Propionyl Groups Research Articles

In vitro and in vivo Metabolism of a Potent Inhibitor of Soluble Epoxide Hydrolase, 1-(1-Propionylpiperidin-4-yl)-3-(4-(trifluoromethoxy)phenyl)urea.

1-(1-Propionylpiperidin-4-yl)-3-(4-(trifluoromethoxy)phenyl)urea (TPPU) is a potent soluble epoxide hydrolase (sEH) inhibitor that is used extensively in research for modulating inflammation and protecting against hypertension, neuropathic pain, and neurodegeneration. Despite its wide use in various animal disease models, the metabolism of TPPU has not been well-studied. A broader understanding of its metabolism is critical for determining contributions of metabolites to the overall safety and effectiveness of TPPU. Herein, we describe the identification of TPPU metabolites using LC-MS/MS strategies. Four metabolites of TPPU (M1–M4) were identified from rat urine by a sensitive and specific LC-MS/MS method with double precursor ion scans. Their structures were further supported by LC-MS/MS comparison with synthesized standards. Metabolites M1 and M2 were formed from hydroxylation on a propionyl group of TPPU; M3 was formed by amide hydrolysis of the 1-propionylpiperdinyl group on TPPU; and M4 was formed by further oxidation of the hydroxylated metabolite M2. Interestingly, the predicted α-keto amide metabolite and 4-(trifluoromethoxy)aniline (metabolite from urea cleavage) were not detected by the LC-MRM-MS method. This indicates that if formed, the two potential metabolites represent <0.01% of TPPU metabolism. Species differences in the formation of these four identified metabolites was assessed using liver S9 fractions from dog, monkey, rat, mouse, and human. M1, M2, and M3 were generated in liver S9 fractions from all species, and higher amounts of M3 were generated in monkey S9 fractions compared to other species. In addition, rat and human S9 metabolism showed the highest species similarity based on the quantities of each metabolite. The presence of all four metabolites were confirmed in vivo in rats over 72-h post single oral dose of TPPU. Urine and feces were major routes for TPPU excretion. M1, M4 and parent drug were detected as major substances, and M2 and M3 were minor substances. In blood, M1 accounted for ~9.6% of the total TPPU-related exposure, while metabolites M2, M3, and M4 accounted for <0.4%. All four metabolites were potent inhibitors of human sEH but were less potent than the parent TPPU. In conclusion, TPPU is metabolized via oxidation and amide hydrolysis without apparent breakdown of the urea. The aniline metabolites were not observed either in vitro or in vivo. Our findings increase the confidence in the ability to translate preclinical PK of TPPU in rats to humans and facilitates the potential clinical development of TPPU and other sEH inhibitors.

The hydrogen bonding network of coproheme in coproheme decarboxylase from Listeria monocytogenes: Effect on structure and catalysis

Coproheme decarboxylase (ChdC) catalyzes the oxidative decarboxylation of coproheme to heme b, i.e. the last step in the recently described coproporphyrin-dependent pathway. Coproheme decarboxylation from Listeria monocytogenes is a robust enzymatic reaction of low catalytic efficiency. Coproheme acts as both substrate and redox cofactor activated by H2O2. It fully depends on the catalytic Y147 close to the propionyl group at position 2. In the present study we have investigated the effect of disruption of the comprehensive and conserved hydrogen bonding network between the four propionates and heme cavity residues on (i) the conformational stability of the heme cavity, (ii) the electronic configuration of the ferric redox cofactor/substrate, (iii) the binding of carbon monoxide and, (iv) the decarboxylation reaction mediated by addition of H2O2. Nine single, double and triple mutants of ChdC from Listeria monocytogenes were produced in E. coli. The respective coproheme- and heme b-complexed proteins were studied by UV–Vis, resonance Raman, circular dichroism spectroscopy, and mass spectrometry. Interactions of propionates 2 and 4 with residues in the hydrophobic cavity are crucial for maintenance of the heme cavity architecture, for the mobile distal glutamine to interact with carbon monoxide, and to keep the heme cavity in a closed conformation during turnover. By contrast, the impact of substitution of residues interacting with solvent exposed propionates 6 and 7 was negligible. Except for Y147A and K151A all mutant ChdCs exhibited a wild-type-like catalytic activity. The findings are discussed with respect to the structure-function relationships of ChdCs.

Rational Design of UCST-type Ureido Copolymers Based on a Hydrophobic Parameter.

Thermoresponsive polymers exhibiting upper critical solution temperature (UCST)-type behavior under physiologically relevant conditions have potential as biomaterials. The phase separation temperature ( Tp) of the UCST-type polymers can be increased by copolymerization with hydrophobic comonomers. Quantitative index parameters that could be used to rationally tune the Tp are lacking, however. We have reported that ureido copolymers such as poly(allylamine- co-allylurea) (AM-PU) and poly(l-ornithine- co-citrulline) exhibit UCST-type solution behavior under physiologically relevant conditions. In this study, AM-PU was hydrophobized by acylation. Tp of AM-PU can be regulated in a wide temperature range from about 20 to 80 °C or even higher by 20 mol % acylation with acetyl, propionyl, isobutanoyl, or pivaloyl groups, implying considerable impacts of hydrophobic groups on UCST phase separation. We observed a liner relationship between Tp and the hydrophobic parameter, log P, of the acyl groups. Furthermore, the acylation significantly reduced the influence of serum components on Tp by eliminating interactions of copolymers with serum components such as proteins and lipids. Acylation also abolished pH dependence of Tp which had been observed for unmodified AM-PU. Owing to the simple relationship between log P and Tp and the inertness of the acylated copolymer to serum components and pH changes, it is possible to rationally design copolymers exhibiting UCST-type behavior at a desired temperature under biological conditions.

Rapid Uptake and Photodynamic Inactivation of Staphylococci by Ga(III)-Protoporphyrin IX.

Antimicrobial photodynamic therapy (aPDT) is a promising method for the topical treatment of drug-resistant staphylococcal infections and can be further improved by identifying mechanisms that increase the specificity of photosensitizer uptake by bacteria. Here we show that Ga(III)-protoporphyrin IX chloride (Ga-PpIX), a fluorescent hemin analog with previously undisclosed photosensitizing properties, can be taken up within seconds by Staphylococcus aureus including multidrug-resistant strains such as MRSA. The uptake of Ga-PpIX by staphylococci is likely diffusion-limited and is attributed to the expression of high-affinity cell-surface hemin receptors (CSHRs), namely iron-regulated surface determinant (Isd) proteins. A structure-activity study reveals the ionic character of both the heme center and propionyl groups to be important for uptake specificity. Ga-PpIX was evaluated as a photosensitizer against S. aureus and several clinical isolates of MRSA using a visible light source, with antimicrobial activity at 0.03 μM with 10 s of irradiation by a 405 nm diode array (1.4 J/cm2); antimicrobial activity could also be achieved within minutes using a compact fluorescent lightbulb. GaPpIX was not only many times more potent than PpIX, a standard photosensitizer featured in clinical aPDI, but also demonstrated low cytotoxicity against HEK293 cells and human keratinocytes. Ga-PpIX uptake was screened against a diverse panel of bacterial pathogens using a fluorescence-based imaging assay, which revealed rapid uptake by several Gram-positive species known to express CSHRs, suggesting future candidates for targeted aPDT.

Metal–Organic Frameworks with Reduced Hydrophilicity for Postcombustion CO2 Capture from Wet Flue Gas

Postcombustion CO2 capture from wet flue gas is a daunting challenge that metal–organic-framework-based (MOF-based) adsorbents need to address, because the moisture in the gas stream may not only hydrolyze the coordination bonds of MOFs but also be competitively adsorbed in MOFs leading to compromised CO2 capture performance. In this study, two isostructural water-stable MOFs decorated with alkyl groups, namely, UiO-66(Zr)-(OAc)2 and UiO-66(Zr)-(OPr)2, are synthesized from UiO-66(Zr)-(OH)2 via a facile postsynthetic esterification strategy and evaluated for their water affinity and CO2 capture performance. The increased water contact angle and reduced water vapor capacity at 60% relative humidity indicate the positive role of the propionyl group of UiO-66(Zr)-(OPr)2 in reducing material hydrophilicity. When the adsorbent beds are not fully saturated with water, breakthrough experiments using simulated wet flue gas reveal that UiO-66(Zr)-(OPr)2 possesses a CO2/N2 adsorption selectivity of 76.6, which is 22...

Improved de novo sequencing of heparin/heparan sulfate oligosaccharides by propionylation of sites of sulfation

The structure of heparin and heparan sulfate (Hep/HS) oligosaccharides, as determined by the length and the pattern of sulfation, acetylation, and uronic acid epimerization, dictates their biological function through modulating interactions with protein targets. But fine structural determination is a very challenging task due to the lability of the sulfate modifications and difficulties in separating isomeric HS chains. Previously, we reported a strategy for chemical derivatization involving permethylation, desulfation, and trideuteroperacetylation, combined with standard reverse phase LC-MS/MS that enables the structural sequencing for heparin/HS oligosaccharides of sizes up to dodecasaccharide by positionally replacing all sulfates with more stable trideuteroacetyl groups, allowing for robust MS/MS sequencing. However, isomeric oligosaccharides that contain both N-sulfation and N-acetylation become isotopomers after labeling, differing only in the sites of deuteration. This prevents chromatographic separation of these different mixed domain sequences post-derivatization, and makes sequencing by MS/MS difficult due to co-fragmentation of the isotopomers leading to chimeric product ion spectra. In order to improve chromatographic separation of mixed domain oligosaccharides, we have introduced a propionylation step in place of trideuteroacetylation for labeling of sites of sulfation. HS standard disaccharides have been used to evaluate the efficiency of this improved chemical derivatization. The results show that we can quantitatively replace sulfation with propionyl groups with the same high efficiency as the previously reported trideuteroacetylation. After derivatization, we demonstrate the ability to chromatographically separate two mixed domain tetrasaccharide isomers differing solely by the order of N-sulfation and N-acetylation, allowing for full sequencing of each by MS/MS. These results represent a marked improvement in the ability of our previously reported derivatization strategy to analyze complex mixtures of Hep/HS oligosaccharides without a decrease in sensitivity.

Unraveling substituent effects on frontier orbitals of conjugated molecules using an absolutely localized molecular orbital based analysis.

It is common to introduce electron-donating or electron-withdrawing substituent groups into functional conjugated molecules (such as dyes) to tune their electronic structure properties (such as frontier orbital energy levels) and photophysical properties (such as absorption and emission wavelengths). However, there lacks a generally applicable tool that can unravel the underlying interactions between orbitals from a substrate molecule and those from its substituents in modern electronic structure calculations, despite the long history of qualitative molecular orbital theory. In this work, the absolutely localized molecular orbitals (ALMO) based analysis is extended to analyze the effects of substituent groups on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of a given system. This provides a bottom-up avenue towards quantification of effects from distinct physical origins (e.g. permanent electrostatics/Pauli repulsion, mutual polarization, inter-fragment orbital mixing). For the example case of prodan (a typical dye molecule), it is found that inter-fragment orbital mixing plays a key role in narrowing the HOMO-LUMO gap of the naphthalene core. Specifically, an out-of-phase mixing of high-lying occupied orbitals on the naphthalene core and the dimethylamino group leads to an elevated HOMO, whereas an in-phase combination of LUMOs on the naphthalene core and the propionyl group lowers the LUMO energy of the entire molecule. We expect this ALMO-based analysis to bridge the gap between concepts from qualitative orbital interaction analysis and quantitative electronic structure calculations.

Analysis of molecular interaction using a pulse-induced ring-down compression ATR-DIRLD step-scan time resolved spectroscopy/2D-IR

A rheo-optical method, based on pulsed compression ATR dynamic infrared linear dichroism (DIRLD) step scan time-resolved-FT-IR/2D-IR spectroscopy, is further improved. By inserting a tungsten carbide block with massive weight between a film sample and a piezo electric actuator, a ring-down response was successfully generated according to the inertial effect. The improved method is used to analyze molecular interactions in cellulose acetate propionate (CAP) films including tricresyl-phosphate (TCP), as compared with cellulose triacetate (CTA) films with the TCP case. The result suggests that the existence of molecular interaction among propionyl groups in the CAP, the TCP's Methyl, and phenyl rings, which is not observed in the CTA-TCP system.

Accessibility of hydroxyl groups in anhydride modified wood as measured by deuterium exchange and saponification

Abstract Acetylated wood (WAc) shows improved properties largely due to the reduced amount of water in its cell wall, but the exact mechanism of water reduction remains unclear. Acetylation reduces hydroxyl (OH) content by acetyl (Ac) substitution but may also limit water access to unmodified OH groups by steric hindrance. In the present work, the accessibility of OH groups in acetylated or propionylated Radiata pine (Pinus radiata D. Don) wood (WAc and WPr) was investigated by deuterium exchange, saponification in sodium hydroxide followed by high-performance liquid chromatography (HPLC) analysis and weight percentage gain determination of the modified samples. Acetylation reduced OH accessibility (OHA) to a greater extent than would be predicted, if OH substitution were the only responsible mechanism for accessibility reduction. The combination of deuterium exchange and saponification results provides strong evidence that steric hindrance plays a key role in reduction of water accessibility to unmodified OH groups in WAc. The supramolecular architecture of WPr samples seems to be modified by the propionylation reaction, which leads to increased OHA at low levels of substitution. This suggests that molecular restructuring within the cell wall exposes new OH groups after propionylation. At higher levels of substitution, however, the WPr exhibited less OHA than expected indicating steric hindrance from the propionyl groups.

Synthesis of cellulose acetate propionate with controllable contents and distributions of acetyl and propionyl in the C2, C3 and C6 positions

In this work, during the synthesis and hydrolysis of cellulose acetate propionate (CAP), the research not only focused on the contents, but also the distributions of acetyl and propionyl groups in the different positions of anhydroglucose unit, i.e. C2, C3 and C6. It was investigated that cellulose propionylation was more difficult than acetylation, which required larger amounts of reagents. At the same temperature, the reaction rate constant of cellulose acetylation was much higher than that of propionylation. Furthermore, the partial degrees of propionyl substitution in CAP were 0.54, 0.54, and 0.48 for C2, C3, and C6. The contents of propionyl distributed on C2 and C3 positions were higher than that on C6 indicating that acetyl took the position of C6 preferentially. During the hydrolysis of CAP, the degrees of hydrolysis were 0.1 for acetyl and 0.3 for propionyl. Acetyl groups in the C6 position and propionyls in the C2 position were hydrolyzed much easier with the degrees of hydrolysis of 0.16 and 0.32, respectively. In addition, it has been investigated that hydroxyl groups in the C3 position exhibited the lowest reactivity during the synthesis of CAP, while acyl groups on C3 was also the hardest to be hydrolyzed.

Birefringence and strain-induced crystallization of stretched cellulose acetate propionate films

We have investigated the wavelength dependence of the birefringence (Δn) for cellulose acetate propionate (CAP) films stretched at various draw ratios (DRs) and strain rates (SRs) by comparing with the result of cellulose triacetate (CTA). CAP exhibits extraordinary wavelength dispersion of Δn although CTA shows ordinary dispersion, indicating that Δn of CAP is determined by the acetyl and propionyl groups. For CAP, the extraordinary dispersion becomes stronger at higher DR and SR. Thermal analysis suggests that hot stretching induces crystallization of CAP and the crystal size increases with increasing DR and SR. Furthermore, the two-dimensional X-ray diffraction patterns of CAP and CTA (a semicrystalline polymer) exhibit orientation of the induced crystal. These results mean that the acetyl orientation in CAP becomes stronger than the propionyl orientation. This conclusion is reasonable because the acetyl group is more tightly confined to the pyranose ring than the propionyl group.

Coating microbubbles with nanoparticles for medical imaging and drug delivery.

Coating microbubbles with nanoparticles for medical imaging and drug delivery.

Characterization of Individual Histone Posttranslational Modifications and Their Combinatorial Patterns by Mass Spectrometry-Based Proteomics Strategies.

Histone posttranslational modifications (PTMs) play an essential role in chromatin biology, as they model chromatin structure and recruit enzymes involved in gene regulation, DNA repair, and chromosome condensation. Such PTMs are mostly localized on histone N-terminal tails where, as single units or in a combinatorial manner, they influence chromatin reader protein binding and fine-tune the abovementioned activities. Mass spectrometry (MS) is currently the most adopted strategy to characterize proteins and protein PTMs. We hereby describe the protocols to identify and quantify histone PTMs and their patterns using either bottom-up or middle-down proteomics. In the bottom-up strategy we obtain 5-20 aa peptides by derivatization with propionylation followed by trypsin digestion. The newly generated N-termini of histone peptides can be further derivatized with light or isotopically heavy propionyl groups to increase chromatographic retention and allow multiplexed analyses. Moreover, we describe how to perform derivatization and trypsin digestion of histones loaded into a gel, which is usually the final step of immunoprecipitation experiments. In the middle-down strategy we obtain intact histone tails of 50-60 aa by digestion with the enzyme GluC. This allows characterization of combinatorial histone PTMs on N-terminal tails.

Dihydroanatoxin-a Is Biosynthesized from Proline in Cylindrospermum stagnale PCC 7417: Isotopic Incorporation Experiments and Mass Spectrometry Analysis

LC-MS and GC-MS analytical conditions have been developed to detect the cis- and trans-epimers (relative configuration of the carbon bearing the acetyl or propionyl group) of dihydroanatoxin-a and dihydrohomoanatoxin-a, in biological samples. These compounds epimerize under acidic conditions, yielding a major species that was tentatively assigned as the cis-epimer. Cylindrospermum stagnale PCC 7417 was definitively shown to produce dihydroanatoxin-a (1.2 mg/g dried cells). Oscillatoria sp. PCC 9107, Oscillatoria sp. PCC 6506, and C. stagnale PCC 7417, which produce anatoxin-a, homoanatoxin-a, and dihydroanatoxin-a, respectively, were cultivated in the presence of isotopically labeled proline, and the toxins were extracted. Interpretation of the GC-MS electron ionization mass spectra of these labeled anatoxins showed that they are all biosynthesized from proline and that the positions of the labels in these molecules are identical. These data and the fact that the ana cluster of genes is conserved in these cyanobacteria suggest that dihydroanatoxin-a is formed by the reduction of either anatoxin-a or its precursor in a specific step involving AnaK, an F420-dependent oxido-reductase whose gene is found in the ana gene cluster in C. stagnale PCC 7417. This is the first report of a cyanobacterium producing dihydroanatoxin-a, suggesting that other producers are present in the environment.

Synthesis and evaluation of (+)-decursin derivatives as inhibitors of the Wnt/β-catenin pathway

We synthesized (+)-decursin derivatives substituted with cinnamoyl- and phenyl propionyl groups originating from (+)-CGK062 and screened them using a cell-based assay to detect relative luciferase reporter activity. Of this series, compound 8b, in which a 3-acetoxy cinnamoyl group was introduced, most potently inhibited (97.0%) the Wnt/β-catenin pathway. Specifically, compound 8b dose-dependently inhibited Wnt3a-induced expression of the β-catenin response transcription (CRT) and increased β-catenin degradation in HEK293 reporter cells. Furthermore, compound 8b suppressed expression of the downstream β-catenin target genes cyclin D1 and c-myc and suppressed PC3 cell growth in a concentration-dependent manner.

Human acetyl-CoA:glucosamine-6-phosphate N-acetyltransferase 1 has a relaxed donor specificity and transfers acyl groups up to four carbons in length

Glucosamine-6-phosphate N-acetyltransferase1 (GNA1) catalyses the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to glucosamine-6-phosphate (GlcN6P) to form N-acetylglucosamine-6-phosphate (GlcNAc6P), which is an essential intermediate in UDP-GlcNAc biosynthesis. An analog of GlcNAc, N-butyrylglucosamine (GlcNBu) has shown healing properties for bone and articular cartilage in animal models of arthritis. The goal of this work was to examine whether GNA1 has the ability to transfer a butyryl group from butyryl-CoA to GlcN6P to form GlcNBu6P, which can then be converted to GlcNBu. We developed fluorescent and radioactive assays and examined the donor specificity of human GNA1. Acetyl, propionyl, n-butyryl, and isobutyryl groups were all transferred to GlcN6P, but isovaleryl-CoA and decanoyl-CoA did not serve as donor substrates. Site-specific mutants were produced to examine the role of amino acids potentially affecting the size and properties of the AcCoA binding pocket. All of the wild type and mutant enzymes showed activities of both acetyl and butyryl transfer and can therefore be used for the enzymatic synthesis of GlcNBu for biomedical applications.

Effect of acetylation site on orientation birefringence of cellulose triacetate

The effect of a substitution site on orientation birefringence for cellulose triacetate (CTA) was investigated by the addition of xylan ester. Since CTA has three substitution sites (C-2, C-3, and C-6) while xylan ester has two substitution sites (C-2 and C-3), the change of birefringence by xylan acetate (XylAc) is attributed to the contribution of the C-6 acetyl group. Dynamic mechanical analysis and thermal measurements showed a single glass transition peak, indicating that XylAc is miscible with CTA at any compositions. The orientation birefringence (Δn) of CTA/XylAc films stretched beyond the glass transition temperature increased with increasing the XylAc content. The result for the stretched film suggested that the contribution of acetyl group in the C-2 and C-3 sites to Δn is positive while that in the C-6 is negative. The negative sign for the C-6 site is in agreement with the result simulated by using the molecular dynamics method. In addition, Δn of CTA films containing xylan propionate (or butyrate) indicated that the propionyl and butyryl groups in the C-2 and C-3 sites show positive birefringence similar to the acetyl group.

Drawbacks in the use of unconventional hydrophobic anhydrides for histone derivatization in bottom-up proteomics PTM analysis

MS-based proteomics has become the most utilized tool to characterize histone PTMs. Since histones are highly enriched in lysine and arginine residues, lysine derivatization has been developed to prevent the generation of short peptides (<6 residues) during trypsin digestion. One of the most adopted protocols applies propionic anhydride for derivatization. However, the propionyl group is not sufficiently hydrophobic to fully retain the shortest histone peptides in RP LC, and such procedure also hampers the discovery of natural propionylation events. In this work we tested 12 commercially available anhydrides, selected based on their safety and hydrophobicity. Performance was evaluated in terms of yield of the reaction, MS/MS fragmentation efficiency, and drift in retention time using the following samples: (i) a synthetic unmodified histone H3 tail, (ii) synthetic modified histone peptides, and (iii) a histone extract from cell lysate. Results highlighted that seven of the selected anhydrides increased peptide retention time as compared to propionic, and several anhydrides such as benzoic and valeric led to high MS/MS spectra quality. However, propionic anhydride derivatization still resulted, in our opinion, as the best protocol to achieve high MS sensitivity and even ionization efficiency among the analyzed peptides.

Binding of azole drugs to heme: A combined MS/MS and computational approach

The binding properties of azole drugs toward ferric heme have been examined, focusing on well known antifungal drugs bearing imidazole and triazole heteroaromatic rings. These drugs are known to act as inhibitors of the Candidaalbicans P450 sterol 14α-demethylase enzyme, through binding to the heme prosthetic group. Absolute binding energies have been determined experimentally by energy variable collision induced dissociation experiments performed on the selected ionic complexes and evaluated theoretically using density functional theory, within the Car–Parrinello Molecular Dynamics method. The two series display some agreement in the relative binding energies data. These findings suggest that the combined ab initio and mass spectrometric approach may prove fruitful in assaying complexes between a prosthetic group and an array of ligands of potential pharmacological activity. It is shown that the axial interaction of the imidazole-based drugs with iron(III) is somewhat stronger than that of the triazole-based drugs. This general observation fails if specific interactions remote from the metal center come into play. For example, a hydrogen bond interaction is established in the ferric heme complex with fluconazole, a drug of the triazole family owning a hydroxyl group prone to interact with the carbonyl oxygen of a propionyl group on the periphery of protoporphyrin IX. However, the relatively uniform values for both the experimental and theoretically calculated binding energies underline the important role played by the prosthetic group environment in tuning the heme interaction with biological and xenobiotic molecules and ultimately in modulating enzyme activity.

Characterisation of Physicochemical Properties of Propionylated Corn Starch and Its Application as Stabiliser.

A series of propionylated starches with different degrees of substitution (DS) was synthesised and their physicochemical properties and application as a stabiliser were investigated. Starch propionates with moderate DS were prepared by esterification of native corn starch with propionic anhydride. By varying the reaction times of the esterification process, twelve starch propionates with DS of 0.47 to 0.94 were prepared. FTIR and NMR confirmed the introduction of propionyl groups to the starch. X-ray diffraction pattern showed reduced crystallinity in the starch propionates. The contact angle was found to increase proportionately with the increase in DS. Swelling power results showed that starch propionates were able to swell more than native corn starch at low temperature (40 °C). Oil-in- -water (O/W) emulsions prepared using starch propionates (DS of 0.64 to 0.86) showed exceptional stability when challenged by centrifugation stress test. These stable O/W emulsions had viscosities in the range of 1236.7-3330.0 mPa·s. In conclusion, moderately substituted short-chain (propionylated) starches could be a promising cold swelling starch, thickener and O/W emulsion stabiliser in food, pharmaceutical and cosmetic industries.