Analytical methodologies for determination of methotrexate and its metabolites in pharmaceutical, biological and environmental samples / 药物分析学报

Methotrexate (MTX) is a folate antagonist drug used for several diseases, such as cancers, various ma-lignancies, rheumatoid arthritis (RA) and inflammatory bowel disease. Due to its structural features, including the presence of two carboxylic acid groups and its low native fluorescence, there are some challenges to develop analytical methods for its determination. MTX is metabolized to 7-hydroxymethotrexate (7-OH-MTX), 2,4-diamino-N10-methylpteroic acid (DAMPA), and the active MTX polyglutamates (MTXPGs) in the liver, intestine, and red blood cells (RBCs), respectively. Additionally, the drug has a narrow therapeutic range; hence, its therapeutic drug monitoring (TDM) is necessary to regulate the pharmacokinetics of the drug and to decrease the risk of toxicity. Due to environmental toxicity of MTX; its sensitive, fast and low cost determination in workplace environments is of great interest. A large number of methodologies including high performance liquid chromatography equipped with UV-visible, fluorescence, or electrochemical detection, liquid chromatography-mass spectroscopy, capillary electrophoresis, UV-visible spectrophotometry, and electrochemical methods have been developed for the quantitation of MTX and its metabolites in pharmaceutical, biological, and environ-mental samples. This paper will attempt to review several published methodologies and the instru-mental conditions, which have been applied to measure MTX and its metabolites within the last decade.

Effects of menthone and piperitone on growth, chlorophyll a and β-carotene production in Dunaliella salina.

Recently, studying essential oils and secondary metabolites of plants and microalgae have received much attention. The biosynthesis of the secondary metabolites is strongly influenced by different environmental factors. Monoterpenes as a main fraction of essential oils of fruits and vegetables have many clinical applications. They could inhibit the carcinogenesis processes and therefore might be effective in treatment of cancers. Dunaliella salina, a photosynthetic green microalga is known as a rich source for β-carotene production. In this study, the effects of some monoterpenes including menthone and piperitone was investigated on yield of production of β-carotene were studied. Menthone and piperitone as parameters of stress can make tensions to the medium of D. salina increasing its β-carotene and chlorophyll a content in every single cell but on the other hand these two monoterpenes cause a decrease in the concentration of β-carotene and chlorophyll a.

Selective Isolation and Identification of Arginine Degrading Bacteria; the Optimized Arginine Deaminase Production by Enterobacter sp. sgn1 as a New Source of This Potentially Anti-Tumor Enzyme.

Since certain tumor cells are auxotrophic for arginine, depletion of the extracellular arginine by means of arginine degrading enzymes might be exploited to target such tumors. Among the arginine degrading enzymes, arginine deaminase has attracted more attention as a potential anti-cancer agent for arginine–auxotrophic tumors. In order to find some new sources for arginine degrading enzymes, this study was designed to screen bacterial species, applying a simple and convenient procedure, using a selective medium and Nessler’s reagent test. The characterization of the isolated samples was carried out using 16S ribosomal DNA gene sequence analysis, which were further identified as Enterobacter sp., Bacillus sp., Erwinia sp., Oceanomonas sp., Acinetobacter sp., Cronobacter sp. Enterobacter sp. sgn1 was further studied as the arginine deiminase producing bacteria, by investigating the effect of some factors on enzyme production (using Minitab software and measuring the amount of citrulline as the product of ADI enzyme). According to our results; the arginine deiminase production and activity of Enterobacter sp. sgn1 were affected by: temperature, the concentration of glucose and Mg+ ion. Moreover, the phylogenetic tree was constructed using Mega 6 software and it was observed that among the isolated species, Bacillus species are very close to Mycoplasma arginini.

Investigating the effects of phytohormones on growth and β-carotene production in a naturally isolates stain of Dunaliella salina.

The algae of the genus Dunaliella especially D. salina is among the microalgae most studied for mass culture. This alga is the richest algal source of glycerol and β-carotene, which is grown as a food source in aquaculture. In this study the effect of growth regulators (kinetin, gibberellic acid, indole-3-acetic acid, 6γ, γ-dimethylallyl aminopurine, salicylic acid and benzyl aminopurine) on the growth and β-carotene production in D. salina (MCCS 001) was investigated. Results pointed out that the β-carotene content and cell growth of D. salina could achieve the highest rates when kinetin and indole-3-acetic acid were used at 1 µM. Besides, it was shown that almost all of plant hormones has a positive effect on cell growth and β-carotene production in the microalga D. salina.

Effects of osmotic shock on production of β-carotene and glycerol in a naturally isolated strain of Dunaliella salina.

In the present study, the effects of hypo-osmotic and hyper-osmotic shock on β-carotene and glycerol production by a native strain of Dunaliella salina isolated from Maharlu Salt Lake, Fars province, Iran, were investigated. The amount of β-carotene and glycerol at 1 h, 2 h, 8 h and 24 h after initiating hypo-osmotic (1 M NaCl) and hyper-osmotic shocks (3 M NaCl); and at normal condition (2 M NaCl) were measured. At hyper-osmotic medium, β-carotene concentration reached to maximum amount after 2 h and remained constant up to 24 h. Even so, increasing of glycerol concentration was initiated after 2 h and reached the highest value at 24 h after salinity stress induction. At hypo-osmotic shock, β-carotene and glycerol concentrations were decreased. There are lots of lakes and salt marshes in Iran, which can be suitable environments for growing D. salina. So it seems that the isolated D. salina is potentially useful for planting in small locations to promote the commercial production of β-carotene and glycerol.