In this article, we determine the pH effect and chemical mechanism of antioxidant higenamine by using four spectrophotometric assays: (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide radical (PTIO•)-scavenging assay (at pH 4.5, 6.0, and 7.4); (2) Fe3+-reducing power assay; (3) Cu2+-reducing power assay; and (4) 1,1-diphenyl-2-picryl-hydrazyl (DPPH•)-scavenging assay. The DPPH•-scavenging reaction product is further analyzed by ultra-performance liquid chromatography, coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) technology. In the four spectrophotometric assays, higenamine showed good dose-response curves; however, its IC50 values were always lower than those of Trolox. In UPLC-ESI-Q-TOF-MS/MS analysis, the higenamine reaction product with DPPH• displayed three chromatographic peaks (retention time = 0.969, 1.078, and 1.319 min). The first gave m/z 541.2324 and 542.2372 MS peaks; while the last two generated two similar MS peaks (m/z 663.1580 and 664.1885), and two MS/MS peaks (m/z 195.9997 and 225.9971). In the PTIO•-scavenging assays, higenamine greatly decreased its IC50 values with increasing pH. In conclusion, higenamine is a powerful antioxidant—it yields at least two types of final products (i.e., higenamine-radical adduct and higenamine-higenamine dimer). In aqueous media, higenamine may exert its antioxidant action via electron-transfer and proton-transfer pathways. However, its antioxidant action is markedly affected by pH. This is possibly because lower pH value weakens its proton-transfer pathway via ionization suppression by solution H+, and its electron-transfer pathway by withdrawing the inductive effect (-I) from protonated N-atom. These findings will aid the correct use of alkaloid antioxidants.
#1Xican Li(Guangzhou University of Chinese Medicine)H-Index: 19
#2Ban Chen(Guangzhou University of Chinese Medicine)H-Index: 8
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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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 dihydrocha...
#1Xican Li(Guangzhou University of Chinese Medicine)H-Index: 9
#2Jian Lin(Guangzhou University of Chinese Medicine)H-Index: 7
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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In this study, two natural phenolic polyamines, kukoamine A and B, were comparatively investigated for their antioxidant and cytoprotective effects in Fenton-damaged bone marrow-derived mesenchymal stem cells (bmMSCs). When compared with kukoamine B, kukoamine A consistently demonstrated higher IC50 values in PTIO•-scavenging (pH 7.4), Cu2+-reducing, DPPH•-scavenging, •O2−-scavenging, and •OH-scavenging assays. However, in the PTIO•-scavenging assay, the IC50 values of each kukoamine varied with...
#1Hong Xie(Guangzhou University of Chinese Medicine)H-Index: 10
#2Xican Li(Guangzhou University of Chinese Medicine)H-Index: 9
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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Tibetan tea (Kangzhuan) is an essential beverage of the Tibetan people. In this study, a lyophilized aqueous extract of Tibetan tea (LATT) was prepared and analyzed by HPLC. The results suggested that there were at least five phenolic components, including gallic acid, and four catechins (i.e., (+)-catechin, (−)-catechin gallate (CG), (−)-epicatechin gallate (ECG), and (−)-epigallocatechin gallate). Gallic acid, the four catechins, and LATT were then comparatively investigated by four antioxidan...
#1Xican Li(Guangzhou University of Chinese Medicine)H-Index: 9
#1Xican Li(Guangzhou University of Chinese Medicine)H-Index: 19
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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In this study, a series of di-O-caffeoylquinic acids (di-COQs) were systematically investigated for their antioxidant and cytoprotective effects towards •OH-damaged bone marrow-derived mesenchymal stem cells (bmMSCs). Five di-COQs were measured using a set of antioxidant assays. The results show that adjacent 4,5-Di-O-caffeoylquinic acid (4,5-COQ) and 3,4-di-O-caffeoylquinic acid (3,4-COQ) always gave lower IC50 values than did non-adjacent di-COQs. In the Fe2+-chelating assay, 4,5-COQ and 3,4-C...
#1Yage Tian(Guangzhou University of Chinese Medicine)H-Index: 3
#2Xican Li(Guangzhou University of Chinese Medicine)H-Index: 9
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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Our study explores the antioxidant and cytoprotective effects of baicalein and further discusses the possible mechanisms. A methyl thiazolyl tetrazolium (MTT) assay revealed that baicalein could considerably enhance the viability of hydroxyl radical-treated bone marrow-mesenchymal stem cells (bmMSCs) at 37–370 µM. The highest viability rate was 120.4%. In subsequent studies, baicalein was observed to effectively scavenge hydroxyl radical and PTIO• radicals, reducing Fe3+ and Cu2+ ions. In the Fe...
Last. Xing Tang(SPU: Shenyang Pharmaceutical University)H-Index: 27
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Abstract In the present study, vincristine (VCR)-loaded liposomes were designed by ion-pairing techniques and the model could be applied to investigate the effect of lipids on the degradation of vinca alkaloids, and how to weaken their influence by adjusting pH and adding antioxidants. It was found that there was a positive correlation between degree of degradation and the unsaturation extent of the phospholipids. In the phospholipid with the lowest oxidation index, only 6% of VCR was degraded i...
Last. Yirong Mo(WMU: Western Michigan University)H-Index: 47
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Abstract Proton-coupled electron transfer (PCET) broadly exists in chemical and biological processes and can be intuitively described in terms of diabatic (resonance) states. The conventional molecular orbital (MO) based methods, however, have the difficulty in rationally defining diabatic states which are strictly electron-localized. Here we used the block-localized wavefunction (BLW) method, which is the simplest variant of valence bond (VB) theory, to define four major diabatic states and com...
#1Xican Li(Guangzhou University of Chinese Medicine)H-Index: 2
Current in vitro antioxidant assays have several limitations, which frequently cause inconsistent results. The study develops a new antioxidant assay using the 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•). After the investigation of various factors, the experimental protocol was briefly recommended as follows: PTIO• and the sample solution were added to phosphate buffer (pH 7.4, 50 mM), incubated at 37 °C for 2 h, and then spectrophotometrically measured at 557 nm. The ...
#1Xican Li(Guangzhou University of Chinese Medicine)H-Index: 19
#2Yage Tian(Guangzhou University of Chinese Medicine)H-Index: 3
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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The aim of this study was to explore the role of p-coumaroyl in the antioxidant and cytoprotective effects of flavonoid glycosides. The antioxidant effects of astragalin and tiliroside were compared using ferric ion reducing antioxidant power, DPPH• scavenging, ABTS•+ scavenging, •O2– scavenging, and Fe2+-chelating assays. The results of these assays revealed that astragalin and tiliroside both exhibited dose-dependent activities; however, tiliroside exhibited lower IC50 values than astragalin. ...
#1Qian Jiang(Guangzhou University of Chinese Medicine)H-Index: 6
#1Qian Jiang(Guangzhou University of Chinese Medicine)H-Index: 6
Last. Dongfeng Chen(Guangzhou University of Chinese Medicine)H-Index: 22
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Mori Fructus and Mori Ramulus are two traditional Chinese herbal medicines from mulberries. The present work explores their beneficial effects on •OH–treated mesenchymal stem cells (MSCs) and discusses possible mechanisms. Lyophilized aqueous extracts of Mori Fructus (LAMF) and Mori Ramulus (LAMR) were prepared and analyzed using HPLC. LAMF and LAMR (along with morin) were further investigated for their effects on •OH-treated MSCs using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. ...
The search for a safe and effective inhibitor of ferroptosis, a recently described cell death pathway, has attracted increasing interest from scientists. Two hydrolyzable tannins, chebulagic acid and chebulinic acid, were selected for the study. Their optimized conformations were calculated using computational chemistry at the B3LYP-D3(BJ)/6-31G and B3LYP-D3(BJ)/6-311 + G(d,p) levels. The results suggested that (1) chebulagic acid presented a chair conformation, while chebulinic acid presented a...
Higenamine (HM), an alkaloid found in various plant species, is obtained when norcoclaurine synthase selectively condenses dopamine and 4-hydroxyphenylacetaldehyde to give (S)-higenamine ((S)-HM). The World Anti-doping Agency has listed HM as a prohibited agent in athletics. As a result, many commercial, academic, and regulatory bodies across the globe are invested in finding a rapid method for (S)-HM detection. In the current study, a lateral flow immunoassay (LFA) was developed in which the re...
Synthetic arylamines and dietary phytophenolics could inhibit ferroptosis, a recently discovered regulated cell death process. However, no study indicates whether their inhibitory mechanisms are inherently different. Herein, the ferroptosis-inhibitory mechanisms of selected ferrostatin-1 (Fer-1) and two dietary stilbenes (piceatannol and astringin) were compared. Cellular assays suggested that the ferroptosis-inhibitory and electron-transfer potential levels decreased as follows: Fer-1 >> piceat...
Powerful antioxidant α-lipoic acid (LA) exhibits limited therapeutic efficiency due to its pharmacokinetic properties. Therefore, the purpose of this work was to evaluate the ability of silica-based composites of LA as well as its amide (lipoamide, LM), as new oral drug formulations, to control their release and maintain their therapeutic concentration and antioxidant activity in the body over a long time. The composites synthesized at different sol–gel synthesis pH and based on silica matrixes ...
#1Sixuan Chen(MOE: Chinese Ministry of Education)H-Index: 2
#2Xuping Li(MOE: Chinese Ministry of Education)H-Index: 1
Last. Yuanyuan Cheng(MOE: Chinese Ministry of Education)H-Index: 2
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Abstract Ethnopharmacological relevance Plumula Nelumbinis, the green embryo of the mature seeds of Nelumbo nucifera Gaertn, has a medical history of over 400 years. It is widely used for clearing the heart and heat, calming the mind, and promoting astringent essence and hemostasis in traditional Chinese medicine. Moreover, it usually dual use as food and medicine. This review aimed to evaluate the therapeutic potential of Plumula Nelumbinis by summarizing its botany, traditional uses, phytochem...
Abstract Hexavalent chromium toxicity remains an indispensible toxicity to bioremediation. It has environmental and health impact in areas of hexavalent chromium discharges. This persistent problem associated with hexavalent chromium toxicity had led to employment of both physical and chemical means of control, which suffers major drawbacks. These drawbacks include; incomplete metal removal, high energy requirement, high reagent consumption and high cost of implementation. Bioremediation via bio...
Abstract The chemical reaction involving phenolic antioxidants from plant´ extracts have not been adequately studied. In this study, we investigate a quick, accurate, and innovative strategy to elucidate the ferulic acid reaction employing a conclusive analytical tool (ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry, UHPLC-ESI-Q-TOF-MS/MS) used in pharmaceutical, cosmetic, food, and biomedical applications. The ...
The study investigated the effect of acidified turmeric, black pepper or its combination on growth and meat quality of broilers. The Averrhoa bilimbi Linn. fruit filtrate was used to acidify the herbs. A number of 392 day-old Lohmann broiler chicks were randomly distributed to four groups, including CONT (control diet), TRMC (diet supplemented with 1% acidified turmeric), BLPR (1% acidified black pepper) and TRPR (1% acidified turmeric and 1% acidified black pepper). Body weight, feed intake and...
The ellagitannin corilagin and its analogue 1,3,6-tri-O-galloyl-β-d-glucopyranose (TGG) were found to protect bone marrow-derived mesenchymal stem cells (bmMSCs) against erastin-induced ferroptosis...