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Journal of Agricultural and Food... May 2023Ma̅nuka honey is known for its strong bioactivity, which arises from the autocatalytic conversion of 1,3-dihydroxyacetone (dihydroxyacetone, DHA) in the floral nectar...
Dihydroxyacetone in the Floral Nectar of (Turcz.) Rye (Myrtaceae) and Endl. (Myrtaceae) Demonstrates That This Precursor to Bioactive Honey Is Not Restricted to the Genus (Myrtaceae).
Ma̅nuka honey is known for its strong bioactivity, which arises from the autocatalytic conversion of 1,3-dihydroxyacetone (dihydroxyacetone, DHA) in the floral nectar of (Myrtaceae) to the non-peroxide antibacterial compound methylglyoxal during honey maturation. DHA is also a minor constituent of the nectar of several other species. This study used high-performance liquid chromatography to test whether DHA was present in the floral nectar of five species in other genera of the family Myrtaceae: (Turcz.) Rye, sp. Bendering (T.J. Alford 110), (Lindl.) A.S. George, Endl., and Endl. DHA was found in the floral nectar of two of the five species: and . The average amount of DHA detected was 0.08 and 0.64 μg per flower, respectively. These findings suggest that the accumulation of DHA in floral nectar is a shared trait among several genera within the family Myrtaceae. Consequently, non-peroxide-based bioactive honey may be sourced from floral nectar outside the genus .
Topics: Plant Nectar; Honey; Leptospermum; Dihydroxyacetone; Myrtaceae; Secale
PubMed: 37191313
DOI: 10.1021/acs.jafc.3c00673 -
Frontiers in Nutrition 2023Polydatin is a biologically active compound found in mulberries, grapes, and , and it has uric acid-lowering effects. However, its urate-lowering effects and the...
INTRODUCTION
Polydatin is a biologically active compound found in mulberries, grapes, and , and it has uric acid-lowering effects. However, its urate-lowering effects and the molecular mechanisms underlying its function require further study.
METHODS
In this study, a hyperuricemic rat model was established to assess the effects of polydatin on uric acid levels. The body weight, serum biochemical indicators, and histopathological parameters of the rats were evaluated. A UHPLC-Q-Exactive Orbitrap mass spectrometry-based metabolomics approach was applied to explore the potential mechanisms of action after polydatin treatment.
RESULTS
The results showed a trend of recovery in biochemical indicators after polydatin administration. In addition, polydatin could alleviate damage to the liver and kidneys. Untargeted metabolomics analysis revealed clear differences between hyperuricemic rats and the control group. Fourteen potential biomarkers were identified in the model group using principal component analysis and orthogonal partial least squares discriminant analysis. These differential metabolites are involved in amino acid, lipid, and energy metabolism. Of all the metabolites, the levels of L-phenylalanine, L-leucine, -butanoylcarnitine, and dihydroxyacetone phosphate decreased, and the levels of L-tyrosine, sphinganine, and phytosphingosine significantly increased in hyperuricemic rats. After the administration of polydatin, the 14 differential metabolites could be inverted to varying degrees by regulating the perturbed metabolic pathway.
CONCLUSION
This study has the potential to enhance our understanding of the mechanisms of hyperuricemia and demonstrate that polydatin is a promising potential adjuvant for lowering uric acid levels and alleviating hyperuricemia-related diseases.
PubMed: 37187876
DOI: 10.3389/fnut.2023.1117460 -
Nanomaterials (Basel, Switzerland) Apr 2023Several biochars were synthesized from olive stones and used as supports for TiO, as an active semiconductor, and Pt as a co-catalyst (Pt/TiO-PyCF and Pt/TiO-AC). A...
Several biochars were synthesized from olive stones and used as supports for TiO, as an active semiconductor, and Pt as a co-catalyst (Pt/TiO-PyCF and Pt/TiO-AC). A third carbon-supported photocatalyst was prepared from commercial mesoporous carbon (Pt/TiO-MCF). Moreover, a Pt/TiO solid based on Evonik P25 was used as a reference. The biochars used as supports transferred, to a large extent, their physical and chemical properties to the final photocatalysts. The synthesized catalysts were tested for hydrogen production from aqueous glycerol photoreforming. The results indicated that a mesoporous nature and small particle size of the photocatalyst lead to better H production. The analysis of the operational reaction conditions revealed that the H evolution rate was not proportional to the mass of the photocatalyst used, since, at high photocatalyst loading, the hydrogen production decreased because of the light scattering and reflection phenomena that caused a reduction in the light penetration depth. When expressed per gram of TiO, the activity of Pt/TiO-PyCF is almost 4-times higher than that of Pt/TiO (1079 and 273 mmol H/g, respectively), which points to the positive effect of an adequate dispersion of a TiO phase on a carbonaceous support, forming a highly dispersed and homogeneously distributed titanium dioxide phase. Throughout a 12 h reaction period, the H production rate progressively decreases, while the CO production rate increases continuously. This behavior is compatible with an initial period when glycerol dehydrogenation to glyceraldehyde and/or dihydroxyacetone and hydrogen predominates, followed by a period in which comparatively slower C-C cleavage reactions begin to occur, thus generating both H and CO.
PubMed: 37177056
DOI: 10.3390/nano13091511 -
The FEBS Journal Sep 2023During glycerol metabolism, the initial step of glycerol oxidation is catalysed by glycerol dehydrogenase (GDH), which converts glycerol to dihydroxyacetone in a NAD...
During glycerol metabolism, the initial step of glycerol oxidation is catalysed by glycerol dehydrogenase (GDH), which converts glycerol to dihydroxyacetone in a NAD -dependent manner via an ordered Bi-Bi kinetic mechanism. Structural studies conducted with GDH from various species have mainly elucidated structural details of the active site and ligand binding. However, the structure of the full GDH complex with both cofactor and substrate bound is not determined, and thus, the structural basis of the kinetic mechanism of GDH remains unclear. Here, we report the crystal structures of Escherichia coli GDH with a substrate analogue bound in the absence or presence of NAD . Structural analyses including molecular dynamics simulations revealed that GDH possesses a flexible β-hairpin, and that during the ordered progression of the kinetic mechanism, the flexibility of the β-hairpin is reduced after NAD binding. It was also observed that this alterable flexibility of the β-hairpin contributes to the cofactor binding and possibly to the catalytic efficiency of GDH. These findings suggest the importance of the flexible β-hairpin to GDH enzymatic activity and shed new light on the kinetic mechanism of GDH.
Topics: NAD; Glycerol; Sugar Alcohol Dehydrogenases; Oxidation-Reduction; Escherichia coli; Kinetics; Glutamate Dehydrogenase
PubMed: 37165682
DOI: 10.1111/febs.16813 -
Biochemistry Jun 2023Four catalytic amino acids at triosephosphate isomerase (TIM) are highly conserved: N11, K13, H95, and E167. Asparagine 11 is the last of these to be characterized in...
Four catalytic amino acids at triosephosphate isomerase (TIM) are highly conserved: N11, K13, H95, and E167. Asparagine 11 is the last of these to be characterized in mutagenesis studies. The ND2 side chain atom of N11 is hydrogen bonded to the O-1 hydroxyl of enzyme-bound dihydroxyacetone phosphate (DHAP), and it sits in an extended chain of hydrogen-bonded side chains that includes T75' from the second subunit. The N11A variants of wild-type TIM from (TIM) and (TIM) undergo dissociation from the dimer to monomer under our assay conditions. Values of = 8 × 10 and 1 × 10 M, respectively, were determined for the conversion of monomeric N11A TIM and TIM into their homodimers. The N11A substitution at the variant of TIM previously stabilized by the E65Q substitution gives the N11A/E65Q variant that is stable to dissociation under our assay conditions. The X-ray crystal structure of N11A/E65Q TIM shows an active site that is essentially superimposable on that for wild-type TIM, which also has a glutamine at position 65. A comparison of the kinetic parameters for E65Q TIM and N11A/E65Q TIM-catalyzed reactions of ()-glyceraldehyde 3-phosphate (GAP) and (DHAP) shows that the N11A substitution results in a (13-14)-fold decrease in / for substrate isomerization and a similar decrease in for DHAP but only a 2-fold decrease in for GAP.
Topics: Triose-Phosphate Isomerase; Catalysis; Amino Acids; Hydrogen
PubMed: 37162263
DOI: 10.1021/acs.biochem.3c00133 -
Proceedings of the National Academy of... May 2023Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) contains an active site Cys and is one of the most sensitive cellular enzymes to oxidative inactivation and redox...
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) contains an active site Cys and is one of the most sensitive cellular enzymes to oxidative inactivation and redox regulation. Here, we show that inactivation by hydrogen peroxide is strongly enhanced in the presence of carbon dioxide/bicarbonate. Inactivation of isolated mammalian GAPDH by HO increased with increasing bicarbonate concentration and was sevenfold faster in 25 mM (physiological) bicarbonate compared with bicarbonate-free buffer of the same pH. HO reacts reversibly with CO to form a more reactive oxidant, peroxymonocarbonate (HCO), which is most likely responsible for the enhanced inactivation. However, to account for the extent of enhancement, we propose that GAPDH must facilitate formation and/or targeting of HCO to promote its own inactivation. Inactivation of intracellular GAPDH was also strongly enhanced by bicarbonate: treatment of Jurkat cells with 20 µM HO in 25 mM bicarbonate buffer for 5 min caused almost complete GAPDH inactivation, but no loss of activity when bicarbonate was not present. HO-dependent GAPDH inhibition in bicarbonate buffer was observed even in the presence of reduced peroxiredoxin 2 and there was a significant increase in cellular glyceraldehyde-3-phosphate/dihydroxyacetone phosphate. Our results identify an unrecognized role for bicarbonate in enabling HO to influence inactivation of GAPDH and potentially reroute glucose metabolism from glycolysis to the pentose phosphate pathway and NAPDH production. They also demonstrate what could be wider interplay between CO and HO in redox biology and the potential for variations in CO metabolism to influence oxidative responses and redox signaling.
Topics: Humans; Animals; Hydrogen Peroxide; Carbon Dioxide; Bicarbonates; Glyceraldehyde-3-Phosphate Dehydrogenases; Peroxiredoxins; Oxidation-Reduction; Mammals
PubMed: 37098065
DOI: 10.1073/pnas.2221047120 -
ACS Applied Materials & Interfaces May 2023In this work, we report for the first time a comprehensive investigation of the intricate correlation between dynamic phase evolution and glycerol electrooxidation...
In this work, we report for the first time a comprehensive investigation of the intricate correlation between dynamic phase evolution and glycerol electrooxidation reaction (GEOR) performance across three primary MnO crystallographic phases (α-, β-, and γ-MnO). The results showed that all three electrocatalysts exhibited comparable selectivity toward three-carbon products (∼90%), but γ-MnO exhibited superior performance, with a low onset potential of ∼1.45 V, the highest current density of ∼1.9 mA cm at 1.85 V, and reasonable stability. Raman spectroscopy revealed the potential-induced surface reconstruction of different MnO structures from which a correlation among the applied potential, electrocatalytic activity, and product distribution was identified. The higher the applied potential, the greater conversion from the original structure to δ-MnO, resulting in lower C-C cleavage and higher 3C product selectivity. This study not only provides a systematic understanding of structure-controlled electrocatalytic activity for high selectivity toward 3C products of MnO but also contributes to the development of a non-noble and environmentally friendly catalyst for valorizing glycerol.
PubMed: 37096961
DOI: 10.1021/acsami.3c00857 -
Physiologia Plantarum 2023Differential rootstock tolerance to Fusarium spp. supports viticulture worldwide. However, how plants stand against the fungus still needs to be explored. We hypothesize...
Differential rootstock tolerance to Fusarium spp. supports viticulture worldwide. However, how plants stand against the fungus still needs to be explored. We hypothesize it involves a differential metabolite modulation. Thus, we performed a gas chromatography coupled with mass spectrometry (GC-MS) analysis of Paulsen P1103 and BDMG573 rootstocks, co-cultured with Fusarium oxysporum (FUS) for short, medium, and long time (0, 4, and 8 days after treatment [DAT]). In shoots, principal component analysis (PCA) showed a complete overlap between BDMG573 non-co-cultivated and FUS at 0 DAT, and P1103 treatments showed a slight overlap at both 4 and 8 DAT. In roots, PCA exhibited overlapping between BDMG573 treatments at 0 DAT, while P1103 treatments showed overlapping at 0 and 4 DAT. Further, there is a complete overlapping between BDMG573 and P1103 FUS profiles at 8 DAT. In shoots, 1,3-dihydroxyacetone at 0 and 4 DAT and maltose at 4 and 8 DAT were biomarkers for BDMG573. For P1103, glyceric acid, proline, and sorbitol stood out at 0, 4, and 8 DAT, respectively. In BDMG573 roots, the biomarkers were β-alanine at 0 DAT, cellobiose and sorbitol at both 4 and 8 DAT. While in P1103 roots, they were galactose at 0 and 4 DAT and 1,3-dihydroxyacetone at 8 DAT. Overall, there is an increase in amino acids, glycolysis, and tricarboxylic acid components in tolerant Paulsen P1103 shoots. Thus, it provides a new perspective on the primary metabolism of grapevine rootstocks to F. oxysporum that may contribute to strategies for genotype tolerance and early disease identification.
Topics: Fusarium; Vitis; Dihydroxyacetone; Plant Diseases; Sorbitol
PubMed: 37087574
DOI: 10.1111/ppl.13918 -
ChemPlusChem May 2023The main aim of research was synthesis and spectroscopic characterization of new conjugates in which stigmasterol was linked via carbonate or succinyl linker with 1,3-...
The main aim of research was synthesis and spectroscopic characterization of new conjugates in which stigmasterol was linked via carbonate or succinyl linker with 1,3- and 1,2-acylglycerols of palmitic and oleic acid. Acylglycerols containing stigmasterol residue at internal position have been synthesized from 2-benzyloxypropane-1,3-diol or dihydroxyacetone. Their asymmetric counterparts containing stigmasterol residue attached to sn-3 position have been obtained from (S)-solketal. Eight synthesized conjugates were used to create the liposomes as nanocarriers of phytosterols to increase their stability and protect them from degradation during thermal-oxidative treatments. Fluorimetric and ATR-FTIR methods were used to determine the impact of synthesized conjugates on the physicochemical properties of the lipid bilayer. The results indicate that conjugates with palmitic acid are better candidates for use as the potential stigmasterol nanocarriers compared to those with oleic acid because they increase the stiffness of the lipid bilayer and temperature of the main phase transition. The obtained results are the first step in designing of stigmasterol-enriched liposomal carriers with higher thermo-oxidative stability for their potential use in the food industry.
Topics: Glycerides; Lipid Bilayers; Stigmasterol; Oleic Acid; Liposomes
PubMed: 36997498
DOI: 10.1002/cplu.202300161 -
Molecules (Basel, Switzerland) Mar 20231,3-dihydroxyacetone (DHA) is an underrated bio-based synthon, with a broad range of reactivities. It is produced for the revalorization of glycerol, a major... (Review)
Review
1,3-dihydroxyacetone (DHA) is an underrated bio-based synthon, with a broad range of reactivities. It is produced for the revalorization of glycerol, a major side-product of the growing biodiesel industry. The overwhelming majority of DHA produced worldwide is intended for application as a self-tanning agent in cosmetic formulations. This review provides an overview of the discovery, physical and chemical properties of DHA, and of its industrial production routes from glycerol. Microbial fermentation is the only industrial-scaled route but advances in electrooxidation and aerobic oxidation are also reported. This review focuses on the plurality of reactivities of DHA to help chemists interested in bio-based building blocks see the potential of DHA for this application. The handling of DHA is delicate as it can undergo dimerization as well as isomerization reactions in aqueous solutions at room temperature. DHA can also be involved in further side-reactions, yielding original side-products, as well as compounds of interest. If this peculiar reactivity was harnessed, DHA could help address current sustainability challenges encountered in the synthesis of speciality polymers, ranging from biocompatible polymers to innovative polymers with cutting-edge properties and improved biodegradability.
Topics: Dihydroxyacetone; Glycerol; Fermentation; Oxidation-Reduction; Cosmetics
PubMed: 36985712
DOI: 10.3390/molecules28062724