TLC Comparison Research Articles

Iridoid Glucosides from Turkish Phlomis tuberosa

From the aerial parts of Phlomis tuberosa a new iridoid glucoside, chlorotuberoside was isolated together with five known iridoid glucosides, lamalbide, shanzhiside methyl ester, 7-epi-phlomiol (= phloyoside I), sesamoside and 5-deoxysesamoside. Two known phenylethanoid glycosides, forsythoside B, and decaffeoylacteoside, three known neolignan glycosides, dehydrodiconiferyl alcohol 9’-O-β -D-glucopyranoside, dihydrodehydrodiconiferyl alcohol 9-O-β -D-glucopyranoside and dihydrodehydrodiconiferyl alcohol 9’-O-β -D-glucopyranoside, one flavone glycoside, luteolin 7-O-β - D-glucopyranoside, as well as β -sitosterol 3-O-β -D-glucopyranoside and 1-methyl-O-β -D-glucopyranoside were also obtained and characterized. The structures of the isolates were elucidated on the basis of spectroscopic data. The three known phenylethanoid glycosides, verbascoside, leucosceptoside A and martynoside were identified by TLC comparison with authentic compounds.

Antibacterial activity of Turkish propolis and its qualitative and quantitative chemical composition

The antibacterial activity of propolis from different regions of Turkey was studied, accompanied by TLC and GC-MS analyses of its chemical composition and spectrophotometric quantification of the most important active principles. All six samples were active against the bacterial test strains used; however, samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) were more active than samples 4 (Adana), 5 (Erzurum) and 6 (Artvin). By TLC comparison all samples were found to contain poplar taxonomic markers but in samples 4 (Adana), 5 (Erzurum) and 6 (Artvin), different substances were observed, which were not present in P. nigra L. bud exudate. The typical poplar samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) displayed very similar phenolic and flavonoid content. Samples 4 (Adana), 5 (Erzurum) and 6 (Artvin) were characterized by low phenolic and very low flavonoid concentrations. Qualitative analysis by GC-MS revealed that sample 4 (Adana) contained diterpenic acids and high percent of cinnamyl cinnamate, sample 5 (Erzurum)-significant amounts of hydroxy fatty acids and triterpenic alcohoLs, and sample 6 (Artvin)-phenolic glycerides, characteristic for the bud exudate of Populus euphratica Oliv. The results confirm the importance of phenolics for propolis antibacterial activity, and the significance of P. nigra L. as a propolis source, which provides the hive with the best defense against microorganisms.

Comparison of TLC and spectrophotometric methods for evaluation of the antioxidant activity of grape and berry anthocyanins

Variation of antioxidant activity was measured for differently prepared extracts of pressed residues (marc) from red wine making and production of blackcurrant and redcurrant juice. On the basis of previous tests ethanol and water were chosen as suitable solvents for preparing phenolic extracts from selected samples. Antioxidant activity was also measured for commercially available standards of the anthocyanins present in grapes and red- and blackcurrants, for example malvidin 3-glucoside (Mv3G), cyanidin 3-glucoside (Cy3G), delphinidin 3-glucoside (Dp3G), peonidin 3-glucoside (Pe3G), and petunidin 3-glucoside (Pt3G). Each standard and a mixture of all standards (concentration 250 μg mL −1 ) were analyzed. Two different analytical methods were used, spectrophotometry and TLC. In both methods DPPH was used as a source of stable free radicals with which components with antioxidant activity react. The strongest antioxidant activity was found for Cy3G, then for Pe3G and Mv3G, and the lowest was for Pt3G and D...

Chemical studies of caribbean sacoglossans : Dietary relationships with green algae and ecological implications

Eight sacoglossan species associated with green algae and collected along Caribbean coasts have been chemically investigated, together with their prey. The main secondary metabolites have been identified either by TLC comparison with standard compounds, or by 1H NMR analysis, defining dietary relationships. In addition, two new compounds, ascobullin-A and ascobullin-B, have been found in the sacoglossan Ascobulla ulla and characterized by spectroscopic methods. Finally, the results obtained, together with those already reported for Caribbean sacoglossans, are summarized in a chemoecological scenario, which could be compared with that previously proposed for Mediterranean species.

Induction of alkaloid diversity in hybrid plant cell cultures

The treatment of Rauwolfia serpentina x Rhazya stricta somatic hybrid cell suspension culture with 100 μM of methyl jasmonate led to a general increase in indole alkaloid content and to qualitative changes in the alkaloid pattern. The content of Six alkaloids were investigated with respect to their content in both the cell biomass and nutrition medium. Intracellular 17-O-acetyl-norajmaline content on the 5th day after treatment had increased about 40-fold compared with the control culture. The respective concentrations of the other alkaloids increased by a factor of two to five. In total 26 indole alkaloids were identified in extracts of the methyl jasmonate-treated culture by TLC, UV, MS and NMR data and comparison with reference alkaloids. The identification of macrophylline, yohimbine oxindole and yohimbine pseudoindoxyl has not been reported before in Rauwolfia serpentina or Rhazya stricta plants nor in cell cultures derived from these plants.

Oximes from seeds of Atalantia ceylanica

The lipophilic seed extract of Atalantia ceylanica is characterized by two new oximes, ataloxime A and B, and the known furanocoumarins bergapten, xanthotoxin, heraclenin, oxypeucedanin and imperatorin. The structures of the oximes were elucidated by spectroscopic methods, whereas the furanocoumarins were identified by HPLC-UV and TLC comparisons with authentic samples. The oximes displayed contact toxicity against freshly hatched larvae of the pest insect Spodoptera littoralis but did not show antifungal activities against Cladosporium herbarum.

Trivaric Acid, a New Tridepside in the Ramalina americana Chemotype Complex (Lichenized Ascomycota: Ramalinaceae)

Trivaric Acid, a New Tridepside in the Ramalina americana Chemotype Complex (Lichenized Ascomycota: Ramalinaceae)

Production of bioactive secondary metabolites in the fruit bodies of macrofungi as a response to injury

The conversion of secondary metabolites as a response to injury in fruit bodies of 121 species of Ascomycetes and Basidiomycetes was investigated. Extracts of intact and injured specimens were compared by analysis with TLC, and by assaying their antifungal (against Nematospora coryli), antibacterial (against Bacillus brevis) and nematicidal (against Caenorhabditis elegans) activities. Significant conversions induced by injury were observed (by TLC comparison) in the extracts of 66 species. For 37 of these the extract of the injured specimen showed higher bioactivity. Of the remaining 55 species, in which no changes between the extracts of intact and injured fruit bodies were observed, 30 were found to contain bioactive compounds. The possibility that these findings reflect the presence of chemical defence systems in mushrooms, mediated by enzymatic conversions activated by physical injury, is discussed.

Norabietane diterpenoids and other terpenoids from salvia recognita

Seven diterpenoids, three of them being new, salvirecognone, salvirecognine, 6 α-hydroxy-11,12-dioxo-8,13-abieta-diene, were isolated from the roots of Salvia recognita together with three known triterpenoids. The structures of the known compounds were established by comparing their spectral data to those of authentic samples as well as by TLC comparisons. The structures of the new compounds were deduced by 1D and 2D NMR techniques including APT, DEPT, COSY and HETCOR.

Diterpenoids from the roots of Salvia sclarea

The roots of Salvia sclarea yieded two triterpenoids, 3-oxo-oleanolic acid, α-amyrin, a steroid sitosterol and 12 diterpenoids, two of which are new. The known diterpenoids are ferruginol, salvipisone, microstegiol, candidissiol, 2,3-dehydrosalvipisone, aethiopinone, 1-oxoaethiopinone, salvinolone, cryptojaponol, Δ 7-manool, and the new compounds are sclareapinone and acetylsalvipisone. The structures were established by spectral data and also by TLC comparison for the known compounds.

Grignard Reaction of an Epoxide: A Mechanistic Study

Addition of PhMgBr to styrene oxide (1) affords a mixture of 2,2-diphenylethanol (3) and 1,2-diphenylethanol (6) (3:6 = 1:3); reversing the order of addition inverts the ratio of 3 to 6 formed (3:6 = 2:1). Students identify 3 and 6 by TLC comparison with authentic samples which they prepare by independent synthesis (hydride reduction of the corresponding carbonyl compounds), and establish the ratios of 3 to 6 by a combination of 1H and 13C NMR spectroscopies. This undergraduate experiment serves as an interesting alternative to more traditional Grignard experiments and is an excellent vehicle for a "discovery-based" experiment in which students are introduced to epoxide chemistry, share their laboratory data and make mechanistic conclusions from their experimental results. Unlike most undergraduate Grignard experiments which are performed merely for the sake of illustrating a textbook reaction, this Grignard synthesis is performed to probe the reactivity of styrene oxide. Students are required to analyze their products by TLC and NMR spectroscopy (instead of just submitting them for a grade) in order to obtain the data necessary for making mechanistic conclusions.

Counterfeit Captagon: an analytical study

Chemical analysis of suspected Captagon tablets seized between 1986 and 1993 by the drug control authorities in the Kingdom of Saudi Arabia revealed that they often contained different ingredients which would induce effects similar to those of fenethylline. Physical and chemical tests characterised and identified the ingredients which were confirmed by IR, UV and TLC comparison with authentic samples. Apart from fenethylline, caffeine, ephedrine and amphetamine, paracetamol was also detected. It was interesting to note that some tablets contained theophylline, fenfluramine andlor quinine.

Norditerpenoid Alkaloids from the Aerial Parts of Aconitum balfourii Stapf

From the aerial parts of Aconitum balfourii Stapf nine norditerpenoid alkaloids: condelphine (1), bullatine C (2), neoline (3), isotalatizi- dine (4), 1-O-methyldelphisine (5), pseudaconitine (6), yunaconitine (7), bikhaconitine (8), and indaconitine (9), were isolated. The iden- tity of these alkaloids was determined by comparison of mp, tlc and ir spectra with those of authentic samples and the carbon-13 nmr spectra of 2, 5, 6, 7 and 8 with the published chemical shifts. Detailed nmr spectral studies ( 1 H, 13 C, 1 H homonuclear COSY, HETCOR, and selective INEPT) carried out on (1), (3), (4) and (9) have provided accurate chemical shift assignments for these alkaloids

Determination of the lipophilicity of some anti-hypoxia drugs: Comparison of TLC and HPLC methods

The lipophilicity of 14 anti-hypoxia drugs has been determined by reversed phase thin-layer (RPTLC) and reversed phase high performance liquid chromatography (RPHPLC) in eluent systems containing different concentrations of acetonitrile and potassium dihydrogen phosphate. There was significant correlation between lipophilicity and the specific hydrophobic surface area of the drugs in RPTLC, indicating that the drugs behave as an homologous series of compounds. In RPTLC the concentration of buffer has a negligible effect on the retention of the drugs whereas in RPHPLC the buffer concentration influenced the retention. This discrepancy can be explained by the lower sensitivity of RPTLC. There was strong correlation between lipophilicity values determined by both methods, proving that both are suitable for the determination of molecular lipophilicity.

Photolytic Behavior of Some Azo Pyridone Disperse Dyes on Polyester Substrates

Photofading of four azo pyridone disperse dyes on polyester fabric and film has been investigated at 254 nm in the presence of air. The results of this research indicate that the same photodegradation products occur in a comparison of the fabric and the film. A photoreduction pathway is involved, which is confirmed by the presence of amines arising from the reduction of the azo group. The fading process follows first-order kinetics, depending on the dye structure. The reaction mechanisms are discussed briefly, and photodegradation products are determined with the aid of TLC comparisons with authentic samples and LC spectra.

Photodegradation of CI Acid Orange 60 and CI Acid Green 25 in an Amide Environment

Photodegradation, in solution and in nylon 66 fiber, of two automotive acid dyes (CI acid orange 60 and CI acid green 25) for nylon carpet has been investigated. Photofading in solution was done in dimethylformamide (DMF) with the aid of a 254-nm light source, and the work in nylon fiber used the xenon arc light of an Atlas CI 65 weatherometer. The results show that these dyes fade via a photoreduction process under both sets of conditions, and they suggest that DMF is a suitable model for nylon in characterizing the photodegradation of acid dyes. The structures of the degradation products of the two dyes were determined with the aid of fast atom bom bardment and desorption chemical ionization mass spectrometry and by HPLC and TLC comparisons with authentic samples.

High-resolution TLC mapping and characterization of 32P-postlabeled monophosphate 7,12-dimethylbenz[a]— DNA adducts

Previous work has shown that 7,12-dimethylbenz[a]anthracene (DMBA)-DNA adducts can be converted by 32P-postlabeling to different types of radiolabeled derivatives (nucleoside 3',5'-bisphosphates, nucleoside 5'-monophosphates and dinucleotides), and that the 32P-labeled 3',5'-bisphosphate derivatives can be further characterized by cross-referencing with 3H-labeled nucleoside DMBA adducts, for which structural information is available. This work has now been extended by TLC comparisons of 5'-monophosphate and 3',5'-bisphosphate DMBA adducts. To this end, DMBA-modified DNA was enzymatically hydrolyzed to 3'-monophosphates (Xp + Np) or to dinucleotides (XpN), and these digestion products were 32P-postlabeled by published procedures to yield 3',5'-bisphosphate (*pXp) or 5'-monophosphate (*pX) adducts. Individual *pXp and *pX fractions were isolated from polyethyleneimine (PEI)-cellulose TLC maps and chromatographically compared after enzymatic 3'-dephosphorylations of the 3',5'-bisphosphate (*pXp) derivatives (*pXp----*pX + Pi). Four reactions were standardized and employed for this purpose: (i) 3'-dephosphorylation by extensive digestion with nuclease P1; (ii) 3'-dephosphorylation catalyzed by polynucleotide kinase; (iii) partial dephosphorylation by bacterial alkaline phosphatase; and (iv) partial dephosphorylation by prostatic acid phosphatase. Individual DMBA adducts displayed marked differences with regard to their susceptibility to enzymatic dephosphorylation. The three major and most minor postlabeled 5'-monophosphate DMBA adducts were cross-referenced this way with 3',5'-bisphosphate and nucleoside adducts, so that specific dihydrodiol epoxide-nucleoside 5'-monophosphate adducts can now be identified and measured by 32P-postlabeling.

Comparison of TLC and RV Single Breath/Multibreath Helium Dilution Tests in the Detection of Obstructive Airways Disease

Comparison of TLC and RV Single Breath/Multibreath Helium Dilution Tests in the Detection of Obstructive Airways Disease

Metabolism of Benoxinate in Humans

The metabolism of benoxinate hydrochloride [2-(diethylamino)ethyl 4-amino-3-butoxybenzoate monohydrochloride; oxybuprocaine] was examined in humans after administration of a single oral dose. The drug was almost completely absorbed and was rapidly excreted in the urine (92.1% of dose in 9 h). Nine metabolites and unchanged drug were isolated from the urine and identified by comparison of TLC, GC, and GC-MS with authentic compounds. Any metabolites reflecting initial loss of the butyl side chain of benoxinate could not be detected. This suggests that the ester portion is metabolized more rapidly than the O-butyl side chain. 3-Butoxy-4-aminobenzoic acid, the hydrolyzed product of benoxinate, was primarily excreted (70–90% of dose) as the glucuronide together with a trace of the glycine conjugate (0.35% of dose). In addition, 3-butoxy-4-acetylaminobenzoic acid, 3-hydroxy-4-aminobenzoic acid, and 3-hydroxy-4-acetylaminobenzoic acid were identified, the latter two being detected partly as the glucuronides (1.20 and 1.43% of dose, respectively).

Photolytic Behavior of Some Popular Disperse Dyes on Polyester and Nylon Substrates

The photodegradation products that form when disperse red 1, red 17, and blue 3 dyed fabrics and films are exposed to carbon arc and xenon arc light sources have been identified. The effects of black panel and dye carrier on the nature of the deg radation products and the fading process itself were also studied. The results of this research indicate that the same photodegradation products occur in comparisons in volving carbon arc versus xenon arc exposures, polyester versus nylon substrates, black panel versus no black panel exposures, and exposures of carrier dyed versus no carrier dyed PET. It is clear that photo-reduction pathways account for the products that form when the two azo disperse dyes (red 1 and red 17) photofade, but photo oxidation characterizes the fading of the anthraquinone disperse dye blue 3. The pho todegradation products were determined with the aid of GC mass spectrometry and by TLC comparisons with authentic samples.