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Rheological Additives
Published in Laba Dennis, Rheological Proper ties of Cosmetics and Toiletries, 2017
The majority of the monosaccharide residues found in the natural thickeners are six-membered rings. These rings, consisting of five carbon atoms and one oxygen atom, are classified as the pyranose group, or the pyrans. The most common is p-D-glucopyranose, more typically called D-glucose. Alternate configurations are possible due to rotation about the ring bonds.
Polysaccharide-Based Polymers in Cosmetics
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
The majority of cosmetically interesting polysaccharides are comprised primarily of six-membered cyclic structures known as pyranose rings, themselves composed of five carbon atoms and one oxygen and numbered as shown in Table 1. Rings of four carbon atoms and one oxygen atom are known as furanose rings and occur less frequently in personal care applications. Although the formal polysaccharide nomenclature employs the term “pyranose,” informally this is shortened by dropping “pyrano” from the name. Thus, D-glucopyranose becomes D-glucose. The monosaccharides vary primarily in the spatial arrangement of the appendage groups , etc.) attached to the pyranose carbon atoms. For instance, D-glucose differs from D-mannose by the arrangement of the hydroxyl group at carbon 2 (see and ); in D-glucose it exists in an axial arrangement and in D-mannose it is equatorial. These structural variations in the monosaccharides confer huge variation to the resulting polysaccharide family.
Bilirubin Conjugates: Isolation, Structure Analysis and Synthesis
Published in Karel P. M. Heirwegh, Stanley B. Brown, Bilirubin, 1982
Karel P. M. Heirwegh, Stanley B. Brown
Heterogeneity of carbohydrate conjugates was demonstrated for dog bile azo pigments by several workers,15–18 who in addition to glucuronosyl esters also isolated and identified xylosyl and glucosyl ester conjugates. Quite generally, the β-1-o-acyl pyranoside structure was assigned to the sugar moieties.16,19,20 TLC separation of the native bilirubin conjugates from dog bile, followed by diazonium cleavage of individual bile pigments, showed the presence of monoconjugates and of homogeneous and mixed diconjugates,* involving the three sugars (Figure 1).18,21-25 Although glucose and xylose are minor components only for rat,26 rhesus monkey,24,25 and human bile,18,24–26 chromatographic evidence suggests that these conjugates constitute an important fraction of bile pigments in some other animal species.26–27
Application of crosslinked chitosan-nanoclay composite beads for efficient removal of Ponceau S azo dye from aqueous medium
Published in Toxin Reviews, 2023
Seda Çınar, Ayşe Dinçer, Ahmet Eser, Tülin Aydemir
The thermal decomposition profile of the crosslinked CS/NC composite beads was investigated using thermogravimetric analysis. The TG-DTG curve of the CS/NC composite beads from 30 to 600 °C at a heating rate of 10 °C min−1 is showed the weight loss of CS/NC as a function of temperature (Figure 1(C)). In the first step, the weight loss observed between 30 °C and 100 °C was about 6% due to the evaporation of physically bound water that is held by clay intensively. By raising the temperature to 200 °C, the decomposition of hydroxyl groups and volatile compounds occurred with mass losses of about 13%. In the second stage, crosslinked CS/NC composite showed sharp thermal decomposition at a temperature ranging from 200 to 400 °C, with a weight loss of 35%. The probable reason for weight loss in the second stage can be the decomposition of aliphatic chains and dehydration of the saccharide rings. The third step started at 400 °C and ended at 600 °C. In this step, the destruction of pyranose rings may cause weight loss of about 42%.
Pullulan based derivatives: synthesis, enhanced physicochemical properties, and applications
Published in Drug Delivery, 2022
Surendra Agrawal, Divya Budhwani, Pravina Gurjar, Darshan Telange, Vijay Lambole
As shown in Figure 1, pullulan (C6H10O5)n consists of repeated units of maltotriose. Each pyranose ring of maltotriose is connected via α-(1,4) glycosidic bond, and one maltotriose unit is connected to another maltotriose unit via α-(1,6) glycosidic bond (Coltelli et al., 2020). Each maltotriose unit has nine OH groups, which can be replaced by groups with different functionality. Chemical modification improves the physical and chemical properties of pullulan, retains the unique properties of pullulan, and expands the application range. Modified pullulan have better mechanical strength, solubility in the organic solvents, and ability to deliver the drug at target site (Supe & Takudage, 2021). This review mainly focuses on the mechanism of pullulan derivatization and applications of pullulan derivatives due to enhanced property.
Extraction and chemical characterization of novel water-soluble polysaccharides from two palm species and their antioxidant and antitumor activities
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Dawood H. Dawood, Mohamed S. Elmongy, Amr Negm, Mohamed A. Taher
It was shown that the IR spectra of CM and CH polysaccharides were mostly similar (Figure 3). The two polysaccharides exhibited the same broad stretching peak near 3419 cm−1 characteristic of hydroxyl (OH) groups [45], and the small C-H stretching of the CH2 groups at 2928 cm−1 [46]. A strong and isomerous extending peak at around 1629 cm−1 and a weak peak at around 1528 cm−1 were attributed to the stretching vibration of the carbonyl bond C = O of the amide group and the bending vibration of the N–H bond in peptides or proteins [47]. The small peak at 1442 cm−1 and 1250 was observed in both samples, which proved the presence of carboxyl group COOH [48]. It can be seen in Figure 3 that CM and CH polysaccharides all specifically displayed a strong peak at around 1070 cm−1, which specified the presence of uronic acids, such as guluronic acid or mannuronic acid. In addition, the small absorption bands at about 880 cm−1 could be related to the β-glycosidic linkages between the sugar units [49]. The bands in the range of 350–600 cm−1 are allotted to skeletal modes of pyranose rings [50]. Therefore, it could be concluded that the two palm polysaccharides belong to β-type heteropolysaccharide with a pyranose group. Finally, there was no important difference between CM and CH polysaccharides in IR spectra.