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Food & Function May 2024Elevated blood glucose concentration is a risk factor for developing metabolic dysfunction and insulin resistance, leading to type 2 diabetes and cardiovascular... (Review)
Review
Elevated blood glucose concentration is a risk factor for developing metabolic dysfunction and insulin resistance, leading to type 2 diabetes and cardiovascular diseases. Nuts have the potential to inhibit α-amylase activity, and so lower postprandial glucose, due to their content of polyphenols and other bioactive compounds. We conducted a systematic literature review to assess the ability of extracts from commonly consumed edible parts of nuts to inhibit α-amylase. Among the 31 included papers, only four utilised human α-amylases. These papers indicated that polyphenol-rich chestnut skin extracts exhibited strong inhibition of both human salivary and pancreatic α-amylases, and that a polyphenol-rich almond skin extract was a potent inhibitor of human salivary α-amylase. The majority of the reviewed studies utilised porcine pancreatic α-amylase, which has ∼86% sequence homology with the corresponding human enzyme but with some key amino acid variations located within the active site. Polyphenol-rich extracts from chestnut, almond, kola nut, pecan and walnut, and peptides isolated from cashew, inhibited porcine pancreatic α-amylase. Some studies used α-amylases sourced from fungi or bacteria, outcomes from which are entirely irrelevant to human health, as they have no sequence homology with the human enzyme. Given the limited research involving human α-amylases, and the differences in inhibition compared to porcine enzymes and especially enzymes from microorganisms, it is recommended that future experiments place greater emphasis on utilising enzymes sourced from humans to facilitate a reliable prediction of effects in intervention studies.
Topics: Nuts; Humans; Plant Extracts; Animals; alpha-Amylases; Swine; Enzyme Inhibitors; Polyphenols; Juglans
PubMed: 38717256
DOI: 10.1039/d4fo00414k -
Molecular Pain 2024Nociception related salivary biomolecules can be useful patients who are not able to self-report pain. We present the existing evidence on this topic using the... (Review)
Review
Nociception related salivary biomolecules can be useful patients who are not able to self-report pain. We present the existing evidence on this topic using the PRISMA-ScR guidelines and a more focused analysis of cortisol change after cold pain induction using the direction of effect analysis combined with risk of bias analysis using ROBINS-I. Five data bases were searched systematically for articles on adults with acute pain secondary to disease, injury, or experimentally induced pain. Forty three articles met the inclusion criteria for the general review and 11 of these were included in the cortisol-cold pain analysis. Salivary melatonin, kallikreins, pro-inflammatory cytokines, soluable TNF-α receptor II, secretory IgA, testosterone, salivary α-amylase (sAA) and, most commonly, cortisol have been studied in relation to acute pain. There is greatest information about cortisol and sAA which both rise after cold pain when compared with other modalities. Where participants have been subjected to both pain and stress, stress is consistently a more reliable predictor of salivary biomarker change than pain. There remain considerable challenges in identifying biomarkers that can be used in clinical practice to guide the measurement of nociception and treatment of pain. Standardization of methodology and researchers' greater awareness of the factors that affect salivary biomolecule concentrations are needed to improve our understanding of this field towards creating a clinically relevant body of evidence.
Topics: Adult; Humans; Hydrocortisone; Acute Pain; Saliva; Nociception; Salivary alpha-Amylases; Biomarkers; Stress, Psychological
PubMed: 38385158
DOI: 10.1177/17448069241237121 -
Food & Function Jul 2023An elevated postprandial glycaemic response is a risk factor for developing type 2 diabetes mellitus (T2DM). Inhibition of digestive enzymes, including membrane-bound...
An elevated postprandial glycaemic response is a risk factor for developing type 2 diabetes mellitus (T2DM). Inhibition of digestive enzymes, including membrane-bound brush-border α-glucosidases, leads to slowed carbohydrate digestion and absorption, and reduced postprandial glycaemia. Nuts are eaten widely around the world, and have the potential to inhibit α-glucosidases through their content of polyphenols and other bioactive compounds. We set out to conduct a systematic literature review exploring the inhibitory effect of extracts from edible parts of various nuts on α-glucosidase activity to ensure, as far as possible, that no papers were missed. After an initial screening, 38 studies were reviewed in full, of which 15 were suitable for the present systematic review. Notably, no studies were found which tested the inhibitory potential of nut extracts against human α-glucosidases. Two studies showed that extracts from almonds and hazelnuts inhibited rat α-glucosidase activity, but the remaining papers reported data on the yeast α-glucosidase enzyme. Where yeast and rat enzymes can be compared, it is clear that nut extracts inhibit yeast α-glucosidase more strongly than mammalian α-glucosidase, which may lead to over-estimation when predicting effects when using data from the yeast enzyme. In contrast, acarbose is a stronger inhibitor of mammalian α-glucosidase compared to the yeast enzyme. Thus, although the present review indicates that extracts from nuts inhibit yeast α-glucosidase, this cannot be extrapolated to humans . There is some evidence that extracts from almonds and hazelnuts inhibit rat α-glucosidase, but no information on human enzyme sources. Since most work has been published on the yeast enzyme, future work must utilise mammalian, and preferably human, α-glucosidases in order to be relevant to human health and disease. This systematic review was registered at INPLASY as INPLASY202280061.
Topics: Rats; Humans; Animals; alpha-Glucosidases; Diabetes Mellitus, Type 2; Glycoside Hydrolase Inhibitors; Nuts; Saccharomyces cerevisiae; Plant Extracts; Hyperglycemia; alpha-Amylases; Hypoglycemic Agents; Mammals
PubMed: 37306209
DOI: 10.1039/d3fo00328k -
Biological Psychology Feb 2023Growing evidence indicates the presence of racial differences in sympathetic nervous system (SNS) functioning, yet the nature of these differences is unclear and appears... (Review)
Review
Growing evidence indicates the presence of racial differences in sympathetic nervous system (SNS) functioning, yet the nature of these differences is unclear and appears to vary across different indices of SNS activity. Moreover, racial differences among commonly used indices of SNS activity are under-investigated. This systematic review examines racial differences among widely used resting SNS indices, such as electrodermal activity (EDA), pre-ejection period (PEP), and salivary alpha-amylase (sAA). Our review reveals that Black participants have consistently been found to display lower resting EDA compared to White participants. The few studies that have investigated or reported racial differences in PEP and sAA yield mixed findings about whether racial differences exist. We discuss potential reasons for racial differences in SNS activity, such as index-specific factors, lab confounds, psychosocial environmental factors, and their interactions. We outline a framework characterizing possible contributors to racial differences in SNS functioning. Lastly, we highlight the implications of several definitional, analytic, and interpretive issues concerning the treatment of group differences in psychophysiological activity and provide future recommendations.
Topics: Humans; Saliva; Race Factors; Salivary alpha-Amylases; Sympathetic Nervous System; Psychophysiology
PubMed: 36641137
DOI: 10.1016/j.biopsycho.2023.108496 -
Developmental Psychobiology Nov 2022The aim of this systematic review was to better understand whether and to what extent psychosocial stressors are associated with hypothalamic-pituitary-adrenal axis or... (Review)
Review
The aim of this systematic review was to better understand whether and to what extent psychosocial stressors are associated with hypothalamic-pituitary-adrenal axis or autonomic nervous system stress responses in young children (1-6 years of age). Studies were classified by psychosocial stressors from the ecobiodevelopmental model: social and economic resources, maternal mental health, parent-child relationships, and the physical environment. Of the 2388 identified studies, 32 met full inclusion criteria, including over 9107 children. Child physiologic stress responses were measured as hair and urinary cortisol and cortisone, salivary diurnal and reactive cortisol, salivary reactive alpha-amylase, and respiratory sinus arrhythmia. There were 107 identified relations between psychosocial stressors and physiologic stress responses. Nearly two thirds of these relations suggested that children have dysregulated stress responses as either significantly blunted (n = 27) or increased (n = 37); 43 relations were not significant. Children most consistently had significantly dysregulated stress responses if they experienced postnatal maternal depression or anxiety. Some reasons for the mixed findings may be related to characteristics of the child (i.e., moderators) or stressor, how the stress response or psychosocial stressor was measured, unmeasured variables (e.g., caregiving buffering), researcher degrees of freedom, or publication bias.
Topics: Child, Preschool; Humans; Pituitary-Adrenal System; Hypothalamo-Hypophyseal System; Hydrocortisone; Cortisone; Stress, Psychological; alpha-Amylases; Saliva
PubMed: 36282746
DOI: 10.1002/dev.22320 -
Oral Diseases Oct 2023The objective of this systematic review was to evaluate which salivary biomarkers are altered in patients with burning mouth syndrome (BMS) compared to a control group... (Meta-Analysis)
Meta-Analysis Review
The objective of this systematic review was to evaluate which salivary biomarkers are altered in patients with burning mouth syndrome (BMS) compared to a control group (CG). A comprehensive literature search was conducted in four databases. Case-control studies evaluating salivary biomarkers in BMS patients were included. Risk of bias was assessed using the Newcastle-Ottawa tool. RevMan was used for meta-analysis. Seventeen studies were selected. The included studies collected 54 different biomarkers. Of these biomarkers, only three (cortisol, α-amylase, and dehydroepiandrosterone) were analyzed in three or more studies. Dehydroepiandrosterone obtained contradictory results among the studies. However, cortisol and α-amylase levels were found to be higher in BMS patients. Cortisol was the only biomarker which could be included for meta-analysis. Cortisol levels were significantly higher in the BMS group compared to the CG (Mean Difference = 0.39; 95% CI [0.14-0.65]; p = 0.003). In conclusion, different studies investigated salivary biomarkers in patients with BMS compared to a CG, with controversial results. Meta-analysis, confirmed by trial-sequential analysis, showed how cortisol levels were significantly higher in BMS. Cortisol emerges as an interesting salivary biomarker in BMS, but future properly designed studies are needed to evaluate its role in diagnosis and/or response to treatment.
Topics: Humans; Saliva; Burning Mouth Syndrome; Hydrocortisone; Biomarkers; alpha-Amylases; Dehydroepiandrosterone
PubMed: 36135356
DOI: 10.1111/odi.14390 -
Caries Research 2022Salivary proteins play an important role in repairing mechanisms of damaged tissues and the maintenance of oral health. However, there is a dearth of information in the...
Salivary proteins play an important role in repairing mechanisms of damaged tissues and the maintenance of oral health. However, there is a dearth of information in the literature regarding the concentrations of salivary proteins in caries-free (CF) and caries-active (CA) subjects. Hence, this systematic review was conducted to update our previous systematic review published in 2013 that aimed to assess the association between caries and salivary proteins by comparing CF and CA individuals. Thereby, evaluating the possibility of whether salivary proteins can be regarded as biomarkers for caries. An extensive search of studies was conducted using PubMed, EMBASE, Clarivate Analytics' Web of Science, and Elsevier's Scopus between July 2012 and January 2022, without any language restriction. Manual searching in Google Scholar and evaluation of bibliographies of the included studies were also undertaken. The Newcastle-Ottawa Scale was used to assess the risk of bias (RoB) within the included studies. Of 22 included studies, 1,551 human subjects (range: 30-213 participants) were recruited, of which 848 individuals (54.7%) were CA and 703 (45.3%) were CF. Regarding the utilization of DMFT as the caries index, high variability was observed across different articles. A statistically significant increase in the salivary levels of alpha-amylase, acidic proline-rich protein-1, histatin-5, lactoperoxidase, and mucin-1 was found in CA patients, while the salivary levels of carbonic anhydrase 6, proteinase-3, and statherin were observed to be significantly increased in CF subjects. Conflicting results were found regarding the salivary levels of immunoglobulin A and total proteins among CA and CF subjects. The included studies were categorized as low RoB (n = 15), medium RoB (n = 4), and high RoB (n = 3). Due to significant heterogeneity among the included studies, no meta-analysis could be performed. In conclusion, the salivary levels of protein(s) might be a useful biomarker for caries diagnosis, especially alpha-amylase, acidic proline-rich protein-1, histatin-5, lactoperoxidase, mucin-1, carbonic anhydrase 6, proteinase-3, and statherin. However, their diagnostic value must be verified by large-scale prospective studies.
Topics: Humans; Mucin-1; Dental Caries; Histatins; Lactoperoxidase; Prospective Studies; Salivary Proteins and Peptides; Biomarkers; Proline; alpha-Amylases; Peptide Hydrolases
PubMed: 36116431
DOI: 10.1159/000526942 -
World Journal of Microbiology &... Aug 2022With the advent of green chemistry, the use of enzymes in industrial processes serves as an alternative to the conventional chemical catalysts. A high demand for... (Review)
Review
With the advent of green chemistry, the use of enzymes in industrial processes serves as an alternative to the conventional chemical catalysts. A high demand for sustainable processes for catalysis has brought a significant attention to hunt for novel enzymes. Among various hydrolases, the α-amylase has a gamut of biotechnological applications owing to its pivotal role in starch-hydrolysis. Industrial demand requires enzymes with thermostability and to ameliorate this crucial property, various methods such as protein engineering, directed evolution and enzyme immobilisation strategies are devised. Besides the traditional culture-dependent approach, metagenome from uncultured bacteria serves as a bountiful resource for novel genes/biocatalysts. Exploring the extreme-niches metagenome, advancements in protein engineering and biotechnology tools encourage the mining of novel α-amylase and its stable variants to tap its robust biotechnological and industrial potential. This review outlines α-amylase and its genetics, its catalytic domain architecture and mechanism of action, and various molecular methods to ameliorate its production. It aims to impart understanding on mechanisms involved in thermostability of α-amylase, cover strategies to screen novel genes from futile habitats and some molecular methods to ameliorate its properties.
Topics: Enzymes, Immobilized; Metagenome; Protein Engineering; Starch; alpha-Amylases
PubMed: 35999473
DOI: 10.1007/s11274-022-03396-0 -
Critical Reviews in Food Science and... 2021Evidence shows that polyphenols can attenuate postprandial blood glucose responses to meals containing digestible carbohydrate. Polyphenol-rich plant extracts are...
A systematic review of studies evaluating the inhibitory effects of polyphenol-rich fruit extracts on carbohydrate digestive enzymes activity: a focus on culinary fruits consumed in Europe.
Evidence shows that polyphenols can attenuate postprandial blood glucose responses to meals containing digestible carbohydrate. Polyphenol-rich plant extracts are emerging as potential ingredients in functional foods and/or beverages despite limited understanding of their physiological effects. Many studies have investigated the mechanisms of polyphenol-rich fruit extracts on inhibition of digestive enzymes. However, the evidence available has yet to be critically evaluated systematically. This report reviews the in vitro literature to quantify the effect of fruit polyphenol extracts on the activities of digestive carbohydrases. A systematic literature search was conducted using six science databases. Included studies, totaling 34 in number, were in vitro digestion models which quantified gut digestive enzyme(s) activity on starch digestion in the presence of fruit polyphenol extracts. Most studies assessed the effects of fruit extracts on either α-amylase (n = 30) or α-glucosidase (n = 30) activity. Studies were consistent overall in showing stronger inhibition of α-amylase compared to α-glucosidase by proanthocyanidin- and/or ellagitannin-rich fruit extracts. Recommendations are proposed for future reporting of this type of research to enable meaningful synthesis of the literature as a whole. Such knowledge could allow effective choices to be made for development of novel functional foods and beverages.
Topics: Fruit; Glycoside Hydrolase Inhibitors; Plant Extracts; Polyphenols; Starch; alpha-Amylases; alpha-Glucosidases
PubMed: 32838552
DOI: 10.1080/10408398.2020.1808585 -
Nutrients Aug 2020Evidence synthesizing the effects of acute body water losses on various markers of glycemic regulation, appetite, metabolism, and stress is lacking. Thus, the purpose of... (Meta-Analysis)
Meta-Analysis
Evidence synthesizing the effects of acute body water losses on various markers of glycemic regulation, appetite, metabolism, and stress is lacking. Thus, the purpose of this review was to summarize the response of various hormonal changes involved in these physiologic functions to dehydration. A comprehensive literature search for peer-reviewed research in the databases PubMed, Scopus, CINAHL, and SportDiscus was conducted. Studies were included if they contained samples of adults (>18 years) and experimentally induced dehydration as measured by acute body mass loss. Twenty-one articles were eligible for inclusion. Findings suggested cortisol is significantly elevated with hypohydration (standard mean difference [SMD] = 1.12, 95% CI [0.583, 1.67], < 0.0001). Testosterone was significantly lower in studies where hypohydration was accompanied by caloric restriction (SMD= -1.04, 95% CI [-1.93, -0.14], = 0.02), however, there were no changes in testosterone in studies examining hypohydration alone (SMD = -0.17, 95% CI [-0.51 0.16], = 0.30). Insulin and ghrelin were unaffected by acute total body water losses. Acute hypohydration increases markers of catabolism but has a negligible effect on markers of glycemic regulation, appetite, anabolism and stress. Given the brevity of existing research, further research is needed to determine the impact of hydration on glucagon, leptin, peptide YY and the subsequent outcomes relevant to both health and performance.
Topics: Adolescent; Adult; Appetite; Blood Glucose; Caloric Restriction; Dehydration; Female; Ghrelin; Humans; Hydrocortisone; Leptin; Male; Peptide YY; Stress, Physiological; Testosterone; Young Adult; alpha-Amylases
PubMed: 32825404
DOI: 10.3390/nu12092526