The role of the 6″-OH (ω-OH) group in the antioxidant activity of flavonoid glycosides has been largely overlooked. Herein, we selected quercitrin (quercetin-3-
-rhamnoside) and isoquercitrin ...(quercetin-3-
-glucoside) as model compounds to investigate the role of the 6″-OH group in several antioxidant pathways, including Fe
-binding, hydrogen-donating (H-donating), and electron-transfer (ET). The results revealed that quercitrin and isoquercitrin both exhibited dose-dependent antioxidant activities. However, isoquercitrin showed higher levels of activity than quercitrin in the Fe
-binding, ET-based ferric ion reducing antioxidant power, and multi-pathways-based superoxide anion-scavenging assays. In contrast, quercitrin exhibited greater activity than isoquercitrin in an H-donating-based 1,1-diphenyl-2-picrylhydrazyl radical-scavenging assay. Finally, in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl assay based on an oxidatively damaged mesenchymal stem cell (MSC) model, isoquercitrin performed more effectively as a cytoprotector than quercitrin. Based on these results, we concluded that (1) quercitrin and isoquercitrin can both indirectly (i.e., Fe
-chelating or Fe
-binding) and directly participate in the scavenging of reactive oxygen species (ROS) to protect MSCs against ROS-induced oxidative damage; (2) the 6″-OH group in isoquercitrin enhanced its ET and Fe
-chelating abilities and lowered its H-donating abilities via steric hindrance or H-bonding compared with quercitrin; and (3) isoquercitrin exhibited higher ROS scavenging activity than quercitrin, allowing it to improve protect MSCs against ROS-induced oxidative damage.
A Na3V2(PO4)3/C composite with 3.8 wt.% carbon, which was synthesized by a one‐step solid state reaction, exhibits Na storage capacity of 107 mAh g−1 and high coulombic efficiency of 99.8% in a new ...NaFSI/PC electrolyte. In situ XRD results reveal its sodium storage mechanism as a typical two‐phase reaction from the Na3V2(PO4)3 to NaV2(PO4)3 phases with 8.26% volume variation. These desired properties make it very promising for application in room‐temperature sodium‐ ion batteries.
A high cut-off voltage is pretty pivotal for the improvement of the energy density of cathode materials. Unfortunately, high-capacity Ni-rich cathode materials usually show serious capacity ...attenuation at high cut-off voltage. Herein, we propose a Li2SiO3-surface modification strategy to highly improve the cycle performance of the Ni-rich LiNi0.8Mn0.1Co0.1O2 material at high voltage. The capacity retention of the pristine and Li2SiO3-coated electrodes is 57.6 and 77.7%, respectively, at the cut-off voltage of 4.6 V after 50 cycles. Meanwhile, the problems of polarization and voltage reduction of LiNi0.8Mn0.1Co0.1O2 are also alleviated. Our results show that Li2SiO3-surface modification is a very effective strategy for improving the cycle stability of Ni-rich cathode materials and can be used for other high capacity electrode materials.
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•The Li2SiO3-modified Ni-rich LiNi0.8Mn0.1Co0.1O2 was prepared for LIB.•The modified LiNi0.8Mn0.1Co0.1O2 shows better cycle stability at high voltage.•The problems of polarization and voltage reduction are also alleviated.•The method will be an effective strategy for other high capacity electrode materials.
To probe the effect of 3',8″-dimerization on antioxidant flavonoids, acacetin and its 3',8″-dimer isoginkgetin were comparatively analyzed using three antioxidant assays, namely, the
O
scavenging ...assay, the Cu
reducing assay, and the 2,2'-azino bis(3-ethylbenzothiazolin-6-sulfonic acid) radical scavenging assay. In these assays, acacetin had consistently higher IC
values than isoginkgetin. Subsequently, the acacetin was incubated with 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxy radicals (4-methoxy-TEMPO) and then analyzed by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF-MS) technology. The results of the UHPLC-ESI-Q-TOF-MS analysis suggested the presence of a dimer with
/
565, 550, 413, 389, 374, 345, 330, and 283 peaks. By comparison, standard isoginkgetin yielded peaks at
/
565, 533, 518, 489, 401, 389, 374, and 151 in the mass spectra. Based on these experimental data, MS interpretation, and the relevant literature, we concluded that isoginkgetin had higher electron transfer potential than its monomer because of the 3',8″-dimerization. Additionally, acacetin can produce a dimer during its antioxidant process; however, the dimer is not isoginkgetin.
Co3O4 with three different crystal plane structures – cubes bounded by {001}planes, truncated octahedra enclosed by {111} and {001} planes, and octahedra with exposed {111}planes – is synthesized ...using a very simple one‐step hydrothermal method. The three kinds of Co3O4 exhibit significantly different electrochemical performances and the effect of different exposed crystal planes on the electrochemical performance of Co3O4 is comprehensively studied.
Th17 cells play an important role in the abnormal immune response in inflammatory bowel disease (IBD) and are involved in the development and progression of inflammation and fibrosis. An increasing ...amount of data has shown that gut microbes are important parts of intestinal immunity and regulators of Th17 cellular immunity. Th17 cell differentiation is regulated by intestinal bacteria and cytokines, and Th17 cells regulate the intestinal mucosal immune microenvironment by secreting cytokines, such as IL-17, IL-21, and IL-26. Solid evidence showed that, regarding the treatment of IBD by targeting Th17 cells, the therapeutic effect of different biological agents varies greatly. Fecal bacteria transplantation (FMT) in the treatment of IBD has been a popular research topic in recent years and is safe and effective with few side effects. To further understand the role of Th17 cells in the progression of IBD and associated therapeutic prospects, this review will discuss the progress of related research on Th17 cells in IBD by focusing on the interaction and immune regulation between Th17 cells and gut microbiota.
To explore whether and how glucuronidation affects pyrogallol-type phytophenols, scutellarein and scutellarin (scutellarein-7-
-glucuronide) were comparatively investigated using a set of antioxidant ...analyses, including spectrophotometric analysis, UV-vis spectra analysis, and ultra-performance liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) analysis. In spectrophotometric analyses of the scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH
), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS
), and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radicals (PTIO
) and the reduction of Cu
ions, scutellarein showed lower IC
values than scutellarin. However, in
O₂
-scavenging spectrophotometric analysis, scutellarein showed higher IC
value than scutellarin. The analysis of UV-Vis spectra obtained after the Fe
-chelating reaction of scutellarin showed a typical UV-Vis peak (λ
= 611 nm), while scutellarein showed no typical peak. In UPLC-ESI-Q-TOF-MS/MS analysis, mixing of scutellarein with DPPH
yielded MS peaks (
/
678, 632, 615, 450, 420, 381, 329, 300, 288, 227, 196, 182, 161, and 117) corresponding to the scutellarein-DPPH adduct and an MS peak (
/
570) corresponding to the scutellarein-scutellarein dimer. Scutellarin, however, generated no MS peak. On the basis of these findings, it can be concluded that glucuronidation of pyrogallol-type phytophenol antioxidants has a dual effect. On the one hand, glucuronidation can decrease the antioxidant potentials (except for
O₂
scavenging) and further lower the possibility of radical adduct formation (RAF), while on the other hand, it can enhance the
O₂
-scavenging and Fe
-chelating potentials.
The study determined the comparative antioxidant capacities of five similar dihydrochalcones: phloretin, phloridzin, trilobatin, neohesperidin dihydrochalcone, and naringin dihydrochalcone. In the ...ferric-reducing antioxidant power (FRAP) assay, the antioxidant activities of pairs of dihydrochalcones had the following relationship: phloretin > phloridzin, phloretin > trilobatin, trilobatin > phloridzin, trilobatin > naringin dihydrochalcone, and neohesperidin dihydrochalcone > naringin dihydrochalcone. Similar relative antioxidant levels were also obtained from 1,1-diphenyl-2-picryl-hydrazl radical (DPPH•)-scavenging, 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS•⁺)-scavenging, and superoxide radical (•O₂
)-scavenging assays. Using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC−ESI−Q−TOF−MS/MS) analysis for the reaction products with DPPH•, phloretin, phloridzin, and trilobatin were found to yield both dihydrochalcone-DPPH adduct and dihydrochalcone-dihydrochalcone dimer, whereas naringin dihydrochalcone gave a naringin dihydrochalcone-DPPH adduct, and neohesperidin dihydrochalcone gave a dimer. In conclusion, the five dihydrochalcones may undergo redox-based reactions (especially electron transfer (ET) and hydrogen atom transfer (HAT)), as well as radical adduct formation, to exert their antioxidant action. Methoxylation at the
-OH enhances the ET and HAT potential possibly via p-π conjugation, whereas the glycosylation of the ⁻OH group not only reduces the ET and HAT potential but also hinders the ability of radical adduct formation. The 2′,6′-di-OH moiety in dihydrochalcone possesses higher ET and HAT activities than the 2′,4′-di-OH moiety because of its resonance with the adjacent keto group.
Gallic acid is an active phenolic acid widely distributed in plants, and there is compelling evidence to prove its anti-inflammatory effects. NLRP3 inflammasome dysregulation is closely linked to ...many inflammatory diseases. However, how gallic acid affects the NLRP3 inflammasome remains unclear. Therefore, in the present study, we investigated the mechanisms underlying the effects of gallic acid on the NLRP3 inflammasome and pyroptosis, as well as its effect on gouty arthritis in mice. The results showed that gallic acid inhibited lactate dehydrogenase (LDH) release and pyroptosis in lipopolysaccharide (LPS)-primed and ATP-, nigericin-, or monosodium urate (MSU) crystal-stimulated macrophages. Additionally, gallic acid blocked NLRP3 inflammasome activation and inhibited the subsequent activation of caspase-1 and secretion of IL-1β. Gallic acid exerted its inhibitory effect by blocking NLRP3-NEK7 interaction and ASC oligomerization, thereby limiting inflammasome assembly. Moreover, gallic acid promoted the expression of nuclear factor E2-related factor 2 (Nrf2) and reduced the production of mitochondrial ROS (mtROS). Importantly, the inhibitory effect of gallic acid could be reversed by treatment with the Nrf2 inhibitor ML385. NRF2 siRNA also abolished the inhibitory effect of gallic acid on IL-1β secretion. The results further showed that gallic acid could mitigate MSU-induced joint swelling and inhibit IL-1β and caspase 1 (p20) production in mice. Moreover, gallic acid could moderate MSU-induced macrophages and neutrophils migration into joint synovitis. In summary, we found that gallic acid suppresses ROS generation, thereby limiting NLRP3 inflammasome activation and pyroptosis dependent on Nrf2 signaling, suggesting that gallic acid possesses therapeutic potential for the treatment of gouty arthritis.
Polysaccharide (DOPA) from the stem of D. officinale, as well as two fractions (DOPA-1 and DOPA-2) of it, were isolated and purified by DEAE cellulose-52 and Sephacryl S-300 chromatography, and their ...structural characteristics and bioactivities were investigated. The average molecular weights of DOPA-1 and DOPA-2 were 394 kDa and 362 kDa, respectively. They were mainly composed of d-mannose, d-glucose, and had a backbone consisting of 1,4-linked β-d-Manp and 1,4-linked β-d-Glcp with O-acetyl groups. Bioactivity studies indicated that both DOPA and its purified fractions (DOPA-1 and DOPA-2) could activate splenocytes and macrophages. The D. officinale polysaccharides had stimulatory effects on splenocytes, T-lymphocytes and B-lymphocytes, promoting the cell viability and NO production of RAW 264.7 macrophages. Furthermore, DOPA, DOPA-1 and DOPA-2 were found to protect RAW 264.7 macrophages against hydrogen peroxide (H₂O₂)-induced oxidative injury by promoting cell viability, suppressing apoptosis and ameliorating oxidative lesions. These results suggested that D. officinale polysaccharides possessed antioxidant activity and mild immunostimulatory activity.
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