Silica Gel Thin-layer Chromatography Research Articles

Detection of Maize Mold Based on a Nanocomposite Colorimetric Sensor Array under Different Substrates.

This study developed a novel nanocomposite colorimetric sensor array (CSA) to distinguish between fresh and moldy maize. First, the headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) method was used to analyze volatile organic compounds (VOCs) in fresh and moldy maize samples. Then, principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA) were used to identify 2-methylbutyric acid and undecane as key VOCs associated with moldy maize. Furthermore, colorimetric sensitive dyes modified with different nanoparticles were employed to enhance the dye properties used in the nanocomposite CSA analysis of key VOCs. This study focused on synthesizing four types of nanoparticles: polystyrene acrylic (PSA), porous silica nanospheres (PSNs), zeolitic imidazolate framework-8 (ZIF-8), and ZIF-8 after etching. Additionally, three types of substrates, qualitative filter paper, polyvinylidene fluoride film, and thin-layer chromatography silica gel, were comparatively used to fabricate nanocomposite CSA combining with linear discriminant analysis (LDA) and K-nearest neighbor (KNN) models for real sample detection. All moldy maize samples were correctly identified and prepared to characterize the properties of the CSA. Through initial testing and nanoenhancement of the chosen dyes, four nanocomposite colorimetric sensitive dyes were confirmed. The accuracy rates for LDA and KNN models in this study reached 100%. This work shows great potential for grain quality control using CSA methods.

Antibacterial and Anti-Inflammatory Properties of Flavonoids from Streptomyces chartreusis RH3.5.

<b>Background and Objective:</b> The RH3.5 was isolated from the rhizosphere of <i>Boesenbergia rotunda</i> (L.) Mansf. and identified to be <i>Streptomyces chartreusis</i> via analysis of its 16S rDNA sequence, chemotaxonomy and morphology. The aim of this study was to identify the major compounds of RH3.5 and assess their biological activities. <b>Materials and Methods:</b> Silica gel column chromatography and thin-layer chromatography were used to purify major compounds, elucidate 5,7,2'-trihydroxy-8-methoxyflavanone (compound <b>1</b>) and 5',2',5'-trihydroxy-7,8-dimethoxyflavanone (compound <b>2</b>). Subsequently, mass spectrometry and NMR techniques were used to identify the structure of these compounds. Antimicrobial, anti-inflammatory and cytotoxic properties were carried out using <i>in vitro</i> assays. <b>Results:</b> The bioassays revealed the antimicrobial effect of compounds <b>1</b> and <b>2</b> on MRSA and <i>Staphylococcus aureus</i>. The minimum inhibitory concentration and minimum bactericidal concentration was calculated in the range of 32-64 and 128-256 μg/mL, respectively. The compounds <b>1</b> and <b>2</b> also exhibited anti-inflammatory potential by inhibiting NO, IL-1β and TNF-α production in LPS-stimulated RAW264.7 cells in a dose-dependent manner. Additionally, they had mild cytotoxic action against Vero and L929 cell lines with IC<sub>50</sub> values greater than 512 μg/mL. <b>Conclusion:</b> These findings showed that flavonoids of <i>Streptomyces</i> <i>chartreusis</i> RH3.5 exhibited antibacterial and anti-inflammatory activities with low cytotoxicity against healthy cells. Thorough research on these compounds could result in the creation of useful methods for treating microbial infections and acute inflammatory responses.

Extraction, Isolation and Biological Activity of Two Glycolipids from Bangia fusco-purpurea.

In order to explore the extraction and activity of macroalge glycolipids, six macroalgae (Bangia fusco-purpurea, Gelidium amansii, Gloiopeltis furcata, Gracilariopsis lemaneiformis, Gracilaria sp. and Pyropia yezoensis) glycolipids were extracted with five different solvents firstly. Considering the yield and glycolipids concentration of extracts, Bangia fusco-purpurea, Gracilaria sp. and Pyropia yezoensis were selected from six species of marine macroalgae as the raw materials for the extraction of glycolipids. The effects of the volume score of methanol, solid-liquid ratio, extraction temperature, extraction time and ultrasonic power on the yield and glycolipids concentration of extracts of the above three macroalgae were analyzed through a series of single-factor experiments. By analyzing the antioxidant activity in vitro, moisture absorption and moisturizing activity, the extraction process of Bangia fusco-purpurea glycolipids was further optimized by response surface method to obtain suitable conditions for glycolipid extraction (solid-liquid ratio of 1:27 g/mL, extraction temperature of 48 °C, extraction time of 98 min and ultrasonic power of 450 W). Bangia fusco-purpurea extracts exhibited a certain scavenging effect on DPPH free radicals, as well as good moisture-absorption and moisture retaining activities. Two glycolipids were isolated from Bangia fusco-purpurea by liquid-liquid extraction, silica gel column chromatography and thin-layer chromatography, and they showed good scavenging activities against DPPH free radicals and total antioxidant capacity. Their scavenging activities against DPPH free radicals were about 60% at 1600 µg/mL, and total antioxidant capacity was better than that of Trolox. Among them, the moisturizing activity of a glycolipid was close to that of sorbierite and sodium alginate. These two glycolipids exhibited big application potential as food humectants and antioxidants.

Application of TLC and HPLC/MS methods in the study of the interaction of N-phenytaconimide with 3-methyl-1-phenyl-5-aminopyrazole

The thin layer chromatography (TLC) method is widely used for the rapid analysis of reaction masses in fine organic synthesis. The use of this method allows not only assessing the purity of substances and identify individual components, but also to monitor the progress of synthesis [1-3]. To reliably identify a large number of substances in multicomponent systems and determine the degree of conversion of starting substances, the HPLC-MS analysis method can be used [4-6]. It was previously shown that N-arylitaconimides are easily recycled by various binucleophiles when they are boiled together in various solvents, but data on the choice of reaction conditions were scattered and unsystematized. The purpose of this study was to investigate the possibility of combining several chromatographic methods to control and optimize the synthesis of pyrazolo[3,4-b]pyridine formed during the reaction N-phenylitaconimide and 3-methyl-1-phenyl-pyrazol-5-amine. The interaction of the components was carried out in low-polar as well as polar protic and aprotic solvents. For the control of the completeness of the reaction, thin layer chromatography on TLC Silica gel 60 F254 (Merck) plates was used, chloroform, methanol and their mixtures in various ratios were used as eluents. The components of the reaction mass were correlated with the declared structures using HPLC/MS studies. It was shown that the interaction of N-phenylitaconimide with 3-methyl-1-phenylpyrazol-5-amine in all studied systems for 10-15 hours did not lead to the complete conversion of the reagents. The use of aprotic solvents, both polar and low-polar, did not allow obtaining preparatively significant yields of the target product. In protic solvents, the yields of pyrazolo[3,4-b]pyridine were significantly higher. It was also shown that an increase in the protonogenicity of the medium due to the addition of acetic acid led to a more complete conversion of the reagents. The TLC and HPLC/MS data correlated well with the data on the preparative yields of pyrazolo[3,4-b]pyridine. It was found that the most suitable medium for synthesis was a mixture of propan-2-ol and acetic acid in a ratio of 25:1.

Two new sesquiterpenes in Qi-nan Aquilariae Lignum Resinatum

This study aimed to investigate the chemical constituents of supercritical extract from Qi-nan Aquilariae Lignum Resinatum by silica gel column chromatography, thin-layer chromatography, and semi-preparative high-performance liquid chromatography. One new elemane-type and one new eudesmane-type sesquiterpene compounds were isolated from the extract, and their structures were identified by MS, UV, IR, NMR, and ECD spectroscopic techniques, and named aquqinanol C(1) and aquqinanol D(2). Both compounds are novel compounds. The neuroprotective effect of the compounds on CORT-induced PC12 cell damage was determined in vitro. The results showed that compounds 1 and 2 exhibited a certain protective effect against CORT-induced damage in PC12 cells.

Cytotoxicity Activity, Metabolite Profiling, and Isolation Compound from Crude Hexane Extract of Cleome rutidospermae.

This study isolated the chemical compounds and evaluated the cytotoxic activity of the crude hexane extract of Cleome rutidospermae herb (CRH). The isolate was purified using silica gel, column chromatography, and preparative thin layer chromatography (PTLC). Furthermore, the structure of the compounds was identified by spectroscopic methods using 1D, 2D NMR, and mass spectrometry. The cytotoxic activity of CRH at a concentration of 20 ug/mL was also tested against MCF-7, A549, KB, KB-VIN, and MDA-MB-231 cancer cells using the sulforhodamine B (SRB) method. The CRH contained compounds of unsaturated fatty acid, saturated fatty acid, lipid, glycerol, ω-3 fatty acid, and cholesterol. Two compounds were obtained from the plant, and their structures were identified as (1) Stigmasta-5,22-dien-3-ol (STML) and (2) 1,2-Benzene dicarboxylic acid, 1,2-bis (2-Ethylhexyl) esters (DEHP). These compounds were reported in this plant for the first time. In comparison, CRH had % growth inhibition in the proliferation of MCF-7 cells up to 28.1%, with cancer cells A549, KB, KB-VIN, and MDA-MB-231 by >50% Compared to the negative DMSO of 0.20%, while the positive control could inhibit the growth of all cancer cells (100%). Our findings suggested that crude herb from the plant CRH was the potential for breast cancer treatment.

Thin layer chromatography‒spectrodensitometric determination of a three-component mixture of propyphenazone, caffeine, ergotamine tartrate, and two of their impurities with application to tablets, spiked human plasma, and green profile assessment

A novel, green, and cost-effective thin-layer chromatography (TLC)‒spectrodensitometric method was designed and validated for the simultaneous determination of a five-component mixture. The analyzed mixture is composed of three active ingredients: propyphenazone (PRO), caffeine (CAF), and ergotamine tartrate (ERG), along with two official impurities which are PRO impurity: phenazone (PHN) and CAF impurity: theophylline (THEO). The suggested method was used for the quantitation of the three coformulated active ingredients in their marketed tablet and in human plasma. The studied compounds were separated on TLC silica gel 60F254 plates using a mobile phase consisting of methanol–ethyl acetate–glacial acetic acid (1:9:0.1, V/V) with diprophylline (DPP) as internal standard. Densitometric scanning was carried out at 210.0 nm. Method validation was assessed according to the International Council for Harmonisation (ICH) guidelines. The greenness profile for the proposed method was evaluated using the National Environmental Method Index (NEMI), analytical eco-scale, and Green Analytical Procedure Index (GAPI) tools. The proposed method offers the advantages of being simple, rapid, economic, and ecofriendly. It is a successful choice for the routine analysis of the studied drugs in pharmaceutical and biological samples.

A new cinnamic acid ester derivative from Liquidambaris Resina

Twelve compounds were isolated from Liquidambaris Resina by silica gel column chromatography and thin layer chromatography. Their structures were identified on the basis of spectral data, electron capture detector data, and physicochemical properties as(2'R, 3'R)-2',3'-dihydroxy-hydrocinnamyl-(E)-cinnamate(1),(E)-cinnamyl-(E)-cinnamate(2), cinnamic acid(3), 28-norlup-20(29)-en-3-one-17β-hydroperoxide(4), erythrodiol(5), 13β,28-epoxy-30-hydroxyolean-1-en-3-one(6),(3β)-olean-12-ene-3,23-diol(7), 2α,3α-dihydroxy-olean-12-en-28-oic acid(8), 28-hydroxyolean-12-en-3-one(9), 3-epi-oleanolic acid(10), 3-oxo-oleanolic acid(11), and hederagenin(12). Compound 1 was a new cinnamic acid ester derivative and compounds 2-4,6-8, and 12 were isolated from Liquidambaris Resina for the first time. Compounds 4, 5, 10, and 12 exerted inhibitory effects on the proliferation of human umbilical vein endothelial cells(HUVEC) with the IC_(50) values of(17.43±2.17),(35.32±0.61),(27.50±0.80), and(46.30±0.30) μmol·L~(-1), respectively.

Integrated methods for fingerprinting of monofloral honeys

Honey is an important functional food due to its content of polyphenolic compounds with beneficial effects on human body. The analysis of polyphenolic compound in honey is very promising in determination of floral origin and so for quality control. This study approaches a new methodology using integrated methods for the determination of honey authenticity. Polyphenolic compounds from seven different types of monofloral honey from two different sources were extracted and analyzed by thin layer chromatography (TLC) and UV-Vis spectroscopy. Chromatographic analysis was performed on TLC Silica gel 60 RP-18 F254 plates using a mobile phase consisting in a mixture of methanol: water: formic acid (5: 5: 0.1, v/v/v). The images from the TLC analysis were processed and the obtained chromatograms together with the UV-Vis deconvoluted spectra of honey were subjected to visual and statistical analysis. The obtained results showed notable differences between the honey samples, which can be used to establish their floral origin and for their authentication. The proposed methodology is easy to perform, cost-effective and offers complementary information, therefore it has the potential of being used for the honey authentication.

Study of the antibacterial activity of Malva Neglegta

Different extract of Malva neglecta were investigated for their antibacterial against Streptococcus pneumonia, Staphylococcus. aureus. Haemophilus. Influenza. Moraxella,. catatahhs. Almost all extract produced significants antibacterial activity against all microorganisim the in comparisom with Gentamicin sulphate.Petrolium.ether was more effective than the other extract . The flavonoids was separated on silica gel thin layer chromatography and responsible for this activity the study determined that t antibacterial action is related to flavonoid.

Quantitative analysis of polyphenolic compounds in two different cultivars of marigold (Tagetes erecta L.) using high-performance thin-layer chromatography

Marigold (Tagetes erecta L.), a popular ornamental plant of the family Asteraceae, is commonly cultivated in many countries, including India, for its decorative flowers. The plants grow easily in a variety of soil and climatic conditions and have been reported to damage the nematode population of soil and control indirectly harmful microbes. High-performance thin-layer chromatography (HPTLC) was utilized in the present study, with a view to identify some important biologically active compounds in the flowers and leaves of two cultivars of marigold, Pusa Narangi Gainda (PNG) and Pusa Basanti Gainda (PBG). Quantitative analyses were carried out using silica gel thin-layer chromatography (TLC) plates and toluene–ethyl acetate–formic acid (T-E-F) (13:11:2 v/v/v) as the mobile phase used. Bands of gallic acid, caffeic acid, quercetin, p-coumaric acid, and kaempferol were observed. The results revealed a greater number of compounds in leaves than in flowers, and that the cultivar PNG accumulated a greater number of compounds than PBG. Gallic acid was found in leaves and flowers of both cultivars; however, it was found maximum in the flowers of cultivar PBG. Caffeic acid and quercetin were detected in the leaves of both cultivars, whereas p-coumaric acid was detected only in the leaves and kaempferol only in the flowers of cultivar PNG. The information generated in this report may be meaningfully used for the furtherance of research on marigolds as a natural source of antioxidants, insecticides, herbicides, etc.

Ecofriendly chromatographic estimation of spasmolytic pharmaceutical mixture along with official toxic impurity, 3,5-dichloroaniline: Complete green profile appraisal.

Nowadays, Green Analytical Chemistry is widely applied to provide various analytical methods with eco-friendly procedures employing the least toxic, harmful reagents on humans and the environment without affecting the efficacy of the determination. Accordingly, two eco-friendly, accurate, and reliable high-performance thin-layer chromatography-densitometry and high-performance liquid chromatographic methods were established for the determination and separation of two antispasmodic drugs, namely phloroglucinol and trimethylphloroglucinol in their pure, combined dosage form along with phloroglucinol toxic impurity, 3,5-dichloroaniline. For high-performance thin-layer chromatography-densitometry, efficient separation was developed via utilizing the stationary phase of high-performance thin-layer chromatography silica gel 60 F254 plates and developing a system comprising of ethyl acetate-butanol-ammonia in the ratio of 8.0:2.0:0.2, by volume and scanning of the developed bands at 210.0nm. The subsequent method is isocratic high-performance liquid chromatography with diode array detection in which separation was successively attained using XTerra RP-C18 (250 × 4.6mm, 5μm) column as stationary phase and methanol-10.0mM phosphate buffer, pH 3.7±0.1 as mobile phase in the ratio of 75.0:25.0, v/v at flow rate 1.0ml/min and scanning at 220.0nm. The developed liquid chromatography methods were validated according to the International Council for Harmonization guidelines, and all results acknowledged their efficacy. Additionally, the proposed methods worked well for assessing the cited drugs in binary combined commercially available pharmaceutical formulation. The greenness profile of the present methods was assessed and estimated using various assessment tools, namely; Green Analytical Procedure Index, analytical eco-scale method, National Environmental Method Index in addition to Analytical GREEnness tool to evaluate the greenness of the provided methods with a statistical comparison between them to assess the more green ones.

Semiquantitative Screening of THC Analogues by Silica Gel TLC with an Ag(I) Retention Zone and Chromogenic Smartphone Detection.

With the ever-evolving cannabis industry, low-cost and high-throughput analytical methods for cannabinoids are urgently needed. Normally, (potentially) psychoactive cannabinoids, typically represented by Δ9-tetrahydrocannabinol (Δ9-THC), and nonpsychoactive cannabinoids with therapeutic benefits, typically represented by cannabidiol (CBD), are the target analytes. Structurally, the former (tetrahydrocannabinolic acid (THCA), cannabinol (CBN), and THC) have one olefinic double bond and the latter (cannabidiolic acid (CBDA), cannabigerol (CBG), and CBD) have two, which results in different affinities toward Ag(I) ions. Thus, a silica gel thin-layer chromatography (TLC) plate with the lower third impregnated with Ag(I) ions enabled within minutes a digital chromatographic separation of strongly retained CBD analogues and poorly retained THC analogues. The resolution (Rs) between the closest two spots from the two groups was 4.7, which is almost 8 times higher than the resolution on unmodified TLC. After applying Fast Blue BB as a chromogenic reagent, smartphone-based color analysis enabled semiquantification of the total percentage of THC analogues (with a limit of detection (LOD) of 11 ng for THC, 54 ng for CBN, and 50 ng for THCA when the loaded volume is 1.0 μL). The method was validated by analyzing mixed cannabis extracts and cannabis extracts. The results correlated with those of high-performance liquid chromatography with ultraviolet detection (HPLC-UV) (R2 = 0.97), but the TLC approach had the advantages of multi-minute analysis time, high throughput, low solvent consumption, portability, and ease of interpretation. In a desiccator, Ag(I)-TLC plates can be stored for at least 3 months. Therefore, this method would allow rapid distinction between high and low THC varieties of cannabis, with the potential for on-site applicability.

Simultaneous ultra-sensitive analysis of tamsulosin hydrochloride and tolterodine tartrate binary mixture in their dosage form via high-performance thin-layer chromatography with fluorimetric detection

A simple, sensitive, selective, and stability-indicating high-performance thin-layer chromatography method with fluorescence detection was developed for the analysis of a mixture of tamsulosin hydrochloride and tolterodine tartrate, used in the management of benign prostatic hyperplasia in their laboratory-prepared binary mixture and dosage form. The separation was employed on thin-layer chromatography silica gel 60 aluminum sheets. As developing system, ethyl acetate–n-hexane–diethylamine (9:3:1, V/V) was used. Tamsulosin and tolterodine had retention factors (RF) of 0.40 ± 0.03 and 0.85 ± 0.03, respectively. A 225 nm excitation wavelength was used for the fluorescence detection. Linearity was in the range of 10.0–200.0 and 100.0–900.0 ng/band for tamsulosin and tolterodine, respectively. The method was validated successfully according to the International Council for Harmonisation guidelines. Our suggested method for determining tamsulosin and tolterodine in their dosage forms and in the presence of their degradation products could be conveniently applied in quality-control laboratories.

Antibacterial and Anticancer Properties of Microbispora sp., AL22: An Endophyte of Alpinia galanga (L.) Willd.

<b>Background and Objective:</b> The AL22 strain was isolated from the rhizosphere soil of <i>Alpinia galanga</i> (L.) Willd (Zingiberaceae) and identified as <i>Microbispora</i> sp., by analysing its morphology, chemotaxonomy and 16S rDNA sequence. Previous studies demonstrated the bactericidal effects of its crude extract against <i>Bacillus cereus</i>, <i>Bacillus subtilis</i>, <i>Staphylococcus aureus</i> and methicillin-resistant <i>Staphylococcus aureus</i>. The present study aimed to isolate the major compounds and evaluate their biological properties. <b>Materials and Methods:</b> Silica gel column chromatography and thin-layer chromatography were used for the purification and identification of 3,4-dihydro-lactucin (compound <b>1</b>) and umbelliferone (compound <b>2</b>) by NMR and mass spectrometry, respectively. Antibacterial and anticancer activities were carried out. <b>Results:</b> The bioassay studies illustrated that compound <b>1</b> had antibacterial activity against gram-positive bacteria, with its minimum inhibitory concentration and minimum bactericidal concentration of 16-32 and 64-128 μg mL<sup></sup><sup>1</sup>, respectively. The crude extract and purified compounds showed weak cytotoxic activity on the L929 and Vero cells with IC<sub>50</sub> values >512.00 μg mL<sup></sup><sup>1</sup>. The cytotoxicity of compound <b>1</b> was observed in the MDA-MB-231 and HeLa cells with IC<sub>50</sub> values of 37.62 and 75.34 μg mL<sup></sup><sup>1</sup>, respectively, while its IC<sub>50</sub> value against the HepG2 cells was 456.67 μg mL<sup></sup><sup>1</sup>. <b>Conclusion:</b> These findings showed that compound <b>1</b> of <i>Microbispora</i> sp., AL22 exhibited antibacterial and anticancer activities. Extensive studies on 3,4-dihydro-lactucin could lead to the development of beneficial approaches for managing bacterial infections and cancer.

Spectrofluorimetric and stability-indicating thin layer chromatographic methods for determination of cabergoline, a prolactin inhibitor in pharmaceuticals

Simple, Economic, and selective spectrofluorimetric and stability-indicating thin layer chromatographic (TLC) with fluorescence detection methods were developed for the determination of Cabergoline, a potent prolactin inhibitor, and long-acting dopamine receptor agonist, in bulk drug and pharmaceutical dosage forms based on its native fluorescence. Method A was based on measuring the fluorescence intensity at 338 nm after excitation at 280 nm. The measured fluorescence was directly proportional to the concentration of the drug over the range of 50.0–450.0 ng/mL with a limit of detection of 14.4 and a limit of quantification of 43.7 ng/mL. The TLC method (method B) was employed on TLC silica gel 60 F254 aluminum sheets previously exposed to concentrated (30–34 %) hydrochloric acid vapor. Ethyl acetate: n-hexane: diethylamine system with a ratio of (10: 3: 1, v/v/v) developing system was used. The retention factor (Rf) of Cabergoline was 0.58 ± 0.03. Linearity was found to be in the range of 100.0–1500.0 ng/band. The LOD and LOQ were 25.4 and 76.9 ng/band, respectively. The methods were validated successfully according to ICH guidelines.

Isolation, Characterization, and Optimization Studies of Bacterial Pigments

Recent concern for human safety and environmental protection has rekindled interest in natural pigment sources. In comparison to synthetic pigments, microbial pigments show better biodegradability and environmental compatibility and are used in a variety of applications ranging from food to cosmetics. The areas of attention for economical pigment synthesis include the identification of novel microbiological sources and improvement of process parameters. The purpose of this research was to screen and identify microbial isolates capable of generating pigments with antimicrobial activity from a variety of soil samples. A total of six pigment-producing bacterial sps were able to isolate from various soil samples such as bore well digging sites, river shores, river beds, forest areas, dumping yards using the enrichment culture technique. All the isolates were morphologically and biochemically identified as Micrococcus sp producing two-color pigments i.e., yellow and orange, Serratia sp producing red and pink color pigments, Salinococcus sp producing orange color pigment, and Exiguobacterium sp producing yellow color pigment respectively. During optimization studies maximum pigment production was observed at pH 7, agitation at 90 rpm (rotations per minute) and 120 rpm, the temperature of 30°C and 37°C, inoculum size up to 2% with NaCl concentration of 2%, 4%, and 6% respectively. Optimization of nutritional parameters such as carbon source and nitrogen source it was found that glucose (1%) and yeast extract (0.1%) work the best. Extraction of the pigment from the fermented broth was done by solvent-solvent extraction method. UV-Visible spectrophotometry and Silica gel Thin-layer chromatography was used to detect the presence of carotene and prodigiosin in the extracted bacterial pigment. The crude bacterial pigments were tested for antimicrobial activity against clinical pathogens including E. coli, Klebsiella sp, Bacillus sp, Staphylococcus sp, and pseudomonas sp respectively. Among all the isolates, pigments of Micrococcus sp and Salinococcus sp showed comparatively good results. Further purification of the pigment will lead to discovering a promising drug in the pharmaceutical industry.

An improved method for the purification and structural analysis of rubropunctatin from red yeast glutinous rice

An improved method for the separation and purification of rubropunctatin from red yeast glutinous rice was developed. In this method, silica gel column chromatography and thin layer chromatography were used to separate the Monascus pigments. Pure methanol and a mixture of ethyl acetate and methanol (13:7, v/v) were selected as the eluent and running solvent, respectively. When compared with previously reported methods, the developed method required fewer types of solvents, and could be suitable for large-scale laboratory production. The extracted pigment was analysed by ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS) and nuclear magnetic resonance (NMR) (1H NMR, 13C NMR). Structural analysis revealed a molecular mass of 353.2 m/z [M－H]－, and a structure including an azaphilone body with two side chains. This structure was consistent with that reported for rubropunctatin. Therefore, the improved purification method reported herein could efficiently be used for the extraction of rubropunctatin from red yeast glutinous rice.

Extraction, Isolation and Characterization of Mycosporine-like Amino Acids from Four Species of Red Macroalgae.

Marine macroalgae is known to be a good source of mycosporine-like amino acids (MAAs), especially red macroalgae. As a new type of active substance with commercial development prospects, the current progress in the extraction, isolation and characterization of MAAs is far from sufficient in terms of effectiveness in application. To determine the extraction processes of MAAs from four species of red macroalgae (Bangia fusco-purpurea, Gelidium amansii, Gracilaria confervoides, and Gracilaria sp.), a series of single-factor and orthogonal experiments were carried out in which the effects of solvents, the solid–liquid ratio, the time of extraction, the extraction degree and the temperature, on the yields of MAA extracts, were analyzed. Further, the isolation and identification of MAAs from Bangia fusco-purpurea and Gracilaria sp. were investigated. The results showed that the solid–liquid ratio, the time of extraction, the extraction degree and the temperature were 1:20 g/mL, 2 h, three times and 40 °C, respectively, when 25% methanol or 25% ethanol were used as the extraction solvent; these values were found to be suitable for the extraction of MAAs from four species of red macroalgae. Silica gel thin-layer chromatography was successfully used, for the first time, for the detection MAAs in this work, and it could be clearly seen that Bangia fusco-purpurea had the highest contents of MAAs among the four species of red macroalgae. MAA extracts from Bangia fusco-purpurea (or Gracilaria sp.) were isolated by silica gel column chromatography to obtain one fraction (or two fractions). The compositions and proportions of the MAAs in these fractions were determined via HPLC-ESI-MS spectra and by comparison with existing studies. Shinorine, palythine and porphyra-334 were found in 95.4% of the T1 fraction, and palythenic acid was found in 4.6% of this fraction, while shinorine, palythine and porphyra-334 were found in 96.3% of the J1 fraction, palythenic acid was found in 3.7% of the J2 fraction, and palythine was found in 100% of the J2 fraction, taken from the MAA extracts found in Bangia fusco-purpurea and Gracilaria sp., respectively. In addition, the relevant compositions and proportions of the MAA extracts taken from Gelidium amansii and Gracilaria confervoides were identified. This was the first study to report on the extraction process, isolation and identification of MAAs from Bangia fusco-purpurea, Gelidium amansii, Gracilaria confervoides, and Gracilaria sp.

Sensitive and validated TLC densitometry method coupled with fluorescence detection for quantitative determination of the newly co-formulated drugs, celecoxib and amlodipine besylate in tablet dosage form

Abstract New, sensitive, rapid, cost-effective, and validated stability-indicating thin layer chromatographic (TLC) method coupled with fluorescence (FL) detection was developed for the quantitative analysis of celecoxib (CEL) and amlodipine besylate (AMLO) in their laboratory prepared binary mixture using the non-fluorescent TLC silica gel 60 plates. Ethyl acetate: diethylamine: 1-propanol (9:1:0.2, V/V) was used as a developing system. The retention factor (Rf) for each drug was 0.80 ± 0.03 and 0.44 ± 0.01 for CEL and AMLO, respectively. The plates were excited at 264 nm for the simultaneous FL measurement of CEL and AMLO, the calibration curves were linear over a concentration ranges of 30.0–300.0 ng/band and 15.0–150.0 ng/band with mean percentage recoveries of 99.80 ± 0.85 and 99.80 ± 0.77 For CEL and AMLO, respectively. The developed method was applied for the stability studies of the cited drugs in their laboratory prepared binary mixture and the forced degradation products were determined when present in presence of the pure drugs so the method can be considered as a stability-indicating one and it was validated as per ICH guidelines and proved to be accurate and precise.