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Chemopreventive Agents
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Chalcone (Figure 12.10) is an aromatic ketone and an enone that forms the central core within a variety of polyphenolic plant-based natural products known collectively as chalcones or chalconoids. Chalcones are related to the flavonoids in that the structure of their central core is similar to the flavone core (Figure 12.7) but with the B-ring broken open. Therefore, there is an assumption that chalcones may interact with the same pharmacological receptors as flavonoids provided they can take up a similar three-dimensional shape. Chalcones have a widespread distribution in fruits, vegetables, and teas. One of the best-known examples is xanthohumol (Figure 12.10), which is described in further detail below. Chemical structures of the parent chalcone core, and xanthohumol.
Biotransformation of Monoterpenoids by Microorganisms, Insects, and Mammals
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Yoshiaki Noma, Yoshinori Asakawa
(−)-Carvone (93′) was incubated with cyanobacterium, enone reductase (43 kDa) isolated from the bacterium, and microsomal enzyme to afford (+)-isodihydrocarvone (101b′) and (+)-dihydrocarvone (101a′). Cyclohexenone derivatives (379 are 385) were treated in the same enone reductase with microsomal enzyme to give the dihydro derivative (382a, 386a) with R-configuration in excellent ee (over 99%) and the metabolites (382b, 386b) with S-configuration in relatively high ee (85% and 80%) (Shimoda et al., 2003) (Figure 22.120).
Diversity of Endophytes and Biotechnological Potential
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Daiani Cristina Savi, Chirlei Glienke
We also described a new species, Phaeophleospora vochysiae (LGMF1215b), isolated from V. divergens that produced secondary metabolites with considerable antifungal activity. Although the strain LGMF1215 was isolated as endophyte, it produced phytotoxic perylenequinones as major compounds, cercosporin and isocercosporin, two toxic metabolites commonly produced by Cercospora species (Savi et al., 2018a). The resistance to cercosporins by P. vochysiae and by the host V. divergens may be due to cercosporin being produced associated with fungal hyphae, in this way the compound is present in reduced form, which makes the compound nontoxic or photoactive. In addition, strain LGMF1215 produced a new compound having antibacterial activity, 3-(sec-butyl)-6-ethyl-4,5-dihydroxy-2-methoxy-6-methylcyclohex-2-enone and absence of cytotoxic activity for human cell lines (Savi et al., 2018), suggesting the possibility to using this compound to treat clinical infections caused by bacteria.
Vanillin enones as selective inhibitors of the cancer associated carbonic anhydrase isoforms IX and XII. The out of the active site pocket for the design of selective inhibitors?
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Leonardo E. Riafrecha, Macarena S. Le Pors, Martín J. Lavecchia, Silvia Bua, Claudiu T. Supuran, Pedro A. Colinas
C-glycosides 1–2 have been prepared by reaction of β-C-glucosyl or β-C-galactosylketone with vanillin in the presence of L-proline/Et3N with moderate yields (Table 1). Next, we studied the aldol condensation of aliphatic or aromatic ketones and vanillin with different catalysts. The best reaction conditions found in the synthesis of the α,β-unsaturated ketones are shown in Table 1. Enones 1–7 were successfully purified by flash chromatography. The 1H NMR, 13 C NMR, 2 D COSY and HSQC were in full agreement with their structures (see Supplementary information). The large coupling constant (J ≈ 16 Hz) between the two olefinic protons, was consistent with the E configuration of the double bond. In enones, 1–2 the large coupling constant (J = 9.4 Hz) between H-10 and H-20 indicated a diaxial relationship and thus confirmed the β-configuration.
Identification and characterization of protein cross-links induced by oxidative reactions
Published in Expert Review of Proteomics, 2018
Per Hägglund, Michele Mariotti, Michael J. Davies
Reaction of carbonyls with amines and related species (e.g. the side chain amino group of Lys, the N-terminal amine, and the guanidine group of arginine, Arg) and other nucleophiles such as thiolate anions (RS− from Cys) and the imidazole group of His, can give Schiff base (imine) species and hence reversible or irreversible cross-links [64,65]. This can occur with both mono- and di-carbonyls (e.g. the metabolic and glucose-derived species glyoxal and methylglyoxal, which give the cross-linked species GOLD and MOLD, respectively with Lys residues) and also the carbonyls present in DOPA and TOPA quinones, resulting in complex (stable) heterocycles [66]. Some of these can be readily detected by their characteristic optical absorbance, or fluorescent, properties. Enone species formed from aromatic residues undergo ready Michael addition reactions where the nucleophile attacks the carbon of the double bond of the enone, to give an adduct species. These reactions can occur both intra- and intermolecularly.