Acetate Esters Research Articles

Stored alcohol and fatty acid intermediates and the biosynthesis of sex pheromone aldehyde in the moth Chloridea virescens.

In most species of moths, the female produces and releases a volatile sex pheromone from a specific gland to attract a mate. Biosynthesis of the most common type of moth sex pheromone component (Type 1) involves de novo synthesis of hexadecanoate (16:Acyl), followed by modification to various fatty acyl intermediates, then reduction to a primary alcohol, which may be acetylated or oxidized to produce an acetate ester or aldehyde, respectively. Our previous work on the moth Chloridea virescens (Noctuidae) showed that females produce 90% of the major pheromone component, (Z)-11-hexadecenal (Z11-16:Ald), via a direct and rapid route of de novo biosynthesis with highly labile intermediates, and ca. 10% from an indirect route that likely mobilizes a pre-synthesized 16-carbon skeleton, possibly, (Z)-11-hexadecenoate (Z11-16:Acyl) or hexadecanoate (16:Acyl). In this paper, we use stable isotope tracer/tracee techniques to study the dynamics of the precursor alcohol (Z)-11-hexadecenol (Z11-16:OH) and stores of Z11-16:Acyl and 16:Acyl to determine their roles in biosynthesis of Z11-16:Ald. We found: (i) that intracellular Z11-16:OH is synthesized at roughly the same rate as Z11-16:Ald, indicating that translocation and oxidation of this moiety does not rate limit biosynthesis of Z11-16:Ald, (ii) intracellular Z11-16:OH consists of two pools, a highly labile one rapidly translocated out of the cell and converted to Z11-16:Ald, and a less labile one that mostly remains in gland cells, (iii) during pheromone biosynthesis, net stores of Z11-16:Acyl increase, suggesting it is not the source of Z11-16:Ald produced by the indirect route, and (iv) no evidence for the gland synthesizing stored 16:Acyl prior to (up to 2days before eclosion), or after, synthesis of pheromone commenced, suggesting the bulk of this stored moiety is synthesized elsewhere and transported to the gland prior to gland maturation. Thus, the pheromone gland of C. virescens produces very little stored fat over its functional lifetime, being optimized to produce sex pheromone.

Predicting sulfanilamide solubility in the binary mixtures using a reference solvent approach.

Solubility is a fundamental physicochemical property of active pharmaceutical ingredients. The optimization of a dissolution medium aims not only to increase solubility and other aspects are to be included such as environmental impact, toxicity degree, availability, and costs. Obtaining comprehensive solubility characteristics of chemical compounds is a non-trivial and demanding process. Therefore, support from theoretical approaches is of practical importance. This study aims to examine the accuracy of the reference solubility approach in the case of sulfanilamide dissolution in a variety of binary solvents. This pharmaceutically active substance has been extensively studied, and a substantial amount of solubility data is available. Unfortunately, using this set of data directly for theoretical modeling is impeded by noticeable inconsistencies in the published solubility data. Hence, this aspect is addressed by data curation using theoretical and experimental confirmations. In the experimental part of our study, the popular shake-flask method combined with ultraviolet (UV) spectrophotometric measurements was applied for solubility determination. The computational phase utilized the conductor-like screening model for real solvents (COSMO-RS) approach. The analysis of the results of solubility calculations for sulfonamide in binary solvents revealed abnormally high error values for acetone-ethyl acetate mixtures, which were further confirmed with experimental measurements. Additional confirmation was obtained by extending the solubility measurements to a series of homologous acetate esters. Our study addresses the crucial issue of coherence of solubility data used for many theoretical inquiries, including parameter fitting of semi-empirical models, in-depth thermodynamic interpretations and application of machine learning protocols. The effectiveness of the proposed methodology for dataset curation was demonstrated for sulfanilamide solubility in binary mixtures. This approach enabled not only the formulation of a consistent dataset of sulfanilamide solubility binary solvent mixtures, but also its implementation as a qualitative tool guiding rationale solvent selection for experimental solubility screening.

Facile synthesis and cytotoxicity of substituted uracil-1'(N)-acetic acid and 4-pyridone-1'(N)-acetic acid esters of 20(S)-camptothecins

A series of novel substituted uracil-1'(N)-acetic acid esters (5–9) and 4-pyridone-1'(N)-acetic acid esters (10–11) of 20(S)-camptothecins (CPTs) have been synthesized by the acylation method. All of these new esters were assayed for in vitro cytotoxicity against five human cancer cell lines A549, Bel7402, BGC-823, HCT-8 and A2780. The in vitro bioassay results showed that all the synthesized compounds 5–11 had cytotoxities that were higher than TPT and comparable to CPT on these five tumor cell lines, some of them even showed comparable or superior cytotoxic activity to CPT. The in vitro data exhibited the cytotoxicity of the ester depended on that of its parent compound. The ester 5, 6, 8, 10, 11 even possessed the cytotoxity activity comparable to or even a little better than CPT on A549, HCT-8 and A2780. The compound 11 had the same level of cytoxity on Bel7402 as that of CPT. Here the synthesis and the in vitro antitumor evaluation of a series of novel 20-O-linked substituted uracil-1'(N)-acetic acid and 4-pyridone-1'(N)-acetic acid esters derivatives of CPTs are reported.

Heteropoly acid catalysis in the valorization of bio-renewables: Acetylation of 1,4-cineole and 1,8-cineole (eucalyptol) in green solvents

In this work, a novel synthesis of monoterpenic acetate esters potentially valuable as flavoring agents was developed. It involves the reactions of 1,4-cineole and 1,8-cineole with acetic anhydride giving the desired products in 80–88 % total yields. The process is performed under ambient conditions in green solvents such as methyl isobutyl ketone, methyl ethyl ketone, dimethyl carbonate or diethyl carbonate in the presence of acidic cesium salt of phosphotungstic acid, Cs2.5H0.5PW12O40, as an efficient solid acid catalyst. The catalyst is stable toward leaching in the reaction system and can be reused. The process produces mixtures of acetate esters with different flavor bouquets which can be used directly as ingredients in fragrance compositions without separating individual compounds.

Folic acid receptor conjugated mesoporous CaCO3 nanoformulation for the therapeutic potential against lung carcinoma

The folic acid conjugation with the nanocarrier system possess enhanced targeting of lung cancer cells due to the folate receptors present in the lung cancer cells. This work plan focused on the development of a mesoporous CaCO3 nanoformulation system for the targeted delivery of citronellyl acetate for lung cancer therapy. CaCO3 nanoparticles were obtained from the marine conch waste and the citronellyl acetate an acetic ester derivative of citronellol reported for its anticancer potential were used for the present study. Here the citronellyl acetate loaded CaCO3 formulation was surface conjugated with folic acid as an extension of our previous work. The physiochemical and material characterizations of folic acid conjugated nanoformulation confirms the loading of citronellyl acetate within CaCO3 nanoparticles and surface conjugation with folic acid. The folic receptor conjugated CaCO3 nanoformulation attained anticancer potential against H460 non-small cell lung cancer cell lines with the IC50 value at 102.09 ± 0.25 μg/mL. In addition, the receptor-conjugated nanoformulation withstands its biocompatibility level in the in-vitro and in-vivo toxicity evaluation models. The findings of this study suggest that, CaCO3 nanoformulation surface conjugated with folic acid can serve as a progressive drug delivery system for lung cancer therapy.

Effect of swelling agent treatment on grape fruit quality and the application of electronic nose identification detection.

The swelling agent is a plant growth regulator that alters the composition and content of nutrients and volatile gases in the fruit. To identify whether grape fruit had been treated with swelling agent, the odor information and quality indexes of grape berries treated with different concentrations of swelling agent were examined by using electronic nose technology and traditional methods. The contents of soluble sugars, soluble solids, soluble proteins and vitamin C were significantly increased in N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) treated fruit. The contents of hexanal, (E)-2-hexenal, and nonanal aldehydes decreased significantly. Similarly, the levels of phenyl ethanol, 1-octanol, ethanol, and ethyl acetate alcohols and esters also decreased noticeably. Additionally, the levels of damascenone, linalool, and geraniol ketones and terpenoids decreased. However, the contents of benzaldehyde, D-limonene, acetic acid and hexanoic acid increased. In addition, the electrical signals generated by the electronic nose (e-nose) were analyzed by linear discriminant analysis (LDA), support vector machine (SVM) and random forest (RF). The average recognition rate of SVM was 94.4%. The results showed that electronic nose technology can be used to detect whether grapes have been treated with swelling agent, and it is an economical and efficient detection method.

Synthesis and characterization of 3,4-dihydroxyphenyl acetic acid esters and study of their efficacy in bulk fish oil

Lipophilization of natural antioxidants is a proven strategy to enhance the solubility in bulk oil systems, thereby increasing their efficacy against oxidative degradation. This study aims to synthesize esters of 3,4-dihydroxyphenylacetic acid (3,4-DHPA) using Amberlyst-15 and to study the application of these esters in refined fish oil. Lipophilic esters were synthesized by esterification and transesterification of 3,4-DHPA in various solvent systems. Esters of methanol, butanol and hexanol were obtained with percent conversion of 81.1, 69.3 and 78.8 respectively, and were subjected to molecular characterization and in vitro oxidant assays. The 3,4-DHPA and its methyl ester showed 36% reduction in the TOTOX value over 30 days of storage. The length of the acyl chain in the ester was found to exert a high influence on its efficacy and lipophilicity. This is the first report of 3,4-DHPA and its lipophilic esters studied for enhancing the oxidative stability of fish oil.

Characterization of the effects of thymol derivatives on colorectal cancer spheroids.

Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies with a high mortality rate. In the last few years, attention has been focused on substances of natural origin with anticancer activity. One such substance is thymol and its derivatives, which have been shown to have an antitumor effect also against CRC cells. In our study, we focused on determining the biological and antibacterial effects of thymol and thymol derivatives. Analyses were performed on a 3D model of human colon carcinoma cell lines (HCT-116 and HT-29) - spheroids. The cytotoxic (MTT assay) and genotoxic effect (comet assay) of thymol and derivatives: acetic acid thymol ester and thymol ß-D-glucoside were determined. ROS levels (ROS-Glo™ H2O2 Assay) and total antioxidant status (Randox TAS Assay) were also monitored. Last but not least, we also detected the effect of the derivatives using a disk diffusion assay and determined the number of colonies on the plates on selected bacteria such as Lacticaseibacillus rhamnosus, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, Lactobacillus brevis, Lactobacillus pentosus and Weizmannia coagulans. The derivatives did not show a significant inhibitory effect on the growth of LAB bacteria (lactic acid bacteria) in contrast to thymol. Overall, thymol derivatives are cytotoxic, genotoxic and increase ROS levels. Among the derivatives tested, acetic acid thymol ester (IC50 ~ 0.2 μg/ml) was more effective. The second derivative tested (thymol β-D-glucoside) was effective at higher concentrations than thymol. Our research confirmed that thymol derivatives have a toxic effect on the 3D model of intestinal tumor cells, while they do not have a toxic effect on selected intestinal bacteria. Thus, they could bring new significance to the prevention or treatment of CRC.

Fatty Acid Origin of Insect Pheromones.

Pheromones are utilized to a great extent in insects. Many of these pheromones are biosynthesized through a pathway involving fatty acids. This chapter will provide examples where the biosynthetic pathways of fatty acid-derived pheromones have been studied in detail. These include pheromones from Lepidoptera, Coleoptera, and Hymenoptera. Many species of Lepidoptera utilize fatty acids as precursors to pheromones with a functional group that include aldehydes, alcohols, and acetate esters. In addition, the biosynthesis of hydrocarbons will be briefly examined because many insects utilize hydrocarbons or modified hydrocarbons as pheromones.

Chemical components of different solvent extracts of Asclepias curassavica L. and antibacterial effect of the extracts on tomato pathogens

The use of environmentally friendly and sustainable agricultural methods in the control of diseases and pests is of great importance. In both conventional and organic agricultural production systems, the utilization of various plant extracts as part of integrated pest management has gained significance in recent years. The chemical constituents of various solutions derived from the flowers, leaves, and roots of the Asclepias curassavica L. plant were investigated, along with the possibilities of utilizing these solutions in the control of tomato plant pathogenic bacteria. As a result of the analysis, acetic acid in 60% and 80% ethanol solutions, as well as acetic acid methy ester in 60% and 80% methanol solutions, were detected in the flowers, leaves, and roots. The effects of A. curassavica flower, leaf, and root extracts, prepared using three different solvents (water, methanol, and ethanol), were investigated on eight different pathogenic bacteria (Agrobacterium tumefaciens, Clavibacter michiganensis, Dickeya zeae, Pectobacterium caratovorum, Pseudomonas phaseolicola, Pseudomonas tomato, Pseudomonas viridiflava, and Xanthomonas euvesicatoria) that cause diseases in plants. Several main compounds such as acetic acid, acetic acid. methyl ester, Furfural, 2-Furanmethanol, 4H-Pyran-4-one. 2.3-dihydro-3.5-dihydroxy-6-methyl-, Glycerin, Benzo furan. 2.3-dihydro- and 5-Hydroxy methyl furfural were identified as analyzed by GC-MS with different concentrations of ethanol and methanol solutions used for the flower, leaves and root of A. curassavica plants. The flower extract prepared with 80% ethanol exhibited a higher inhibition zone (ranging from 1.5 mm to 5.3 mm) in all pathogens, compared to other applications. The successful suppression effect of A. curassavica flower extracts on this disease is promising, especially in organic farming areas. Additionally, since it is environmentally friendly and sustainable, it can be included in integrated control methods to prevent the loss of productivity caused by diseases.

Aspilia africana (Pers.) C.D. Adams and Manihot esculenta Crantz Exhibit Antibacterial Activity against Resistant Salmonella typhi Strains

Typhoid fever, caused by Salmonella typhi, has plagued underdeveloped countries for many years. Recently, there has been a surge in S. typhi strains identified to be multidrug‐resistant in endemic areas. Aspilia africana and Manihot esculenta have been reported to exhibit activity against S. typhi; however, this study aimed to investigate the effect of A. africana and M. esculenta against resistance strains of S. typhi. The leaves of the plants were extracted using distilled water (hot (AQH) and cold (AQC)), methanol (MET), ethyl acetate, and petroleum ether. The extracts were screened in vitro for anti‐Salmonella effects against fourteen S. typhi isolates (five multidrug‐resistant (MDRST), five ciprofloxacin‐resistant (CRST), three nalidixic acid‐resistant (NARST), and one sensitive isolate (SS)) using agar well diffusion and microbroth dilution methods. Phytochemical screening showed the presence of tannins, saponins, glycosides, and flavonoids in all polar solvent extracts. Alkaloids were found in all extracts, while triterpenoids were present in all except the aqueous extracts. The AQC of A. africana had the best inhibitory effect on the MDRST and NARST with diameter zones of inhibitions (DZOIs) of 40.0 ± 2.08 mm and 34.0 ± 3.22 mm, respectively. Methanol extract of A. africana had the best inhibitory effect on CRST and SS with DZOIs of 34.0 ± 2.08 and 43.0 ± 3.06 mm, respectively. The AQC and AQH of A. africana and AQH of M. esculenta produced the best MICs and MBCs of 2.5 and 5.0 mg/mL against the MDRST. There was no significant difference in ZOIs of the different solvent extracts against test organisms at p < 0.05. Gas chromatography‐mass spectrometry analysis of the extracts showed compounds such as n‐hexadecanoic acid, 9,12,15‐octadecatrienoic acid (9.55%), and 2H‐benzo[F]oxireno[2,3‐E]benzofuran‐8(9H)‐one in the A. Africana extracts and D‐mannose, 3‐nitrophenyl, methanol acetate (ester), and 9‐octadecenamide in the M. esculenta extracts. The leaves of M. esculenta and A. Africana are effective against multidrug‐resistant Salmonella isolates.

Unveiling the Launaea nudicaulis (L.) Hook medicinal bioactivities: phytochemical analysis, antibacterial, antibiofilm, and anticancer activities.

Commonly used antimicrobial agents are no longer effective due to their overuse or misuse. In addition, many medicinal plant extracts can combat infectious diseases due to their main active constituents or secondary metabolites. The current study aimed to assess the bioactivities of Launaea nudicaulis (LN) leaf extract (LE) against different multi-drug resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) isolates. The ethyl acetate extract of a Launaea nudicaulis (LN) leaf was analyzed using GC-MS, which identified 27 key bioactive compounds. The major constituents found were as follows: 7-acetyl-6-ethyl-1,1,4,4-tetramethyltetralin, isopropyl myristate, thiocarbamic acid, N,N-dimethyl, S-1,3-diphenyl-2-butenyl ester, hahnfett, cyclopentane acetic acid, 3-oxo-2-pentyl-, methyl ester, hexadecanoic acid, and dotriacontane. Our study demonstrated that the LN leaf was a rich source of other important phytochemicals, including phenolic acids, tannins, saponins, and steroids. The relative biosafety of the L. nudicaulis LE was determined from the elevated inhibitory concentration 50 (IC50) of 262 μg/mL, as calculated from the cytotoxicity assay against the Wi-38 normal cell line. Conversely, 12.7 and 24.5 μg/mL were the recorded low IC50 values for the tested extract against the MCF-7 and Hep-G2 cancerous cell lines, respectively, reflecting its potent activity against the tested cancerous cell lines. Microbiologically, the susceptible P. aeruginosa isolates to the tested extract showed a growth inhibition zone diameter, in the well diffusion assay, ranging from 11.34 ± 0.47 to 26.67 ± 0.47 mm, and a percent inhibition (PI) value of 50-106.2%, reflecting its acceptable activity. In addition, the broth microdilution assay recorded minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the ranges of 15.625-1,000 μg/mL and 125-1,000 μg/mL, respectively. In conclusion, the L. nudicaulis LE revealed showed promising activity and high selectivity against P. aeruginosa. Moreover, the extract exhibited natural anticancer activities with safe low concentrations, indicating its potential as a superior candidate for future studies of its active constituents.

Elucidating the mechanism and origin of stereoselectivity in the activation/transformation of an acetic ester catalyzed by an N-heterocyclic carbene.

The activation of an ester by N-heterocyclic carbene (NHC) organocatalysis is an efficient and important approach for generating an NHC-bound enolate intermediate, an important active intermediate in the transformation of carbonyl compounds. Herein, we perform a theoretical study on the NHC-catalyzed activation and transformation reaction of an acetic ester in which the NHC-bound enolate intermediate is a key intermediate. Multiple activation and transformation pathways are proposed and analyzed to identify an energetically favorable pathway. The use of different substrates for the reaction is considered. When a chalcone substrate is used, [4+2] cycloaddition between the enolate intermediate and the chalcone is identified to be both the rate- and stereoselectivity-determining step for the reaction, with the R-configured product being generated as the major isomer. Noncovalent interaction (NCI) and atoms-in-molecules (AIM) analyses are performed to identify the origin of the stereoselectivity of the reaction, and a local reactivity analysis is conducted to explore substrate and catalyst effects on the reaction.

A comparative study to investigate the individual contribution of metabolic and physical interaction on volatiles formation in the mixed fermentation of Torulaspora delbrueckii and Saccharomyces cerevisiae

It is well-known that the co-inoculation of Saccharomyces cerevisiae and non-Saccharomyces strains can modulate and improve the aromatic quality of wine through their multi-level interactions. However, the individual contribution of metabolic interaction (MI) and physical interaction (PI) on wine volatiles remains poorly understood. In this work, we utilized a double-compartment bioreactor to examine the aromatic effect of MI and PI by comparing the volatiles production in Torulaspora delbrueckii and Saccharomyces cerevisiae single fermentations to their mixed fermentations with or without physical separation. Results showed that the PI between T. delbrueckii and S. cerevisiae increased the production of most aroma compounds, especially for acetate esters and volatile fatty acids. In comparison, the MI only promoted a few volatile compounds, including ethyl decanoate, isoamyl acetate, and isobutanol. Noticeably, the MI significantly decreased the levels of ethyl dodecanoate, 2-phenylethyl alcohol, and decanoic acid, which exhibited opposite profiles in PI. Our results indicated that the PI was mainly responsible for the improved volatiles in T. delbrueckii/S. cerevisiae mixed fermentation, while the MI can be targeted to modulate the specific aroma compounds. A thorough understanding of the PI and MI aromatic effect will empower winemakers to accurately and directionally control the volatile profile of the wine, promoting the application of multi-starters to produce diverse styles of wines.

The influence of different yeast strains and yeast nutrients on the aroma of Krstač and Žižak wines

Krstač and Žižak are autochthonous grape varieties grown in Montenegro. Although international varieties are more popular, the autochthonous varieties are very important, especially for countries developing tourism. The fermentation aromas produced during alcoholic fermentation contribute significantly to wine quality. The effects of yeasts (Saccharomyces cerevisiae and Saccharomyces bayanus) and yeast nutrients (Fermaid E and Fermaid O) on aromatic compounds in wines were investigated. Using GC/FID-MS analysis, aroma compounds in Krstač and Žižak wines were characterized and quantified. Wines produced with the addition of yeast and yeast nutrients had mostly lower total alcohol content than wines obtained by spontaneous fermentation of Krstač and Žižak varieties. The results of this study showed that the concentration of compounds depends on the yeast strains. The yeast S. cerevisiae (ICV) provided a higher content of higher alcohols, while S. bayanus produced a higher concentration of esters and (medium chain) fatty acids. Total ester content ranged from 3.34 to 11.97 mg/l for Krstač wines and 8.51 to 13.68 mg/l for Žižak wines. Among all wines, Krstač and Žižak wines produced with S. bayanus and Fermaid E addition had the highest concentration of total esters. The yeast nutrients Fermaid E and O emphasized different characteristics of the yeasts. They had a statistically significant effect on the content of ethyl and acetate esters. The highest overall scores were obtained for ICVE and BayE Krstač wines (18.1 out of 20 points) and Žižak ICVE wine (18.2 out of 20 points).

(Invited) Electrosynthesis of Long-Chain Hydrocarbons and Oxygenates

The electroreduction of CO(2), driven by renewable electricity, can be used to sustainably generate synthetic fuels and chemical feedstocks. Long carbon chain molecules are of particular interest due to their high energy densities and utilities. However, to date, most of the CO(2) reduction products formed are limited to C2 and C3. Herein, we discuss the development of electrocatalysts for the reduction of CO(2) to long-chain oxygenates and hydrocarbons, and their underlying reaction mechanisms.CO(2) electroreduction has been previously reported to yield a range of carbonaceous products including alcohols, hydrocarbons and carboxylic acids. Interestingly, esters, an important family of organic compounds, have not been formed. We show how C3–C6 acetate esters could be produced from CO reduction in a membrane electrode assembly (MEA) cell. The near water-free reaction environment and the high local pH in the MEA played key roles in forming the esters with a Faradaic efficiency of 22 % and a current density up to −55 mA cm−2. We also disclose that inorganic nickel oxygenate (INO)-derived electrocatalysts can reduce CO2 to linear and branched C3-C6 hydrocarbons with Faradaic efficiencies up to 6.5%. We identified Niδ+ active sites which bind CO moderately. Our results show that Ni atom polarization to be important in hindering CO poisoning of nickel and thus facilitating CO2 reduction to a wider pool of valuable products.Finally, we show how MgAl layered double hydroxide (LDH) nanosheets ‘House-of-cards’ structures help to disperse CuO-derived Cu (OD-Cu) catalysts. The porous structures formed enhanced CO gas percolation through the catalyst layer. OD-Cu dispersed by the ‘House-of-cards’ structures catalysed CO electroreduction to C2+ products with a partial current density that is an order of magnitude higher than that shown by the unsupported OD-Cu.

Synthesis and quantification of short-chain fatty acid esters of hydroxy fatty acids in rat intestinal contents and fecal samples by LC-MS/MS

Short-chain fatty acid esters of hydroxy fatty acids (SFAHFAs) are a new class of endogenous lipids belonging to the fatty acid esters of the hydroxy fatty acid family. We previously uncovered their chemical structure and discussed their potential biological significance. We anticipate an increased need for SFAHFA measurements as markers of metabolic and inflammatory health. In this study, we synthesized sixty isomeric SFAHFAs by combining 12 hydroxy fatty acids (C16–C24) and five short-chain fatty acids (C2–C6) including a labelled internal standard. SFAHFA enrichment was achieved by solid-phase extraction and established a sensitive method for their quantitation by targeted LC-MS/MS. The method was applied to profile SFAHFAs in intestinal contents and fecal samples collected from rats fed a high-fat diet (HFD). The results demonstrated a significant decrease in SFAHFAs in the intestinal contents of the HFD group compared with the control group. The fecal time course (0–8 weeks) profile of SFAHFAs showed significant downregulation of acetic and propanoic acid esters in just 2 weeks after HFD administration. This study offers the first synthesis and quantitation method for SFAHFAs, demonstrating their potential use in elucidating SFAHFA sources, their role in various diseases, and potential biochemical signalling pathways.

“Turn-on” and ratiometric detection of carboxylesterases using acetyl-based fluorescent strategies for bacterial applications

Carboxylesterases (CEs) are involved in the biotransformation of numerous drugs, environmental toxicants, and carcinogens containing ester groups. Abnormal CEs levels are associated with various diseases, and as such they are widely studied in cells. CEs are also characteristic biomarkers for assisting in the detection of certain strains of bacteria and are involved in important biological processes. Herein, we used two probes including an indene-chalcone-based fluorescent probe which displays green “turn-on” fluorescence response, and a merocyanine-based ratiometric probe to detect CEs, as well as detect and image S. aureus and their chronic biofilms using an acetate ester as recognition group.

Applying beet peels as a brewing adjunct and its impact on flavour formation

Beer is a complex product, which can use a large diversity of matters as adjuncts. Beet peels (BP) is as a food waste generated from restaurant kitchens/industries. This study investigated the effect of BP as a brewing adjunct on volatile/phenolic compounds, and antioxidant properties of Beer. Worts supplemented with BP were produced using 4 treatments (including a control, B1, B2, and B3). Fermentations were conducted for 11 days at 18 °C, aged for 15 days at 3 °C, and bottled using 7 g of sucrose per bottle. Then maturated for 15 days at 20 °C. Samples were analysed using HPLC (non-volatile compounds), GC-MS (volatile compounds), and antioxidant activity. Increasing the amount of BP during wort preparation revealed a significant increase of volatile profile, phenolic composition, and antioxidant activity. In contrast, was observed a significant decrease in glycerol content. Finally, B2 contained a higher content of acetate esters, hydroxybenzoic/hydroxycinnamic acids and antioxidant activity.

Characterization of alcohol acetyltransferases in the ripe flesh of ‘Monthong’ and ‘Chanthaburi 1′ durians

Durian is economically significant in Southeast Asia due to its distinctive aroma and palatability. During fruit ripening, the flesh generates a substantial quantity of esters and some sulfur-containing compounds. This study aimed to analyze the ester profiles and characteristics of alcohol acetyltransferase (AAT; EC. 2.3.1.84) in the ripe flesh of two Thai durian (Durio zibethinus Merr.) cultivars, ‘Chanthaburi 1' (a hybrid cultivar with a soft aroma) and ‘Monthong’ (a renowned cultivar with a medium scent). The primary esters responsible for the aromatic compounds found in durian are ethyl-2-methyl butanoate, ethyl hexanoate, and ethyl octanoate. The AAT's efficacy was assessed in its ability to catalyze the synthesis of acetate esters through the reaction between acetyl CoA and different alcohols. The AAT enzymes extracted from ‘Chanthaburi 1′ and ‘Monthong’ cultivars exhibited a notable affinity towards 3-methyl-1-butanol and hexanol as alcohol substrates. Propanol and butanol exhibited moderate activity as AAT substrates, whereas methanol and ethanol demonstrated the lowest. Both durians exhibited favorable enzyme activity at a temperature of 30 °C. However, ‘Monthong’ AAT demonstrated superior performance across a broader pH range compared to ‘Chanthaburi 1′ AAT. The partially purified proteins precipitated with ammonium sulfate and subsequently gel-filtered through a DEAE-Sephadex® column enhanced the potency of ‘Chanthaburi 1′ AAT, resulting in increased purity (1.20-fold) and specificity (1.08-fold) compared to ‘Monthong’. The AAT of ‘Chanthaburi 1′ and ‘Monthong’ exhibited molecular weights of 39.52 and 41.51 kDa, respectively. This study presents the initial documentation of AAT in durians through an enzyme assay and activity staining technique.