Propionate Esters Research Articles

Resveratrol Propionate Ester Supplement Exerts Antihypertensive Effect in Juvenile Rats Exposed to an Adenine Diet via Gut Microbiota Modulation.

Resveratrol, acting as a prebiotic, and propionate, functioning as a postbiotic, hold promise for preventing hypertension in chronic kidney disease (CKD). Previously, we employed propionate to enhance the bioavailability of resveratrol through esterification, resulting in the production of a resveratrol propionate ester (RPE) mixture. In this study, we purified 3-O-propanoylresveratrol (RPE2) and 3,4'-di-O-propanoylresveratrol (RPE4) and investigated their protective effects in a juvenile rat adenine-induced CKD model. To this end, male Sprague Dawley rats aged three weeks (n = 40) were divided into five groups: control; CKD (rats fed adenine); CKRSV (CKD rats treated with 50 mg/L resveratrol); CDRPE2 (CKD rats treated with 25 mg/L RPE2); and CKRPE4 (CKD rats treated with 25 mg/L RPE 4). RPE2 and PRE4 similarly exhibited blood pressure-lowering effects comparable to those of resveratrol, along with increased nitric oxide (NO) availability. Furthermore, RPE2 and RPE4 positively influenced plasma short-chain fatty acid (SCFA) levels and induced distinct alterations in the gut microbial composition of adenine-fed juvenile rats. The supplementation of RPE2 and RPE4, by restoring NO, elevating SCFAs, and modulating the gut microbiota, holds potential for ameliorating CKD-induced hypertension.

Molecularly engineered lignin to polyphenol via organocatalysis as an active sunscreen ingredient

Phenolation is one of the effective strategies to synthesize lignin-based polyphenols, improve lignin's properties, and extend its value-added applications in biological, medicinal and cosmetic fields. Herein, by taking the structural feature advantage of lignin, an effective and green strategy was developed to molecularly engineer lignin into a robust lignin-3-(2-hydroxyphenyl)propionate ester (LPPE) derivative via a transesterification reaction between 3,4-dihydrocoumarin (DHC) and the aliphatic hydroxyls in lignin under organocatalysis. The strategy is optimized and the novel derivative was systematically characterized by 1H, 13C and 31P nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopy. The findings indicated that the successful introduction of 3-(2-hydroxyphenyl)propionate groups using a OH groups/DHC/organic base molar ratio of 1꞉1꞉0.3 at 120 °C for 6 h increased the content of phenolic hydroxyl groups from 1.793 1 to 3.017 9 mmol/g, and the LPPE exhibited excellent ultraviolet-absorbing and antioxidant performance with up to 90% free radical scavenging activity within 20 min using 5 mg/mL of LPPE. In addition, good biocompatibility and a high Sun protection factor (SPF) value of 40.9 were achieved at 5% (w) dosage of LPPE in the cream, indicating its significant application potential in sunscreen.

The Effects of the Steroids 5-Androstenediol and Dehydroepiandrosterone and Their Synthetic Derivatives on the Viability of K562, HeLa, and Wi-38 Cells and the Luminol-Stimulated Chemiluminescence of Peripheral Blood Mononuclear Cells from Healthy Volunteers.

In order to evaluate the role of substituents at 3-C and 17-C in the cytotoxic and cytoprotective actions of DHEA and 5-AED molecules, their derivatives were synthesized by esterification using the corresponding acid anhydrides or acid chlorides. As a result, seven compounds were obtained: four DHEA derivatives (DHEA 3-propionate, DHEA 3-butanoate, DHEA 3-acetate, DHEA 3-methylsulfonate) and three 5-AED derivatives (5-AED 3-butanoate, 5-AED 3,17-dipropionate, 5-AED 3,17-dibutanoate). All of these compounds showed micromolar cytotoxic activity toward HeLa and K562 human cancer cells. The maximum cytostatic effect during long-term incubation for five days with HeLa and K562 cells was demonstrated by the propionic esters of the steroids: DHEA 3-propionate and 5-AED 3,17-dipropionate. These compounds stimulated the growth of normal Wi-38 cells by 30-50%, which indicates their cytoprotective properties toward noncancerous cells. The synthesized steroid derivatives exhibited antioxidant activity by reducing the production of reactive oxygen species (ROS) by peripheral blood mononuclear cells from healthy volunteers, as demonstrated in a luminol-stimulated chemiluminescence assay. The highest antioxidant effects were shown for the propionate ester of the steroid DHEA. DHEA 3-propionate inhibited luminol-stimulated chemiluminescence by 73% compared to the control, DHEA, which inhibited it only by 15%. These data show the promise of propionic substituents at 3-C and 17-C in steroid molecules for the creation of immunostimulatory and cytoprotective substances with antioxidant properties.

Attraction of Male Pine Sawflies, Diprion jingyuanensis, to Synthetic Pheromone Candidates: Synergism between Two Stereoisomers

The pine sawfly Diprion jingyuanensis Xiao and Zhang (Hymenoptera: Diprionidae) is a serious pest of Pinus tabulaeformis Carr. in the Shanxi, Gansu, and Inner Mongolia provinces in P. R. China. The sex pheromone of D. jingyuanensis was shown to be the propionate ester of 3,7-dimethyl-2-tridecanol. Virgin females contained an approximate 1:3 blend of the pheromone precursors erythro-(2S,3S,7R/S and 2R,3R,7R/S)-3,7-dimethyl-2-tridecanol and threo-(2S,3R,7R/S and 2R,3S,7R/S)-3,7-dimethyl-2-tridecanol, but the exact stereoisomers were not determined. Males responded the strongest to the propionate ester of the two threo-isomers, (2S,3R,7R) and (2S,3R,7S), in electroantennogram (EAG) recordings, followed by a significant EAG response to the (2S,3R,7R) propionate of diprionol (pheromone component of D. similis), whereas the remaining two isomers (2S,3S,7S and 2S,3S,7R) of the propionate ester of 3,7-dimethyl-2-tridecanol and the acetate of the (2S,3R,7R) isomer (one of the two pheromone components of D. pini) did not elicit any significant increase in antennal response. In the field, the strongly EAG-active (2S,3R,7R)-isomer alone was only weakly (but significantly) attractive to D. jingyuanensis males at 100 µg, while the equally EAG- active (2S,3R,7S)-isomer alone at the same loading was 8–14 times more attractive than was the (2S,3R,7R)-isomer alone. Traps baited with the same amounts of the two threo-isomers ((2S,3R,7R) and (2S,3R,7S), 100 µg + 100 µg) caught significantly more males than did traps baited with other isomers, either of the two isomers alone or other proportions of the two isomers. Thus, the (2S,3R,7S)-isomer is considered as a strong and essential sex-attractant component for D. jingyuanensis males, whereas the (2S,3R,7R)-isomer is a weak but synergistic sex-attractant. This is one of the few examples of a pine sawfly responding significantly stronger to a binary blend of stereoisomers in a synergistic fashion than to a single stereoisomer alone.

Increase in colonic PRopionate as a method of prEVENTing weight gain in adults aged 20–40 years (iPREVENT): protocol of a multi-centre, double-blind, randomised, parallel-group trial to investigate the efficacy of inulin-propionate ester versus inulin (control) in the prevention of weight gain over 12 months

Introduction: Overweight and obesity affects over 70% of the UK population and is a major risk factor for the development of co-morbidities, including type 2 diabetes and cardiovascular disease. There now exists a considerable evidence base for the management of obesity. However, this is not the case for the prevention of obesity. Preventing weight gain in periods of life where there is an elevated risk of fat mass expansion could be beneficial to preventing associated diseases in later life. This protocol investigates the impact of novel food ingredient inulin propionate ester (IPE) in the prevention of weight gain. This trial aims to investigate the primary hypothesis that IPE has a superior effect on preventing body weight gain, compared with inulin, in young (<40 years old) adults over 12 months, whilst also investigating several complementary mechanisms that may explain the prevention of weight gain and improved long-term energy balance from consuming IPE. Methods: In this multi-centre, double-blind, randomised, parallel-group study, eligible participants will be randomly assigned to consume 10g IPE or 10g inulin (control) daily for 12 months. Study visits will be conducted at baseline, two-month, six-month and 12-month time points. The primary outcome is weight gain from baseline to 12 months. Secondary outcomes will examine changes in metabolic and cardiovascular health biomarkers, body composition and appetite. A mechanistic sub-group will explore causal mechanisms around energy balance, body composition, appetite regulation and the gut microbiota. Based on the power calculation, the sample size required is 270 participants or 135 per study group. Ethics and dissemination: The trial protocol and participant-facing documents have been reviewed and approved, by the London Hampstead Ethics Committee (REC Reference 19/LO/0095, 29th January 2019). Upon completion, the trial results will be published in peer-reviewed journals and presented at scientific conferences. Trial registration number: ISRCTN16299902, 1st March 2018.

EFFECT OF AQUO-N-PROPANOL SOLVENT SYSTEMS ON THE MEDICINAL EFFICIENCY OF HEAVY PROPIONATES

For highlighting the Solvent-effect of a diapolar aprotic solvent, n-propanol on the biochemical behaviour of propionate ester, the kinetics of alkali catalysed hydrolysis of butyl propionate was carried out in aquo-n-propanol solvent systems having different concentration of the organic component (n-propanol) varying from 20 to 80% (v/v) at different temperatures ranging from 20 to 40°C. The number of water molecules associated with the activated complex of the reaction were found to increase from 0.338 to 1.401 and from this, it is it inferred that n-propanol acts as structure breaker of water converting its dense form into bulky form and it changes the mechanistic path way of the reaction from bimolecular to unimolecular, From the numerical value of the kinetic temperature of the reaction, which is evaluated to be 281.0, it is concluded that there is weak but appreciable interaction between solvent and solute in the reaction media.

Synthesis of a fully biobased cellulose-3-(2-hydroxyphenyl) propionate ester with antioxidant activity and UV-resistant properties by the DBU/CO2/DMSO solvent system

A novel fully biobased cellulose-3-(2-hydroxyphenyl) propionate ester with satisfactory antioxidant activity and UV-resistant properties was first prepared using cellulose and 3,4-dihydrocoumarin (DHC) in a DMSO/DBU/CO2 solvent system without adding any external catalyst.

Potential of Cinnamomum iners wood as antimicrobial agent

The wood of Cinnamomum iners (Medang Teja) believe in giving multiple beneficial, especially in traditional usage. However, due to the lack of studies regarding this species made this species unable to express its full potential being commercialised by the industry. Thus, this study is prosecuted with the objectives to evaluate the chemical composition and analyse the biological activity of extractive and essential oil derived from Cinnamomum iners (Medang Teja) wood. The samples that evaluated comprises of 100%, 1%, 2%, 3% essential oils and extractive of chemical composition are conducted through Fourier Transform Infrared Spectroscopy (FTIR) and Gas-Chromatography Mass Spectrometry (GCMS) analysis. Meanwhile analysing of its biological activity is made through antifungal and antimicrobial activity. The results found that the functional group presents in all the samples shared one similar functional groups which are aliphatic hydrocarbons. For 100% essential oil, the functional groups are aliphatic propionate ester, aliphatic hydrocarbons and tertiary aliphatic alcohols. 1%, 2%, and 3% essential oil consist of the same functional groups which are olefins, aliphatic hydrocarbons and aliphatic acetate esters. Extractives have aliphatic hydrocarbons and primary aliphatic alcohols. Through GCMS, the major compounds found in the samples are 2(1H)-Naphthalenone, octahydro-, trans-Linalool,. beta. Fenchyl alcohol, Camphor, Benzene, ethyl-(CAS) EB. The similar compound found in all samples are Linalool, terpinene-4-ol, Terpineol, Copaene, Cadinene. From the antifungal analysis, it is proved that all of the samples can hold the antifungal traits, as all the samples show the effects of inhibitory on both brown-rot, Coniophora puteana and white-rot fungi, Pycnoporus sanguineus. The most susceptible organisms are the Coniophora puteana which showed a lower average diameter of inhibition zone for all the sample. Lastly, the samples shown a positive result in being antimicrobial agents for both gram negative, Escherichia coli and gram positive, Staphylococcus aureus.

Effects of Inulin Propionate Ester on Obesity-Related Metabolic Syndrome and Intestinal Microbial Homeostasis in Diet-Induced Obese Mice.

Short-chain fatty acid (SCFA) plays an important role in improving obesity and related metabolic syndrome induced by high-fat diet. We used the prepared inulin propionate ester (IPE) as a system for the targeted release of propionate to the colon to elucidate the role of IPE in regulating obesity and metabolic syndrome, and intestinal microbial homeostasis, in diet-induced obese mice. With this strategy, IPE significantly increased the SCFA contents in the colon and resulted in significant body weight reduction, insulin resistance amelioration, and gastrointestinal hormone (glucagon-like peptide and peptide YY) secretion (P < 0.05). The IPE intervention reduced liver fatty accumulation, which improved obesity-related fatty liver disease (P < 0.05). IPE supplementation increased the richness and diversity of the microbial community and altered bacterial population at both the phylum and family level. Intestinal microbial results showed that the relative abundance of Desulfovibrionaceae and Erysipelotrichaceae, which promote the production of inflammatory factors, was reduced. Our results demonstrate that IPE can be used as an effective strategy for delivering propionate to obese mice colon, which can ameliorate obesity and associated metabolic syndrome and modify intestinal microbial homeostasis.

Moderate intensity exercise training combined with inulin-propionate ester supplementation increases whole body resting fat oxidation in overweight women

BackgroundOur previous work has shown that oral supplementation with inulin propionate ester (IPE) reduces intra-abdominal fat and prevents weight gain and that oral propionate intake enhances resting fat oxidation. The effects of IPE combined with exercise training on energy substrate utilisation are unknown. The aim of this study was to investigate the impact of 4-weeks IPE supplementation, in combination with a moderate intensity exercise training programme, on whole body fat oxidation and on plasma GLP-1 and PYY. MethodsTwenty overweight healthy women participated in randomised parallel study and underwent 4 weeks of supervised exercise training either with IPE (EX/IPE group) or Placebo (EX/Placebo group) supplementation. Before and after the intervention participants conducted an experimental trial, which involved collection of expired gas and blood samples in the fasted state and during 7 h of the postprandial state. ResultsWithin groups, the EX/IPE group significantly enhanced the amount of fat (Pre, 24.1 ± 1.2 g; Post, 35.9 ± 4.0 g, P < 0.05) oxidised and reduced CHO (Pre, 77.8 ± 6.0 g; Post, 57.8 ± 7.7 g, P < 0.05) oxidised, reduced body weight (Pre, 77.3 ± 4.2 kg; Post, 76.6 ± 4.1 kg, P < 0.05) and body fat mass (Pre, 37.7 ± 1.9%; Post, 36.9 ± 1.9%, P < 0.05). In EX/Placebo group, changes in amount of fat (Pre, 36.8 ± 3.9 g; Post, 37.0 ± 4.0 g) and CHO (Pre, 62.7 ± 6.5 g; Post, 61.5 ± 7.4 g) oxidised, body weight (Pre, 84.2 ± 4.3 kg; Post, 83.6 ± 4.3 kg) and body fat mass (Pre, 40.1 ± 1.9%; Post, 38.7 ± 1.5%) were not significant (P > 0.05). Comparing between groups, changes in the amount of fat oxidised were significantly (P < 0.05) different and a trend for difference was observed for amount of CHO oxidised (P = 0.06) and RER (P = 0.06). The interventions had no impact on fasting or postprandial plasma concentrations of GLP-1 and PYY. ConclusionModerate intensity exercise training programmes when combined with daily oral IPE supplementation may help overweight women to achieve increase in fat oxidation.The study was registered at clinicaltrials.gov as NCT04016350.

Stereoselective Synthesis of the A,E-Ring Bicyclic Core of Calyciphylline B-Type Alkaloids

A stereoselective synthesis of the bicyclic unit constituting the A and E rings of calyciphylline B-type alkaloids is disclosed. The propionate ester of (1R)-cyclohex-2-en-1-ol, obtained by enzymatic resolution, is subjected to an Ireland–Claisen rearrangement. Subsequent reduction of the acid, Mitsunobu reaction to introduce a nitrogen functionality, oxidative cleavage to a dialdehyde, and intramolecular aldol and aza-Michael reactions afford the bicyclic subunit.

Effects of Inulin Propionate Ester Incorporated into Palatable Food Products on Appetite and Resting Energy Expenditure: A Randomised Crossover Study.

Supplementation with inulin-propionate ester (IPE), which delivers propionate to the colon, suppresses ad libitum energy intake and stimulates the release of satiety hormones acutely in humans, and prevents weight gain. In order to determine whether IPE remains effective when incorporated into food products (FP), IPE needs to be added to a widely accepted food system. A bread roll and fruit smoothie were produced. Twenty-one healthy overweight and obese humans participated. Participants attended an acclimatisation visit and a control visit where they consumed un-supplemented food products (FP). Participants then consumed supplemented-FP, containing 10 g/d inulin or IPE for six days followed by a post-supplementation visit in a randomised crossover design. On study visits, supplemented-FP were consumed for the seventh time and ad libitum energy intake was assessed 420 min later. Blood samples were collected to assess hormones and metabolites. Resting energy expenditure (REE) was measured using indirect calorimetry. Taste and appearance ratings were similar between FP. Ad libitum energy intake was significantly different between treatments, due to a decreased intake following IPE-FP. These observations were not related to changes in blood hormones and metabolites. There was an increase in REE following IPE-FP. However, this effect was lost after correcting for changes in fat free mass. Our results suggest that IPE suppresses appetite and may alter REE following its incorporation into palatable food products.

Dietary fibers inhibit obesity in mice, but host responses in the cecum and liver appear unrelated to fiber-specific changes in cecal bacterial taxonomic composition

Dietary fibers (DF) can prevent obesity in rodents fed a high-fat diet (HFD). Their mode of action is not fully elucidated, but the gut microbiota have been implicated. This study aimed to identify the effects of seven dietary fibers (barley beta-glucan, apple pectin, inulin, inulin acetate ester, inulin propionate ester, inulin butyrate ester or a combination of inulin propionate ester and inulin butyrate ester) effective in preventing diet-induced obesity and links to differences in cecal bacteria and host gene expression. Mice (n = 12) were fed either a low-fat diet (LFD), HFD or a HFD supplemented with the DFs, barley beta-glucan, apple pectin, inulin, inulin acetate ester, inulin propionate ester, inulin butyrate ester or a combination of inulin propionate ester and inulin butyrate ester for 8 weeks. Cecal bacteria were determined by Illumina MiSeq sequencing of 16S rRNA gene amplicons. Host responses, body composition, metabolic markers and gene transcription (cecum and liver) were assessed post intervention. HFD mice showed increased adiposity, while all of the DFs prevented weight gain. DF specific differences in cecal bacteria were observed. Results indicate that diverse DFs prevent weight gain on a HFD, despite giving rise to different cecal bacteria profiles. Conversely, common host responses to dietary fiber observed are predicted to be important in improving barrier function and genome stability in the gut, maintaining energy homeostasis and reducing HFD induced inflammatory responses in the liver.

Synthesis, Characterization of Inulin Propionate Ester, and Evaluation of its in Vitro Effect on SCFA Production

In this study, the authors developed a method for the synthesis of inulin propionate ester as dietary fiber carrier to increase the amounts of short chain fatty acids (SCFA). The propionylated inulin showed an appreciable effect for increasing SCFA compared with control inulin. The structure characteristics of inulin propionate ester are established based on FT‐IR, 1H NMR, and 13C NMR spectra. Meanwhile, response surface methodology (RSM) is used to optimize the synthesis conditions and investigate the effect of three parameters on the degree of substitution (DS). The optimal conditions are as follows: the ratio of anhydride to inulin of 4.5:1, the concentration of 30%, the temperature of 40 °C. The results indicated that the ratio of anhydride to inulin and the concentration has a significant effect on DS. Under these conditions, the experimental DS was 2.86. In a 48 h in vitro fermentation experiment, the results of propionylated inulin had a good potential for enhancing propionate ratio compared to control inulin. This experiment provides a novel carrier molecule whereby SCFA is chemically bound by an ester bond to inulin which would be beneficial for delivering high concentration of SCFA and influencing intestinal health.

New chemical data on the ant Myrmecina graminicola (Formicidae, Myrmicinae): Unusual abundance of alkene hydrocarbons and esters

We investigated the possible origin of the specific odor of the terricolous ant Myrmecina graminicola by elucidating its pattern of volatiles. It appeared to have a very large hypertrophied poison gland reservoir, which contains copious amounts of acetate and propionate esters that are also present on the cuticule. The poison gland was previously reported as the source of sex pheromone, but the finding that queens and workers exhibited the same ester patterns tends to refute their role in sex attractants, and their biological significance remains elusive. The composition of cuticular hydrocarbons in this species is also highly original as it mostly comprises alkadienes and alkatrienes (70%), which is unusual and may be an adaptation to subterranean life. Neither the esters nor the cuticular hydrocarbons vary qualitatively and quantitatively between various localities in France, including Corsica.

Solution Refining for MOD-YBCO Optimization: An NMR Study

In this paper, a study of both pure and 5% BaZrO33-doped YBCO low-fluorine coating solutions performed by 1 H-Nuclear Magnetic Resonance (NMR) spectroscopic techniques is presented. This investigation enabled us to unequivocally identify the chemical species involved in the solution aging process. It was found that the presence of traces of methanol, typically used for the preparation of the solutions, promoted methyl propionate formation. Since the methanol concentration reduction in time is not completely balanced by methyl propionate formation, it is supposed that additional esterification reactions involving other acids might occur. The presence of methyl propionate ester was not recognized in solutions obtained through a refining process in which residual methanol traces were fully removed. The modification in time of the solution composition was found to be in strong correlation with the degradation of the film properties for standard solution, whereas no degradation, in the same time frame, was observed for the films prepared with the refined solutions. Indeed, both YBCO and YBCO + 5% BaZrO 3 films, grown with aged refined solutions, exhibit critical temperature values above 91 K and microstructure comparable with the ones recorded in samples obtained with freshly prepared solutions. Even though the exact role of the ester in the YBCO phase formation and film quality could not be identified yet, some possible mechanisms have been proposed and discussed.

Synthesis of Guar gum Propionate Nanoparticles for Antimicrobial Applications

Biopolymer guar gum (GG) is available from the seed endosperm of annual legume plant Cyamopsis tetragonoloba. The surface exposed free hydroxyl groups in GG were decorated with propionate esters. The base catalyzed formylation reaction prompted introduction of propionate groups. The surfactant free water dispersible and self-assemble propionate nanoparticles were developed using a facile solvent-shifting method. The FTIR, XRD, 13CNMR, DLS and TEM studies confirmed newly derivatized polymeric nanomaterial. The spherical shaped ouzo particles were effective for fungus and bacteria contact killing. This was considered due to the presence of high surface area and propionate moieties.

Photoelectron spectroscopy of a series of acetate and propionate esters

The electronic state and photoionization spectroscopy of a series of acetate esters: methyl acetate, isopropyl acetate, butyl acetate and pentyl acetate as well as two propionates: methyl propionate and ethyl propionate, have been determined using vacuum-ultraviolet photoelectron spectroscopy. These experimental investigations are complemented by ab initio calculations. The measured first adiabatic and vertical ionization energies were determined as: 10.21 and 10.45 eV for methyl acetate, 9.99 and 10.22 eV for isopropyl acetate, 10.07 and 10.26 eV for butyl acetate, 10.01 and 10.22 eV for pentyl acetate, 10.16 and 10.36 eV for methyl propionate and 9.99 and 10.18 eV for ethyl propionate. For the four smaller esters vibrational transitions were calculated and compared with those identified in the photoelectron spectrum, revealing the most distinctive ones to be a CO stretch combined with a CO stretch. The ionization energies of methyl and ethyl esters as well as for a series of formates and acetates were compared showing a clear dependence of the value of the ionization energy on the size of the molecule with very little influence of its conformation.

Sensitive and Precise Characterization of Combinatorial Histone Modifications by Selective Derivatization Coupled with RPLC-EThcD-MS/MS.

Deciphering the combinatorial histone codes has been a long-standing interest in the epigenetics field, which requires the reliable and robust characterization of the post-translational modifications (PTMs) coexisting on histones. To this end, weak cation exchange hydrophilic interaction liquid chromatography is commonly used in middle-down liquid chromatography-mass spectrometry approaches for online separation of variously modified histone peptides. Here we provide a novel strategy that combines the selective histone peptide derivatization using N-hydroxysuccinimide propionate ester with reversed-phase liquid chromatography (RPLC) for the robust, sensitive, and reliable characterization of combinatorial histone PTMs. Derivatization amplifies the subtle physical differences between similarly modified histone peptides, thereby allowing baseline separation of these peptides by standard RPLC. Also, the sensitivity of MS is enhanced greatly by derivatization due to the increased peptide hydrophobicity and concentrated charge-state envelope during electrospray ionization. Furthermore, we systematically optimized the dual electron transfer and higher energy collision dissociation and achieved near-complete peptide sequence coverage in MS/MS spectra, allowing highly precise and reliable PTM identification. Using this method, we identified 311 and 293 combinations of histone H3 PTMs from the lymphoma cells Karpas-422 with/without drug treatment, confirming the advantages of our method in serving as a platform for profiling combinatorial histone PTMs.

Randomised clinical study: inulin short-chain fatty acid esters for targeted delivery of short-chain fatty acids to the human colon.

SummaryBackgroundShort‐chain fatty acids (SCFA) produced through fermentation of nondigestible carbohydrates by the gut microbiota are associated with positive metabolic effects. However, well‐controlled trials are limited in humans.AimsTo develop a methodology to deliver SCFA directly to the colon, and to optimise colonic propionate delivery in humans, to determine its role in appetite regulation and food intake.MethodsInulin SCFA esters were developed and tested as site‐specific delivery vehicles for SCFA to the proximal colon. Inulin propionate esters containing 0–61 wt% (IPE‐0–IPE‐61) propionate were assessed in vitro using batch faecal fermentations. In a randomised, controlled, crossover study, with inulin as control, ad libitum food intake (kcal) was compared after 7 days on IPE‐27 or IPE‐54 (10 g/day all treatments). Propionate release was determined using 13C‐labelled IPE variants.Results In vitro, IPE‐27–IPE‐54 wt% propionate resulted in a sevenfold increase in propionate production compared with inulin (P < 0.05). In vivo, IPE‐27 led to greater 13C recovery in breath CO 2 than IPE‐54 (64.9 vs. 24.9%, P = 0.001). IPE‐27 also led to a reduction in energy intake during the ad libitum test meal compared with both inulin (439.5 vs. 703.9 kcal, P = 0.025) and IPE‐54 (439.5 vs. 659.3 kcal, P = 0.025), whereas IPE‐54 was not significantly different from inulin control.Conclusions IPE‐27 significantly reduced food intake suggesting colonic propionate plays a role in appetite regulation. Inulin short‐chain fatty acid esters provide a novel tool for probing the diet–gut microbiome–host metabolism axis in humans.