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Pharmaceuticals and Nutraceuticals from Fish and Their Activities
Published in Ramasamy Santhanam, Santhanam Ramesh, Subramanian Nivedhitha, Subbiah Balasundari, Pharmaceuticals and Nutraceuticals from Fish and Fish Wastes, 2022
Ramasamy Santhanam, Santhanam Ramesh, Subramanian Nivedhitha, Subbiah Balasundari
Antioxidant, anti-inflammatory, and DNA-protective activities: The collagen peptides derived from the scales of this species showed high antioxidant activity, and anti-inflammatory activity by reducing lipoxygenase activity and nitric oxide (NO·) radicals. Further, these peptides have been reported to protect against cyclobutane di-pyrimidine production and DNA single-strand breaks, which are responsible for harmful UV radiation and H2O2 (Chen et al., 2018).
Biotransformation of Sesquiterpenoids, Ionones, Damascones, Adamantanes, and Aromatic Compounds by Green Algae, Fungi, and Mammals
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Yoshinori Asakawa, Yoshiaki Noma
It is noteworthy that Chlorella and Mucor species introduce hydroxyl group at C2 of the substrate (36) as seen in the biotransformation of valencene (1), while D. gossypina and B. megaterium oxidize C2, C8, C9, and/or 1,1-dimethyl group on a cyclopropane ring. A. niger oxidizes not only C2 but also stereoselectively oxidized one of the gem-dimethyl groups on cyclopropane ring. Stereoselective oxidation of one of gem-dimethyl of cyclopropane and cyclobutane derivatives is observed in biotransformation using mammals (see later).
Mutagenic Consequences Of Chemical Reaction with DNA
Published in Philip L. Grover, Chemical Carcinogens and DNA, 2019
It is not possible to consider chemical mutagenesis separately from DNA repair, because of the dual importance of repair in removing potentially mutagenic lesions from the DNA, and in converting such lesions into mutations. As a starting point, the author will try to describe our current knowledge of how DNA damage is accurately repaired by E. coli. Primarily, ultraviolet light (UV) induced damage will be discussed, and the responses of the bacterium to the whole spectrum of chemical carcinogens can then be considered as variations on a basic theme. UV is by far the most comprehensively investigated DNA damaging agent, and E. coli its most studied victim. As a reference agent, UV has several advantages, including easy administration, accurate dosimetry, and virtually instant treatment for kinetic studies. Moreover, the principal lesion is well characterized. Pyrimidine dimers are formed in which adjacent pyrimi-dines on the same DNA strand are joined by a cyclobutane type ring.38 Formation of the cyclobutane structure saturates the 5,6-double bond in the pyrimidine ring, causing it to become nonplanar.
Insights and controversies on sunscreen safety
Published in Critical Reviews in Toxicology, 2020
Juliana P. Paiva, Raiane R. Diniz, Alvaro C. Leitão, Lucio M. Cabral, Rodrigo S. Fortunato, Bianca A. M. C. Santos, Marcelo de Pádula
The most frequent DNA lesions generated directly by UV radiation are the pyrimidine cyclobutane dimmers (CPDs) and the 6-4-pyrimidine-pyrimidone photoproducts (6-4PPs). These lesions are responsible for promoting structural alterations to the DNA helix, which can lead to the inhibition of replication and transcription. CPDs are formed after a covalent bond between two adjacent pyrimidine bases generating a cyclobutane ring formed from the saturation of the double bond between carbons 5 and 6 of the neighbor pyrimidine nitrogen bases (Friedberg et al. 2006). These bonds have a high mutagenic potential and need to be corrected by DNA repair mechanisms (Mancebo et al. 2014). The 6-4PPs are characterized by a covalent bond between the 5′ end of carbon 6 from a base to the 3′ end of carbon 4 from its adjacent base (Friedberg et al. 2006). These two lesions appear to induce differential biological effects in the cell exposed to UV. Scientific evidence suggests that 6-4PPs participate more effectively in UV-induced apoptosis, whereas CPDs appear to be more important in arresting progression cell cycle (Lo et al. 2005). The conversion of 6-4PPs into their Dewar valence isomers, other type of lesion, results from the intramolecular electrocyclization of the pyrimidone ring after the photon absorption (Perdiz et al. 2000; Douki 2016). The formation of a Dewar isomer requires at least two photons: the first induces the 6-4PP and the second, arisen from UVA, is required for the isomerization of the initial 6-4PP.
Current state on tryptophan 2,3-dioxygenase inhibitors: a patent review
Published in Expert Opinion on Therapeutic Patents, 2019
Arina Kozlova, Raphaël Frédérick
In WO2016131381 [47], Shanghai De Novo Pharmatech reported a series of fused-ring compounds based on the initial imidazoisoindole tricyclic scaffold, but introducing a methylurea linker (Figure 3). Only one data is available for TDO2 in this application (levogyrous isomer of 17, 17 (-): IC50 < 0.5 µM). As for IDO1, the most potent compounds had an IC50 below 0.05 µM (17: IC50 < 0.05 µM). Finally, in WO2018082567 [48], the Shanghai Institute of organic chemistry showed that a spiro cyclobutane linker (18, 19) was able to get them a dual inhibition with biochemical IC50s below 10 µM for both enzymes.
Pharmacokinetics and tissue distribution in rats of a novel anticancer platinum compound LLC-1903
Published in Xenobiotica, 2020
Yingxue Li, Fanzhuo Meng, Zhijian Chen, Fuguo Han, Donglin He, Yanli Hao, Anli Gao, Jing Jiang, Zhao Wang, Weiping Liu, Qingfei Liu
Synthesis of LLC-1903 (Gao et al., 2017): 16.0 g (18.4 mmol) of trans-1,2-bis(aminomethyl)cyclobutane diiodoplatinum(II) was dissolved in 400 mL distilled water. To the solution was added 10.5 g (28.2 mmol) of 3-oxo-1,1 cyclobutanedicarboxylato Ag under stirring for 72 h at 40–45 °C without exposure to light till the color of the solution changed to yellow from brown. A KI solution was added dropwise till there was no AgI produced. The mixture was filtrated, and the retentate was dried by lyophilization. The raw product of LLC-1903 was further purified by chromatography and re-crystallization. The structure was confirmed by 1HNMR.