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Influence of Air on Essential Oil Constituents
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Darija Gajić, Gerhard Buchbauer
Still, no peracid was detected in the autoxidation mixture, and two possible scenarios were offered: either peracid is consumed prior to identification of oxidation mixture, or radical C1 reacted directly with some other agent in the solution. Given that peracids are established as epoxidation inducers, it is expected to react with geranial (an olefin) and thus an epoxide 49 and a carboxylic acid 48 are formed (Figure 29.24a). The reaction then proceeds so that the epoxide reacts with acyl radical and the dioxolane hydroperoxide is yielded. It was also suggested that the dioxolane derivative is created in an acid-catalyzed closed shell reaction between 6,7-epoxygeranial and geranial. A more detailed review on dioxolane formation will be proposed later on. Peroxyl radical C1 can, alternatively to hydrogen abstraction, be engaged in a direct reaction with olefins, which can also result in an epoxide and a carboxyl radical creation (Figure 29.24b).
Design, synthesis, molecular modelling and antitumor evaluation of S-glucosylated rhodanines through topo II inhibition and DNA intercalation
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Ahmed I. Khodair, Fatimah M. Alzahrani, Mohamed K. Awad, Siham A. Al-Issa, Ghaferah H. Al-Hazmi, Mohamed S. Nafie
To compare the effect of dioxolane, 3f, and dioxane, 3c, substituents on the biological activity of inhibitor 3a, the calculations showed that inhibitors 3f and 3c have higher activity than that of unsubstituted 3a inhibitor. Moreover, the calculations showed that the dioxolane substituent has higher reactivity than that of dioxane substituent. This was shown from the decreasing the energy of the LUMO (−0.087 au) which means that 3f inhibitor has more electron accepting ability from enzyme than that of 3c compound (-0.084 au), Table 1. Also, 3f has a lower energy gap, ΔE (0.131 au), than that of 3c (0.134) which could be responsible for increasing the reactivity of 3f more that of 3c. Meanwhile, increasing the softness and chemical potential of compound 3f (15.152 au−1 and −0.153 au, respectively) could increase its reactivity with respect to 3c with dioxane substituent. This is in a good agreement with the experimental data.
Characterization of hydrocoptisonine metabolites in human liver microsomes using a high-resolution quadrupole-orbitrap mass spectrometer
Published in Xenobiotica, 2020
Su Min Choi, Younah Kim, Jaeick Lee, Ju-Hyun Kim, Taeho Lee, Byung Sun Min, Jeong Ah Kim, Sangkyu Lee
In this study, we used HR-MS/MS to observe a total of 13 metabolites of hydrocoptisonine in HLMs. There were six demethyl- and/or mono-hydroxyl metabolites and seven glucuronide conjugates. Among them, O-demethylation of hydrocoptisonine was the dominant metabolic pathway in HLMs, and eight metabolites (M1–M4 and M7–M10) were related to O-demethylation (Figure 6). The M1 and M2 metabolites were demethylated in dimethoxybenzene at position C9 or C10, and M3 metabolite was demethylated in dioxolane structures to become quinone structure. Although they are the same demethylated metabolites, M3 was unlike M1 and M2, in that it was demethylated in dioxolane structures (cyclohexa-3,5-diene-1,2-dione). In a previous study, it was confirmed that O-demethylation in dioxolane structures became a catechol and then a quinone structure (Antolino-Lobo et al., 2010). For example, 3,4-methylenedioxymethamphetamine (MDMA) with a dioxolane structure was metabolized to O-demethylation by CYP2D6 and other CYPs (Meyer et al., 2008). In the case of O-demethylation of MDMA in the dioxolane moiety, it generated dihydroxyl-MDMA. In the present study, M3 was not thought to be a dihydroxylated metabolite as a result of the elemental composition analysis of the fragment ions and because CYP1A2 contributed the O-demethylation of hydrocoptisonine in HLMs instead of CYP2D6.
A highly potent and selective inhibitor Roxyl-WL targeting IDO1 promotes immune response against melanoma
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Guangwei Xu, Tianqi Wang, Yongtao Li, Zhi Huang, Xin Wang, Jianyu Zheng, Shengyong Yang, Yan Fan, Rong Xiang
As inherent limitations of each of screening techniques are not easily resolved, pharmacophore-based VS and docking-based VS combination in a hybrid protocol can help to mutually compensate for these limitations and capitalize on their mutual strengths25. In the pharmacophore-based VS approach, a pharmacophore hypothesis is taken as a template. Based on the crystal structure of IDO1/Amg-1 complex (PDB entry: 4PK5) as shown in Supplementary Figure S2, we found that the nitrogen of thiazolotriazole in Amg-1 was directly bound to the heme iron and that tolyl group located adjacent to Val130, Phe164, and Cys129. In addition, there is a hydrogen bond formed between the oxygen of dioxolane and Arg231. Therefore, we created a pharmacophore model manually which contained three features: hydrophobe, metal interaction point, and acceptor feature (Supplementary Figure S2). The 3 D database was built from the 15,000 top ranking compounds screened by molecular docking. Then pharmacophore-model-based VS was performed against the 15,000 compounds and 232 molecules match the condition.