, Non-U.S. Gov't]
- Langmuir 2011 Mar 1; 27(5):1547-50.
We describe the fabrication of polymer nanofibers with entrapped molecularly imprinted polymer (MIP) nanoparticles and study their possible use in a fluorescence-based biosensor application. The MIP was imprinted with the fluorescent amino acid derivative dansyl-L-phenylalanine. Poly(vinyl alcohol) was used as a support for MIP nanoparticles because it is water-soluble and can be spun into very thin fibers. The fibers were characterized by atomic force microscopy and optical microscopy, and fluorescence microscopy was used for the characterization of target binding to the MIP. The fibers show close to 100% recovery upon extraction and rebinding of the target molecule. The selectivity of the system has been demonstrated through competitive binding experiments with nonfluorescent analogues boc-L-phenylalanine and boc-D-phenylalanine.
- A review of nateglinide in the management of patients with type 2 diabetes. [Journal Article, Review]
- Vasc Health Risk Manag 2007; 3(6):797-807.
Impaired insulin secretion occurs early in the pathogenesis of type 2 diabetes mellitus (T2DM) and is chronic and progressive, resulting initially in impaired glucose tolerance (IGT) and eventually in T2DM. As most patients with T2DM have both insulin resistance and insulin deficiency, therapy for T2DM should aim to control not only fasting, but also postprandial plasma glucose levels. While oral glucose-lowering treatment with metformin and thiazolidinediones corrects fasting plasma glucose, these agents do not address the problem of mealtime glucose spikes that have been shown to trigger atherogenic processes. Nateglinide is a derivative of the amino acid D-phenylalanine, which acts directly on the pancreatic beta-cells to stimulate insulin secretion. Nateglinide monotherapy controls significantly mealtime hyperglycemia and results in improved overall glycemic control in patients with T2DM by reducing glycosylated hemoglobin (HbA1c) levels. The combination of nateglinide with insulin-sensitising agents, such as metformin and thiazolidinediones, targets both insulin deficiency and insulin resistance and results in reductions in HbA1c that could not be achieved by monotherapy with other antidiabetic agents. In prediabetic subjects with IGT, nateglinide restores early insulin secretion and reduces postprandial hyperglycemia. Nateglinide has an excellent safety and tolerability profile and provides a lifetime flexibility that other antidiabetic agents could not accomplish. The aim of this review is to identify nateglinide as an effective "gate-keeper" in T2DM, since it restores early-phase insulin secretion and prevents mealtime glucose spikes throughout the day and to evaluate the results of ongoing research into its potential role in delaying the progression to overt diabetes and reducing its complications and mortality.
- Effect of the administration of a single dose of nateglinide on insulin secretion at two different concentrations of glucose in healthy individuals. [Journal Article, Randomized Controlled Trial]
- J Diabetes Complications 2005 Nov-Dec; 19(6):356-60.
Nateglinide is a D-phenylalanine derivative that stimulates fast insulin secretion with a short activity span. It has been suggested that the hypoglycemic effect of nateglinide is related to the glucose concentration, an aspect that still has not been completely evaluated in human beings.The aim of this study is to evaluate the effect of nateglinide on the insulin secretion at two different concentrations of glucose level.A randomized, double-blind, cross-over, placebo-controlled clinical trial with two parallel groups was carried out; each group was made up by six healthy volunteers who were submitted to a hyperglycemic-hyperinsulinemic clamp technique on two different occasions, one of them prior to the administration of 120 mg nateglinide and the other one prior to the administration of an homologated placebo. One group was submitted to and maintained at a hyperglycemia of 6.9 mmol/l above the fasting glucose level and the other group at a hyperglycemia of 4.1 mmol/l above the baseline of fasting glucose level.In volunteers submitted to the clamp at 4.1 mmol/l above the baseline of glucose level, the insulin secretion in the early phase was 212.4+/-55.8 pmol/l in the placebo test versus 338.4+/-124.8 pmol/l in the nateglinide test (P<.05), whereas in the group submitted at 6.9 mmol/l over the baseline, no significant differences were observed.Nateglinide increased the early insulin secretion in healthy individuals submitted to a mild hyperglycemia, but not at high glucose concentrations.
- Nateglinide--current and future role in the treatment of patients with type 2 diabetes mellitus. [Journal Article, Review]
- Int J Clin Pract 2005 Oct; 59(10):1218-28.
Therapy for type 2 diabetes mellitus should aim to control not only fasting, but also postprandial glucose levels. Nateglinide, a d-phenylalanine derivative, restores postprandial early phase insulin secretion in a transient and glucose-sensitive manner without affecting basal insulin levels. As nateglinide is administered immediately before meals it provides greater lifestyle flexibility than agents that require patients to eat to avoid hypoglycemic events (e.g. long-acting sulfonylureas). In randomised, double-blind trials in patients with type 2 diabetes, nateglinide monotherapy (mealtime treatment of 120 mg three times daily) significantly improved long-term glycaemic control by significantly reducing glyated haemoglobin (HbA 1c) and preventing mealtime glucose spikes. The combination of nateglinide with insulin-sensitising agents, for example, metformin and thiazolidinediones, addresses the dual defects of loss of insulin secretion and insulin resistance to provide optimal management of type 2 diabetes, and more patients achieve HbA 1c goal with nateglinide combination therapy rather than with monotherapy with other oral agents. Nateglinide also restores early insulin secretion and reduces postprandial hyperglycaemia in prediabetic subjects with impaired glucose tolerance (IGT) and appears similarly effective in elderly and non-elderly populations with type 2 diabetes. It has an excellent safety and tolerability profile, with a low propensity to cause hypoglycaemia due to its transient, selective effect on early phase insulin secretion. Nateglinide as monotherapy or combination therapy is an effective option to reduce mealtime glucose in patients with type 2 diabetes. The results of ongoing research into its potential role in delaying progression to overt diabetes, and protecting against cardiovascular events, in prediabetic patients with IGT are awaited.
- Effect of N-benzoyl-D-phenylalanine, a new potential oral antidiabetic agent, in neonatal streptozotocin-induced diabetes in rats. [Journal Article]
- Pharmacol Rep 2005 Jul-Aug; 57(4):498-503.
The present investigation was undertaken to study the effect of treatment with D-phenylalanine derivative and metformin in neonatal streptozotocin (nSTZ)-induced non-insulin-dependent diabetes mellitus (NIDDM) in rats. To induce NIDDM, a single dose injection of streptozotozin (STZ) (100 mg kg(-1); ip) was given to 2-day-old rats. After 10-12 weeks, rats weighing above 150 g were selected for screening in NIDDM model. They were checked for fasting blood glucose levels to conform the status of NIDDM. D-phenylalanine derivative (50, 100 and 200 mg kg(-1)) was administered per os (po) for 6 weeks to the rats with confirmed diabetes. A group of diabetic rats was also maintained and this group received metformin as comparative drug. Significant decrease in blood glucose with significant increase in plasma insulin was observed in group receiving 100 mg of D-phenylalanine derivative plus 500 mg of metformin.
- A new strategy for the selective determination of D-amino acids: enzymatic and chemical modifications for pre-column derivatization. [Journal Article, Validation Studies]
- J Chromatogr A 2005 Jun 17; 1078(1-2):51-8.
A new strategy for the selective determination of D-amino acids (DAAs) employing a pre-column derivatization was designed with concepts based on both enzymatic and chemical modifications. Selective determination of DAAs was accomplished by following: DAA was enzymatically modified with D-amino acid oxidase (DAAO: EC 188.8.131.52) to form an alpha-keto acid. Subsequently, resulting alpha-keto acid was detected by high-performance liquid chromatography (HPLC) after chemical modification with o-phenylenediamine (PDA) in the presence of 2-mercaptoethanol (2ME) to give the corresponding quinoxalinol derivative (PDA-alpha-keto acid derivative). After optimizing the pre-column derivatization and HPLC separation, five peaks corresponding to DAAs (D-alanine, D-leucine, D-methionine, D-phenylalanine, D-valine (as the standard mixture of DAAs in this paper) were separately eluted and monitored by means of a conventional HPLC system with a gradient elution on octadecyl silica gel (ODS) column and a fluorescence detector (Ex.: 341 nm, Em.: 413 nm), respectively. It was confirmed that the present method was incapable of detecting L-amino acids (LAA) when a sample solution consisting of both LAAs and DAAs was examined. The linearity of the peak-area responses to their concentration range of DAAs from 10 to 500 microM is 0.994-1.000, and their detection limits were 0.2-1 microM (signal/noise = 3). When this method was applied to a methanolic extract of short-necked clams, Ruditapes philippinarum (in Japanese, Asari), a big peak, corresponding to D-alanine was detected, corresponding to 2.9 mg/g D-alanine. In this paper, we present an example of pre-column derivatization method that was newly configured to take into account both the biological and chemical properties of the substances in question.
- [A 50-year history of new drugs in Japan-the development and progress of anti-diabetic drugs and the epidemiological aspects of diabetes mellitus]. [English Abstract, Historical Article, Journal Article]
- Yakushigaku Zasshi 2003; 38(1):11-27.
The development and progress of antidiabetic drugs (e.g., insulin preparations and hypoglycemic drugs) are retrospectively investigated in Japan. Their influences on the treatment of diabetes mellitus (DM) and its epidemiological aspects are also discussed. 1) Insulin preparations: Insulin was introduced for DM therapy in 1925, two or three years after its discovery in Canada. The preparations were raw extracts of bovine or porcine pancreas. These did not prevail widely in Japan because of the low incidence of DM before World Wan II. After the war, a shortage of mammalian materials compelled the use of fish pancreatic tissues such as bonito and/or tuna for insulin production. Insulin infection, so-called regular insulin, was first promoted in the 6th "Pharmacopoeia Japonica" (JP6) in 1951 and has been maintained to the present edition (JP14, 2001). Although depot-type insulin preparations were developed in the USA and Europe during the war, the introduction of those preparations to Japan was delayed until 1951, when Protamine zinc insulin appeared. Globin zinc insulin and Isophane insulin were introduced for clinical use in 1952 and 1955, respectively. These were also adopted for JP7 (1961). Biphasic-type insulin, which has a rapid onset and long duration of activity, appeared in 1965. Purified preparations from bovine or porcine sources have been available since 1980, which might be a strong reason for the decrease in insulin allergy. Insulin from animal origin has been supplied for almost 60 years since its discovery. Amino acid sequences of insulins from various species of animals were determined by the pioneering studies of Sanger and his associates. Human insulin, which differs from porcine insulin by only one amino acid, was produced by Novo researchers in 1982 using a semi-synthetic method. Then the Lilly group soon succeeded in obtaining human insulin by recombinant DNA technology in the same year. Both products were introduced to Japan in 1985, and the recombinant products prevailed throughout the 1990s. Human insulin analogues (i.e., Insulin lispro and Insulin aspart) appeared in 2001. These are applied for after-meal glycosmia owing to their ultrarapid onset of activity. Self-injection by DM patients was legalized in 1981. To make the infection technique sure and easy, cartridge (pen-type) and disposable kit-type needles were devised in the 1990s. 2) Oral hypoglycemic drugs: Instead of the exclusive parenteral usage of insulins, there was also demand for oral dosage forms. The first of the sulfonyrlurea (SU) group, BZ-55, was used for DM clinically in 1955 in Germany. But it was soon withdrawn because of its antibacterial action. This led to the development of various SU groups. Tolbutamide (1956), chlorpropamide (1959), acetohexamide (1964) and tolazamide (1961) were introduced to Japan as first-generation SUs. Then glyclopyramide (Kyorin, 1965), glybenclamide (1971), gliclazide (1984) and glimepiride (1999) appeared as the second-generation SUs. These were used orally for Type 2 diabetes. Biguanide (BG) group, phenformin HC1 (1959), metformin HC1 (1961) and buformin HC1 (1961) had also been in use by oral treatment of Type 2 diabetes. SU appears to act by increasing the sensitivity of b-cells, which secrete insulin. BG probably exerts by increasing glucose transport across the membranes of target organs. 3) New types of antidiabetic drugs: a-Glucosidase inhibitors (i.e., acarbose: Bayer, 1993; and voglibose: Takeda, 1994) act on hyperglycemia after meals by decreasing glucose absorption. Thiazolidinedione compounds, such as troglitazone (Sankyo, 1995) and pioglitazone HC1 (Takeda, 1994) act by increasing the insulin sensitivity of the target tissues. These are useful for Type 2 DM patients when SUs are ineffective. Nevertheless, troglitazone was discontinued in 2000 due to severe liver damage. Nateglinide (Ajinomoto Co., 1999), which is a D-phenylalanine derivative acting similar to SUs, is useful orally for after-meal hyperglycemia of Type 2 diabetes. Epalrestat (Ono Yakuhin Co., 1992) is effective for diabetic neuropathy by reducing the formation of sorbitol. These anti-DM drugs were recently studied and developed in Japan. 4) The Japan Diabetes Society proposed a guideline on diagnostic criteria and treatment of diabetes mellitus (DM) in 1999 and revised it in 2002. DM is classified as insulin-dependent DM (Type l) and non-insulin dependent DM (Type 2). Type 1, juvenile onset DM, requires insulin therapy to prevent ketosis and to sustain life. Treatment of type 2, adult onset DM, is recommended as a step-by-step method, starting with dietary-exercise therapy, followed by oral hypoglycemic drugs and then insulin therapy. DM patients with complications should have a therapy devised to match their circumstances. 5) Epidemiological aspects: The mortality rate of DM compared to the time of drug appearance was traced from 1920 to 2000. The curve goes down slowly in the time frame of World War II, but rises from 1950 to 1970. The elevation could not be suppressed by the appearance of SUs, BGs or improved insulin preparations. The curve runs flat from 1980 to 1990, which might be related to the use of purified insulin or human insulin therapy. The mortality rate of DM indicates that death by hyperglycemic coma and other deaths resulting from complications are excluded. The survey of the principal cause of death by DM during the period of 1981-1990 indicates that the death rate due to hyperglycemic coma is only 1.7% of the total deaths caused by DM. The effect of drug therapy on all of the death resulting from DM is not detected. Hospital visitation and admission rates of the DM patients have been recorded since 1952 in Japan. This curve is rising continuously, and none of the antidiabetic drugs has been able to suppress it. These data show that the antidiabetic drugs relieve DM symptoms through their effective hypoglycemic actions, but that they cannot suppress the mortality rate of DM. It is possible that none of the drugs currently available can suppress the increasing tendency of DM patients.