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1.
Comput Biol Med ; 166: 107495, 2023 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-37742414

RESUMO

The lotus leaf, Nelumbinis folium (NF), has frequently appeared in obesity clinical trials as an intervention to promote weight loss and improve metabolic profiles. However, the molecular mechanisms by which it interacts with important obesity targets and pathways, such as the peroxisome proliferator-activated receptor gamma (PPARγ) within the PPAR signalling pathway, were not well understood. This study aims to screen for candidate compounds from NF with desirable pharmacokinetic properties and examine their binding feasibility at the PPARγ ligand-binding domain (LBD). Ligand- and structure-based screening of NF compounds were performed, and a consensus approach has been applied to identify druggable candidates. By examining the pharmacokinetic profiles, a large proportion of NF compounds exhibited favourable drug-likeness and oral bioavailability properties. Furthermore, the binding affinity scores and poses provided new insights on the distinctive binding behaviours of NF compounds at the LBD of PPARγ in its inactive form. Several NF compounds could bind strongly to PPARγ at sub-pockets where partial agonists and antagonists were found to bind and may induce conformational changes that influence co-repressor binding, trans-repression, and gene expression inhibition. Subsequent molecular dynamics simulations of a candidate compound (NF129 narcissin) bound to PPARγ revealed conformational stability, residue fluctuation, and binding behaviours comparable to that of the known inhibitor, SR1664. Therefore, it can be proposed that narcissin exhibits characteristics of a PPARγ antagonist. Further experimental validation to support the development of NF129 as a future anti-obesity agent is warranted.

2.
Foods ; 12(15)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37569113

RESUMO

The degradation of anthraquinones extracted from aloe vera plants can be prevented by encapsulating them in casein micelles (CMs). The oral, gastric, and intestinal digestion behavior of spray-dried microcapsules of casein micelles loaded with aloe vera-extracted anthraquinone powder (CMAQP), freeze-dried powder (CMFDP), and whole-leaf aloe vera gel (CMWLAG) obtained through ultrasonication was investigated. The results found that CMAQP and CMFDP dissolved slowly and coagulated into large curds during gastric digestion, improving the retention of anthraquinones in the digestive tract. In contrast, CMWLAG structure was destroyed and increased amounts of anthraquinones were released during oral and gastric digestion phases, indicating increased amounts of surface anthraquinones instead of the encapsulation of anthraquinones in the interior of CMs. The strong hydrophobic interactions protected anthraquinones within the core of CM for CMAQP and delayed diffusion. However, during SIF digestion, both CMAQP and CMFDP released significant amounts of anthraquinones, although CMAQP showed a much more controlled release for both aloin and aloe-emodin over SIF digestion time. The release behavior of anthraquinones from CM microcapsules was a function of the type of anthraquinone that was used to encapsulate. The present study provides insight into the release behavior of loaded bioactive compounds using food-grade CMs as the wall material during in vitro digestion and highlights the importance of the type of bioactive component form that will be encapsulated.

3.
Front Nutr ; 10: 1150789, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37502726

RESUMO

Growing populations, changing dietary preferences and limitations on natural resources have meant that finding an alternative to traditional animal-based protein sources is a priority. Insects have been proposed as a possible solution due to their many benefits including low resource inputs and rich nutritional profile. However, insects are not consumed on a large scale by Australians. Food neophobia (reluctance to try new foods) could be contributing to this delay and as such, this study aimed to explore the role of food neophobia on protein food source habits and willingness to eat insects as food. A total of 601 participants (76.2% female, 23.8% male) completed an online survey which included a questionnaire measuring food neophobia status, participants' self-reported usual protein dietary habits, their previous insect-eating experience, future willingness to eat insects, and potential motivations to include insects in their diet. Results indicated a strong association between food neophobia and participants' dietary choices such as following a vegan or vegetarian diet (p = 0.024). In addition, food neophobia was correlated with a reduced likelihood of previous insect-eating experience (p < 0.001), as well as a decreased willingness to eat insects in the future (p < 0.001). This study provides a greater understanding of the role of food neophobia status and dietary choices in consumers' willingness to eat insects and identifies possible motivating factors that may increase the likelihood of consumers' future insect eating.

4.
PLoS One ; 18(6): e0277873, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37390097

RESUMO

Poria cocos (PC) is a medicinal herb frequently used in weight-loss clinical trials, however the mechanisms by which its compounds target orexigenic receptors including the neuropeptide Y1 receptor (Y1R) remain largely unknown. This study aimed to screen PC compounds for favourable pharmacokinetics profiles and examine their molecular mechanisms targeting Y1R. Forty-three PC compounds were systematically sought from pharmacological databases and docked with Y1R (PDB: 5ZBQ). By comparing the relative binding affinities, pharmacokinetics and toxicity profiles, we hypothesised that compounds designated PC1 3,4-Dihydroxybenzoic acid, PC8 Vanillic acid, PC40 1-(alpha-L-Ribofuranosyl)uracil, could be potential antagonists as they contact major residues Asn283 and Asp287, similar to various potent Y1R antagonists. In addition, PC21 Poricoic acid B, PC22 Poricoic acid G and PC43 16alpha,25-Dihydroxy-24-methylene-3,4-secolanosta-4(28),7,9(11)-triene-3,21-dioic acid, contacting Asn299, Asp104 and Asp200 proximal to the extracellular surface could also interfere with agonist binding by stabilising the extracellular loop (ECL) 2 of Y1R in a closed position. Owing to their selective interaction with Phe302, an important residue in binding of selective Y1R antagonists, PC12 beta-Amyrin acetate, PC26 3-Epidehydrotumulosic acid and PC27 Cerevisterol were proposed as putative antagonists. Following the consensus approach, PC12 beta-Amyrin acetate, PC26 3-Epidehydrotumulosic acid and PC27 Cerevisterol were identified as candidate compounds due to their high affinities (-12.2, -11.0 and -10.8 kcal, respectively), high drug-likeness and low toxicity profiles. Trajectory analyses and energy contributions of PC12-Y1R complex further confirmed their structural stability and favourable binding free energies, highlighting the feasibility and possible development of PC12 beta-Amyrin acetate as a future Y1R inhibitor.


Assuntos
Neuropeptídeos , Wolfiporia , Simulação de Dinâmica Molecular , Ligantes
5.
Microorganisms ; 11(4)2023 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-37110350

RESUMO

Since its emergence in 2019 in Wuhan City, Hubei Province, China, SARS-CoV-2 has spread across hundreds of countries and all continents [...].

6.
PLoS One ; 18(4): e0284842, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37098051

RESUMO

Cannabis flower odour is an important aspect of product quality as it impacts the sensory experience when administered, which can affect therapeutic outcomes in paediatric patient populations who may reject unpalatable products. However, the cannabis industry has a reputation for having products with inconsistent odour descriptions and misattributed strain names due to the costly and laborious nature of sensory testing. Herein, we evaluate the potential of using odour vector modelling for predicting the odour intensity of cannabis products. Odour vector modelling is proposed as a process for transforming routinely produced volatile profiles into odour intensity (OI) profiles which are hypothesised to be more informative to the overall product odour (sensory descriptor; SD). However, the calculation of OI requires compound odour detection thresholds (ODT), which are not available for many of the compounds present in natural volatile profiles. Accordingly, to apply the odour vector modelling process to cannabis, a QSPR statistical model was first produced to predict ODT from physicochemical properties. The model presented herein was produced by polynomial regression with 10-fold cross-validation from 1,274 median ODT values to produce a model with R2 = 0.6892 and a 10-fold R2 = 0.6484. This model was then applied to terpenes which lacked experimentally determined ODT values to facilitate vector modelling of cannabis OI profiles. Logistic regression and k-means unsupervised cluster analysis was applied to both the raw terpene data and the transformed OI profiles to predict the SD of 265 cannabis samples and the accuracy of the predictions across the two datasets was compared. Out of the 13 SD categories modelled, OI profiles performed equally well or better than the volatile profiles for 11 of the SD, and across all SD the OI data was on average 21.9% more accurate (p = 0.031). The work herein is the first example of the application of odour vector modelling to complex volatile profiles of natural products and demonstrates the utility of OI profiles for the prediction of cannabis odour. These findings advance both the understanding of the odour modelling process which has previously only been applied to simple mixtures, and the cannabis industry which can utilise this process for more accurate prediction of cannabis odour and thereby reduce unpleasant patient experiences.


Assuntos
Cannabis , Alucinógenos , Criança , Humanos , Cannabis/química , Odorantes/análise , Terpenos , Flores , Agonistas de Receptores de Canabinoides
7.
Food Chem ; 407: 135082, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36493485

RESUMO

Application of non-thermal treatment to proteins prior to enzymatic hydrolysis can facilitate the release of novel bioactive peptides (BPs) with unique biological activities. In this study, lupin protein isolate was pre-treated with ultrasound and hydrolysed using alcalase and flavourzyme to produce alcalase hydrolysate (ACT) and flavourzyme hydrolysate(FCT). These hydrolysates were fractionated into 1, 5, and 10 kDa molecular weight fractions using a membrane ultrafiltration technique. The in vitro angiotensin-converting enzyme (ACE) studies revealed that unfractionated ACT (IC50 = 3.21 mg mL-1) and FCT (IC50 = 3.32 mg mL-1) were more active inhibitors of ACE in comparison to their ultrafiltrated fractions with IC50 values ranging from 6.09 to 7.45 mg mL-1. Molecular docking analysis predicted three unique peptides from ACT (AIPPGIPY, SVPGCT, and QGAGG) and FCT (AIPINNPGKL, SGNQGP, and PPGIP) as potential ACE inhibitors. Thus, unique BPs with ACE inhibitory effects might be generated from ultrasonicated lupin protein.


Assuntos
Anti-Hipertensivos , Hidrolisados de Proteína , Anti-Hipertensivos/química , Simulação de Acoplamento Molecular , Hidrolisados de Proteína/química , Peptídeos/química , Peptidil Dipeptidase A/química , Hidrólise , Subtilisinas/metabolismo
8.
Foods ; 11(21)2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36359988

RESUMO

The use of natural ingredients for managing diabetes is becoming more popular in recent times due to the several adverse effects associated with synthetic antidiabetic medications. In this study, we investigated the in vitro antidiabetic potential (through inhibition of α-glucosidase (AG) and α-amylase (AA)) of hydrolysates from lupin proteins pretreated with ultrasound and hydrolyzed using alcalase (ACT) and flavourzyme (FCT). We further fractionated ACT and FCT into three molecular weight fractions. Unfractionated ACT and FCT showed significantly (p < 0.05) higher AG (IC50 value = 1.65 mg/mL and 1.91 mg/mL) and AA (IC50 value = 1.66 mg/mL and 1.98 mg/mL) inhibitory activities than their ultrafiltrated fractions, where lower IC50 values indicate higher inhibitory activities. Then, ACT and FCT were subjected to peptide sequencing using LC-MS-QTOF to identify the potential AG and AA inhibitors. Molecular docking was performed on peptides with the highest number of hotspots and PeptideRanker score to study their interactions with AG and AA enzymes. Among the peptides identified, SPRRF, FE, and RR were predicted to be the most active peptides against AG, while AA inhibitors were predicted to be RPR, PPGIP, and LRP. Overall, hydrolysates prepared from lupin proteins using alcalase and flavourzyme may be useful in formulating functional food for managing diabetics.

9.
Gels ; 8(9)2022 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-36135309

RESUMO

Aloe-vera extracted anthraquinones (aloin, aloe-emodin, rhein) possess a wide range of biological activities, have poor solubility and are sensitive to processing conditions. This work investigated the ultrasound-assisted encapsulation of these extracted anthraquinones (AQ) into casein micelles (CM). The particle size and zeta potential of casein micelles loaded with aloin (CMA), aloe-emodin (CMAE), rhein (CMR) and anthraquinone powder (CMAQ) ranged between 171-179 nm and -23 to -17 mV. The AQ powder had the maximum encapsulation efficiency (EE%) (aloin 99%, aloe-emodin 98% and rhein 100%) and encapsulation yield, while the whole leaf Aloe vera gel (WLAG) had the least encapsulation efficiency. Spray-dried powder (SDP) and freeze-dried powder (FDP) of Aloe vera showed a significant increase in size and zeta potential related to superficial coating instead of encapsulation. The significant variability in size, zeta potential and EE% were related to anthraquinone type, its binding affinity, and its ratio to CM. FTIR spectra confirmed that the structure of the casein micelle remained unchanged with the binding of anthraquinones except in casein micelles loaded with whole-leaf aloe vera gel (CMWLAG), where the structure was deformed. Based on our findings, Aloe vera extracted anthraquinones powder (AQ) possessed the best encapsulation efficiency within casein micelles without affecting its structure. Overall, this study provides new insights into developing new product formulations through better utilization of exceptional properties of casein micelles.

10.
Foods ; 11(13)2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35804638

RESUMO

Bioactive peptides (BPs) derived from animal and plant proteins are important food functional ingredients with many promising health-promoting properties. In the food industry, enzymatic hydrolysis is the most common technique employed for the liberation of BPs from proteins in which conventional heat treatment is used as pre-treatment to enhance hydrolytic action. In recent years, application of non-thermal food processing technologies such as ultrasound (US), high-pressure processing (HPP), and pulsed electric field (PEF) as pre-treatment methods has gained considerable research attention owing to the enhancement in yield and bioactivity of resulting peptides. This review provides an overview of bioactivities of peptides obtained from animal and plant proteins and an insight into the impact of US, HPP, and PEF as non-thermal treatment prior to enzymolysis on the generation of food-derived BPs and resulting bioactivities. US, HPP, and PEF were reported to improve antioxidant, angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, and antidiabetic properties of the food-derived BPs. The primary modes of action are due to conformational changes of food proteins caused by US, HPP, and PEF, improving the susceptibility of proteins to protease cleavage and subsequent proteolysis. However, the use of other non-thermal techniques such as cold plasma, radiofrequency electric field, dense phase carbon dioxide, and oscillating magnetic fields has not been examined in the generation of BPs from food proteins.

11.
Foods ; 11(11)2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35681363

RESUMO

The present study explored the stability of extracted anthraquinones (aloin, aloe-emodin and rhein) from whole-leaf Aloe vera gel (WLAG), its freeze-dried powder (FDP) and spray-dried powder (SDP) under varying pH and temperature conditions during storage. Each anthraquinone behaved differently under different processing parameters. The amount of anthraquinones present in the gel was higher than in FDP and SDP. The aloin contents decreased by more than 50% at 50 °C and 70 °C, while at 25 °C and 4 °C, the decrease was moderate. A substantial reduction in aloin concentration was noticed at pH 6.7, whereas it remained unaffected at pH 3.5. The temperature and pH had no significant effect on the stability of aloe-emodin. Interestingly, a small quantity of rhein was detected during storage due to the oxidative degradation of aloin into aloe-emodin and rhein. These findings can provide significant insight into retaining anthraquinones during processing while developing functional foods and nutraceuticals to obtain maximum health benefits.

12.
Food Chem ; 383: 132457, 2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35183959

RESUMO

This study evaluated the impact of ultrasound pretreatment (UP) and enzyme type (flavourzyme, alcalase) on amino acid composition, antihypertensive, antidiabetic, and antioxidant activities of lupin protein hydrolysate (LPH). The UP altered molecular weight of the hydrolysates as revealed by SDS-PAGE and MALDI-TOF and their surface hydrophobicity and thermal stability. Amino acid analysis revealed that glutamic acid, aspartic acid, arginine, and leucine were the dominant amino acids lupin protein. Generally, sonicated hydrolysates exhibited higher biological activity than non-sonicated samples and the original LPI. Alcalase hydrolysate pretreated for 10 min showed the highest DPPH and metal chelating activities. Highest ACE inhibitory activity was observed in flavourzyme hydrolysate after 5 min of UP, while maximum α-amylase and glucosidase inhibitory activity was achieved after 10 min of UP in flavourzyme hydrolysate. The results obtained in this study demonstrated the potentials of UP as a valuable tool for enhancing the biological activity of lupin proteins.


Assuntos
Anti-Hipertensivos , Antioxidantes , Aminoácidos , Anti-Hipertensivos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Hidrólise , Hipoglicemiantes/farmacologia , Hidrolisados de Proteína/química , Subtilisinas/metabolismo
13.
Artigo em Inglês | MEDLINE | ID: mdl-35082903

RESUMO

This study was conducted to assess the effects and safety of Chinese herbal medicine (CHM) on blood lipids among adults with overweight or obesity. Fourteen bibliographic databases were comprehensively searched, from their respective inceptions up to April 2021, for randomised placebo-controlled weight-loss trials using CHM formulation on total cholesterol, triglycerides, LDL cholesterol, and HDL cholesterol over ≥4 weeks. Data collection, risk of bias assessment, and statistical analyses were guided by the Cochrane Handbook (v6.1). Continuous outcomes were expressed as the mean difference with 95% confidence intervals, and categorical outcomes were expressed as a risk ratio with 95% confidence intervals. All analyses were two-tailed with a statistical significance of p < 0.05. Fifteen eligible studies with 1,533 participants were included in this meta-analysis. Findings from meta-analyses indicated that CHM interventions, compared to placebo, reduced triglyceride (MD -0.21 mmol/L, 95% CI -0.41 to -0.02, I 2 = 81%) and increased HDL cholesterol (MD 0.16 mmol/L, 95% CI 0.04 to 0.27, I 2 = 94%) over a median of 12 weeks. The reduction in total cholesterol and LDL cholesterol were not statistically significant. Furthermore, the tendency of reduced triglycerides was identified among overweight participants with high baseline triglycerides. Attrition rates and frequency of adverse events were indifferent between the two groups. CHM may provide lipid-modulating benefits on triglycerides and HDL cholesterol among participants with overweight/obesity, with the tendency for significant triglyceride reduction observed among overweight participants with high baseline triglycerides. However, rigorously conducted randomised controlled trials with larger sample sizes are required to validate these findings.

14.
Appetite ; 169: 105832, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34896167

RESUMO

Increasing global populations and limitations on the natural resources required in food production such as land and water will place further pressure on an already strained food production system. To meet the future food production requirements, it is essential to find viable alternatives to current food sources, without the high resource challenges. Protein production is of particular concern and insects are a nutritious and sustainable source yet, despite a rich history in parts of the world, Australians have been reluctant to adopt the practice as a societal norm. This study aimed to explore Australian consumers' experiences with edible insects, identify barriers to consumption, and explore possible factors that may motivate Australians to consume insects. A total of 601 participants (23.8% male, 76.2% female), completed an online survey using a variety of open-ended questions; 5- or 7-point Likert scales and check-all-that-apply questions. Consumer willingness was measured through self-reporting willingness-to-try insects or insect-based foods. Results indicated 35.4% of participants had previously consumed insects, with Orthoptera (crickets, grasshoppers) the most commonly consumed order (60.1%). Participants with no previous experience consuming insects cited 'lack of opportunity' as the main reason (57.2%). 'Increased accessibility' (56.6%) and 'increased nutrition knowledge' (56.6%) were identified as major factors that may increase the likelihood of future insect consumption. Participants reporting that they were willing to try insects were most likely to accept 'insect-based flour' (65.6%) and 'chocolate-covered ants' (52.1%). By providing increased opportunity, accessibility and education of insect-based food products, a higher proportion of Australians may be willing to eat insects, particularly if presented in indistinguishable forms (i.e. flour). This may lead to a greater acceptance of insects as an alternative, more sustainable protein source than previously anticipated.


Assuntos
Insetos Comestíveis , Animais , Austrália , Comportamento do Consumidor , Feminino , Farinha , Humanos , Insetos , Masculino
15.
Insects ; 12(7)2021 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-34357268

RESUMO

The Black Soldier Fly (BSF) offers the potential to address two global challenges; the environmental detriments of food waste and the rising demand for protein. Food waste digested by BSF larvae can be converted into biomass, which may then be utilized for the development of value-added products including new food sources for human and animal consumption. A systematic literature search was conducted to identify studies investigating the influence of food waste rearing substrates on BSF larvae protein composition. Of 1712 articles identified, 23 articles were selected for inclusion. Based on the results of this review, BSF larvae reared on 'Fish waste Sardinella aurita' for two days reported the highest total protein content at 78.8% and BSF larvae reared on various formulations of 'Fruit and vegetable' reported the lowest protein content at 12.9%. This review is the first to examine the influence of food waste on the protein composition of BSF larvae. Major differences in larval rearing conditions and methods utilized to perform nutritional analyses, potentially influenced the reported protein composition of the BSF larvae. While this review has highlighted the role BSF larvae in food waste management and alternative protein development, their application in nutrition is still in its infancy.

16.
Foods ; 10(8)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34441743

RESUMO

Bioactive food components have potential health benefits but are highly susceptible for degradation under adverse conditions such as light, pH, temperature and oxygen. Furthermore, they are known to have poor solubilities, low stabilities and low bioavailabilities in the gastrointestinal tract. Hence, technologies that can retain, protect and enable their targeted delivery are significant to the food industry. Amongst these, microencapsulation of bioactives has emerged as a promising technology. The present review evaluates the potential use of casein micelles (CMs) as a bioactive delivery system. The review discusses in depth how physicochemical and techno-functional properties of CMs can be modified by secondary processing parameters in making them a choice for the delivery of food bioactives in functional foods. CMs are an assembly of four types of caseins, (αs1, αs2, ß and κ casein) with calcium phosphate. They possess hydrophobic and hydrophilic properties that make them ideal for encapsulation of food bioactives. In addition, CMs have a self-assembling nature to incorporate bioactives, remarkable surface activity to stabilise emulsions and the ability to bind hydrophobic components when heated. Moreover, CMs can act as natural hydrogels to encapsulate minerals, bind with polymers to form nano capsules and possess pH swelling behaviour for targeted and controlled release of bioactives in the GI tract. Although numerous novel advancements of employing CMs as an effective delivery have been reported in recent years, more comprehensive studies are required to increase the understanding of how variation in structural properties of CMs be utilised to deliver bioactives with different physical, chemical and structural properties.

17.
J Obes ; 2021: 3250723, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33763238

RESUMO

Objective: This review investigated the effects and safety of Chinese herbal medicine (CHM) formulas on weight management. Methods: Eighteen databases in English, Chinese, Korean, and Japanese were searched from their inceptions to September 2019. The treatment groups included CHM formulations, and the control included placebo, Western medication (WM), and lifestyle intervention (LI), with or without cointerventions (WM and/or LI). Quality of studies was assessed using Cochrane Collaboration's risk of bias assessment tool. Body weight and body mass index (BMI) were analysed in RevMan v5.4.1 and expressed as mean differences with 95% confidence intervals (CI), while adverse events were expressed as risk ratio with 95% CI. Results: Thirty-nine RCTs were eligible for qualitative analysis, 34 of which were included in the meta-analyses. The majority of studies had a high or unclear risk of selection, performance, and detection bias. Twenty-five CHM studies involving cointerventions revealed that CHM had significant adjunct effects on body weight and BMI at the end of treatment compared to control. No serious adverse events were reported in the CHM groups. Conclusion: CHM indicates a promising adjunct to facilitate WM or lifestyle change for weight management. However, methodological barriers such as lack of allocation concealment and double-blinding may have led to challenges in data synthesis. More rigorously designed RCTs involving cointerventions are warranted.


Assuntos
Medicamentos de Ervas Chinesas , Medicamentos de Ervas Chinesas/uso terapêutico , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
18.
Plant Methods ; 17(1): 3, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407662

RESUMO

BACKGROUND: Enzyme assays have widespread applications in drug discovery from plants to natural products. The appropriate use of blanks in enzyme assays is important for assay baseline-correction, and the correction of false signals associated with background matrix interferences. However, the blank-correction procedures reported in published literature are highly inconsistent. We investigated the influence of using different types of blanks on the final calculated activity/inhibition results for three enzymes of significance in diabetes and obesity; α-glucosidase, α-amylase, and lipase. This is the first study to examine how different blank-correcting methods affect enzyme assay results. Although assays targeting the above enzymes are common in the literature, there is a scarcity of detailed published protocols. Therefore, we have provided comprehensive, step-by-step protocols for α-glucosidase-, α-amylase- and lipase-inhibition assays that can be performed in 96-well format in a simple, fast, and resource-efficient manner with clear instructions for blank-correction and calculation of results. RESULTS: In the three assays analysed here, using only a buffer blank underestimated the enzyme inhibitory potential of the test sample. In the absorbance-based α-glucosidase assay, enzyme inhibition was underestimated when a sample blank was omitted for the coloured plant extracts. Similarly, in the fluorescence-based α-amylase and lipase assays, enzyme inhibition was underestimated when a substrate blank was omitted. For all three assays, method six [Raw Data - (Substrate + Sample Blank)] enabled the correction of interferences due to the buffer, sample, and substrate without double-blanking, and eliminated the need to add substrate to each sample blank. CONCLUSION: The choice of blanks and blank-correction methods contribute to the variability of assay results and the likelihood of underestimating the enzyme inhibitory potential of a test sample. This highlights the importance of standardising the use of blanks and the reporting of blank-correction procedures in published studies in order to ensure the accuracy and reproducibility of results, and avoid overlooked opportunities in drug discovery research due to inadvertent underestimation of enzyme inhibitory potential of test samples resulting from unsuitable blank-correction. Based on our assessments, we recommend method six [RD - (Su + SaB)] as a suitable method for blank-correction of raw data in enzyme assays.

20.
Front Microbiol ; 11: 592060, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33324371

RESUMO

Cheese maturation and flavor development results from complex interactions between milk substrates, cheese microbiota and their metabolites. In this study, bacterial 16S rRNA-gene sequencing, untargeted metabolomics (gas chromatography-mass spectrometry) and data integration analyses were used to characterize and differentiate commercial Cheddar cheeses of varying maturity made by the same and different manufacturers. Microbiota and metabolite compositions varied between cheeses of different ages and brands, and could be used to distinguish the cheeses. Individual amino acids and carboxylic acids were positively correlated with the ripening age for some brands. Integration and Random Forest analyses revealed numerous associations between specific bacteria and metabolites including a previously undescribed positive correlation between Thermus and phenylalanine and a negative correlation between Streptococcus and cholesterol. Together these results suggest that multi-omics analyses has the potential to be used for better understanding the relationships between cheese microbiota and metabolites during ripening and for discovering biomarkers for validating cheese age and brand authenticity.

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