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13 pages, 295 KiB  
Article
On Subprojectivity of Goldie Torsion Modules
by Hashem Bordbar, Yılmaz Durğun, Yara Şihkayad and Ergül Türkmen
Axioms 2025, 14(7), 536; https://doi.org/10.3390/axioms14070536 - 16 Jul 2025
Viewed by 133
Abstract
Recently, the concept of subprojectivity domains for modules has been introduced as a means of quantifying the level of projectivity exhibited by a module. In this research article, we focus on the subprojectivity domain of Goldie torsion modules. In particular, we establish that [...] Read more.
Recently, the concept of subprojectivity domains for modules has been introduced as a means of quantifying the level of projectivity exhibited by a module. In this research article, we focus on the subprojectivity domain of Goldie torsion modules. In particular, we establish that a ring denoted as R is classified as right nonsingular if and only if the subprojectivity domain of each Goldie torsion module is closed under submodules. In addition, we demonstrate that a right C-ring is a right nonsingular ring if and only if every module possesses an epic ecf-flat envelope, which is further equivalent to each Goldie torsion module having an epic projective envelope. Full article
16 pages, 3385 KiB  
Article
Effects of C-Ring Structural Differences on the Inhibition of Nε-(Carboxyethyl)lysine in the Methylglyoxal-Lysine System by Flavonoids
by Yating Ling, Linlin Zhang, Bangzhu Peng and Zhuo Zhang
Int. J. Mol. Sci. 2025, 26(12), 5914; https://doi.org/10.3390/ijms26125914 - 19 Jun 2025
Viewed by 418
Abstract
This study investigated the effects of taxifolin (Tax), quercetin (Que), (+)-catechin (Cat) and luteolin (Lute) on the advanced Maillard reaction stage in the methylglyoxal-lysine (MGO-Lys) system. Since the four flavonoids share identical A- and B-ring structures, the inhibitory effects and molecular [...] Read more.
This study investigated the effects of taxifolin (Tax), quercetin (Que), (+)-catechin (Cat) and luteolin (Lute) on the advanced Maillard reaction stage in the methylglyoxal-lysine (MGO-Lys) system. Since the four flavonoids share identical A- and B-ring structures, the inhibitory effects and molecular mechanisms of flavonoids with different C-ring structures on Nε-(carboxyethyl)lysine (CEL) formation were revealed. The results demonstrated that Cat exhibited the best inhibitory effect on CEL with an inhibition rate of 53.78%, while Lute showed the lowest inhibition rate of 3.97%. The flavonoids (i.e., Tax, Que, Cat and Lute) inhibited the formation of non-fluorescent CEL, where hydroxylation at C3 on the C-ring favored the enhancement of the inhibitory effect of the flavonoids on CEL, while the C2-C3 double bond and the carbonyl group at the C4 position reduced their inhibitory ability. The alkaline environment favored the enhancement of the inhibition of CEL by Tax, Que, Cat and Lute. Notably, Tax, Que, Cat and Lute can inhibit CEL formation by competitively capturing MGO to form mono- or di-adducts and reducing lysine consumption. This study provides innovative strategies and a theoretical foundation for developing effective CEL inhibitors in food thermal processing. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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14 pages, 1716 KiB  
Article
Beyond Empirical Trends: Density Functional Theory-Based Nuclear Magnetic Resonance Analysis of Mono-Hydroxyflavone Derivatives
by Feng Wang and Vladislav Vasilyev
Appl. Sci. 2025, 15(11), 5928; https://doi.org/10.3390/app15115928 - 24 May 2025
Viewed by 456
Abstract
Flavone derivatives have emerged as promising antiviral agents, with baicalein demonstrating the potent inhibition of the SARS-CoV-2 main protease (Mpro). In this study, the unique electronic and structural properties of 3-hydroxyflavone (3-HF) were investigated using the density functional theory (B3PW91/cc-pVTZ), providing insights into [...] Read more.
Flavone derivatives have emerged as promising antiviral agents, with baicalein demonstrating the potent inhibition of the SARS-CoV-2 main protease (Mpro). In this study, the unique electronic and structural properties of 3-hydroxyflavone (3-HF) were investigated using the density functional theory (B3PW91/cc-pVTZ), providing insights into its potential as a bioactive scaffold. Among mono-hydroxyflavone (n-HF) isomers, 3-HF exhibits an extensive intramolecular hydrogen-bonding network linking the phenyl B-ring to the A- and γ-pyrone C-rings, enabled by the distinctive C3-OH substitution. Despite a slight non-planarity (dihedral angle: 15.4°), this hydrogen-bonding network enhances rigidity and influences the electronic environment. A 13C-NMR chemical shift analysis revealed pronounced quantum mechanical effects of the C3-OH group, diverging from the trends observed in other flavones. A natural bond orbital (NBO) analysis highlighted an unusual charge distribution, with predominantly positive charges on the γ-pyrone C-ring carbons, in contrast to the typical negative charges in flavones. These effects impact C1s orbital energies, suggesting that the electronic structure plays a more significant role in 13C-NMR shifts than simple ring assignments. Given the established antiviral activity of hydroxylated flavones, the distinct electronic properties of 3-HF may enhance its interaction with SARS-CoV-2 Mpro, making it a potential candidate for further investigation. This study underscores the importance of quantum mechanical methods in elucidating the structure–activity relationships of flavones and highlights 3-HF as a promising scaffold for future antiviral drug development. Full article
(This article belongs to the Section Chemical and Molecular Sciences)
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17 pages, 7001 KiB  
Article
Effect of Butein, a Plant Polyphenol, on Apoptosis and Necroptosis of Prostate Cancer Cells in 2D and 3D Cultures
by Yeji Lee, Changyeol Lee, Sang-Han Lee and Yoon-Jin Lee
Life 2025, 15(6), 836; https://doi.org/10.3390/life15060836 - 22 May 2025
Viewed by 593
Abstract
Butein (3,4,2′,4′-tetrahydroxycalone) is a chalcone derivative and plant polyphenol extracted from Rhus verniciflua Stokes. Butein has an open C-ring structure and a variety of biological activities. Molecular mechanisms by which butein could affect cell viability, ROS levels, mitochondrial function, apoptosis, and necrosis [...] Read more.
Butein (3,4,2′,4′-tetrahydroxycalone) is a chalcone derivative and plant polyphenol extracted from Rhus verniciflua Stokes. Butein has an open C-ring structure and a variety of biological activities. Molecular mechanisms by which butein could affect cell viability, ROS levels, mitochondrial function, apoptosis, and necrosis in prostate cancer cells were investigated using 2D monolayer and 3D sphere culture systems. Cytotoxicity and cell cycle monitoring showed that butein treatment decreased cell viability and increased peaks of sub-G0/G1 and G2/M phases analyzed by flow cytometry. These changes were observed with a concurrent induction of DNA damage, apoptosis, and necrosis. Although 3D spheres treated with butein showed decreased cell viability, they were slightly more resistant than cells in 2D cultures. This phenomenon was accompanied by an increase in mediators of apoptosis and necrosis. Monitoring changes of apoptosis-related proteins via Western blot showed that butein decreased caspase-3, PARP, and Bcl-2, but increased Bax. Meanwhile, butein increased levels of p-receptor interacting serine/threonine–protein kinase 3 (p-RIP3) and p-mixed lineage kinase domain-like kinase (p-MLKL) known to be mediators of necrosis. Overall, our data suggest that butein can induce apoptosis and necrosis of prostate cancer cells by regulating pro- and anti-apoptotic proteins via ROS. Thus, butein might be a potential agent for treating prostate cancer. Full article
(This article belongs to the Special Issue Advances in the Biomedical Applications of Plants and Plant Extracts)
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16 pages, 2719 KiB  
Article
Methoxylated Chrysin and Quercetin as Potent Stimulators of Melanogenesis
by Pattara Poungcho, Rita Hairani, Chatchai Chaotham, Wanchai De-Eknamkul and Warinthorn Chavasiri
Int. J. Mol. Sci. 2025, 26(7), 3281; https://doi.org/10.3390/ijms26073281 - 1 Apr 2025
Cited by 1 | Viewed by 626
Abstract
Polymethoxyflavonoids (PMFs) from plants are known to exhibit melanogenic activity. Very little is known about their structure-activity relationships, and this was the aim of this study. Several series of alkoxy flavonoids were synthesized via semisynthetic and total synthetic pathways. Their structures were identified [...] Read more.
Polymethoxyflavonoids (PMFs) from plants are known to exhibit melanogenic activity. Very little is known about their structure-activity relationships, and this was the aim of this study. Several series of alkoxy flavonoids were synthesized via semisynthetic and total synthetic pathways. Their structures were identified by NMR analyses, followed by evaluating their potency on the stimulation of melanogenesis using mouse B16F10 and human MNT-1 cells. Among more than twenty methoxylated flavonoids, 5,7-dimethoxychrysin (dimethoxylated chrysin, F1) and 3,3′,4′,5,7-pentamethoxyquercetin (pentamethoxylated quercetin, F21) appeared to be the most active melanogenic-stimulating compounds in a dose-dependent manner. Both compounds showed no effect on cell viability as determined by MTT assay. The structure-activity relationship study of PMFs revealed that the -OCH3 substituent at 5 and 7 positions of A-ring are the most important as melanogenic-stimulating part (e.g., 5,7-dimethoxychrysin, F1) followed by at 3′ and 4′ positions of B-ring, and at 3 positions of C-ring (e.g., 3,3′,4′,5,7-pentamethoxyquercetin, F21), Therefore, both natural methoxylated flavonoid derivatives of chrysin and quercetin have a potential to be developed further as melanogenic stimulators. Full article
(This article belongs to the Special Issue Research Progress of Metabolomics in Health and Disease)
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24 pages, 3005 KiB  
Article
A Chalcone Synthase-like Bacterial Protein Catalyzes Heterocyclic C-Ring Cleavage of Naringenin to Alter Bioactivity Against Nuclear Receptors in Colonic Epithelial Cells
by Ebru Ece Gülşan, Farrhin Nowshad, Meredith Davis Leigh, Jimmy Walter Crott, Hyejin Park, Greg Martin, Stephen Safe, Robert S. Chapkin, Arul Jayaraman and Kyongbum Lee
Metabolites 2025, 15(3), 146; https://doi.org/10.3390/metabo15030146 - 21 Feb 2025
Viewed by 872
Abstract
Gut microbial metabolism of dietary flavonoids leads to a diverse array of bioactive products that are closely associated with human health. Combining enzyme promiscuity prediction, metabolomics, and in vitro model systems, we identified a chalcone-synthase-like bacterial polyketide synthase that can initiate the metabolism [...] Read more.
Gut microbial metabolism of dietary flavonoids leads to a diverse array of bioactive products that are closely associated with human health. Combining enzyme promiscuity prediction, metabolomics, and in vitro model systems, we identified a chalcone-synthase-like bacterial polyketide synthase that can initiate the metabolism of naringenin by catalyzing the C-ring cleavage. This was validated using a mutant strain of the model organism Bacillus subtilis (ATCC 23857). Our prediction–validation methodology could be used to systematically characterize the products of gut bacterial flavonoid metabolism and identify the responsible enzymes and species. In vitro experiments with Caco-2 cells revealed that naringenin and its bacterial metabolites differentially engage the aryl hydrocarbon receptor (AhR) and orphan nuclear receptor 4A (NR4A). These results suggest that metabolism by gut bacterial species could directly impact the profile of bioactive flavonoids and influence inflammatory responses in the intestine. These results are significant for understanding gut-microbiota-dependent physiological effects of dietary flavonoids. Full article
(This article belongs to the Section Cell Metabolism)
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20 pages, 3593 KiB  
Article
Synthesis and Evaluation of Colchicine C-Cyclic AmineDerivatives as Potent Anti-Biofilms Agents AgainstMethicillin-Resistant Staphylococcus aureus
by Yuxin Yang, Xin Liu, Can Sun, Yuan Fang, Danyang Qu, Zhengbin Tang, Zetao Sun, Xiaoping Zhou and Dacheng Wang
Antibiotics 2025, 14(2), 173; https://doi.org/10.3390/antibiotics14020173 - 10 Feb 2025
Viewed by 912
Abstract
Background/Objectives: The elimination of bacterial biofilm formation is an effective strategy against bacterial infections. The objective was to design 27 colchicine C-ring modified amine derivatives and evaluate their inhibitory activities against the biofilms of MRSA USA300. Methods: Design 27 colchicine C-ring modified amine [...] Read more.
Background/Objectives: The elimination of bacterial biofilm formation is an effective strategy against bacterial infections. The objective was to design 27 colchicine C-ring modified amine derivatives and evaluate their inhibitory activities against the biofilms of MRSA USA300. Methods: Design 27 colchicine C-ring modified amine derivatives. Evaluate their inhibitory activities against MRSA USA300 biofilms. Conduct antibacterial or synergistic antibacterial experiments. Research the phenotypic mechanisms related to biofilm-related genes icaA and agrA. Results: The experiments showed that most compounds in this series exhibited varying degrees of biofilm inhibitory activity (with inhibition rates ranging from 7.72% to 40.79%). Further verification through antibacterial or synergistic antibacterial experiments revealed that the compounds with biofilm-inhibiting effects (compounds 7b–11b) generally had certain antibacterial activities (MICs = 16–32 μg/mL) or synergistic antibacterial effects (FICIs < 0.5). Furthermore, through in-depth research on their phenotypic mechanisms (i.e., research on biofilm-related mechanisms), it was found that the compounds with antibacterial or synergistic antibacterial properties could inhibit the formation of biofilms by affecting the regulation of the biofilm-related genes icaA and agrA. Conclusions: The designed colchicine C-ring modified amine derivatives showed potential in inhibiting MRSA biofilms, and their antibacterial or synergistic antibacterial properties are related to the regulation of biofilm-related genes icaA and agrA, demonstrating inhibitory activity against MRSA. Full article
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33 pages, 18701 KiB  
Article
Flavonoids as Potential Modulators of Pancreatic Lipase Catalytic Activity
by Sílvia Rocha, Carina Proença, Alberto N. Araújo, Marisa Freitas, Ismael Rufino, Natália Aniceto, Artur M. S. Silva, Félix Carvalho, Rita C. Guedes and Eduarda Fernandes
Pharmaceutics 2025, 17(2), 163; https://doi.org/10.3390/pharmaceutics17020163 - 25 Jan 2025
Viewed by 1249
Abstract
Background/Objectives: Obesity has reached pandemic proportions, with predictions suggesting that, by 2030, over 1.5 billion people will be affected. Pancreatic lipase (PL), the enzyme primarily responsible for the absorption of dietary lipids, presents a potential target for obesity management. However, while porcine [...] Read more.
Background/Objectives: Obesity has reached pandemic proportions, with predictions suggesting that, by 2030, over 1.5 billion people will be affected. Pancreatic lipase (PL), the enzyme primarily responsible for the absorption of dietary lipids, presents a potential target for obesity management. However, while porcine pancreatic lipase (PPL) is commonly used as the enzyme source for screening potential inhibitors, its effect on human pancreatic lipase (HPL) is rarely reported. This work aimed to screen the inhibitory effects of a library of flavonoids with different functional groups on the activity of PL from the human pancreas (triacylglycerol acyl hydrolase, EC 3.1.1.3) and compare it to the effects of the porcine pancreas (type II, EC 3.1.1.3), establishing, whenever possible, a structure–activity relationship. Methods: The inhibitory effects of a library of 48 flavonoids with different hydroxy, glycosyl, rutinosyl, galloyl, and extended alkyl groups were evaluated against PPL and HPL. The kinetic parameters and inhibitory mechanisms of the most active flavonoids were determined, and in silico docking studies of the more potent flavonoids were also performed, using the active site of HPL. Results/Conclusions: Variations in enzyme catalytic activity were observed depending on the source of the enzyme. The inhibitory effect was particularly influenced by the presence of extended alkyl groups at the C-3 of the C-ring and the C2=C3 double bond of the C-ring and the presence of a pyrogallol group at the C-2′, C-3′ and C-4′ of the B-ring. Docking results showed a strong correlation between docking scores and observed inhibitory activities, highlighting the critical role of specific substituents on the flavonoid backbone in enhancing detailed interaction dynamics with key amino acids. Compounds 28, 29, and 30, with alkyl groups, showed the highest docking scores, interacting with residues HIS151, PHE215, ARG256, and HIS263. Further analysis also revealed that specific substituents improved pocket occupancy and formed additional interactions with residues TYR114, PRO180, ILE209, and PHE215, which are crucial for inhibition. These binding characteristics closely mimic those observed with orlistat, reinforcing their mechanistic similarities in inhibiting HPL and validating their inhibitory activities. Full article
(This article belongs to the Section Drug Targeting and Design)
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18 pages, 4028 KiB  
Article
Exploration of the Fusidic Acid Structure Activity Space for Antibiotic Activity
by Yoon-Suk Kang, Simone C. Silva, Kenneth Smith, Krissty Sumida, Yuhan Wang, Lucius Chiaraviglio, Ramachandra Reddy Donthiri, Alhanouf Z. Aljahdali, James E. Kirby and George A. O’Doherty
Molecules 2025, 30(3), 465; https://doi.org/10.3390/molecules30030465 - 21 Jan 2025
Viewed by 1260
Abstract
Fusidic acid is a translation inhibitor with activity against major Gram-positive bacterial pathogens such as S. aureus. However, its activity against Gram-negatives is poor based on an inability to access its cytoplasmic target in these organisms. Opportunities for functionalization of the fusidic [...] Read more.
Fusidic acid is a translation inhibitor with activity against major Gram-positive bacterial pathogens such as S. aureus. However, its activity against Gram-negatives is poor based on an inability to access its cytoplasmic target in these organisms. Opportunities for functionalization of the fusidic acid scaffold to enhance activity against Gram-negative pathogens have not been explored. Using an activity-guided synthetic strategy, the tolerance of the tetracyclic natural product to derivatization at the A- and C-rings and its carboxylic acid side chain was explored with the goal of enhancing its activity spectrum and pharmacological properties. All side-chain carboxylic acid esters were inactive. Oxidation of the C-ring alcohol and oxime were not tolerated either. A number of esters of the A-ring alcohol retained modest activity against Gram-positive bacteria and were informative for future activity-guided studies. For the A-ring esters, differences in antibacterial activity relative to inhibitory activity in a ribosome in vitro translation assay suggested the possibility of a pro-druglike effect for the fusidic acid pyrazine-2-carboxylate. This study furthers the understanding of the activity of the fusidic acid scaffold against Gram-positive bacteria. These results suggest promise for future modification of the A-ring alcohol of fusidic acid in the advancement of its antibiotic properties. Full article
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26 pages, 8350 KiB  
Review
Naturally Occurring Xanthones and Their Biological Implications
by Ayodeji O. Oriola and Pallab Kar
Molecules 2024, 29(17), 4241; https://doi.org/10.3390/molecules29174241 - 6 Sep 2024
Cited by 14 | Viewed by 4499
Abstract
Xanthones are chemical substances in higher plants, marine organisms, and lower microorganisms. The most prevalent naturally occurring sources of xanthones are those belonging to the families Caryophyllaceae, Guttiferae, and Gentianaceae. Structurally, xanthones (9H xanthan-9-one) are heterocyclic compounds with oxygen and a γ-pyrone component. [...] Read more.
Xanthones are chemical substances in higher plants, marine organisms, and lower microorganisms. The most prevalent naturally occurring sources of xanthones are those belonging to the families Caryophyllaceae, Guttiferae, and Gentianaceae. Structurally, xanthones (9H xanthan-9-one) are heterocyclic compounds with oxygen and a γ-pyrone component. They are densely packed with a two-benzene ring structure. The carbons in xanthones are numbered from their nucleus and biosynthetic construct. They have mixed shikimate-acetate (higher plants) and acetate-malonate (lower organisms) biosynthetic origins, which influence their classification. Based on the level of oxidation of the C-ring, they are classified into monomers, dimers, and heterodimers. While based on the level of oxygenation or the type of ring residue, they can be categorized into mono-, di-, tri-, tetra-, penta- and hexa-oxygenated xanthones, bis-xanthones, prenylated and related xanthones, xanthonolignoids, and other miscellaneous xanthones. This structural diversity has made xanthones exhibit considerable biological properties as promising antioxidant, antifungal, antimicrobial, and anticancer agents. Structure-activity relationship studies suggest C-1, C-3, C-6, and C-8 as the key positions that influence the biological activity of xanthones. Furthermore, the presence of functional groups, such as prenyl, hydroxyl, glycosyl, furan, and pyran, at the key positions of xanthones, may contribute to their spectrum of biological activity. The unique chemical scaffolds of xanthones, their notable biological activities, and the structure–activity relationships of some lead molecules were discussed to identify lead molecules as possible drug candidates. Full article
(This article belongs to the Special Issue Plant Bioactive Compounds in Pharmaceuticals)
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21 pages, 406 KiB  
Article
Language Attitudes in Australia: Results from a Nationwide Survey
by Chloé Diskin-Holdaway and Paola Escudero
Languages 2024, 9(6), 200; https://doi.org/10.3390/languages9060200 - 31 May 2024
Cited by 1 | Viewed by 6531
Abstract
Recent research on attitudes to Australian English (AusE) shows that there is a general increase in its acceptance, legitimacy, and endonormativity. However, a certain “cultural cringe” exists, particularly when “broad” AusE is seen as representative of the variety. A significant gap in the [...] Read more.
Recent research on attitudes to Australian English (AusE) shows that there is a general increase in its acceptance, legitimacy, and endonormativity. However, a certain “cultural cringe” exists, particularly when “broad” AusE is seen as representative of the variety. A significant gap in the literature is how the perceptions and usage of AusE may change as the population becomes more diverse. This paper presents findings of an online survey of language attitudes towards AusE with 661 respondents across Australia, over a third of whom were born overseas. Overall, there is minimal evidence of a standard language ideology, with 80% of respondents reporting having an accent to some degree. Almost half of respondents report occasionally or frequently changing their accents due to context, interlocutor, or making themselves understood. When asked to rate AusE along six traits on a seven-point scale, the traits of educatedness, professionalism, and attractiveness were consistently centered on neutral. For friendliness and likeability, the majority skewed towards neutral and positive. For the trait of clarity, there was a greater range of responses, but overall, 50% of respondents found AusE to be somewhat, moderately, or really clear. These findings further our understanding of attitudes and ideologies in Australia’s increasingly diverse language ecology. Full article
(This article belongs to the Special Issue Advances in Australian English)
18 pages, 3204 KiB  
Review
Progress on the Synthesis of the Aromathecin Family of Compounds: An Overview
by Takashi Nishiyama, Shota Mizuno, Yuhzo Hieda and Tominari Choshi
Molecules 2024, 29(10), 2380; https://doi.org/10.3390/molecules29102380 - 18 May 2024
Cited by 1 | Viewed by 1286
Abstract
We present a systematic review of the methods developed for the synthesis of the aromathecin family of compounds (benz[6,7]indolizino[1,2-b]quinolin-11(13H)-ones) and their derivatives. These methods can be broadly classified into four categories based on the construction of pentacyclic structures: Category [...] Read more.
We present a systematic review of the methods developed for the synthesis of the aromathecin family of compounds (benz[6,7]indolizino[1,2-b]quinolin-11(13H)-ones) and their derivatives. These methods can be broadly classified into four categories based on the construction of pentacyclic structures: Category 1: by constructing a pyridone moiety (D-ring) on the pyrroloquinoline ring (A/B/C-ring), Category 2: by constructing a pyridine moiety (B-ring) on the pyrroloisoquinolone ring (C/D/E-ring), Category 3: by constructing an indolizidinone moiety (C/D-ring) in a tandem reaction, and Category 4: by constructing a pyrrolidine moiety (C-ring) on the isoquinolone ring (D/E-ring). Full article
(This article belongs to the Special Issue Recent Advances in the Organic Synthesis of Bioactive Compounds)
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11 pages, 3633 KiB  
Article
Relationship between Flavonoid Chemical Structures and Their Antioxidant Capacity in Preventing Polycyclic Aromatic Hydrocarbons Formation in Heated Meat Model System
by Thi Thu Huong Huynh, Wanwisa Wongmaneepratip and Kanithaporn Vangnai
Foods 2024, 13(7), 1002; https://doi.org/10.3390/foods13071002 - 25 Mar 2024
Cited by 9 | Viewed by 1819
Abstract
The relationship between the chemical structures of six flavonoids and their abilities to inhibit the formation of polycyclic aromatic hydrocarbons (PAHs) in a heated meat model system was investigated. The PAH8 forming in samples was analyzed by using QuEChERS coupled GC-MS. Inhibitory effects [...] Read more.
The relationship between the chemical structures of six flavonoids and their abilities to inhibit the formation of polycyclic aromatic hydrocarbons (PAHs) in a heated meat model system was investigated. The PAH8 forming in samples was analyzed by using QuEChERS coupled GC-MS. Inhibitory effects of PAHs were myricetin (72.1%) > morin (55.7%) > quercetin (57.3%) > kaempferol (49.9%) > rutin (32.7%) > taxifolin (30.2%). The antioxidant activities of these flavonoids, assessed through (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging activity assay (DPPH), [2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid)] free radical scavenging activity assay (ABTS) and ferric ion reducing antioxidant power assay (FRAP) assays, exhibited a significant negative correlation with PAH reduction. Notably, myricetin that contained three hydroxyl groups on the B-ring, along with a 2,3-double bond in conjugation with a 4-keto moiety on the C-ring, demonstrated strong antioxidant properties and free radical scavenging abilities, which significantly contributed to their ability to inhibit PAH formation. However, rutin and taxifolin, substituted at the C-3 position of the C-ring, decreased the PAH inhibitory activity. The ABTS assay proved the most effective in demonstrating the correlation between flavonoid antioxidant properties and their capacity to inhibit PAH formation in heated meat model systems. Thus, the inhibition of PAHs can be achieved by dietary flavonoids according to their chemical structures. Full article
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9 pages, 2885 KiB  
Article
The CYP80A and CYP80G Are Involved in the Biosynthesis of Benzylisoquinoline Alkaloids in the Sacred Lotus (Nelumbo nucifera)
by Chenyang Hao, Yuetong Yu, Yan Liu, An Liu and Sha Chen
Int. J. Mol. Sci. 2024, 25(2), 702; https://doi.org/10.3390/ijms25020702 - 5 Jan 2024
Cited by 4 | Viewed by 1942
Abstract
Bisbenzylisoquinoline and aporphine alkaloids are the two main pharmacological compounds in the ancient sacred lotus (Nelumbo nucifera). The biosynthesis of bisbenzylisoquinoline and aporphine alkaloids has attracted extensive attention because bisbenzylisoquinoline alkaloids have been reported as potential therapeutic agents for COVID-19. Our [...] Read more.
Bisbenzylisoquinoline and aporphine alkaloids are the two main pharmacological compounds in the ancient sacred lotus (Nelumbo nucifera). The biosynthesis of bisbenzylisoquinoline and aporphine alkaloids has attracted extensive attention because bisbenzylisoquinoline alkaloids have been reported as potential therapeutic agents for COVID-19. Our study showed that NnCYP80A can catalyze C-O coupling in both (R)-N-methylcoclaurine and (S)-N-methylcoclaurine to produce bisbenzylisoquinoline alkaloids with three different linkages. In addition, NnCYP80G catalyzed C-C coupling in aporphine alkaloids with extensive substrate selectivity, specifically using (R)-N-methylcoclaurine, (S)-N-methylcoclaurine, coclaurine and reticuline as substrates, but the synthesis of C-ring alkaloids without hydroxyl groups in the lotus remains to be elucidated. The key residues of NnCYP80G were also studied using the 3D structure of the protein predicted using Alphafold 2, and six key amino acids (G39, G69, A211, P288, R425 and C427) were identified. The R425A mutation significantly decreased the catalysis of (R)-N-methylcoclaurine and coclaurine inactivation, which might play important role in the biosynthesis of alkaloids with new configurations. Full article
(This article belongs to the Section Molecular Biophysics)
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19 pages, 6067 KiB  
Article
Identification of a β-Carboline Alkaloid from Chemoselectively Derived Vanilla Bean Extract and Its Prevention of Lipid Droplet Accumulation in Human Hepatocytes (HepG2)
by Dya Fita Dibwe, Nire Takeishi, Saki Oba, Akiko Sakurai, Toshihiro Sakurai, Takayuki Tsukui, Hitoshi Chiba and Shu-Ping Hui
Molecules 2023, 28(24), 8024; https://doi.org/10.3390/molecules28248024 - 9 Dec 2023
Cited by 6 | Viewed by 1996
Abstract
Targeting bioactive compounds to prevent lipid droplet accumulation in the liver, we explored an antioxidative extract from vanilla bean (Vainilla planifolia) after chemo-selective derivatization through heating and acid modification. The chemical analysis of vanilla bean extract through chemoselective derivatization resulted in [...] Read more.
Targeting bioactive compounds to prevent lipid droplet accumulation in the liver, we explored an antioxidative extract from vanilla bean (Vainilla planifolia) after chemo-selective derivatization through heating and acid modification. The chemical analysis of vanilla bean extract through chemoselective derivatization resulted in the identification of sixteen compounds (3450) using LC-MS/MS analysis. A β-carboline alkaloid with a piperidine C-ring and a vanillin moiety at C-1 (34) was identified by molecular networking and diagnostic fragmentation filtering approaches. β-carboline alkaloid 34 exhibited significant inhibitory activity of lipid droplet accumulation (LDAI) in oleic acid-loaded hepatocellular carcinoma HepG2 cells. The LDAI activity was associated with both activation of lipolysis and suppression of lipogenesis in the cells. The study indicates that crude plant extracts, following chemoselective derivatization, may contain bioactive compounds that could be beneficial in preventing hepatosteatosis and could serve as a source of lead compounds for drug development. This approach may be useful to investigate other mixtures of natural products and food resources. Full article
(This article belongs to the Special Issue Recent Advances in Alkaloids and Their Derivatives)
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