China
Africa
Explore chapters and articles related to this topic
Approaches for Identification and Validation of Antimicrobial Compounds of Plant Origin: A Long Way from the Field to the Market
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Lívia Maria Batista Vilela, Carlos André dos Santos-Silva, Ricardo Salas Roldan-Filho, Pollyanna Michelle da Silva, Marx de Oliveira Lima, José Rafael da Silva Araújo, Wilson Dias de Oliveira, Suyane de Deus e Melo, Madson Allan de Luna Aragão, Thiago Henrique Napoleão, Patrícia Maria Guedes Paiva, Ana Christina Brasileiro-Vidal, Ana Maria Benko-Iseppon
The purification of peptides and proteins from fractions or even crude extract can follow one or more chromatographic processes. Before performing a chromatographic procedure, the insoluble matrix and the chromatographic conditions of pH, ionic strength, volume of the chromatographic bed, amount of protein applied per mL of matrix, flow rate in the column, elution strategy and sample volume must be chosen (Paiva et al. 2010; Procópio et al. 2017b). Column chromatography occurs in the steps of equilibrating the column with the solution in which the process will take place, applying the sample and obtaining fractions.
Conjugation and Other Methods in Polymeric Vaccines
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Chromatography is known as an important biophysical technique that can separate, identify, and purify the blend segments for subjective and quantitative investigation. Proteins can be purified based on properties such as size and shape, total charge, hydrophobic groups present on the surface, and the ability to bind to the stationary phase. It is based on molecular properties and interaction type use mechanism, four separation technologies, ion exchange, dispersion, surface adsorption, and size exclusion. Column chromatography is one of the most used and common techniques for protein purification methods. This technique is basically used to purify biological molecules. The application of the method can be summarized as follows. The sample is separated on the column (stationary phase) and then the wash buffer is added to the column (mobile phase). It flows through the column material placed on the fiberglass support. With the help of the wash buffer, the samples are accumulated at the bottom of the column chromatography instrument, based on time and volume (Coskun 2016). Column chromatography is a powerful purification and separation process that is closely controlled to the hydrodynamic diameters of the macromolecules depending on the diameter of the pores in the filling material (see in HPLC Method) (Acar 2006; Fornaguera and Solans 2018).
Technetium-Labeled Compounds
Published in Garimella V. S. Rayudu, Lelio G. Colombetti, Radiotracers for Medical Applications, 2019
Suresh C. Srivastava, Powell Richards
Chromatographic techniques have enjoyed wide popularity for determining the radiochemical purity of 99mTc-labeled radiopharmaceuticals. These methods are applicable at the no-carrier-added level, require inexpensive equipment, and are easy to perform. The techniques employed include paper, thin-layer (TLC), and column chromatography. Determination of free (unreduced) pertechnetate is accomplished conveniently by TLC systems or by using short alumina columns. These systems generally do not separate components other than pertechnetate and thus do not provide complete information on radiochemical purity. On the other hand, certain paper and column chromatographic systems are capable of separating the labeled compound, pertechnetate, and reduced unbound technetium impurity. Thus these systems provide a more complete picture of the radiochemical composition of 99wTc radiopharmaceuticals.
Promising anti-Helicobacter pylori and anti-inflammatory metabolites from unused parts of Phoenix dactylifera CV ‘Zaghloul’: in vitro and in silico study
Published in Pharmaceutical Biology, 2023
Nada Elhefni, Sherif S. Ebada, Marwa M. Abdel-Aziz, El-Sayed M. Marwan, Saleh El-Sharkawy, Mona El-Neketi
Nuclear Magnetic Resonance spectra (1H, 13C, APT, DEPT135, 1H-1H COSY, HMBC, HSQC and ROESY) were recorded on Bruker DRX 400 NMR spectrometer (Bruker Daltonics Inc., MU, Egypt). Deuterated NMR solvents including chloroform-d, methanol-d4 and DMSO-d6 were used. Chemical shifts were measured in parts per million (ppm) using TMS as an internal standard. HRESIMS was determined using LCMS-IT-TOF (Shimadzu, Tokyo, Japan). Column chromatography was performed using silica gel G 60 M (Merck, Germany) or Sephadex LH20 (Pharmacia, USA) as stationary phases. Thin-layer chromatography (TLC) plates pre-coated with silica gel 60 GF254 (20 × 20 cm × 0.2 mm thick, Merck) were used and spots were made visible by spraying vanillin-sulfuric acid reagent.
Ginsenoside Rg3 liposomes regulate tumor microenvironment for the treatment of triple negative breast cancer
Published in Drug Development and Industrial Pharmacy, 2023
Linan Miao, Hao Ma, Tingjun Dong, Chengcheng Zhao, Tingyu Gao, Tianyi Wu, Huan Xu, Jing Zhang
Oxazoline polymers are usually prepared using cationic ring-opening reactions [24]. The electrophilic reagents were used to initiate the reaction, and the nucleophilic reagents were used to terminate the synthesis process, thus obtaining oxazoline polymers with different side-chain groups and different properties [25]. In this study, Boc-NH-PEOz, where the amino group at one end is protected, can be synthesized using Boc-OTS as initiator and potassium hydroxide/methanol solution as terminator [26]. At the other end, the hydroxyl group underwent esterification with CHM to obtain Boc-NH-PEOz-CHMC, which was further deprotected by Boc and coupled with activated FA to get the final product FPC. In the separation and purification process of Boc-OTS, the recrystallization method was selected first. Ethyl acetate was used as the benign solvent to dissolve the precipitate, and n-hexane was used as the poor solvent to precipitate the product. However, there are still impurities in the product purified by recrystallization. Therefore, the column chromatography method was chosen to separate and purify the product.
Salvia hispanica L. seeds extract alleviate encephalopathy in streptozotocin-induced diabetes in rats: role of oxidative stress, neurotransmitters, DNA and histological indices
Published in Biomarkers, 2022
Amal M. El-Feky, Marwa M. Elbatanony, Asmaa F. Aboul Naser, Eman A. Younis, Manal A. Hamed
The conventional column chromatography technique had been applied for the isolation of the major compounds. Elution was carried out using methylene dichloride (CH2Cl2), then increasing the polarity with ethyl acetate. The resulting similar fractions had been assembled based on their Rf values where the isolated compounds were identified by several spectral analyses (IR, mass spectrometry, 1H-NMR and C13-NMR). Compounds 1 and 2 were eluted with (CH2Cl2: ethyl acetate 80%), compound 3 was isolated with (CH2Cl2: ethyl acetate 70%), while compounds 4, 5 and 6 were isolated from CH2Cl2:ethyl acetate (60%). All the isolated compounds that developed a colour with p-anisaldehyde were further purified separately with preparative TLC technique using (Toluene: ethyl acetate, 8:2 and 19:1 v/v). Additionally, the isolated compounds were chromatographed on TLC alongside with available authentic references.