- The comparison of neuroprotective effects of isoliquiritigenin and its Phase I metabolites against glutamate-induced HT22 cell death
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It is becoming increasingly important to investigate drug metabolites to evaluate their toxic or preventive effects after administration of the parent compound. In our previous study, isoliquiritigenin isolated from Glycyrrhizae Radix effectively protected mouse-derived hippocampal neuronal cells (HT22) against 5 mM glutamate-induced oxidative stress. However, there is little information on the protective effects of the metabolites of isoliquiritigenin on HT22 cells. In this study, isoliquiritigenin and its Phase I metabolites were prepared and their neuroprotective activities on glutamate-treated HT22 cells were compared. The prepared metabolites were liquiritigenin (1), 2′,4,4′,5′-tetrahydroxychalcone (2), sulfuretin (3), butein (4), davidigenin (5), and cis-6,4′-dihydroxyaurone (6). Among the six metabolites, 4 showed better neuroprotective effects than the parent compound, isoliquiritigenin. Our study suggests that the neuroprotective effect of isoliquiritigenin could be elevated by its active metabolite 4, which is a chalcone containing a catechol group in the B ring.
- Yang, Eun-Ju,Kim, Minjun,Woo, Ji Eun,Lee, Taeho,Jung, Jong-Wha,Song, Kyung-Sik
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- Discovery of benzofuran-3(2H)-one derivatives as novel DRAK2 inhibitors that protect islet β-cells from apoptosis
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Death-associated protein kinase-related apoptosis-inducing kinase-2 (DRAK2) is a serine/threonine kinase that plays a key role in a wide variety of cell death signaling pathways. Inhibition of DRAK2 was found to efficiently protect islet β-cells from apoptosis and hence DRAK2 inhibitors represent a promising therapeutic strategy for the treatment of diabetes. Only very few chemical entities targeting DRAK2 are currently known. We carried out a high throughput screening and identified compound 4 as a moderate DRAK2 inhibitor with an IC50value of 3.15?μM. Subsequent SAR studies of hit compound 4 led to the development of novel benzofuran-3(2H)-one series of DRAK2 inhibitors with improved potency and favorable selectivity profiles against 26 selected kinases. Importantly, most potent compounds 40 (IC50?=?0.33?μM) and 41 (IC50?=?0.25?μM) were found to protect islet β-cells from apoptosis in dose-dependent manners. These data support the notion that small molecule inhibitors of DRAK2 represents a promising strategy for the treatment of diabetes.
- Wang, Sheng,Xu, Lei,Lu, Yu-Ting,Liu, Yu-Fei,Han, Bing,Liu, Ting,Tang, Jie,Li, Jia,Wu, Jiangping,Li, Jing-Ya,Yu, Li-Fang,Yang, Fan
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- Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases
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Tyrosinases and catechol oxidases belong to the family of polyphenol oxidases (PPOs). Tyrosinases catalyze the o-hydroxylation and oxidation of phenolic compounds, whereas catechol oxidases were so far defined to lack the hydroxylation activity and catalyze solely the oxidation of o-diphenolic compounds. Aurone synthase from Coreopsis grandiflora (AUS1) is a specialized plant PPO involved in the anabolic pathway of aurones. We present, to our knowledge, the first crystal structures of a latent plant PPO, its mature active and inactive form, caused by a sulfation of a copper binding histidine. Analysis of the latent proenzyme's interface between the shielding C-terminal domain and the main core provides insights into its activation mechanisms. As AUS1 did not accept common tyrosinase substrates (tyrosine and tyramine), the enzyme is classified as a catechol oxidase. However, AUS1 showed hydroxylase activity toward its natural substrate (isoliquiritigenin), revealing that the hydroxylase activity is not correlated with the acceptance of common tyrosinase substrates. Therefore, we propose that the hydroxylase reaction is a general functionality of PPOs. Molecular dynamics simulations of docked substrate-enzyme complexes were performed, and a key residue was identified that influences the plant PPO's acceptance or rejection of tyramine. Based on the evidenced hydroxylase activity and the interactions of specific residues with the substrates during the molecular dynamics simulations, a novel catalytic reaction mechanism for plant PPOs is proposed. The presented results strongly suggest that the physiological role of plant catechol oxidases were previously underestimated, as they might hydroxylate their - so far unknown - natural substrates in vivo.
- Molitor, Christian,Mauracher, Stephan Gerhard,Rompel, Annette
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- Exploring the 2′-hydroxy-chalcone framework for the development of dual antioxidant and soybean lipoxygenase inhibitory agents
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2′-hydroxy-chalcones are naturally occurring compounds with a wide array of bioactiv-ity. In an effort to delineate the structural features that favor antioxidant and lipoxygenase (LOX) inhibitory activity, the design, synthesis, and bioactivity profile of a series of 2′-hydroxy-chalcones bearing diverse substituents on rings A and B, are presented. Among all the synthesized derivatives, chalcone 4b, bearing two hydroxyl substituents on ring B, was found to possess the best combined activity (82.4% DPPH radical scavenging ability, 82.3% inhibition of lipid peroxidation, and satisfac-tory LOX inhibition value (IC50 = 70 μM). Chalcone 3c, possessing a methoxymethylene substituent on ring A, and three methoxy groups on ring B, exhibited the most promising LOX inhibitory activity (IC50 = 45 μM). A combination of in silico techniques were utilized in an effort to explore the crucial binding characteristics of the most active compound 3c and its analogue 3b, to LOX. A common H-bond interaction pattern, orienting the hydroxyl and carbonyl groups of the aromatic ring A towards Asp768 and Asn128, respectively, was observed. Regarding the analogue 3c, the bulky (-OMOM) group does not seem to participate in a direct binding, but it induces an orientation capable to form H-bonds between the methoxy groups of the aromatic ring B with Trp130 and Gly247.
- Detsi, Anastasia,Hadjipavlou-Litina, Dimitra,Karadendrou, Maria-Anna,Kostopoulou, Ioanna,Kritsi, Eftichia,Liargkova, Thalia,Polyzos, Nestor-Ioannis,Pontiki, Eleni,Tzani, Andromachi,Zoumpoulakis, Panagiotis
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- Biflavonoids from flowers of Butea monosperma (Lam.) Taub.
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A new aurone glucoside (1) and three new biflavonoids (12 - 14), together with fourteen known compounds, were isolated from the flowers of Butea monosperma (Lam.) Taub. The structures of the new compounds were established by 1D, 2D NMR, MS and CD analyses. The isolated compounds were evaluated for their influenza A neuraminidase inhibitory activity and DPPH free-radical scavenging activity.
- Ahmed, Fakhruddin Ali,Kim, Sang-Yong,Kurimoto, Shin-Ichiro,Sasaki, Hisako,Shibata, Hirofumi,Kashiwada, Yoshiki,Takaishi, Yoshihisa
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- Fabrication, characterisation and in vitro biological activities of a sulfuretin-supplemented nanofibrous composite scaffold for tissue engineering
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Electrospun micro/nanofibrous scaffolds are widely used in various tissue regeneration applications because they have a similar structure to the extracellular matrix and can induce high attachment, proliferation and even differentiation of cultured cells. Here, we designed a new composite scaffold consisting of poly(ε-caprolactone) (PCL), bone morphogenetic protein (BMP-2) and sulfuretin fabricated using a combined process, i.e. electrospinning/plasma-treatment/coating. In the composite, we introduced a new bioactive component, sulfuretin, which was used as a cell stimulant to regenerate bone tissue. Sulfuretin release from the composite was controlled by coating of a fixed concentration of alginate. The in vitro biocompatibilities of the fibrous composites were examined using preosteoblasts (MC3T3-E1s), and the composite showed high cell adhesion and differentiation for a limited range of sulfuretin compared to the control, which lacked sulfuretin. These results suggest sulfuretin to be an effective supplemental bioactive agent for enhancing bone tissue growth on fibrous composite scaffolds.
- Koo, Youngwon,Lee, Hyeongjin,Kim, Suji,Song, No-Joon,Ku, Jin-Mo,Lee, Jaehwan,Choi, Chang Hyun,Park, Kye Won,Kim, Geunhyung
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- Design, synthesis and biological activities of dihydroaurones
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To widen aurones applicability in achromatic food and cosmetic applications, a series of dihydroaurones were designed to mimic natural aurones as well as synthetic aurones. Dihydroaurones have been synthesized from the corresponding aurones by hydrogenation. These dihydroaurones and their corresponding aurones were screened for antioxidant, anti-inflammatory and tyrosinase enzyme inhibitory activity. Synthesized dihydroaurones (3b-f) displayed superior antioxidant activity in superoxide free radical scavenging assay than the standard gallic acid. Dihydroaurones (3b-f) also exhibited significant tyrosinase enzyme inhibitory activity and two dihydroaurones (3h, 3j) showed promising 5-lipoxygenase inhibitory activity.
- VENKATESWARLU, SOMEPALLI,MURTY, GANDROTU NARASIMHA,SATYANARAYANA, MEKA,SIDDAIAH, VIDAVALUR
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p. 1396 - 1402
(2021/06/09)
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- Hydroxyaurone derivative as well as preparation method and application thereof
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The invention relates to a hydroxyaurone derivative as well as a preparation method and application thereof. A monomeric compound aurone separated from Kunlun chrysanthemum in Xinjiang is used as a mother nucleus compound, hydroxyl is introduced into auro
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Paragraph 0138-0139; 0143-0144
(2021/07/14)
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- Flavone inspired discovery of benzylidenebenzofuran-3(2H)-ones (aurones) as potent inhibitors of human protein kinase CK2
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In this work, we describe the design, synthesis and SAR studies of 2-benzylidenebenzofuran-3-ones (aurones), a new family of potent inhibitors of CK2. A series of aurones have been synthesized. These compounds are structurally related to the synthetic flavones and showed nanomolar activities towards CK2. Biochemical tests revealed that 20 newly synthesized compounds inhibited CK2 with IC50 values in the nanomolar range. Further property-based optimization of aurones was performed, yielding a series of CK2 inhibitors with enhanced lipophilic efficiency. The most potent compound 12m (BFO13) has CLipE = 4.94 (CLogP = 3.5; IC50 = 3.6 nM) commensurable with the best known inhibitors of CK2.
- Bdzhola, V. G.,Bilokin, Y. V.,Borysenko, I. P.,Lukashov, S. S.,Protopopov, M. V.,Prykhod'ko, A. O.,Starosyla, S. A.,Vdovin, V. S.,Yarmoluk, S. M.
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supporting information
(2020/07/21)
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- Aurones as new porcine pancreatic α-amylase inhibitors
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Background: Aurones, (Z)-2-benzylidenebenzofuran-3-one derivatives, are naturally-occurring structural isomers of flavones, with promising pharmacological potential. Methods: In this study, the structural requirements for the inhibition of porcine pancreatic α-amylase by hydroxylated or methoxylated aurone derivatives were investigated by assessing their in vitro biological activities against porcine pancreatic α-amylase. Results: The structure-activity relationship of these inhibitors based on both in vitro and in silico findings showed that the hydrogen bonds between the OH groups of the A or B ring of (Z)-benzylidenebenzofuran-3-one derivatives and the catalytic residues of the binding site are crucial for their inhibitory activities. Conclusion: It seems that the OH groups in aurones inhibit α-amylase in a manner similar to that of OH groups in flavones and flavonols.
- Roshanzamir, Khashayar,Kashani-Amin, Elaheh,Ebrahim-Habibi, Azadeh,Navidpour, Latifeh
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p. 333 - 340
(2019/06/20)
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- "On water" synthesis of aurones: First synthesis of 4,5,3',4',5'-pentamethoxy-6-hydroxyaurone from Smilax riparia
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A simple and green method for the synthesis of aurones by condensation of benzofuranone with aromatic aldehyde in neat water has been developed. The main advantages of this protocol include good yields, absence of catalyst, reagent, organic solvent, work-up and chromatographic purification. 4,5,3',4',5'-Pentamethoxy-6-hydroxyaurone, isolated from Smilax riparia was synthesized for the first time from 3-benzyloxy-4,5-dimethoxybenzaldehyde in five steps. {figure presented}.
- Venkateswarlu, Somepalli,Murty, Gandrotu Narasimha,Satyanarayana, Meka
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p. 303 - 314
(2017/06/19)
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- Synthesis of 6-hydroxyaurone analogues and evaluation of their α-glucosidase inhibitory and glucose consumption-promoting activity: Development of highly active 5,6-disubstituted derivatives
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A series of 6-hydroxyaurones and their analogues have been synthesized and evaluated for their in vitro α-glucosidase inhibitory and glucose consumption-promoting activity. These compounds exhibited varying degrees of α-glucosidase inhibitory activity, 11 of them showing higher potency than that of the control standard acarbose (IC50?=?50.30?μM). Surprisingly, analogues devoid of a substituent at C-2 but having an aryl group at C-5 were found to be highly active (e.g., 7f, IC50?=?9.88?μM). Docking analysis substantiated these findings. The kinetic analysis of compound 7f, the most potent α-glucosidase inhibitor of this study, revealed that it inhibited α-glucosidase in an irreversible and mixed competitive mode. In addition, compounds 7f and 10c exhibited significant glucose consumption promoting activity at 1?μM.
- Sun, Hua,Ding, Weina,Song, Xiaotong,Wang, Dong,Chen, Mingzhu,Wang, Kaili,Zhang, Yazhou,Yuan, Peng,Ma, Ying,Wang, Runling,Dodd, Robert H.,Zhang, Yongmin,Lu, Kui,Yu, Peng
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p. 3226 - 3230
(2017/07/07)
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- Practical, modular, and general synthesis of 3-coumaranones through gold-catalyzed intermolecular alkyne oxidation strategy
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A gold-catalyzed intermolecular alkyne oxidation for the preparation of 3-coumaranones has been developed. Using 8-isopropylquinoline N-oxides as oxidants, the reactions of o-ethynylanisoles afford versatile 3-coumaranones in moderate to good isolated yields. The synthetic utility of this chemistry is also indicated by the synthesis of the natural product sulfuretin.
- Shu, Chao,Liu, Rongfu,Liu, Shuang,Li, Jian-Qiao,Yu, Yong-Fei,He, Qiao,Lu, Xin,Ye, Long-Wu
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- Investigation of binding-site homology between mushroom and bacterial tyrosinases by using aurones as effectors
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Tyrosinase is a copper-containing enzyme found in plants and bacteria, as well as in humans, where it is involved in the biosynthesis of melanin-type pigments. Tyrosinase inhibitors have attracted remarkable research interest as whitening agents in cosmetology, antibrowning agents in food chemistry, and as therapeutics. In this context, commercially available tyrosinase from mushroom (TyM) is frequently used for the identification of inhibitors. This and bacterial tyrosinase (TyB) have been the subjects of intense biochemical and structural studies, including X-ray diffraction analysis, and this has led to the identification of structural homology and divergence among enzymes from different sources. To better understand the behavior of potential inhibitors of TyM and TyB, we selected the aurone family - previously identified as potential inhibitors of melanin biosynthesis in human melanocytes. In this study, a series of 24 aurones with different hydroxylation patterns at the A- and B-rings were evaluated on TyM and TyB. The results show that, depending on the hydroxylation pattern of A- and B-rings, aurones can behave as inhibitors, substrates, and activators of both enzymes. Computational analysis was performed to identify residues surrounding the aurones in the active sites of both enzymes and to rationalize the interactions. Our results highlight similarities and divergence in the behavior of TyM and TyB toward the same set of molecules. A lighter future: Aurones have been identified as inhibitors of melanin biosynthesis. In this study, 24 aurones were evaluated on mushroom and bacterial tyrosinases (TyM and TyB). The compounds behaved as inhibitors, substrates, or activators of both enzymes. Our results highlight similarities and differences in behavior between TyM and TyB with the same set of molecules.
- Haudecoeur, Romain,Gouron, Aurelie,Dubois, Carole,Jamet, Helene,Lightbody, Mark,Hardre, Renaud,Milet, Anne,Bergantino, Elisabetta,Bubacco, Luigi,Belle, Catherine,Reglier, Marius,Boumendjel, Ahcene
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p. 1325 - 1333
(2014/06/24)
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