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Chemopreventive Agents
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Flavonoids have diverse and complex structures but generally consist of a core 15-carbon skeleton containing two phenyl rings (A and C) and a heterocyclic ring (B). The parent ring system known as “flavone” is shown in Figure 12.7. Many different flavonoid structures have been documented and categorized into subgroups. For example, the flavonols are flavonoid-type molecules containing hydroxyl groups. They are present in a wide variety of fruits and vegetables with an estimated daily intake of 20–50 mg per day in Western populations. Flavonol aglycones in plants are potent antioxidants that serve to protect the plant from reactive oxygen species (ROS). However, there are many other structural subgroups such as the flavones, flavanones, flavononols, anthocyanins, and catechins. There is also a related family of isoflavonoids in which the phenyl C-ring is attached to the 3-position of the central B-ring rather than the 2-position. General structure of the flavonoid skeleton (flavone).
Components of Nutrition
Published in Christopher Cumo, Ancestral Diets and Nutrition, 2020
Note that hydrogen in glycerol and the hydroxyl group in the fatty acid—each within a rectangle in Figure 2.3—play important roles in forming the above fat molecule. Hydrogen has a positive charge (H+), and the hydroxyl group has a negative charge (OH−). These opposites attract so that H+ and OH− form H2O. This reaction liberates or releases water and is known as dehydration. The liberation of water leaves the oxygen in glycerol to bond with the carbon that had been part of the terminal carboxylic acid in the fatty acid to form the fat molecule. In this case, the result is a triglyceride (also rendered triacylglycerol or TAG), named after the three-part structure.
Contrast enhancement agents and radiopharmaceuticals
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
A number of factors influence the viscosity of a contrast agent: The temperature of the solution.The molecular weight of the contrast medium.The number of hydroxyl groups and the size of substituent groups.
Design, synthesis, biological evaluation and molecular docking study of 2,4-diarylimidazoles and 2,4-bis(benzyloxy)-5-arylpyrimidines as novel HSP90 N-terminal inhibitors
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Man Yang, Chenyao Li, Yajing Li, Chen Cheng, Meiyun Shi, Lei Yin, Hongyu Xue, Yajun Liu
16l presented a “T-shaped lock” conformation and was possibly able to block the entrance of ATP into the binding pocket. The benzyloxy group at the N1 position of 16l was directed towards the bottom of the binding pocket, while two 4-chlorophenyl groups were positioned at the mouth of the binding pocket. 16l may form a halogen bond with GLY132, a Pi-cation interaction with LYS58, a Pi-sulphur interaction with MET98, and multiple hydrophobic interactions with residues ALA55, ILE96, and MET98 (Figure 5b). In the case of 22k, the benzyloxy group at the C2 position of the pyrimidine ring was oriented towards the bottom of the binding pocket. It should be noted that 22k may have formed hydrogen bonds with LYS58 and ASP102 (Figure 5c). The hydrogen bond interaction between the hydroxyl group of 22k and ASP102 indicated that the hydroxyl group may be important for stabilising the protein-ligand complex. This result is consistent with the observations in the biological evaluation that the introduction of the hydroxyl group enhanced the antiproliferative activity. In addition, hydrophobic interactions with residues ALA55, MET98, and VAL186 and a Pi-Anion interaction with ASP102 were observed in the predicted binding mode of 22k and the HSP90 N-terminus.
Development and characterization of orodispersible film containing cefixime trihydrate
Published in Drug Development and Industrial Pharmacy, 2020
Qurrat-ul-ain Khan, Muhammad Irfan Siddique, Fatima Rasool, Muhammad Naeem, Muhammad Usman, Muhammad Zaman
Compatibility study of CFX and β-CD (Figure 2) were performed by using matching approach of FT-IR spectra. The functional group (C=O) at 1770 cm−1 showed that β-lactam absorbance band is present. The hydroxyl group (OH) at 3640 cm−1 indicates that in the reaction, OH groups are not involved. The appearance of the band at 1540 cm−1 (C=N) also revealed the nonreactivity of CFX and β-CD. Ether functional group (C-O-C) band at 1024 cm−1 is present and gives more proof for nonreactivity of the drug and β-CD. This indicates that CFX was compatible with the β-CD. Physical mixing shown less complexation because the spectra of PM1 was more like with the spectra of pure CFX. On the other hand, better complexation shown by kneading and freeze-dried complexes as their spectra slightly varied from the spectra of pure CFX. The peak intensity sharpness was reduced in complexes formed by kneading and freeze drying method, which indicate that the inclusion complex was formed.
Standardizing and increasing the utility of lipidomics: a look to the next decade
Published in Expert Review of Proteomics, 2020
Yuqin Wang, Eylan Yutuc, William J Griffiths
Steroid profiling can be thought of the analysis of C21 – C18 steroids, usually by MS analysis of body fluids [9–11]. Importantly, urinary steroids are not the secreted hormones or their precursors, but end products of hepatic or renal metabolism. As illustration, 3-oxo-4-ene structures of typical steroid hormones or their precursors are reduced to form 3α-hydroxysteroids with either a 5α- or 5β-hydrogen at the A/B ring junction. Commonly a carbonyl at C-20 is converted to a hydroxy group, while hydroxy groups at 17β and 11β are converted to carbonyls. Metabolites with a 3α-hydroxy group are usually excreted as glucuronides while those with a 3β-hydroxy-5-ene are excreted as sulfates [11]. Following de-conjugation essentially all neutral steroids can be profiled by GC-MS following methyloxime protection of carbonyl groups and trimethylsilylation of hydroxyls. When steroid conjugates are of interest then LC-MS/MS is the method of choice [141].