Explore chapters and articles related to this topic
Recent Advancements of Curcumin Analogs and Curcumin Formulations in Context to Modern Pharmacotherapeutics Perspectives
Published in Debarshi Kar Mahapatra, Cristóbal Noé Aguilar, A. K. Haghi, Applied Pharmaceutical Practice and Nutraceuticals, 2021
Animeshchandra G. M. Haldar, Kanhaiya M. Dadure, Debarshi Kar Mahapatra
The antioxidant properties of the new seven synthesized compounds have been examined by Sokmen et al.45 through two assays, β-carotene/linoleic acid and DPPH. It was found that, in general, the free radical scavenging ability of compounds was concentration-dependent. Higher free radical scavenging values were showed by compounds that contained p-OH phenolic groups than BHT which resulted that synthetic analogs are more potent antioxidants than BHT. The inhibition of the generation of conjugated dienes confirmed its free radical scavenging activity of hydroxy phenolic compound by using β-carotene-linoleic acid assay.
Current Perspectives and Methods for the Characterization of Natural Medicines
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Muthusamy Ramesh, Arunachalam Muthuraman, Nallapilai Paramakrishnan, Balasubramanyam I. Vishwanathan
UV spectroscopy is another type of spectroscopy. The basic principles of UV spectroscopy are absorption of light and make the changes of the incident after passing to samples. It lies between the wavelength of 200–400 nm and visible spectroscopy lie at the wavelength of 400–800 nm. The instrument used for obtaining the spectrum is UV-Vis spectrophotometer. Ethyl alcohol and hexane are the solvents widely used to prepare the sample for UV-Vis spectroscopy. UV-Vis spectrum assists to characterize the aromatic group of compounds and conjugated dienes in qualitative analysis. In quantitative analysis, UV-Vis spectroscopy also helps to determine the molar concentration of constituents present in a given sample. In addition, it is also used to detect impurities, isomers, and molecular weight (Perkampus, 2013). UV-Vis spectroscopy was employed to characterize diarylheptanoids in association with other spectral techniques (Alberti et al., 2018). Diarylheptanoids have a specific absorption range, i.e., 250–290 nm. Acetonitrile was used as a solvent to get the UV-Vis spectrum. Further, a wider absorption band observed for curcumin, i.e., 410–430 nm. Keto-enol tautomerism of curcumin was characterized from the intra- and intermolecular hydrogen bonding. UV-Vis spectroscopy method is also used for the quantification of the curcuminoid content of Curcuma Longa extract (Alberti et al., 2018). The UV-Visible spectroscopy-based characterized phytoconstituents and marine compounds are listed in Table 2.2.
The Role of Neutrophils and Reactive Oxygen Metabolites in Reperfusion Injury
Published in John J. Lemasters, Constance Oliver, Cell Biology of Trauma, 2020
Barbara J. Zimmerman, D. Neil Granger
The ability of hydroxyl radicals to initiate lipid peroxidation can result in the formation of lipid-derived free radicals such as conjugated dienes, lipid hydroperoxide radicals, and lipid hydroperoxides. Schoenberg and co-workers10,11 measured mucosal levels of conjugated dienes in cat intestine subjected to ischemia/reperfusion. These studies indicated that tissue-conjugated diene levels are not affected by ischemia, but the levels are doubled 10 min after reperfusion. The reperfusion-induced increase in conjugated dienes was significantly attenuated in animals treated with SOD. Otamiri and Tagesson12,13 measured mucosal and plasma levels of malondialdehyde in rats following reperfusion of ischemic intestine. They demonstrated that malondialdehyde concentrations in both intestinal mucosa and plasma increased three- to fourfold 5 min following reperfusion. These observations, along with those described earlier, suggest that the hydroxyl radical mediates the lipid peroxidation associated with reperfusion of the small intestine.
Anti-COVID-19 and antidiabetic activities of new oleanane and ursane-type triterpenoids from Salvia grossheimii: an in-silico approach
Published in Journal of Receptors and Signal Transduction, 2022
Somayeh Zare, Somayeh Pirhadi, Hesham R. El Seedi, Amir Reza Jassbi
We have previously reported S. grossheimii to produce polyhydroxylated ursane and oleanane PTs with rare oxidation at C-1, C-11, and C-20 [7]. Unlike the previous report, none of the isolated compounds are C-1 oxidized, while 3, 6, and 7 are hydroxylated at C-11 and/or C-20. On the other hand, the occurrence of the rare conjugated homoannular diene system at C-9(11),12 positions in ursane and oleanane PTs among Salvia species, has been reported in S. kronenburgii [24], S. argentea [25], and S. mellifera [26]. The C-9(11),12-diene PTs derivatives in three mentioned sages were considered from dehydration reaction of the corresponding allylic C-11(α) alcohol or acetyl isomer [25,26]. The isolates 1, 2, 4, 5, and 7 were bearing uncommon 9(11),12 conjugated dienes which may undergo dehydration reaction from the respective derivatives. In this study, 7 was a reduction product formed by dehydration reaction of 6, which had been left in an NMR tube in spectroscopic CDCl3 at room temperature.
Does oxidative stress contribute to toxicity in acute organophosphorus poisoning? – a systematic review of the evidence
Published in Clinical Toxicology, 2020
Lekaashree Rambabu, Ian L. Megson, Michael Eddleston
Alternative markers of lipid peroxidation are 4-hydroxynonenal (measured by HPLC or more sensitively by gas chromatography mass spectrometry; GC-MS) [49] and F2-isoprostanes (measured in urine or plasma by ELISA or, preferably, by mass spectrometry [LC or GC-MS]) [38]. F2-isoprostanes and 4-hydroxynonenal are considered to be more specific indicators of lipid peroxidation than malondialdehyde because they are more stable molecules and the TBARs assay for malondialdehyde is influenced by its reaction with several other compounds found in plasma [37,38,49]. Malondialdehyde concentrations rise after acute and chronic inflammation, or after exposure to toxins, suggesting that it can be a good marker of toxicity or inflammation, but it lacks specificity for oxidative stress per se [51,52]. 4-hydroxynonenal is a product of lipid peroxidation that modifies protein. An increase in hydroxynonenal leads to an increase in hydroxynonenal-modified GAPDH which eventually undergoes ubiquitination. Conjugated dienes are chemical structures with two double bonds separated by a single bond. They are used as evidence for lipid peroxidation as they are not found in unsaturated fatty acids; rearrangement of the double bond to the conjugated diene formation is mediated by reaction with oxygen or ROS [53]. Dienes are usually measured spectrophotometrically by their absorbance at 234 nm. Although accepted as “evidence for lipid peroxidation”, dienes are not used for “absolute quantification” because a wide range of other compounds also absorbs at this wavelength [53].
Antifouling activity of portimine, select semisynthetic analogues, and other microalga-derived spirocyclic imines
Published in Biofouling, 2018
Darby G. Brooke, Gunnar Cervin, Olivier Champeau, D. Tim Harwood, Henrik Pavia, Andrew I. Selwood, Johan Svenson, Louis A. Tremblay, Patrick L. Cahill
The mixture of hydrogenated products (8–11) was also less potent than 1, with an ∼100-fold decrease in potency. This reduced potency suggests that the diene is also important for optimal binding of the cyclic imine pharmacophore of 1 to its subcellular target(s). Taken together, these data show that that the cyclic imine and diene moieties contribute to the single-digit ng ml−1 AF activity of 1. Acetylation of portimine was well tolerated, with the mixture of portimine monoacetates 6 and diacetate 7 being essentially equipotent with portimine. The negligible effect that acetylation has on AF activity suggests that the acyloin (α-hydroxy ketone) portion of 1 is non-essential to bioactivity, potentially allowing the construction of portimine–biological tag conjugates at this position for subcellular-localisation and/or targeting studies. Such attempts to fully characterise the bioactivity of 1 are steps towards developing a commercial AF biocide.