Chromatographic Studies Research Articles

Isolation and Characterization of One New Natural Compound with Other Potential Bioactive Secondary Metabolites from Glycosmis cyanocarpa (Blume) Spreng. (Family: Rutaceae)

Glycosmis cyanocarpa (Blume) Spreng is a plant in the Rutaceae family and a species in the Glycosmis genus that has received little attention. Therefore, this research aimed to report the chemical and biological analysis of Glycosmis cyanocarpa (Blume) Spreng. The chemical analysis involved the isolation and characterization of secondary metabolites through an extensive chromatographic study, and the structures of these metabolites were elucidated on the basis of a detailed analysis of NMR and HRESIMS spectroscopic data and by comparison with those of related compounds reported in the literature. Different partitions of the crude ethyl acetate (EtOAc) extract were evaluated for antioxidant, cytotoxic, and thrombolytic potentials. In chemical analysis, one new phenyl acetate derivative, namely 3,7,11,15-tetramethylhexadec-2-en-1-yl 2-phenylacetate (1), along with four known compounds N-methyl-3-(methylthio)-N-(2-phenylacetyl) acrylamide (2), penangin (3), β-Caryophyllene oxide (4), and acyclic diterpene-phytol (5) were isolated for the first time from the stem and leaf of the plant. The ethyl acetate fraction showed significant free radical scavenging activity with an IC50 value of 11.536 µg/mL compared to standard ascorbic acid (4.816 µg/mL). In the thrombolytic assay, the dichloromethane fraction showed the maximum thrombolytic activity of 16.42% but was still insignificant compared to the standard streptokinase (65.98%). Finally, in a brine shrimp lethality bioassay, the LC50 values of dichloromethane, ethyl acetate, and aqueous fractions were found to be 0.687 µg/mL, 0.805 µg/mL, and 0.982 µg/mL which are significant compared to the standard vincristine sulfate of 0.272 µg/mL.

Study of volatile compounds of Сalendula officinalis L. flowers by the method of gas chromatography with MAS detection

A promising direction for improving the procedure of standardization of multicomponent phytoremedies is the use of so-called marker compounds, or markers – substances whose presence is characteristic only for individual medicinal raw materials. The introduction of methods of qualitative and quantitative analysis based on the use of markers is not only of great practical importance, but also of significant scientific expediency.
 One of the most common components used to make complex herbal collections are the flowers of medicinal plants, which are successfully used in medical practice both in the form of mono preparations and in the form of components of over-the-counter medicinal product of herbal origin.
 The pharmacological activity of the flowers of marigolds is due to the presence in their composition of a complex of biologically active substances, in particular essential oils, the content of which is associated with such pharmacological properties of the plant as bactericidal, antioxidant, etc. That is why it was considered expedient to search on markers for plant standardization in mixtures among essential oil components.
 The aim of the work was to study the components of the essential oil of calendula flowers (Calendula officinalis L.) by the method of gas chromatography with mass detection
 The object of the study was marigold flowers in packs of 50 g (CJSC «Liktravy», series 80310).
 The study of volatile components was carried out using the method of gas chromatography with mass detection. Chromatographic study of the studied extracts was carried out on an Agilent 6890 gas chromatograph equipped with a mass spectrometric detector (model 5973). The identification of the studied components was carried out by mass spectra and the retention time of the components.
 As a result of the conducted research, using library spectra, 59 volatile components were identified in the extract of the flowers of Calendula officinalis L., 50 were recognized: monocyclic and bicyclic monoterpenoids, sesquiterpenoids, sesquiterpene alcohols, etc.
 The major volatile components of flowers of Calendula officinalis L. are the following substances: α-cadinol, δ-cadinene, α-muurolol and epi-α-cadinol, the content of which is equal to 417.2 mg/kg, 284.2 mg/kg, 92.4 mg/kg and 75.7 mg/kg of raw material, respectively.
 The total content of all four major volatile compounds of the flowers of Calendula officinalis L. is 44.14% of the total amount of volatile compounds found in the object of research.

Comparative investigation of key aroma terpenoids of Litsea cubeba essential oil by sensory, chromatographic, spectral and molecular studies

Litsea cubeba essential oil (LcEO) is a natural product extracted form L. cueba fruits. LcEO is widely used for flavoring in Chinese cooking and provides diverse aromas from different chemotypes, but their characteristic flavor and odorants determining the usage remain unknown. In this study, LcEOs were extracted from three chemotypes L. cubeba fruits by hydrodistillation for 4 h, the liquid to material ratio is 20:1 (mL·g−1) and comprehensively investigated at the sensorial, spectral and molecular levels. Twenty-seven crucial odorants in the LcEOs were quantified using gas chromatography-olfactometry/mass spectrometry (GC-O/MS), and ten odorants with odor activity value (OAV) > 1 were further confirmed, particularly geranial (57917.84), neral (41932.79), β-pinene (4041.23), β-myrcene (1936.86), citronellal (2215.11), terpinen-4-ol (233.97) and 1,8-cineole (7573.95) were identified as the potential odor-active markers. The aroma-spectral/gene expression network elucidated the aroma variation by determining the differential expression pattern of the terpene synthase (TPS) gene LcTPS22. And spectrum bands at 1635 nm, 1902 nm, 2125 nm, 2220 nm and 2250 nm contributed to the variation in the LcEOs. Comparative investigation of the characteristic flavor of LcEOs will significantly expand our knowledge of L. cubeba aroma, provide new insights into LcEO utilization and improve the direct breeding of L. cubeba.

Chromatography in Catalysis

The main applications of gas chromatography for investigation of catalysts and catalytic processes are considered. The development of the sampling method as well as the microcatalytic and pulsed methods is described in historical aspect. The paper presents the advanced and promising directions of gas chromatographic studies, and the instruments providing efficient separation of multicomponent mixtures of substances with the control of complex catalytic reactions.

Detection of adulteration of dairy products with vegetable fats using the method of luminescent analysis

This article describes a technique for detecting pesticides in poultry meat samples using thin layer chromatography. In the course of the study, the qualitative indicators of the content of pesticides in samples of poultry carcasses treated with the insecticide esbiotrin, used to prevent the reproduction of the red chicken mite among the poultry population, were determined. The studies were carried out at various time intervals from the moment the poultry was treated with the drug; quantitative determination of the content of the residual concentration of pesticides by thin-layer chromatography will reveal the feasibility and safety of using the active substance as an insecticide in poultry farming. Chromatographic studies were carried out on the basis of the Department of Veterinary and Sanitary Expertise of the SPbGUVM.During the experiment, 3 experimental groups of laying hens and 1 control group (10 animals each) were selected. The experimental groups were treated with a 0.001% solution of esbiotrin after which the birds were slaughtered 24, 72 and 120 hours after treatment. The selected samples were subjected to chromatographic examination to detect residual concentrations of synthetic pyrethroids.

Применение мультимодального трансформера для прогнозирования выходных параметров насыщенных углеводородных соединений из состава тяжелой нефти в присутствии катализаторов

Heavy oil fields are a promising energy source in the future due to the depletion of natural sources of light oil. However, extraction, transportation and refining of heavy oil is significantly more complicated than light oil - difficulties arise at almost all technological stages. One of such stages is laboratory analytics of heavy oil and selection of the most optimal catalyst for extraction of required fractions from crude oil sample. Different catalysts are actively used in petrochemical laboratories, but special attention is paid to those of them, the basis of which is metal. In this study, catalysts based on six different metals namely zinc, nickel, copper, manganese, lead and sodium were analyzed. In order to analyze the yield ratios of the required components from the crude heavy oil composition, it is necessary to test different types of catalysts sequentially on a base sample. The yield of different hydrocarbons on a small volume of oil can be reliably estimated by chromatographic study, which takes about 68 minutes for both the base oil sample and the different catalysts. Since testing 6 different catalysts would require almost 7 hours of chromatographic analysis, a rational solution would be to apply data mining techniques to this task. A multimodal transformer model was proposed to solve this problem. It takes as input two modalities: a chromatogram of a sample of pure crude oil presented as graphical data and accompanying tabular data, which are also generated by the chromatograph and consist of text and numbers. At the output, the model produces predictive tabular data that formalize the redistributed group composition of the oil and describe both the names of the newly produced hydrocarbons and their two qualitative characteristics: time and yield area. Obtaining the prediction makes it possible to significantly reduce the time, hardware and human resources required to select the right type of catalyst in petrochemical laboratories. In the process of the study, it was found that training of the intellectual model on the data of one field allows to perform further similar forecast with acceptable accuracy for the data of another heavy oil field. The magnitude of the prediction error of the intelligent model satisfies the requirements set by the petrochemical laboratory for practical application of the multimodal transformer.

Development of quality control parameters for classical ayurvedic formulation: Vyoshadi Churna

Introduction: Ayurvedic formulations have a long history of use and have increased amazingly to follow the global interest in natural products. However, for many classical ayurvedic formulations, no quality parameters of standardization are available. Vyoshadi Churna, a classical Ayurvedic polyherbal formulation that cures indigestion and diarrhea, is being used since ancient times. However, there is no standard method available for its formulation and evaluation. Hence, the current study aims to develop the quality standards for Vyoshadi churna. Methods: The standard procedures for preparation and standardization of Churna described in Ayurvedic Pharmacopoeia of India (API) were used in the present study. Standardization includes pharmacognostical, chromatographic, and physico-chemical studies. The other essential studies were also done in accordance to API and World Health Organization guidelines to find the limits of microbial load, aflatoxin, heavy metals, and pesticide residue using modern analytical techniques such as gas chromatography-mass spectroscopy (MS) and inductively coupled plasma-MS/MS. Results: Vyoshadi Churna is of brown color and bitter in taste. Pharmacognostical studies have shown the characteristic features of almost each contributory crude drug. A unique chemical profile was also developed using toluene: ethyl acetate: methanol: formic acid (4:4:1:0.5) as the mobile phase to resolve maximum components. Furthermore, the standardized limits for the physicochemical studies, microbial load, heavy metals, aflatoxins, and pesticide residues were established and found in limits. Conclusion: This is for the first time when the standard operating procedure of Vyoshadi Churna was developed. Hence, the current technical work would be practically helpful for the future preparation and standardization study of Vyoshadi Churna.

Microwave Assisted Synthesis and Characterization of Pithecellobium dulce GumGrafted-Polyacrylamide

The isolation and spectral data of seed extracts in various solvents of Pithecellobium dulce(PD) was done. The synthesis of acrylamide-grafted gum and efficiency was carried out by microwave-assisted free radical polymerization using silver nitrate and ascorbic acid. A table of graft copolymers was prepared, varying in the amount of acrylamide, AgNO3, thermal grafting & microwave irradiation time.FTIR and Chromatographic studies characterized these graft copolymers. Comparing grafting factors such as efficiency, percentage grafting and percentage conversion was carried out among various graft copolymers and then correlated with elemental analysis.

THE EXPERIMENTAL DETERMINATION OF THE NUMBER OF FREEZING STAGES OF CANDIDA TROPICALIS FUNGAL CELLS FOR THEIR DESTRUCTION AND OBTAINING OF PROTEINS AND POLYSACCHARIDES

Candidiasis is a disease that occurs due to excessive growth of the Candida fungus. Several types of this pathogen are known, each of which can cause damage to various organs and systems. Recently, there have been reports of the loss of sensitivity of Candida fungi to most of antifungal drugs that have been used for more than 40 years. An alternative to antifungal drugs for candidiasis can be the use of a vaccine for the prevention and treatment of candidal infection. In our opinion, it is promising to use a candidal vaccine based on a subunit vaccine that contains fragments of a microorganism without ballast substances. Cell fragments of Candida fungi that have antigenic properties include proteins and polysaccharides. To isolate antigenic substances from Candida fungal cells, we chose freezing as the method of destruction. The aim of this work was to experimentally substantiate the number of freezing stages for the destruction of C. tropicalis АТСС 20336 fungi cells and the subsequent production of proteins and polysaccharides. To determine the optimal number of freezing stages in the temperature range from (25 ± 2)°С to (-25 ± 2)°С, in order to destroy the cells of C. tropicalis fungi, the studies were conducted with freezing stages 3, 4, 5, and 6. Centrifugation was used to separate the excess components. Then the preliminary and sterilizing filtration was performed on membrane filters with pore diameters of 0.45 μm and 0.22 μm. The content of protein, polysaccharides and monosaccharides were determined in each case. The protein content was determined according to the State Pharmacopoeia of Ukraine (SPhU). To determine polysaccharides, a reaction with phenol and sulfuric acid was performed. Chromatographic studies of monosaccharides were conducted using paper chromatography according to the SPhU. Based on the results of the research, it was found that solutions obtained at stages 5 and 6 of freezing the biomass of C. tropicalis fungi cells at a temperature from (25 ± 2) °C to (-25 ± 2) °C contained the highest amount of proteins and polysaccharides. It is likely that with these number of stages for freezing the biomass of C. tropicalis fungi cells, active substances are released from all layers of Candida fungi cells. Thus, it can be concluded that five stages of freezing are the optimal number that ensures the maximum extraction of polysaccharides and proteins quickly and economically.

Development of Quality Control Parameters for Standardization of Herb of the Cultivated Plant <i>Alchemilla mollis</i> (Buser) Rothm.

Introduction. Alchemilla herb is proposed for introduction into pharmaceutical practice, for obtaining extracts with various pharmacological activity. To expand, resource base of Alchemilla it has been proposed to use a high biomass cultivated plant – Alchemilla mollis (Buuser) Rothm. In terms of qualitative and quantitative characteristics of the chemical composition Alchemilla mollis herb is comparable to the samples of raw materials of wild-growing Alchemilla. The presence of chemotaxonomic features necessitates the preparation of regulatory documentation for the introduction of this plant as a source of medicinal raw materials.Aim. Development of a methodology for assessing the main group of biologically active substances and the quantitative determination of flavonoids in Alchemilla mollis herb.Materials and methods. As objects of study, we used Alchemilla mollis herb harvested from plants cultivated in the Perm Krai. The chromatographic parameters of raw material authenticity were determined by thin layer chromatography (TLC). To develop the parameters for the quantitative determination of flavonoids in Alchemilla mollis herb, a modification of the method proposed for Alchemilla herb was carried out.Results and discussion. During chromatographic study of Alchemilla mollis herb were identified cinaroside, rutin, and quercetin. Cynaroside was referred to the marker substances. Ethyl acetate : acetic acid (85 : 15) was chosen as the optimal chromatographic system. A modification and validation of the method for the quantitative determination of flavonoids in Alchemilla herb was carried out. The change of the extractant, particle size, time and frequency of extraction for sample preparation and the optimal use of cynaroside as a standard substance are substantiated. The optimal conditions for the reaction of complex formation with aluminum chloride are established.Conclusion. To determine the authenticity of Alchemilla mollis herb, it was proposed to use the identification of cynaroside by TLC. The modified method for the quantitative determination of flavonoids in terms of cynaroside for the Alchemilla mollis herb, reproducible, correct and can be used for standardization. When testing the methodology on samples of raw materials harvested in the Perm region, a range of values for the content of flavonoids was 3.14–4.84 %, with an average level of variability.

Stability Indicating RP-HPLC Method for the estimation of Favipiravir in API and Pharmaceutical Dosage Forms (Tablets)

Favipiravir is an anti-viral agent used for the treatment of a large number of RNA viruses including influenza and was considered for the treatment of COVID-19. A new stability indicating RP-HPLC has been developed for the estimation of Favipiravir and the method was validated. Hypersil BDS C18 column was used for the chromatographic study with a flow rate 1ml/min (Detection wavelength 230nm). The LOD and LOQ were found to be 0.2918μg/mL and 0.9207μg/mL respectively. Linearity was observed over the concentration 1-300μg/mL with linear regression equation, y = 28444x + 21853 (R2 = 09998) and the method is precise, accurate and robust. Stress degradation studies were performed and the method was found to be selective and specific.

Development and Validation of Analytical Standards of Coconut (Cocos nucifera Linn.) shell based on Pharmacognostic, Phytochemical and Chromatographic Techniques

Background: Cocos nucifera Linn. belongs to the Arecaceae family and is the only accepted species from the genus Cocos. Coconut shell is a usually discarded material from the plant source Cocos nucifera Linn. However, scientifically validated data regarding the chemical and conforming therapeutic profile of Coconut shell is not available till date. It is important to develop analytical standards of Coconut shell using pharmacognostic, phytochemical and chromatographic techniques. Materials and Methods: The present analytical study was designed to determine the organic compounds present in the active fraction of dried ripe Coconut shell and to develop drug standards using powder microscopy, quantitative and qualitative phytochemical analysis and TLC techniques. Results: Powder microscopy and preliminary phytochemical analysis of Cocos nucifera Linn. endocarp indicated the presence of high fibre content in the drug. Further studies revealed the test drug as a rich source of alkaloids, steroids, phenols, flavonoids and tannins. Bioactive chemical profile and analytical standards of the test drug were derived by Thin Layer Chromatographic studies as well. Conclusion: The findings of the current research work ensued in establishing the botanical and analytical standards for Coconut (Cocos nucifera Linn.) shell.

Hyperoxidized Peroxiredoxin 2 Is a Possible Biomarker for the Diagnosis of Obstructive Sleep Apnea.

Peroxiredoxin (Prx) 2 in red blood cells (RBCs) reacts with various reactive oxygen species and changes to hyperoxidized Prx2 (Prx2-SO2/3). Therefore, Prx2 may serve as an indicator of oxidative stress in vivo. This study aimed to analyze Prx2-SO2/3 levels in clinical samples to examine whether the oxidation state of Prx2 in human RBCs reflects the pathological condition of oxidative stress diseases. We first focused on obstructive sleep apnea (OSA), a hypoxic stress-induced disease of the respiratory system, and investigated the levels of Prx2-SO2/3 accumulated in the RBCs of OSA patients. In measurements on a small number of OSA patients and healthy subjects, levels of Prx2-SO2/3 accumulation in patients with OSA were clearly increased compared to those in healthy subjects. Hence, we proceeded to validate these findings with more samples collected from patients with OSA. The results revealed significantly higher levels of erythrocytic Prx2-SO2/3 in patients with OSA than in healthy subjects, as well as a positive correlation between the severity of OSA and Prx2-SO2/3 levels in the RBCs. Moreover, we performed a chromatographic study to show the structural changes of Prx2 due to hyperoxidation. Our findings demonstrated that the Prx2-SO2/3 molecules in RBCs from patients with OSA were considerably more hydrophilic than the reduced form of Prx2. These results implicate Prx2-SO2/3 as a promising candidate biomarker for OSA.

DEVELOPMENT OF METHODS OF STANDARDIZATION OF FLOWERS OF SPREADING MARIGOLD (TAGETES PATULA L.)

The spreading marigold (Tagetes patula L.), the family Aster (Asteraceae), or Composite (Compositae), is a prospective source of flavonoids. The aim of the study is to develop methods of standardization of marigold flowers rejected, consisting in determining the identity of this raw material and the quantitative determination of biologically active compounds. As a result of a comparative chromatographic study, the presence of flavonoids was detected upon detection at a wavelength of 254 and 366 nm and before and after reaction with an alcohol solution of aluminum chloride. The presence of patuletin and patulitrin was confirmed in extracts of different varietal forms of Tagetes patula L.. Using column chromatography on silica gel L 40/100, two flavonoid substances were isolated patuletin (3,5,7,3′,4′-pentahydroxy-6-methoxyflavone) and patulitrin (7-O-β-D-glucopyranoside of 3,5,7,3',4′-pentahydroxy-6-methoxyflavone), which have been identified by UV-, 1H-NMR -, 13C-NMR-spectroscopy and mass spectrometry, as well as acid hydrolysis. In the solvent system chloroform- ethanol-water (26 : 16 : 3) Rf values of patuletin and patulitrin are about 0.7 and 0.4, respectively. It was found that patulitrin is the main flavonoid in the flowers of spreading marigold and determines the character of the absorption curve of the electronic spectra of water-alcohol extraction from this raw material. During the quantitative analysis of the total flavonoids in the flowers of spreading marigold, it is necessary to recalculate the content of active substances to the dominant and diagnostically significant flavonoid patulitrin. It was determined that the content of the total flavonoids in the studied samples of flowers of different varieties of the spreading marigold varies from 4.36±0.02% to 11.71±0.05% (calculated on patulitrin).

Site-selective covalent immobilization of PPARγ using a label-free strategy for chromatographic study

The development of site-selective covalent protein immobilization strategies is crucial for many protein-based bioanalytical assays. Herein, we proposed a label-free, site-selective, covalent immobilization strategy for the functionalization of PPARγ on GW9662 modified macroporous silica gels. The gels were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). Molecular docking in combination with competitive study, adsorption energy distribution (AED) calculation, and frontal analysis were used to investigate the binding of ligands with GW9662 occupied PPARγ. Docking results indicated that rosiglitazone, pioglitazone, and gensenoside Rh1 could cooperatively bind to the receptor with GW9662. Competitive studies revealed that the three ligands bond with PPARγ through the same site in the presence of GW9662. AED calculation showed one type of binding site for the three ligands on the receptor. Due to the presence of GW9662, the affinities of the three ligands ((2.35 ± 0.05) × 105 M−1 for rosiglitazone, (1.27 ± 0.02) × 105 M−1 for pioglitazone, and (3.18 ± 0.13) × 105 M−1 for gensenoside Rh1) with PPARγ were one or two orders of magnitude smaller than the literature reported values. The good performance of the immobilized PPARγ provided an opportunity for application in receptor-ligand interactions and cooperative partner screening. Our strategy is, therefore, a promising way to realize the label-free, covalent immobilization of functional proteins.

PAHs in medium and high rank Bulgarian coals – insights from aromatic indices

The study presents analyses of aromatic components in bitumen extracts from Bulgarian medium and high rank coals. Bulk samples from Balkan, Ro = 0.96%, Dobroudzha, Ro = 1.13%, and Svoge, Ro = 5.20% coal-bearing provinces, were considered. After extensive chromatographic separation and GC-MS study of the aromatic fractions, our attention was focused on polycyclic aromatic hydrocarbons (PAHs) compositions. Aromatic indices, based on quantification of individual compounds, revealed that: (i) the highest amounts of PAHs were present in Balkan and Dobroudzha samples, 219–365 μg/g TOC, and dropped to 3.5 μg/g TOC at Svoge sample; (ii) the alkylated naphthalenes and phenantrenes prevalence confirmed published data; (iii) the relationship between aromatic indices vs. Ro, % is in agreement with the previously obtained results, indicating their decrease with thermal maturity. For some indices only weak correlation was obtained, suggesting that PAH concentrations are not solely affected by coal rank, but also by environmental conditions and vegetation.

Development of an HPLC Method for the Determination of Levothyroxine Applied to Four Different Preparations

HPLC is an important research tool that can identify, extract and measure the substance, its numerous components and drug-related additives that may occur during either the manufacture or storage of the medication. Understanding the chemistry of the drug ingredient is required for this, which makes it easier to create analytical methods. To find the most effective way to conduct the procedure, many chromatographic parameters were investigated and tested. It is essential to identify a suitable mobile phase, column, column temperature, wavelength, and gradient to achieve the desired suitability and durability of the medicine in addition to its degradants and contaminants. This study aims to develop simply and rapidly the HPLC method for the determination of levothyroxine and its different brands. Levothyroxine is the drug of choice for hypothyroidism. In this study, a high liquid chromatography method was developed for the quantification of different brands of levothyroxine. The chromatographic study was analyzed at an ambient temperature of 28°C with isocratic elution. The mobile phase of the chromatograph was water and methanol Me OH (45:55) (1:1V/V) or 0.01 M phosphate buffer, the solution with adjusted pH=3. The flow rate of the pump was set at 1.5ml/min, the volume of the solution was 20 ml injected into the HPLC column, and the wavelength at 225 nm. The accuracy (99.9% recovery), precision (99.9 to 100% recovery), linearity (³ 0.99), and retention time (16.8 min) were observed for all brands of levothyroxine. In this study, we have evaluated the HPLC method for the quantification of levothyroxine and its different brands. Levothyroxine is considered as a controversial drug throughout the globe. In the recent past, we have found no study that proved clinical and biological interchangeability between levothyroxine brands. Our study is its self-unique in its case. There is no such publication proving that generic drugs are equivalent.

Preparation of miniaturized hydrophilic affinity monoliths: Towards a reduction of non-specific interactions and an increased target protein density

In affinity chromatography, non-specific interactions between the ligands and the affinity column may affect the results, leading to misinterpretations during the investigation of protein-ligand interactions (detection of false positives in ligand screening, lack of specificity in purification). Such non-specific interactions may arise both from the underlying support or from the target protein itself. If the second ones are protein-dependent (and cannot be studied in a general framework), the first ones occur in the same way regardless of the immobilized target. We propose a methodology to identify the origin of such non-specific interactions with the underlying material of the affinity column. This methodology relies on the systematic investigation of the retention behavior of a set of 41 low-molecular weight compounds covering a wide chemical space (net charge, log D, functionality). We first demonstrate that the main source of non-specific interactions on the most commonly used GMA-co-EDMA monolith comes from hydrophobic effects. To reduce such non-specific interactions, we developed a new hydrophilic glycidyl methacrylate-based monolith by replacing the EDMA crosslinker by the more hydrophilic NN’ Methylenebisacrylamide (MBA). Optimization of the synthesis parameters (monomer content, initiation type, temperature) has focused on the reduction of non-specific interaction with the monolithic support while maximizing the amount of protein that can be grafted onto the monolith at the issue of its synthesis. The retention data of the 41 test solutes on the new poly(GMA-co-MBA) monolith shows a drastic reduction of non-specific interactions except for cationic compounds. The particular behavior of cationic compounds is due to their electrostatic interactions with carboxylic groups resulting from the partial acidic hydrolysis of amide groups of MBA during the epoxide ring opening step. So, the ring opening step in acidic media was replaced by a hot water treatment to avoid side reaction on MBA. The new monolith poly(GMA-co-MBA) not only has improved hydrophilic surface properties but also a higher protein density (16 ± 0.8 pmol cm−1 instead of 8 ± 0.3 pmol cm−1). To highlight the benefits of this new hydrophilic monolith for affinity chromatographic studies, frontal affinity chromatography experiments were conducted on these monoliths grafted with con A.

CHARACTERIZATION THE INFLUENCE OF THE ROOTSTOCKS SO4, 44-53M, 110R AND FERCAL ON THE VOLATILE COMPOSITION OF RED WINES FROM THE HYBRID VARIETIES STORGOZIA (THREE HARVESTS) AND RUBIN (TWO HARVESTS) IN THE CONDITIONS OF CENTRAL NORTHERN BULGARIA

A gas chromatographic (GC-FID) study to characterize the influence of SO4, 44-53M, 110R and Fercal rootstocks on the volatile composition of red wines from the hybrid varieties Storgozia (harvests: 2017, 2018 and 2019) and Rubin (harvests: 2017 and 2019) under the soil and climatic conditions of Central Northern Bulgaria was conducted. The 110R rootstock in Storgozia has been shown to generate the highest total volatile content (756.10 mg/dm3) in 2017 harvest. 110R also affected the higher alcohols content of Storgozia. It generated the highest content of this indicator (713.00 mg/dm3) again in wines from the 2017 harvest. Regarding the content of esters, aldehydes and terpenes no significant differences were observed between the experimental variants of wines from this grapevine variety. In the case of Rubin wines, a very high final total volatile content was proved at rootstock 44-53M (1717.24 mg/dm3), harvest 2019. The highest concentration of higher alcohols in the 2017 harvest was identified for SO4, while in Rubin - the 2019 harvest, 110R generated the highest presence of higher alcohols. This fraction in both harvests was mainly represented by 2-methyl-1-butanol and 3-methyl-1-butanol. The esters were dominated by ethyl acetate and propyl acetate. In both harvests, the highest total terpene content was found in the wines from SO4 rootstock. The conducted research was evidence of the significant influence of different rootstocks on the volatile composition of wines from hybrid grapevine varieties in the conditions of Central Northern Bulgaria.

A Review on Phytochemical Investigation of Gymnema sylvestre Leaves

Gymnema sylvestre is a plant included in Apocynaceae family and is located in many regions of Asia, Africa and Australia. It is known to have blood glucose lowering potential and, thus, is widely used in traditional and Ayurvedic systems of medicine. A scrutiny of literature revealed some notable pharmacological activities of the plant such as antidiabetic, antiobesity, hypolipidaemic, antimicrobial, free radical scavenging and anti-inflammatory. The phytoconstituents responsible for sweet suppression activity includes triterpene saponins known as gymnemic acids, gymnemasaponins, and a polypeptide, gurmarin. Efforts have been made to prepare gudmar dried extract. These extracts were subjected for preliminary qualitative analysis, quantitative estimation of terpenoides, alkaloids and various other compounds. The present review is an attempt to highlight the phytochemical screening as well as its extraction process. Also chromatographic studies gave the presence of different compounds which can be used in creating monograph for this species.