Chromatographic Studies Research Articles

Degradation of oil and oil products by microorganisms isolated from the Azerbaijani coast of the Caspian Sea at low temperatures

The object of the study is microorganisms isolated from the Azerbaijani territory of the Caspian Sea, capable of decomposing oil and oil products at low temperatures of 4–6 °C. The purpose of this work was to study bacteria and fungi capable of actively assimilating oil, gasoline, kerosene, diesel fuel at a temperature of 4–6 °C in order to solve the problem of environmental pollution in this region. The studied most effective biodestructors are combined into associations that can be used to create an active biological product based on native microorganisms with its further use for water bioremediation, as well as treatment of tanks and other containers used for long-term storage of petroleum products at a temperature of 4–6 °C. The process of degradation of samples of used oils at the molecular level of the selected compounds was studied by reverse-phase high-performance liquid chromatography. As a result of chromatographic and spectroscopic studies, it was found that almost all microorganisms decompose the tested oil products. Only weak peaks remained on the chromatogram, which is a clear indicator of the deep biodegradation carried out by these microorganisms. Thanks to the chromatographic and spectral analysis of oil and products of its decomposition, an oxidation sequence has been established, indicating the decomposition of the last aromatic fraction. As a result, a general picture was obtained on the amount of degradation products containing carboxyl, keto-, hydroxyl groups, which is not enough to determine the processes of transformation of initial products into final ones. All this testifies to the multidirectionality of biodegradation processes

Interpopulation Variability of Polyphenol Concentration in the Leaves of <i>Spiraea aquilegifolia</i> (Rosaceae) from the Republic of Buryatia

Abstract—Composition and content of flavonoids and phenol carboxylic acids in the leaves of Spiraea aquilegifolia Pall. from natural populations of the Republic of Buryatia (Western Transbaikalia) are given in the article. Aqueous ethanol (40%) extracts from raw materials were used for chromatographic study of phenolic compounds. The analysis of phenolic compounds was carried out on an analytical High-Performance Liquid Chromatography (HPLC) system consisting of an Agilent 1200 liquid chromatograph (USA) with a diode array detector, an autosampler, and a system for collecting and processing chromatographic data ChemStation. At least 24 phenolic compounds were identified in aqueous ethanol extracts from Spiraea aquilegifolia Pall. leaves by HPLC. Three acids (chlorogenic, p-coumaric and p-hydroxybenzoic) and six flavonols (hyperoside, isoquercitrin, avicularin, astragalin, quercitrin and kaempferol) were identified among them. Flavonols hyperoside (2.9–8.2 mg/g), avicularin (3.0–5.8 mg/g) and isoquercitrin (0.8–2.5 mg/g) are the main substances in aqueous ethanol extracts from leaves. Plants from populations located at the northern distribution limit in the Western Transbaikalia have a higher content of phenol carboxylic acids (near the village Koma) and flavonols (near the village Klyuchi). Plants from populations located to the eastern limit (near villages Kusoty and Zagan) have the lowest concentration of identified phenolic compounds. A high and very high level of interpopulation variability of the studied biochemical parameters has been established. This can be explained by the functional significance of the identified compounds and their active participation in general metabolic processes in the plant. The content of identified free phenolic acids and flavonols in S. aquilegifolia was characterized by medium and high levels, compared to other studied Spiraea species. This confirms the prospects for further study of the composition of phenolic compounds of S. aquilegifolia.

Phytochemical screening, antibacterial activity, and chromatographic study of Camellia sinensis

Abstract Background: This study highlights the use of plants as a vital part of Iraq’s health care. One of the most significant plants for medicine is Camellia sinensis. Objectives: phytochemically and chromatographically evaluation of C. sinensis and its antibacterial activity. Materials and Methods: The phytochemical analysis revealed the occurrence of alkaloids, tannins, flavonoids, and phenols, but glycosides are not found in extracts of C. sinensis leaves. Antibacterial efficacy of the herbal extracts revealed that both aqueous and ethanol extracts showed some degree of inhibition of growth in Salmonella spp., Escherichia coli, Streptococcus pyogenes, Streptococcus pneumonia, and Staphylococcus aureus. Results: Nine functional groups were identified through Fourier-transform infrared spectrophotometer, and 10 phytochemical compounds were identified through gas chromatography–mass spectrum in the ethanol extract. The antibacterial activity of aqueous and ethanolic green tea extracts was tested. Both types of extracts showed clear biological activity against the studied bacterial species; the inhibitory effect increased with increasing concentration, with the highest activity of ethanolic and aqueous extracts against Salmonella spp.(inhibition zone 40, 36 mm, respectively) at 200 mg/mL, but less inhibitory effect appears on S. pyogenes when using aqueous extract (12 mm) at 50 mg/mL and (18 mm) at 200 mg/mL. Conclusions: Various therapeutically active compounds are present in the aqueous and ethanolic extract of C. sinensis, which encourages its use in the treatment of microbial infections. Further investigations are needed for the chemical composition of green tea, and other techniques like HPLC may be used. Further tests are necessary for its antimicrobial activity, either in vitro or in vivo.

Menthol- and thymol-based ciprofloxacin derivatives against Mycobacterium tuberculosis: in vitro activity, lipophilicity, and computational studies

In this work, we investigated the antitubercular properties of Ciprofloxacin derivatives conjugated with menthol and thymol moieties. For the sixteen derivatives, we established minimal inhibitory concentrations (MIC) using isolates of Mycobacterium tuberculosis that were resistant or susceptible to other antibiotics. For the most potent compound 1‐cyclopropyl‐6‐fluoro‐7‐{4‐[6‐((1R,2S,5R)‐2‐isopropyl‐5‐methylcyclohexyloxy)‐6‐oxohexyl]piperazin‐1‐yl}‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylic acid (6), we determined fractional inhibitory concentration index (FICI) values to confirm antibacterial susceptibility and synergistic effects with other reference drugs. In addition, chromatographic studies of all the derivatives demonstrated a significant three to four-fold increase in lipophilicity and affinity to phospholipids compared to Ciprofloxacin. Finally, we conducted structure-based studies of the investigated compounds using molecular docking and taking into account protein target mutations associated with fluoroquinolone resistance. In summary, our findings indicate that the investigated compounds possess tuberculostatic properties, with some showing similar or even better activity against resistant strains compared to reference drugs. Increased lipophilicity and affinity to phospholipids of the new derivatives can offer several advantages for new drug candidates, beyond just improved cell membrane penetration. However, further studies are needed to fully understand their safety, efficacy, and mechanism of action.

Adsorption behavior of platinum-group metals and Co-existing metal ions from simulated high-level liquid waste using HONTA and Crea impregnated adsorbent

The volume and toxicity of radioactive waste can be decreased by separating the components of high-level liquid waste according to their properties. An impregnated silica-based adsorbent was prepared in this study by combining N,N,N′,N′,N″,N″-hexa-n-octylnitrilotriacetamide (HONTA) extractant, N′,N′-di-n-hexyl-thiodiglycolamide (Crea) extractant, and macroporous silica polymer composite particles (SiO2–P). The performance of platinum-group metals adsorption and separation on prepared (HONTA + Crea)/SiO2–P adsorbent was then assessed together with that of co-existing metal ions by batch-adsorption and chromatographic separation studies. From the batch-adsorption experiment results, (HONTA + Crea)/SiO2–P adsorbent showed high adsorption performance of Pd(II) owing to an affinity between Pd(II) and Crea extractant based on the Hard and Soft Acids and Bases theory. Additionally, significant adsorption performance was observed toward Zr(IV) and Mo(VI). Compared with studies using the Crea extractant, the high adsorption performance of Zr(IV) and Mo(VI) is attributed to the HONTA extractant. As revealed from the chromatographic experiment results, most of Pd(II) was recovered from the feed solution using 0.2 M thiourea in 0.1 M HNO3. Additionally, the possibility of recovery of Zr(IV), Mo(VI), and Re(VII) was observed using the (HONTA + Crea)/SiO2–P adsorbent.

Bioprospecting of Adhatoda vasica for Identification of Novel Compounds using Chromatographic Methods and Screening for Anti-diabetic and Antioxidant Activity

This investigation column eluted fractions of leaf Adhatoda vasica of was assessed for its phytochemical screening, column chromatography, thin layer chromatographic studies, protease activity, anti-inflammatory activity, antidiabetic activity and antioxidant activity. Phytochemical screening reflects the presence of alkaloid, flavonoids, coumarins, terpenoids, steroids, emodin’s, Quinone’s. Column chromatography method was used for purification of bioactive compounds. Thin layer chromatographic study was carried out by using various solvent system of different type of polarity of n- butanol, acetic acid and acetone. TLC profiling shows pure band at 254nm and 366 nm. The strong “proteolytic activity” also pointed out in purified fraction of eluted fraction. In vitro anti-inflammatory activity was evaluated using albumin denaturation fraction 3, showing highest activity 75% followed by fraction 5 (62.73%), membrane stabilization assay fraction 6 (80.23%) followed by fraction 3 (64.65%) and proteinase inhibitory activity of fraction 5(88%) followed by fraction 7 (87.68%) at concentration 500 µg/ml. Aspirin (90.87%) was used as standard drug for the study of anti-inflammatory activity. In vitro antidiabetic activity was performed using Alfa amylase inhibition assay. Highest activity was showed in fraction 4 (79.05 %) and fraction 5 (77.05 %) at concentration 500 µg/ml. Antioxidant activity was performed by reducing power assay fraction number 2 has higher absorbance 1.04 at 500µg/ml followed by reducing power of column eluted fraction was compared with ascorbic acid as standard showing higher absorbance 0.93 at 500µg/ml.

SYNTHESIS AND ANTICONVULSANT ACTIVITY OF 4-THIAZOLIDINONE ANALOGUES OF 2-AMINO-5-CHLOROPYRIDINE

The synthesis of 4-thiazolidinones of 2-amino-5-chloropyridine was performed by novel method of stirring involving the cyclocondensation of the appropriate Schiffs bases (2a–c) with thioglycolic acid, followed by the addition of zinc chloride in the presence of molecular sieves. Characterization of the synthesized compounds, determination of purity and identity of the compounds using following spectroscopic and chromatographic techniques- Solubility,Thin Layer Chromatographic studies, Ultra-Violet studies,Rotational and vibrational studies (FT-IR), 1H-NMR studies. The compounds were investigated for their Anticonvulsant activity by isoniazid induced convulsions in mice model.Compound3-(5-chloropyridin-2-yl)-2-(4-fluorophenyl) thiazolidin-4-one(3c)was found to be the most activeand compound 3-(5-chloropyridin-2-yl)-2-(2-hydroxyphenyl) thiazolidin-4-one (3a) was found to be less active among the tested compound according to pharmacological evaluation exhibited anticonvulsant activity.

Liquid chromatographic determination of lumacaftor in the presence of ivacaftor and identification of five novel degradation products using high-performance liquid chromatography ion trap time-of-flight mass spectrometry.

Lumacaftor is a transmembrane conductance regulator potentiator drug, prescribed for the treatment of cystic fibrosis in patients who are homozygous for the F508del mutation. Quantitation of lumacaftor besides its degradation products and ivacaftor was achieved on a fused-core silica particle column packed with pentafluorophenylpropyl stationary phase (Ascentis Express F5, 2.7μm particle size 100mm × 4.6mm; Supelco) using gradient elution (A: 0.1% [v/v] formic acid in water, B: 0.1% [v/v] formic acid in acetonitrile [the mobile phase pH 2.5]). A constant flow rate at 1mL/min was applied, and the detection was realized using a photodiode array detector set at 216nm. The pseudo tablet formulation of the lumacaftor/ivacaftor fixed-dose combination preparation, namely, Orkambi®, was prepared in vitro and used for the analytical performance validation and method application studies. In addition, five novel degradation products, four of which even have no Chemical Abstracts Services registry number, were identified using high-resolution mass spectrometry instrument, and their possible mechanisms of formation were proposed. According to current literature, this paper can be regarded as the most comprehensive liquid chromatographic study on lumacaftor determination, among its counterparts.

Chromatographic Enantioseparation of Chiral Sulfoximines on Polysaccharide-Based Chiral Stationary Phases.

Chiral sulfoximines have significant roles in pharmaceutical industry and agricultural chemicals. Furthermore, chiral structurally related sulfoximines are used for their wide potential applications in some uncharted territory. However, chromatographic study on these compounds has not been systematically performed. Herein, this paper describes the enantioseparation of 12 chiral sulfoximines on polysaccharide-based chiral stationary phases (CSPs). Separation factors of chiral column, high-performance liquid chromatography parameters such as mobile phase composition and column temperature were carefully investigated. Chiralcel OJ-H column can resolve all of the 12 compounds, while Chiralpak AD-H column and Chiralpak AS-H column can separate eight and nine molecules, respectively. The sulfoximines are effectively resolved with Chiralcel OJ-H column with a mixture of n-hexane/2-propanol (80:20) as the mobile phase.

Phytochemical Screening, Chromatographic and Quantitative Study of Phenols and Flavonoids in Leaves of Oroxylum indicum and Pongamia pinnata

Number of secondary compounds is produced by plants as natural antioxidants. The current study's goal was to identify the phytochemical components, thin-layer chromatographic profile, total phenol, and total flavonoid content in the leaves of Pongamia pinnata and Oroxylum indicum (O. indicum) (P. pinnata). The well-known test protocol described in the literature was used to determine the qualitative analysis of different phytochemical constituents, thin-layer chromatography, and quantitative analysis of total phenolics and flavonoids. By using the Folins Ciocalteau reagent method and the aluminium chloride method, respectively, phenolic and flavonoid quantities were analysed quantitatively. Both plants contained glycosides, flavonoids, diterpenes, phenol, proteins, saponins, and carbohydrates, according to a phytochemical analysis. Studies using thin-layer chromatography and various solvent systems revealed homogeneous spots with various Rf values. According to the findings of the current study, O. indicum and P. pinnata crude extracts are a rich source of secondary phytoconstituents that have significant antioxidant potential. The pharmaceutical industries, pharmacologists, and phytochemists will all benefit from the study's findings.

Oil Inclusions Found in Skeleton Crystals of Quartz Indicated the Existence of Organic Matter Surrounding Ancient Growth Environments.

In nature, minerals record various origins and information for geology and geobiochemistry. Here, we investigated the origin of organic matter and growth mechanism of quartz with oil inclusion revealing fluorescence under short ultraviolet (UV) light, obtained from the clay vein at Shimanto-cho, Kochi, Shikoku Island, Japan. Geological investigation indicated that the oil-quartz was formed in hydrothermal metamorphic veins found in the late Cretaceous interbedded sandstone and mudstone. The obtained oil-quartz crystals are mostly double-terminated. Micro-X-ray computed tomography (microCT) indicated that oil-quartz crystals have various veins originating as skeleton structures along the quartz crystal {111} and {1-11} faces. Spectroscopic and chromatographic studies indicated that aromatic ester and tetraterpene (lycopene) molecules, which revealed fluorescence, were detected. Large molecular weight sterol molecules, such as C40, were also detected in the vein of oil-quartz. This investigation indicated that organic inclusions in mineral crystals would form with ancient microorganism culture environments.

Identification of Substances from the Extracts of Sea Weeds Grateloupia Filicina and Gracelaria Corticata from Visakhapatnam Coast Using Chromatography Techniques.

Sea weeds belonging to the Rhodophyceae (red algae) are an important source of bio active substances of medicinal value. Many of these substances are used in the drug development to treat diseases caused by bacterial and fungal infections, inflammation, pain, arthritis, as well as cancerous diseases. The paper chromatographic studies reveals that Grateloupia filicina contained photosynthetic pigment carotene and Gracelaria corticata contained the amino acid leucine. The thin layer chromatographic studies indicates that Grateloupia filicina contained amino acid phenylalanine and Gracelaria corticata contains Leucine. All the three substances having pharmaceutical importance

Molecular Identification of Methylorubrum extorquens using PCR-Amplified MxaF Gene Fragments as A Molecular Marker

Methylotrophs bacteria are ubiquitous, and they have the ability to consume single carbon (C1) which makes them biological conversion machines. It is the first study to find facultative methylotrophic bacteria in contaminated soils in Iraq. Conventional PCR was employed to amplify MxaF that encodes methanol dehydrogenase enzyme. DNA templates were extracted from bacteria isolated from five contaminated sites in Basra. The gene specific PCR detected Methylorubrum extorquens as the most dominant species in these environments. The ability of M. extorquens to degrade aliphatic hydrocarbons compound was tested at the laboratory. Within 7 days, gas chromatographic (GC) studies of remaining utilized crude oil revealed that 61.14 % of the initial content had been degraded, and GC fingerprinting of the utilized aliphatic compounds revealed significant reductions in C12, C13, C14, and C15. Globally this is the first time found a new strain of M. extorquens has the ability to degrade aliphatic hydrocarbons compound. Conventional PCR and gene sequencing revealed the presence of the facilitative methylotrophic bacteria in polluted areas in Basra. M. extorquens was dominant and showed a substantial ability to degrade crude oil which makes them an important tool to be employed in bioremediation.

New Tricholidic Acid Triterpenoids from the Mushroom Tricholoma ustaloides Collected in an Italian Beech Wood.

The secondary metabolites produced by Tricholoma ustaloides Romagn., a mushroom species belonging to the large Tricholoma genus (Basidiomycota, Tricholomataceae), are unknown. Therefore, encouraged by the interesting results obtained in our previous chemical analyses of a few Tricholoma species collected in Italian woods, we aimed to investigate the secondary metabolites of Tricholoma ustaloides. The chemical analysis involved the isolation and characterization of secondary metabolites through an extensive chromatographic study. The structures of isolated metabolites, including the absolute configuration, were established based on a detailed analysis of MS, NMR spectroscopic, optical rotation, and circular dicroism data, and on comparison with those of related compounds reported in the literature. Two novel lanostane triterpenoids, named tricholidic acids B and C, together with triglycerides, a mixture of free fatty acids, five unidentified metabolites, and the known rare saponaceolides F and J, tricholidic acid, and tricholomenyn C, were isolated from an EtOAc extract of fruiting bodies of Tricholoma ustaloides that were collected in an Italian beech wood. This is the second example of isolation of tricholidic acid derivatives from a natural source. Saponaceolides F and J exhibited high cytotoxicity (IC50 values ≤ 10 μM) against a panel of five human cancer cell lines. The toxicity against myeloid leukemia (HL-60), lung cancer (A-549), hepatocellular cancer (HepG2), renal cancer (Caki-1), and breast cancer (MCF-7) cells was higher than that shown by the very well-known cytotoxic drug cisplatin.

Recycling of Wind Turbine Blades into Microfiber Using Plasma Technology.

As the industry develops and energy demand increases, wind turbines are increasingly being used to generate electricity, resulting in an increasing number of obsolete turbine blades that need to be properly recycled or used as a secondary raw material in other industries. The authors of this work propose an innovative technology not yet studied in the literature, where the wind turbine blades are mechanically shredded and micrometric fibers are formed from the obtained powder using plasma technologies. As shown by SEM and EDS studies, the powder is composed of irregularly shaped microgranules and the carbon content in the obtained fiber is lower by up to seven times compared with the original powder. Meanwhile, the chromatographic studies show that no hazardous to the environment gases are formed during the fiber production. It is worth mentioning that this fiber formation technology can be one of the additional methods for recycling wind turbine blades, and the obtained fiber can be used as a secondary raw material in the production of catalysts, construction materials, etc.

β-Carboline Alkaloids in Soy Sauce and Inhibition of Monoamine Oxidase (MAO)

Monoamine oxidase (MAO) oxidizes neurotransmitters and xenobiotic amines, including vasopressor and neurotoxic amines such as the MPTP neurotoxin. Its inhibitors are useful as antidepressants and neuroprotectants. This work shows that diluted soy sauce (1/3) and soy sauce extracts inhibited human MAO-A and -B isozymes in vitro, which were measured with a chromatographic assay to avoid interferences, and it suggests the presence of MAO inhibitors. Chromatographic and spectrometric studies showed the occurrence of the β-carboline alkaloids harman and norharman in soy sauce extracts inhibiting MAO-A. Harman was isolated from soy sauce, and it was a potent and competitive inhibitor of MAO-A (0.4 µM, 44 % inhibition). The concentrations of harman and norharman were determined in commercial soy sauces, reaching 243 and 52 μg/L, respectively. Subsequently, the alkaloids 1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (THCA) and 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) were identified and analyzed in soy sauces reaching concentrations of 69 and 448 mg/L, respectively. The results show that MTCA was a precursor of harman under oxidative and heating conditions, and soy sauces increased the amount of harman under those conditions. This work shows that soy sauce contains bioactive β-carbolines and constitutes a dietary source of MAO-A and -B inhibitors.

Investigation of the fatty acid composition of vegetable oils

Emulsion fat products are a promising direction for the enrichment of unsaturated groups with fatty acids. This is possible by introducing rarely used types of vegetable oils into the formulations of these products. Due to the fact that the fatty acid composition of vegetable oils differs depending on the properties of the raw materials from which it is produced, there is a need for its analysis for a more accurate formulation of the emulsion product. As a result of the conducted studies, 17.3% saturated fatty acids and 83% unsaturated, respectively, were found in pumpkin oil. Pumpkin oil is rich in monounsaturated fatty acids, such as oleic acid (47%). Chromatographic study of the fatty acid composition showed that ginger oil contains 9.7% saturated fatty acids and about 90.3% unsaturated acids. Linolenic acid turned out to be the most in the oil (32.6%). It was found that the sample of black cumin oil contains 21.9% saturated and 78.1% unsaturated fatty acids. Most of all in linoleic acid oil (about 56.9%). The studied oils are rich in unsaturated fatty acids and can be used as additives in mayonnaise sauces to saturate certain groups with unsaturated fatty acids, each of the studied oils will saturate a certain group. Pumpkin oil is a source of monounsaturated fatty acids (oleic fatty acid), ginger oil is a source of omega–3 fatty acids (linolenic fatty acid), black cumin oil is a source of omega–6 fatty acids (linoleic fatty acid).

Pharmagonostical Analysis and Chromotographical Fingerprinting of Vajradanti (Potentilla fulgens (Wall.) ex Hook.)

Poor oral hygiene or tooth disorders are very common and severely agonizing ailment leads to teeth loss or damaging of teeth, so it is the need of the hour to search for a potent drug which can fight this condition. Vajradanti is first described in Ayurvedic text Arka Prakash and Dravyagunakosha. Later in some Ethnomedicinal books Vajradanti is mentioned as potent medicine for Dantvikar, Udarshoola etc. Potentilla fulgens (Wall.) ex Hook. of Rosaceae family is an alpine medicinal plant that is found in temperate Himalaya between 2000-3000m. The root of the plant is of good medicinal value and has been used as folk remedy for treating ailments like diabetes mellitus, gastric problems, peptic ulcers, diarrhoea, cancer, toothache, pyorrhoea, cough, cold and also has anthelmintic property. A detailed pharmacognostical character of its root is not reported still yet. Methods: An attempt has been made to study the macroscopic and microscopic character, physicochemical analysis, phytochemical analysis, and chromatographic studies of its root following standard procedures. Two different extracts of Vajradanti root was used to access the physicochemical and HPTLC analysis. Research work was carried out as per standard operating procedures and specified protocols. Result: Results showed that in physicochemical evaluation aqueous extract 2.4%, hydro-ethanol extract 2.5%, total ash 8.6%, water soluble ash 1.38%, acid and insoluble ash 3.01%. HPTLC results for the quantification of epicatechin in EPF was analyzed for the first time by scanning at wavelength (λmax 366nm) and the quantity of epicatechin present in Vajradanti was estimated to be 0.032% w/w. In phytochemical analysis presence of carbohydrate, protein, glycosides, amino acid, protein in extract of Vajradanti. Conclusion: Vajradanti is a highly potent medicine for oral diseases due to presence of flavanols like epicatechin.

Evaluation of the hypoglycemic and antimicrobial activities of the essential oil of Myrtus nivellei from Tamanrasset (southern Algeria)

The Myrtus nivellei Batt. & Trab. is a shrub native to the Mediterranean and endemic to the central Sahara in the Hoggar massif of southern Algeria, whose leaves are used by the Tuareg, in infusion mixed with tea, against diarrhea, fever, diabetes and for its anti-infective properties. The hypoglycemic activity of the essential oil extracted from the leaves by hydrodistillation. has been demonstrated, with a significant decrease (P<0.001) in blood sugar levels and blood triglyceride levels in diabetic rats after the 2nd hour and up to the 3rd hour of administration (14% and 22%). This drop in blood sugar was not observed in healthy rats treated with the essential oil. The essential oil did not improve the weight of the rats, nor their cholesterolemia. The antimicrobial activity of the essential oil has been studied for six microorganisms. Bacillus subtilis and Candida albicans are the most sensitive, they were inhibited from 2.5/1000 v/v. This oil is also active on Staphylococcus aureus at a concentration of 5/1000 v/v. This activity was weak against Escherichia coli and absent against Pseudomonas aeruginosa and no activity was detected against Enterococcus faecium. It would be interesting to combine these evaluations with chromatographic and spectral studies to determine the compounds responsible for these activities.

A new stability indicating RP-UFLC method for the quantification of Gemifloxacin tablets using an ion pairing agent

Gemifloxacin is a new broad-spectrum quinolone antibacterial with activity against both Gram-negative and Gram-positive organisms. A new stability indicating RP-UFLC method was proposed for the estimation of Gemifloxacin in pharmaceutical dosage forms (tablets). Shimadzu Model CBM-20A/20 Alite UFLC system with PDA detector and Zorbox C18 column were used for the chromatographic study. Mobile phase mixture consisting of Tetra butyl ammonium hydrogen sulphate and Acetonitrile in the ratio 68: 32, v/v with a flow rate 0.8 mL/min was chosen for the chromatographic elution of Gemifloxacin (Detection wavelength 273 nm). The method was linear over the concentration range 0.02-200 mg/ml with linear regression equation, y = 207068x + 19935 (R² = 0.9999). The LOD and LOQ were found to be 0.0553 mg/ml and 0.1693 respectively. Forced degradation studies were performed and the method was validated as per ICH guidelines.