Hydroxylation Pattern Research Articles

Hydroxylation patterns associated with pheromone synthesis and composition in two honey bee subspecies Apis mellifera scutellata and A. m. capensis laying workers

Colony losses due to social parasitism in the form of reproductive workers of the Apis mellifera capensis clones results from the production of queen-like pheromonal signals coupled with ovarian activation in these socially parasitic honey bees. While the behavioral attributes of these social parasites have been described, their genetic attributes require more detailed exploration. Here, we investigate the production of mandibular gland pheromones in queenless workers of two sub-species of African honey bees; A. m. scutellata (low reproductive potential) and A. m. capensis clones (high reproductive potential). We used standard techniques in gas chromatography to assess the amounts of various pheromone components present, and qPCR to assess the expression of cytochrome P450 genes cyp6bd1 and cyp6as8, thought to be involved in the caste-dependent hydroxylation of acylated stearic acid in queens and workers, respectively. We found that, for both subspecies, the quality and quantity of the individual pheromone components vary with age, and that from the onset, A. m. capensis parasites make use of gene pathways typically upregulated in queens in achieving reproductive dominance. Due to the high production of 9-hydroxy-decenoic acid (9-HDA) the precursor to the queen substance 9-oxo-decenoic acid (9-ODA) in newly emerged capensis clones, we argue that clones are primed for parasitism upon emergence and develop into fully fledged parasites depending on the colony's social environment.

Synthesis of 4'/5'-Spirocyclopropanated Uridine and d-Xylouridine Derivatives and Their Activity against the Human Respiratory Syncytial Virus.

The Simmons-Smith-Furukawa reaction was used to generate 4'/5'-spirocyclopropanated uridine analogs from electron-rich exocyclic enol esters. During synthesis, the native hydroxylation pattern of the nucleoside is preserved and offers the possibility for a late stage 5'-phosphorylation at the spirocyclopropanol moiety. All synthesized spirocyclopropanated uridine derivatives, including the corresponding 5'-monophosphate (cpUMP), were evaluated with respect to their antiviral activity in an HRSV assay showing moderate, but promising activity.

Functional analysis of flavonoid 3′-hydroxylase and flavonoid 3′,5′-hydroxylases from tea plant (Camellia sinensis), involved in the B-ring hydroxylation of flavonoids

Flavonoids are major polyphenol compounds in plant secondary metabolism. The hydroxylation pattern of the B-ring of flavonoids is determined by the flavonoid 3′-hydroxylase (F3’H) and flavonoid 3′,5′-hydroxylase (F3′5′H). In this paper, one CsF3′H and two CsF3′5′Hs (CsF3′5′Ha and CsF3′5′Hb) were isolated. The phylogenetic tree results showed that F3′H and F3′5′Hs belong to the CYP75B and CYP75A, respectively. The Expression pattern analysis showed that the expression of CsF3′5′Ha and CsF3′5′Hb in the bud and 1st leaf were higher than other tissues. However, the CsF3′H had the highest expression in the 4th and mature leaf. The correlation analysis showed that the expression of CsF3′5′Hs is positively associated with the concentration of B-trihydroxylated catechins, and the expression of CsF3′H is positively associated with the Q contentration. Heterologous expression of these genes in yeast showed that CsF3′H and CsF3′5′Ha can catalyze flavanones, flavonols and flavanonols to the corresponding 3′, 4′ or 3′, 4′, 5′-hydroxylated compounds, for which the optimum substrate is naringenin. The enzyme of CsF3′5′Hb can only catalyze flavonols (including K and Q) and flavanonols (DHK and DHQ), of which the highest activities in catalyzing are DHK. Interestingly, The experiment of site-directed mutagenesis suggested that two novel sites near the C-terminal were discovered impacting on the activity of the CsF3′5′H. These results provide a significantly molecular basis on the accumulation B-ring hydroxylation of flavonoids in tea plant.

Evolutionary dynamic analyses on monocot flavonoid 3\u2032-hydroxylase gene family reveal evidence of plant-environment interaction

BackgroundFlavonoid 3′-hydroxlase (F3’H) is an important enzyme in determining the B-ring hydroxylation pattern of flavonoids. In monocots, previous studies indicated the presence of two groups of F3’Hs with different enzyme activities. One F3’H in rice was found to display novel chrysoeriol-specific 5′-hydroxylase activity. However, the evolutionary history of monocot F3’Hs and the molecular basis for the observed catalytic difference remained elusive.ResultsWe performed genome-wide survey of 12 common monocot plants, and identified a total of 44 putative F3’H genes. The results showed that F3’H gene family had underwent volatile lineage-specific gene duplication and gene loss events in monocots. The expansion of F3’H gene family was mainly attributed to dispersed gene duplication. Phylogenetic analyses showed that monocot F3’Hs have evolved into two independent lineages (Class I and Class II) after gene duplication in the common ancestor of monocot plants. Evolutionary dynamics analyses had detected positive natural selection in Class II F3’Hs, acting on 7 specific amino acid sites. Protein modelling showed these selected sites were mainly located in the catalytic cavity of F3’H. Sequence alignment revealed that Class I and Class II F3’Hs displayed amino acid substitutions at two critical sites previously found to be responsible for F3’H and flavonoid 3′5’-hydroxylase (F3’5’H) activities. In addition, transcriptional divergence was also observed for Class I and Class II F3’Hs in four monocot species.ConclusionsWe concluded that monocot F3’Hs have evolved into two independent lineages (Mono_F3’H Class I and Class II), after gene duplication during the common ancestor of monocot plants. The functional divergence of monocot F3’H Class II has been affected by positive natural selection, which acted on specific amino acid sites only. Critical amino acid sites have been identified to have high possibility to affect the substrate specificity of Class II F3’Hs. Our study provided an evolutionary and protein structural explanation to the previously observed chrysoeriol-specific 5′-hydroxylation activity for CYP75B4 in rice, which may also be true for other Class II F3’Hs in monocots. Our study presented clear evidence of plant-environmental interaction at the gene evolutionary level, and would guide future functional characterization of F3’Hs in cereal plants.

Re-investigating substrate specificity of dihydroflavonol 4-reductase with respect to the B-ring hydroxylation pattern of substrates

Dihydroflavonol 4-reductase (EC 1.1.1.219, DFR) catalyses the reduction of (2R,3R)-(+)-dihydroflavonols into (2R,3S,4S)-cis-3,4-leucoanthocyanidins. Depending on the plant species, DFR can be unspecific with regard to the B-ring hydroxylation pattern or selective, as in Petunia hybrida in which the DFR does not convert DHK, or in Fragaria species where a pair of DFRs are present that shows contrasting substrate specificity with regard to DHK. DFR substrate specificity has been largely investigated in many plant species. The amino acids determining DFR substrate specificity are not yet completely understood, but previous studies have identified a region of 26 amino acids putatively relevant and in particular, an aspartic acid in position 134, that seems to be responsible for the non-acceptance of DHK as substrates. The recently identified pair of Fragaria DFRs with contrasting substrate specificity was used to study putative regions responsible for the divergent substrate specificity. We demonstrate that neither the versatile C-terminus nor the DFR length nor two of three putative regions are of any relevance. In addition, we analyse previously published DFRs of Malus × domestica, Pyrus communis and Ginkgo biloba and the correlation between their substrate specificity and amino acid sequences. Technical constraints of DFR enzyme assays and potential putative substrate specificity bias is discussed.

Oxygen vacancies in nano-sized TiO2 anatase nanoparticles

Anatase nanoparticles containing surface oxygen vacancies (VO) and Ti3+ are of great importance for applications in photocatalysis, batteries, catalysis, sensors among other uses. The properties of VO and their dependence on the size of nanoparticles are of great research interest and could allow obtaining advanced functional materials. In this work, a complete set of oxygen vacancies in an anatase nanoparticle of size 1.1 nm was investigated and compared to those of a twice larger nanoparticle, having the same shape and surface hydroxylation pattern. It turned out that the decrease in the size of the anatase nanoparticle strongly facilitated creation of surface oxygen vacancies and Ti3+. After their creation, oxygen vacancies undergo three transformation paths — (1) small repulsion of surrounding Ti cations with retention of the vacancy, (2) transfer of oxygen anion, leading to the movement of oxygen vacancy to a more stable position, and (3) collapse of oxygen vacancy accompanied by structure deformation towards Magneli-like phase.

Phenylpropanoid Glycerol Glucosides Attenuate Glucose Production in Hepatocytes

An activity-guided fractionation approach revealed several phenylpropanoid glycerol glucosides isolated from the bulbs of Lilium longiflorum Thunb. (Easter lily) with gluconeogenesis inhibitory activities. The strongest activity was observed for (2S)-1-O-p-coumaroyl-2-O-β-d-glucopyranosylglycerol (3), (2S)-1-O-caffeoyl-2-O-β-d-glucopyranosylglycerol (1), and (2R)-1-O-β-d-glucopyranosyl-2-O-p-coumaroylglycerol (2) with inhibitions of 51.2, 39.2, and 36.8%, respectively. The p-coumaroyl-based (3) and its acetylated derivative (5) exhibited differential inhibition activity (51.2% as compared to 3.6%), suggesting that natural acetylation decreases the hypoglycemic activity of these compounds. Direct structure–activity analysis of phenylpropanoid glycerol glucosides indicated that the hydroxylation pattern of the hydroxy cinnamic acid moiety and acetylation were responsible for the differences in activity. This is the first report of phenylpropanoid glycerol glucosides as a phytochemical class of hepatic glucose production inhibitors.

Natural Polyphenols: Chemical Classification, Definition of Classes, Subcategories, and Structures.

Background: Polyphenols are natural compounds synthesized exclusively by plants with chemical features related to phenolic substances and eliciting strong antioxidants properties. Objective: The aim of this paper is to give a reliable overview of the chemical classification of natural polyphenols. Methods: Literature survey was done through google scholar, pubmed and scopus search engine. Results and Discussion: These molecules or classes of natural substances are characterized by two phenyl rings at least and one or more hydroxyl substituents. This description comprehends a large number of heterogeneous compounds with reference to their complexity. Therefore, polyphenols can be simply classified into flavonoids and non-flavonoids, or be subdivided in many sub-classes depending on the number of phenol units within their molecular structure, substituent groups, and/or the linkage type between phenol units. Polyphenols are widely distributed in plant tissues where they mainly exist in form of glycosides or aglycones. The structural diversity of flavonoid molecules arises from variations in hydroxylation pattern and oxidation state resulting in a wide range of compounds: flavanols, anthocyanidins, anthocyanins, isoflavones, flavones, flavonols, flavanones, and flavanonols.

Selection of Fusarium Trichothecene Toxin Genes for Molecular Detection Depends on TRI Gene Cluster Organization and Gene Function.

Food security is a global concern. Fusarium are among the most economically important fungal pathogens because they are ubiquitous, disease management remains a challenge, they produce mycotoxins that affect food and feed safety, and trichothecene mycotoxin production can increase the pathogenicity of some Fusarium species depending on the host species. Although trichothecenes may differ in structure by their patterns of hydroxylation or acetylation, these small changes have a significant impact on toxicity and the biological activity of these compounds. Therefore, detecting and identifying which chemotype is present in a given population are important to predicting the specific toxins that may be produced and, therefore, to evaluating the risk of exposure. Due to the challenges of inducing trichothecene production by Fusarium isolates in vitro for subsequent chemical analysis, PCR assays using gene-specific primers, either singly or in combination, designed against specific genes of the trichothecene gene cluster of multiple species of Fusarium have been developed. The establishment of TRI genotypes that potentially correspond to a specific chemotype requires examination of an information and knowledge pipeline whose critical aspects in sequential order are: (i) understanding the TRI gene cluster organization which differs according to Fusarium species under study; (ii) knowledge of the re-arrangements to the core TRI gene cluster over evolutionary time, which also differs according to Fusarium species; (iii) the functions of the TRI genes in the biosynthesis of trichothecene analogs; and (iv) based on (i)–(iii), selection of appropriate target TRI gene(s) for primer design in PCR amplification for the Fusarium species under study. This review, therefore, explains this pipeline and its connection to utilizing TRI genotypes as a possible proxy to chemotype designation.

Synthesis and glycosidase inhibition of conformationally locked DNJ and DMJ derivatives exploiting a 2-oxo-C-allyl iminosugar.

A series of analogs of the iminosugars 1-deoxynojirimycin (DNJ) and 1-deoxymannojirimycin (DMJ), in which an extra five or six-membered ring has been fused to the C1-C2 bond have been prepared. The synthetic strategy exploits a key 2-keto-C-allyl iminosugar, easily accessible from gluconolactam, which upon Grignard addition and RCM furnishes a bicyclic scaffold that can be further hydroxylated at the C[double bond, length as m-dash]C bond. This strategy furnished DNJ mimics with the piperidine ring locked in a 1C4 conformation with all substituents in axial orientation when fused to a six-membered ring. Addition of an extra ring to DNJ and DMJ motif proved to strongly modify the glycosidase inhibition profile of the parent iminosugars leading to modest inhibitors. The 2-keto-C-allyl iminosugar scaffold was further used to access N-acetylglycosamine analogs via oxime formation.

Multivalent Presentation of Ice Recrystallization Inhibiting Polymers on Nanoparticles Retains Activity.

Poly(vinyl alcohol) (PVA) has emerged as the most potent mimic of antifreeze (glyco)proteins ice recrystallization inhibition (IRI) activity, despite its lack of structural similarities and flexible, rather than rigid, backbone. The precise spacing of hydroxyl groups is hypothesized to enable PVA to recognize the prism planes of ice but not the basal plane, due to hydroxyl pattern matching of the ice surface giving rise to the macroscopic activity. Here, well-defined PVA derived from reversible addition–fragmentation chain-transfer (RAFT) polymerization is immobilized onto gold nanoparticles to enable the impact of nanoscale assembly and confinement on the observed IRI activity. Unlike previous reports using star-branched or bottle-brush PVAs, the nanoparticle–PVA retains all IRI activity compared to polymers in solution. Evidence is presented to show that this is due to the low grafting densities on the particle surface meaning the chains are free to explore the ice faces, rather than being constrained as in star-branched polymers. These results demonstrate a route to develop more functional IRI’s and inclusion of metallic particle cores for imaging and associated applications in cryobiology.

Phytochemistry and bioactivity of Acacia sensu stricto (Fabaceae: Mimosoideae)

Acacia sensu lato (Fabaceae: Mimosoideae) was recently retypified and divided into five genera worldwide: Acacia, Acaciella, Mariosousa, Senegalia and Vachellia. Acacia sensu stricto is now considered to be a large genus of predominantly Australian origin comprising seven sections: Acacia, Alatae, Botrycephalae, Juliflorae, Lycopodiifoliae, Plurinerves and Pulchellae. This review presents an overview of the current taxonomy of A. sensu stricto and the natural products isolated and identified from it. Further, the traditional uses of different species and known bioactivities of isolated natural products are summarised. The flavonoids and tannins are the best studied classes of natural products from Acacia with characteristic hydroxylation patterns of flavonoids isolated from the heartwood of species positioned in different sections of the genus. These compounds display a range of activities including antioxidant, enzyme inhibitory and antimicrobial effects. Peltogynoid compounds, differing from other flavonoids by the presence of a fourth ring, have been isolated from a small group of species, however, their biological activities remain to be defined. Only a limited number of terpenes and steroids have been identified, but complex triterpenoid saponins with various bioactivities are present across various sections. Despite their economic importance and the traditional use, only a limited number of species have been thoroughly studied for their chemical composition. Further investigation of the sections Alatae and Lycopodiifoliae would be of interest for bioactive compound research as these sections are largely unexplored.

Phenolic Substances in Beer: Structural Diversity, Reactive Potential and Relevance for Brewing Process and Beer Quality.

For the past 100 years, polyphenol research has played a central role in brewing science. The class of phenolic substances comprises simple compounds built of 1 phenolic group as well as monomeric and oligomeric flavonoid compounds. As potential anti- or prooxidants, flavor precursors, flavoring agents and as interaction partners with other beer constituents, they influence important beer quality characteristics: flavor, color, colloidal, and flavor stability. The reactive potential of polyphenols is defined by their basic chemical structure, hydroxylation and substitution patterns and degree of polymerization. The quantitative and qualitative profile of phenolic substances in beer is determined by raw material choice. During the malting and brewing process, phenolic compounds undergo changes as they are extracted or enzymatically released, are subjected to heat-induced chemical reactions or are precipitated with or adsorbed to hot and cold trub, yeast cells and stabilization agents. This review presents the current state of knowledge of the composition of phenolic compounds in beer and brewing raw materials with a special focus on their fate from raw materials throughout the malting and brewing process to the final beer. Due to high-performance analytical techniques, new insights have been gained on the structure and function of phenolic substance groups, which have hitherto received little attention. This paper presents important information and current studies on the potential of phenolics to interact with other beer constituents and thus influence quality parameters. The structural features which determine the reactive potential of phenolic substances are discussed.

Different Inhibitory Potencies of Oseltamivir Carboxylate, Zanamivir, and Several Tannins on Bacterial and Viral Neuraminidases as Assessed in a Cell-Free Fluorescence-Based Enzyme Inhibition Assay.

Neuraminidase is a key enzyme in the life cycle of influenza viruses and is present in some bacterial pathogens. We here assess the inhibitory potency of plant tannins versus clinically used inhibitors on both a viral and a bacterial model neuraminidase by applying the 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (MUNANA)-based activity assay. A range of flavan-3-ols, ellagitannins and chemically defined proanthocyanidin fractions was evaluated in comparison to oseltamivir carboxylate and zanamivir for their inhibitory activities against viral influenza A (H1N1) and bacterial Vibrio cholerae neuraminidase (VCNA). Compared to the positive controls, all tested polyphenols displayed a weak inhibition of the viral enzyme but similar or even higher potency on the bacterial neuraminidase. Structure–activity relationship analyses revealed the presence of galloyl groups and the hydroxylation pattern of the flavan skeleton to be crucial for inhibitory activity. The combination of zanamivir and EPs® 7630 (root extract of Pelargonium sidoides) showed synergistic inhibitory effects on the bacterial neuraminidase. Co-crystal structures of VCNA with oseltamivir carboxylate and zanamivir provided insight into bacterial versus viral enzyme-inhibitor interactions. The current data clearly indicate that inhibitor potency strongly depends on the biological origin of the enzyme and that results are not readily transferable. The therapeutic relevance of our findings is briefly discussed.

Proline Hydroxylation in Cell Wall Proteins: Is It Yet Possible to Define Rules?

Cell wall proteins (CWPs) play critical and dynamic roles in plant cell walls by contributing to developmental processes and response to environmental cues. Since the CWPs go through the secretion pathway, most of them undergo post-translational modifications (PTMs) which can modify their biological activity. Glycosylation is one of the major PTMs of CWPs and refers to N-glycosylation, O-glycosylation and glypiation. Each of these PTMs occurs in different amino acid contexts which are not all well defined. This article deals with the hydroxylation of Pro residues which is a prerequisite for O-glycosylation of CWPs on hydroxyproline (Hyp) residues. The location of Hyp residues is well described in several structural CWPs, but yet rarely described in other CWPs. In this article, it is studied in detail in five Arabidopsis thaliana proteins using mass spectrometry data: one of them (At4g38770, AtPRP4) is a structural CWP containing 32.5% of Pro residues arranged in typical motifs, the others are either rich (27–28%, At1g31580 and At2g10940) or poor (6–8%, At1g09750 and At3g08030) in Pro residues. The known rules of Pro hydroxylation allowed a good prediction of Hyp location in AtPRP4. However, they could not be applied to the other proteins whatever their Pro content. In addition, variability of the Pro hydroxylation patterns was observed within some amino acid motifs in all the proteins and new patterns of Pro hydroxylation are described. Altogether, this work shows that Hyp residues are present in more protein families than initially described, and that Pro hydroxylation patterns could be different in each of them. This work paves the way for completing the existing Pro hydroxylation code.

Metabolite profiling of red and blue potatoes revealed cultivar and tissue specific patterns for anthocyanins and other polyphenols.

Metabolite profiling of tuber flesh and peel for selected colored potato varieties revealed cultivar and tissue specific profiles of anthocyanins and other polyphenols with variations in composition and concentration. Starchy tubers of Solanum tuberosum are a staple crop and food in many countries. Among cultivated potato varieties a huge biodiversity exists, including an increasing number of red and purple colored cultivars. This coloration relates to the accumulation of anthocyanins and is supposed to offer nutritional benefits possibly associated with the antioxidative capacity of anthocyanins. However, the anthocyanin composition and its relation to the overall polyphenol constitution in colored potato tubers have not been investigated closely. This study focuses on the phytochemical characterization of the phenolic composition of a variety of colored potato tubers, both for peel and flesh tissues. First, liquid chromatography (LC) separation coupled to UV and mass spectrometry (MS) detection of polyphenolic compounds of potato tubers from 57 cultivars was used to assign groups of potato cultivars differing in their anthocyanin and polyphenol profiles. Tissues from 19 selected cultivars were then analyzed by LC separation coupled to multiple reaction monitoring (MRM) to detect quantitative differences in anthocyanin and polyphenol composition. The measured intensities of 21 anthocyanins present in the analyzed potato cultivars and tissues could be correlated with the specific tuber coloration. Besides secondary metabolites well-known for potato tubers, the metabolic profiling led to the detection of two anthocyanins not described for potato tuber previously, which we tentatively annotated as pelargonidin feruloyl-xylosyl-glucosyl-galactoside and cyanidin 3-p-coumaroylrutinoside-5-glucoside. We detected significant correlations between some of the measured metabolites, as for example the negative correlation between the main anthocyanins of red and blue potato cultivars. Mainly hydroxylation and methylation patterns of the B-ring of dihydroflavonols, leading to the formation of specific anthocyanidin backbones, can be assigned to a distinct coloring of the potato cultivars and tuber tissues. However, basically the same glycosylation and acylation reactions occur regardless of the main anthocyanidin precursor present in the respective red and blue/purple tissue. Thus, the different anthocyanin profiles in red and blue potato cultivars likely relate to superior regulation of the expression and activities of hydroxylases and methyltransferases rather than to differences for downstream glycosyl- and acyltransferases. In this regard, the characterized potato cultivars represent a valuable resource for the molecular analysis of the genetic background and the regulation of anthocyanin side chain modification.

Assessing Spatial Variability of Grape Skin Flavonoids at the Vineyard Scale Based on Plant Water Status Mapping.

Plant water stress affects grape (Vitis vinifera L. cv. Cabernet Sauvignon) berry composition and is variable in space due to variations in the physical environment at the growing site. We monitored the natural variability of grapevine water stress by stem water potential (Ψstem) and leaf gas exchange in an equi-distant grid in a commercial vineyard. Spatial differences were measured and related to topographical variation by modeling. Geospatial analysis and clustering allowed researchers to differentiate the vineyard block into two distinct zones having severe and moderate water stress where it varied by 0.2 MPa. Differences in stem water potential affected stomatal conductance, net carbon assimilation, and intrinsic water use efficiency that were different in all measurement dates. The two zones were selectively sampled at harvest for measurements of berry chemistry. The water status zones did not affect berry mass or yield per vine. Significant difference in total soluble solids was observed (3.56 Brix), and in titratable acidity, thus indicating a direct effect of water stress on ripening acceleration. Berry skin flavonol and anthocyanin composition and concentration were measured by C18 reversed-phased high-performance liquid chromatography (HPLC). The anthocyanins were most affected by the two water stress zones. The dihydroxylated anthocyanins were more affected than trihydroxylated; therefore, the ratio of the two forms increased. Flavonols were different in total amounts, but hydroxylation patterns were not affected. Proanthocyanidin isolates were characterized by acid catalysis in the presence of excess phloroglucinol followed by reversed-phase HPLC. Proanthocyanidins showed the least significant difference, although (+)-catechin terminal subunits were important predictors in a partial least square model used to summarize the multivariate relationships, predicting Ψstem or the management zone. The results provide fundamental information on vineyard water status to discriminate harvest or direction to vineyard operators to modify irrigation management to equilibrate berry composition at harvest.

Inhibition of Alpha-Amylase Activity by Gymnocarpos decandrus Forssk. Constituents

The methanolic extract of the aerial parts of Gymnocarpos decandrus, the plant growing wildly in the middle east area and north Africa, showed a promising -amylase inhibitory activity. The ethyl acetate fraction of the plant showed the highest inhibitory activity followed by the methylene chloride fraction. Phytochemical investigation of both fractions led to the isolation of 10 compounds; oleanolic acid (1), maslinic acid (2), apigenin (3), β-sitosterol glucoside (4), luteolin (5), afzelechin (6), epiafzelechin (7), catechin (8), epicatechin (9) and gallocatechin (10). The structures of compounds 1-10 were established on the basis of extensive 1D- and 2D-NMR spectroscopic techniques. This is the first report for the isolation of these compounds from G. decandrus. The phenolic compounds (6-10) isolated from the ethyl acetate fraction showed the highest -amylase inhibitory activity. The more the hydroxylation pattern of the isolated phenolic compounds (6, 8, 9 and 10), the higher the ability to inhibit the -amylase activity. This was confirmed through the molecular docking experiment. The wild plant G. decandrus is a promising -amylase inhibitor that can be used in the management of obesity and diabetes mellitus.

A Chaperone Complex Formed by HSP47, FKBP65, and BiP Modulates Telopeptide Lysyl Hydroxylation of Type I Procollagen.

Lysine hydroxylation of type I collagen telopeptides varies from tissue to tissue, and these distinct hydroxylation patterns modulate collagen cross-linking to generate a unique extracellular matrix. Abnormalities in these patterns contribute to pathologies that include osteogenesis imperfecta (OI), fibrosis, and cancer. Telopeptide procollagen modifications are carried out by lysyl hydroxylase 2 (LH2); however, little is known regarding how this enzyme regulates hydroxylation patterns. We identified an ER complex of resident chaperones that includes HSP47, FKBP65, and BiP regulating the activity of LH2. Our findings show that FKBP65 and HSP47 modulate the activity of LH2 to either favor or repress its activity. BiP was also identified as a member of the complex, playing a role in enhancing the formation of the complex. This newly identified ER chaperone complex contributes to our understanding of how LH2 regulates lysyl hydroxylation of type I collagen C-telopeptides to affect the quality of connective tissues. © 2017 American Society for Bone and Mineral Research.

Tentative Characterization of Polyphenolic Compounds in the Male Flowers of Phoenix dactylifera by Liquid Chromatography Coupled with Mass Spectrometry and DFT.

Phoenix dacylifera is an ancient palm species rich in (poly)phenols. These phenolic compounds were tentatively identified by using liquid chromatography coupled with ion spray mass spectrometry in tandem mode (LC/MS/MS) with negative ion detection. Negative identification of the compounds was based on their retention times and mass spectra in full scan mode (MS), and in different MS/MS modes. For the first time, complete hypothesis, and routs for both p-coumaroylshikimic acids (CoSA) and caffeoylshikimic acids (CSA) were suggested and confirmed by Density Fonctional Theory (DFT) study. Notably, of the 53 compounds characterized, 19 hydroxycinnamates derivatives were tentativelycharacterized in male flowers of date palm and 15 of them were recorded for the first time. In addition, five organic acids, six B-type proanthocyanidins, two anthocyanidin and 21 flavonoid derivatives have been tentatively characterized. Identification of B-type proanthocyanidins were based on the diagnostic ions resulting from heterocyclic ring fission (HRF) and retro-Diels-Alder (RDA) reaction of flavan-3-ol provided information on the hydroxylation pattern and the type of inter-flavan bond proanthocyanidins. The sequence of proanthocyanidins was detected through ions extracted from quinone methide (QM) cleavage of the inter-flavan bond.