scholarly journals Extraction and Isolation of Antineoplastic Pristimerin from Mortonia greggii (Celastraceae)

2015 ◽  
Vol 10 (11) ◽  
pp. 1934578X1501001
Author(s):  
Luis Alberto Mejía-Manzano ◽  
Bertha A. Barba-Dávila ◽  
Janet A. Gutierrez-Uribe ◽  
Edgardo J. Escalante-Vázquez ◽  
Sergio O. Serna-Saldívar
Keyword(s):  
Size Exclusion ◽  
Root Extract ◽  
Root Bark ◽  
Extraction Temperature ◽  
Experimental Conditions ◽  
Plant Weight ◽  
Exclusion Chromatography ◽  
Solvent Systems ◽  
Solid Liquid ◽  
Solvent Volume

The aim of this research was to identify, extract and isolate pristimerin in leaves, stems and roots of the Mexican plant Mortonia greggii ( Celastraceae). The principal objective was to determine the best laboratory experimental conditions for the extraction and isolation of this powerful natural anticancer agent from the root tissue. Six experimental factors in solid-liquid pristimerin extraction were analyzed: solvent systems, number of extractions, ratio of plant weight (g)/solvent volume (mL) used, time of extraction, temperature and agitation. A mathematical model was generated for pristimerin purity and yield. Ethanol, first extraction, 0.5 ratio of plant weight/solvent volume (g/mL), 0.5 h, 200 rpm and 49.7°C were optimal conditions for the extraction of this phytochemical. The degree of purification of pristimerin root extract was studied by size-exclusion chromatography (SEC) using Sephadex LH-20 reaching fractions with purification indexes (PI) greater than 2 and recoveries of 28.3%. When fractions with purification indices higher than 1 and less than 2 were accumulated, the recovery of pristimerin increased by about 73.6%. By combining the optimum extracts and SEC purification protocols, an enriched fraction containing 245.6 mg pristimerin was obtained from 100 g of root bark, representing about 14.4%, w/w, pristimerin from the total solids presented in the fraction.

Optimization of the Technology of Extracting Dihydromyricetin from Ampelopsis by Orthogonal Experimental Design

2012 ◽  
Vol 550-553 ◽  
pp. 1709-1714
Author(s):  
Ling Yang ◽  
Cheng Zheng
Keyword(s):  
Experimental Design ◽  
Orthogonal Test ◽  
Orthogonal Experimental Design ◽  
Extraction Temperature ◽  
Extraction Solvent ◽  
Solid Liquid ◽  
Solvent Volume

The optimum extracting condition of dihydromyricetin from ampelopsis was studied. The MAE conditions, such as the extraction solvent volume, extraction temperature, and the period of extraction, were all studied in the orthogonal test. The most suitable conditions for the extractions were showed as follows: the extracting temperature was 95°C,the extracting time was 15min,and the solid-liquid leaching ration was 1:20.

Network Structures, Flexibility and Stability in Thermal and Chemical Environments of Polyurethane Prepared from Rubber Seed Oil.

2009 ◽  
Vol 62-64 ◽  
pp. 324-334 ◽  
Author(s):  
F.E. Okieimen ◽  
I.O. Bakare ◽  
C. Pavithran
Keyword(s):  
Seed Oil ◽  
Hexamethylene Diisocyanate ◽  
Toluene Diisocyanate ◽  
Size Exclusion ◽  
Network Structures ◽  
Structure Property ◽  
Experimental Conditions ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Exclusion Chromatography

Rubber seed oil monoglyceride was prepared by glycerolysis and characterized by chemical and spectroscopic methods. The monoglyceride was reacted with excess diisocyanates (hexamethylene -diisocyanate and toluene diisocyanate), and the network structures and molecular mass of the polyurethane were determined from swelling experiments in toluene and size exclusion chromatography respectively. The polyurethane films obtained were characterized in terms of their resistance to chemicals (water, brine, dilute acid and alkali) thermal stability and tensile and flexural strength and modulus. It was found that under the experimental conditions, conversion of the triglyceride content of the rubber seed oil to monoglyceride not quantitative less than 70%. The measured properties of the RSO-based polyurethanes were attributed to the degree of crosslinking and the observed superior properties of the polyurethane obtained with hexamethylene diisocyanate in comparison with polyurethane obtained with toluene diisocyanate were explained in terms of structure-property relationship. The measured properties of RSO-based polyurethanes compare favourably with the properties reported for polyurethanes derived from other vegetable oils.

scholarly journals Fragmentation of Chitosan by Acids

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammad Reza Kasaai ◽  
Joseph Arul ◽  
Gérard Charlet
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Kinetic Data ◽  
Chemical Structure ◽  
Size Exclusion ◽  
Experimental Conditions ◽  
First Order ◽  
H Nmr ◽  
Exclusion Chromatography ◽  
Kinetics Of

Fragmentation of chitosan in aqueous solution by hydrochloric acid was investigated. The kinetics of fragmentation, the number of chain scissions, and polydispersity of the fragments were followed by viscometry and size exclusion chromatography. The chemical structure and the degree of N-acetylation (DA) of the original chitosan and its fragments were examined by1H NMR spectroscopy and elemental analysis. The kinetic data indicates that the reaction was of first order. The results of polydispersity and the DA suggest that the selected experimental conditions (temperature and concentration of acid) were appropriate to obtain the fragments having the polydispersity and the DA similar to or slightly different from those of the original one. A procedure to estimate molecular weight of fragments as well as the number of chain scissions of the fragments under the experimental conditions was also proposed.

Fractionation and characterization of xylan rich extracts from birch

Holzforschung ◽  
2008 ◽  
Vol 62 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Peter Westbye ◽  
Tobias Köhnke ◽  
Paul Gatenholm
Keyword(s):  
Liquid Extraction ◽  
Water Soluble ◽  
Size Exclusion ◽  
Separation Processes ◽  
Lignin Concentration ◽  
Liquid Liquid Extraction ◽  
Exclusion Chromatography ◽  
Acid Soluble Lignin ◽  
Molecular Masses ◽  
Solid Liquid

Abstract There is a need for efficient separation processes that provide clean fractions of individual wood polymers. The purpose of this study was to remove lignin from a xylan rich fraction from birch by solid-liquid extraction followed by a liquid-liquid extraction. By this means, it was possible to diminish the lignin concentration (12%) of mildly extracted xylans from birch to a total lignin concentration of 3%, as determined as a sum of Klason lignin and acid soluble lignin. The molecular masses of the fraction were determined by size exclusion chromatography (SEC). The two xylan rich fractions obtained by the removal of lignin have molecular masses (M W) of 15 300 and 27 900 Da in comparison to 11 900 Da for the lignin rich starting material. NMR and IR analysis revealed that the lignin removed is mostly unbound to the polysaccharides. The lignin was water soluble in the presence of xylan (as part of the xylan rich fraction), but not in isolated form in water alone. The remaining lignin in the xylan fractions has obviously a closer interaction with the xylan, and thereby its separation by liquid-liquid extraction is more difficult. It is also observed with NMR that the extractable lignin is built up mainly of syringyl units, chiefly bonded by β-O-4 linkages.

scholarly journals Characterization of Temperature-Dependent Kinetics of Oculocutaneous Albinism-Causing Mutants of Tyrosinase

2021 ◽  
Vol 22 (15) ◽  
pp. 7771
Author(s):  
Samuel A. Wachamo ◽  
Milan H. Patel ◽  
Paul K. Varghese ◽  
Monika B. Dolinska ◽  
Yuri V. Sergeev
Keyword(s):  
Trichoplusia Ni ◽  
Oculocutaneous Albinism ◽  
Size Exclusion ◽  
Temperature Dependent ◽  
Experimental Conditions ◽  
Rate Limiting Step ◽  
Its Gene ◽  
Exclusion Chromatography ◽  
First Time ◽  
Kinetics Of

Human tyrosinase (Tyr) is a glycoenzyme that catalyzes the first and rate-limiting step in melanin production, and its gene (TYR) is mutated in many cases of oculocutaneous albinism type phenotype in patients with OCA1 have only began to be examined and remain to be delineated. Here, we analyze the temperature-dependent kinetics of wild-type Tyr (WT) and two OCA1B mutant variants (R422Q and P406L) using Michaelis–Menten and Van’t Hoff analyses. Recombinant truncated human Tyr proteins (residues 19–469) were produced in the whole insect Trichoplusia Ni larvae. Proteins were purified by a combination of affinity and size-exclusion chromatography. The temperature dependence of diphenol oxidase protein activities and kinetic parameters were measured by dopachrome absorption. Using the same experimental conditions, computational simulations were performed to assess the temperature-dependent association of L-DOPA and Tyr. Our results revealed, for the first time, that the association of L-DOPA with R422Q and P406L followed by dopachrome formation is a complex reaction supported by enthalpy and entropy forces. We show that the WT has a higher turnover number as compared with both R422Q and P406L. Elucidating the kinetics and thermodynamics of mutant variants of Tyr in OCA1B helps to understand the mechanisms by which they lower Tyr catalytic activity and to discover novel therapies for patients.

CHARACTERIZATION OF A NEW LCAT MUTATION CAUSING FAMILIAL LCAT DEFICIENCY (FLD) AND THE ROLE OF APOE AS A MODIFIER GENE OF THE FLD PHENOTYPE

2009 ◽  
Vol 32 (6S) ◽  
pp. 3
Author(s):  
A Baass ◽  
H Wassef ◽  
M Tremblay ◽  
L Bernier ◽  
R Dufour ◽  
...  
Keyword(s):  
Modifier Gene ◽  
Size Exclusion ◽  
Plasma Lipoproteins ◽  
Lipoprotein Profile ◽  
Exclusion Chromatography ◽  
Low Hdl ◽  
Lcat Deficiency ◽  
Apoe Genotypes

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.

Structure of a shear-thickening polysaccharide extracted from the New Zealand black tree fern, Cyathea medullaris

2020 ◽  
Author(s):  
M Wee ◽  
M Mastrangelo ◽  
Susan Carnachan ◽  
Ian Sims ◽  
K Goh
Keyword(s):  
New Zealand ◽  
Uronic Acid ◽  
Average Molecular Weight ◽  
Shear Thickening ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Tree Fern ◽  
13C Nuclear Magnetic Resonance ◽  
Exclusion Chromatography

A shear-thickening water-soluble polysaccharide was purified from mucilage extracted from the fronds of the New Zealand black tree fern (Cyathea medullaris or 'mamaku' in Māori) and its structure characterised. Constituent sugar analysis by three complementary methods, combined with linkage analysis (of carboxyl reduced samples) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR) revealed a glucuronomannan comprising a backbone of 4-linked methylesterified glucopyranosyl uronic acid and 2-linked mannopyranosyl residues, branched at O-3 of 45% and at both O-3 and O-4 of 53% of the mannopyranosyl residues with side chains likely comprising terminal xylopyranosyl, terminal galactopyranosyl, non-methylesterified terminal glucopyranosyl uronic acid and 3-linked glucopyranosyl uronic acid residues. The weight-average molecular weight of the purified polysaccharide was ~1.9×106Da as determined by size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS). The distinctive rheological properties of this polysaccharide are discussed in relation to its structure. © 2014 Elsevier B.V.

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