Isolation of Bioactive Compounds (Carotenoids, Tocopherols, and Tocotrienols) from Calendula Officinalis L., and Their Interaction with Proteins and Oils in Nanoemulsion Formulation.

Calendula officinalis L. has numerous health-promoting properties due to the presence of a large number of lipophilic compounds. Their effective delivery to the body requires the use of an appropriate technique such as emulsification. So, the main purpose of this study was to understand how the profile of lipophilic compounds from pot marigold and the pro-health potential are shaped by different types of protein, oil, and drying techniques in o/w nanoemulsion. To obtain this, the profiles of carotenoid compounds and tocols were measured. Additionally, antioxidant potential and the ability to inhibit α-amylase and α-glucosidase were measured. Pea protein emulsion exhibited a higher final content of carotenoid compounds (23.72-39.74 mg/100 g), whereas those with whey protein had stronger α-amylase inhibition (487.70 mg/mL). The predominant compounds in the studied nanoemulsions were ß-carotene (between 19% and 40%), followed by α-tocopherol/γ-tocopherol. The type of proteins shaped the health-promoting properties and determined the content of health-promoting compounds.

Naphthoquinone fused diazepines targeting hyperamylasemia: potential therapeutic agents for diabetes and cancer.

Aim: Elevated levels of amylase in the blood, known as hyperamylasemia, have been correlated with diabetes and cancer. To investigate the impact of hyperamylasemia on cellular proliferation, it is imperative to design dual inhibitors targeting both α-amylase activity and cancer progression.Materials & methods: Naphthoquinone fused diazepines have been synthesized using multicomponent reaction with high Eco-score of 87 and evaluated for bio efficacy using antioxidant and α-amylase inhibition assay. A correlation between diabetes and cancer has been established via preliminary screening against A549 based lung cancer cell line at 5 µM.Results & conclusion: Compound 4b exhibited superior anti-oxidant and α-amylase inhibitory potential over butylated hydroxytoluene (BHT) and acarbose, respectively with uncompetitive mode of inhibition. Compounds possessing more than 50 % inhibition were then investigated for their IC50 against A549 (Lung cancer), and Breast cancer (MCF-7 and MDA-MB-231) cells. Among all, compound 4p has been selected for further studies, as it demonstrated significant cytotoxicity, while compound 4b showed no effect on AKT gene expression but upregulated IGF-1R gene expression, suggesting a role in managing diabetes. Compound 4p exhibited the ability to decrease AKT expression and increase IGF-1R expression, indicating its potential for treating both diabetes and cancer.

[Box: see text].

Mild hunger elicits attentional desensitization to visual food cues in healthy, non-obese individuals.

Introduction: Food is a vital human need, and the human visual system is finely tuned to detect and respond to food cues in the environment. The omnipresence of food cues across various settings has been linked to the prevalence of obesity in susceptible populations. However, the influence of the post-prandial state on visual attention to food stimuli remains poorly understood. This study aimed to elucidate how a 12 hour fast affects visual attention to food and non-food stimuli in healthy, non-obese individuals. Methods: Visual attention was assessed by measuring the total duration of visual fixations on stimuli presented on a computer screen, using a screen-based eye tracker (Tobii X2-60). Participants were divided into two groups: those who had fasted for 12 hours and those tested within two hours after consuming breakfast (satiated state). Additionally, performance on the Food Stroop task and electrodermal activity (EDA) responses were measured to evaluate attentional interference and physiological arousal, respectively. Salivary samples were also collected to assess levels of alpha-amylase and cortisol. Results: Fasted participants exhibited a progressive decline in visual attention toward food stimuli compared to satiated individuals, reflecting a satiated state. This effect was independent of the palatability of the depicted food items and was not observed with stimuli representing non-food items. The Food Stroop task revealed no differences between fasting and satiated participants, indicating that the presence of food-related stimuli does not differentially impact attentional interference under varying hunger states. Moreover, no significant variations were observed in EDA responses across participant groups and stimulus types, suggesting that the modulation of visual attention to food cues by hunger is independent of physiological arousal. Interestingly, satiated subjects exhibited higher levels of salivary alpha-amylase, which was inversely related to their subjective hunger ratings. No differences in salivary cortisol levels were found between groups. Discussion: The findings indicate a novel influence of mild hunger on the processing of visual food cues, independent of physiological arousal. The decline in visual attention to food stimuli in fasted individuals suggests that satiety modulates visual processing. The lack of differences in attentional interference and physiological arousal between fasting and satiated states further supports the notion that visual attention to food cues is primarily driven by hunger-related mechanisms rather than stress. Additionally, the inverse relationship between salivary alpha-amylase levels and hunger ratings implies that alpha-amylase may serve as a marker of satiety rather than stress.

Amylase intrapancreatic infusion delays insulin release during an intravenous glucose tolerance test, proof of acini-islet-acinar interactions.

BACKGROUND: The possible existence of an acini-islet-acinar (AIA) reflex, involving mutual amylase and insulin interactions, was investigated in the current acute experiment on pigs. AIM: To confirm the existence of an AIA reflex and justify the placement of the exocrine and endocrine pancreatic components within the same organ. METHODS: The study was performed on six pigs under general anesthesia. An intravenous glucose tolerance test was performed, with a bolus infusion of 50% glucose to the jugular vein, while amylase (5000 U/kg) or vehicle intrapancreatic infusions were administered via the pancreaticoduodenalis cranialis artery during 30 min with a 1 mL/min flow rate. RESULTS: The amylase infusion to pancreatic arterial circulation inhibited and delayed the insulin release peak which is usually associated with the highest value of blood glucose and is typically observed at 15 min after glucose infusion, for > 1 h. The intrapancreatic infusion of the vehicle (saline) did not have any effect on the time frame of insulin release. Infusion of 1% bovine serum albumin changed the insulin release curve dramatically and prolonged the high range of insulin secretion, far beyond the glucose peak. CONCLUSION: Intrapancreatic arterial infusion of amylase interrupted the integrated glucose-insulin interactions. This confirms an AIA reflex and justifies placement of the exocrine and endocrine pancreatic components within the same organ.

Diagnostic Accuracy of Lipase as Early Predictor of Postoperative Pancreatic Fistula: Results from the LIPADRAIN study.

Objective: To evaluate the diagnostic accuracy of drain fluid lipase as an early predictor of postoperative pancreatic fistula and establish the most appropriate day for their measure. Background: Clinically relevant postoperative pancreatic fistula remains a potentially life-threatening complication after pancreatic surgery. Early detection strategies remain key to reduce both the incidence and the burden of pancreatic fistula. Methods: The LIPAse DRAIN (LIPADRAIN) study is a multicenter, prospective diagnostic study conducted in 7 tertiary university hospitals. Drain fluid values to detect clinically relevant postoperative pancreatic fistula from postoperative day 1 to postoperative day 6 were evaluated using receiver operating characteristic curve analysis. A biomarker was considered to be relevant for clinical use if its area under the curve (AUC) was greater than 0.75. Results: Of the 625 patients included in the analysis, clinically relevant postoperative pancreatic fistula occurred in 203 (32%) patients. On postoperative days 3 and 4, drain fluid lipase was a reliable biomarker to detect clinically relevant postoperative pancreatic fistula (AUC: 0.761; 95% confidence interval [CI]: 0.761-0.799 and AUC: 0.784; 95% CI: 0.743-0.821, respectively). On postoperative day 3, with a threshold of 299 units/L, drain fluid lipase yielded a negative predictive value of 51%, sensitivity of 78%, and specificity of 63% for the detection of clinically relevant postoperative pancreatic fistula. Conclusions: In this multicenter prospective study, drain fluid lipase is a reliable biomarker at postoperative days 3 and 4 for the diagnosis of clinically relevant postoperative pancreatic fistula after pancreatic surgery and should be systematically measured on postoperative day 3.

Evaluations of the in vitro and in vivo antidiabetic activity of 70 % ethanolic fruit extracts of Rosa abyssinica.

Background: Diabetes mellitus is becoming major health challenge with continually increasing burden. High costs of conventional medicines and numerous side effects associated with them, on the other hand, easy availability and accessibility of traditional herbal medicines calls upon experimental investigations to validate their effect on lowering blood glucose level. Methods: The dried fruit of Rosa abyssinica was macerated with 70 % ethanol and the extract's in vitro antidiabetic activity was investigated using dinitrosalisylic acid method for alpha amylase inhibitory activity. Furthermore, the in vivo hypoglycemic and Antihyperglycemic effects of various doses of the extract (100, 200 and 400 mg/kg) was determined on normoglycemic, glucose loaded (1500 mg/kg) and Streptozotocine (180 mg/kg)-induced diabetic mice models. Results: The acute oral toxicity study revealed the plant showed no toxic effect on swiss albino mice at 2000 mg/kg. The in vitro alpha amylase inhibitory activity study showed that the extract has comparable IC50 value of 21.37 ± 4.252 µg/ml with the standard drug acarbose (IC50 value of 26.72 ± 3.59 µg/ml). On the other hand, in normal mice, none of the dose levels except at 400 mg/kg significantly reduces blood glucose level. This is in contrast to the oral glucose tolerance test, which the extract produced significant reduction at 60, 90 and 120 min following glucose challenge. The 70 % ethanolic fruit extracts of Rosa abyssinica also experienced profound antidiabetic activity in streptozotocin-induced diabetic model. In the single-dose study, both RAFE200 and RAFE400 demonstrated a significant (P˂0.05) reduction in blood glucose levels at 1, 2, 3, and 4 h. Similarly, in the repeated-dose study, RAFE200 and RAFE400 not only significantly reduced blood glucose levels but also produced a notable improvement in animal body weight. Conclusion: The 70 % ethanolic fruit extracts of Rosa abyssinica have shown significant in vitro alpha amylase inhibition effect and an in vivo blood glucose level lowering effects in diabetic mice.Therefore, this study supports the traditional use of Rosa abyssinica in the management of diabetes mellitus.

A Captivating Potential of Schiff Bases Derivatives for Antidiabetic Activity.

A double bond between the nitrogen and carbon atoms characterizes a wide class of compounds known as Schiff bases. The flexibility of Schiff bases is formed from several methods and may be combined with alkyl or aryl substituents. The group is a part of organic compounds, either synthetic or natural, and it serves as a precursor and an intermediate in drugs that have therapeutic action. The review focuses on molecular docking and structure-activity relationship (SAR) analysisfor antidiabetic effects of the different non-metal Schiff bases. Many studies have found that Schiff bases are used as linkers in an extensive range of synthesized compounds and other activities. Thus, this current study aims to give the scientific community a thoughtful look at the principal ideas put forward by investigators regarding antidiabetic actions exhibited by certain Schiff-based derivatives, as this review covered many aspects, including docking and SAR analysis. For individuals who intend to create novel antidiabetic compounds with Schiff bases as pharmacophores or physiologically active moieties, it will be an invaluable informational resource.

Impact of increased pre-start diet density on broiler chick behavior, corticosterone levels, and performance responses under cold stress during early life.

This study assessed the effects of increased pre-start diet density on the metabolism, crop filling, and overall performance of broilers under cold stress during their initial 14 days of life. Using 576 one-day-old Cobb500 male chicks from 27-week-old breeders, the experiment employed a 2 × 2 arrangement, varying thermal conditions (thermoneutrality or cold stress at 18 °C for 8 h) and pre-start diet composition (21.5% crude protein, 2970 kcal/kg or 22.5%, 3050 kcal/kg). The cold stress group exhibited lower cloacal temperature and decreased crop filling rate during the first two days (P < 0.05). Chick behavior was significantly affected at 1 and 5 days (P < 0.05), and corticosterone levels in serum were higher for the cold stress group at 7 days (P < 0.05). Feed intake at 7 days was lower in the high-density feed group (P < 0.05). No significant interactions were observed for feed intake, body weight gain, or feed conversion ratio at 7 and 35 days (P > 0.05). Cold stress resulted in performance losses, impacting feed conversion and the Productive Efficiency Index. The dense diet influenced performance only within the first week, with subsequent diets showing no effect, suggesting dietary manipulation alone was insufficient to mitigate cold stress-induced losses.

Discovery of novel dihydro-pyrimidine hybrids: insight into the design, synthesis, biological evaluation and absorption, distribution, metabolism and excretion studies.

Aim: By keeping in aspects, the pharmacological potential of heterocyclic compounds, pyrimidine-based compounds were designed, synthesized and evaluated for α-amylase inhibitory potential.Materials & methods: Five new series 1a-l, 2a-d, 3a-d, 4a-d and 5a-d of 1,2,3,4-tetrahydroprimidine-5-carboxylate derivatives were designed by de novo method by taking Alogliptin as reference compound. Here in we describe synthesis and characterization of compounds as potential α-amylase inhibitor.Results: Structure activity relationship (SAR), in vitro analysis and molecular modelling approaches generate compounds 1 h, 1i, 1k and 4c as potential lead with good α-amylase inhibitory selection. However, compound 1k failed the criteria of optimization as drug lead by ADME studies while all other compounds showed optimum range for all in silico ADME parameters.Conclusion: Therefore, these compounds can serve as potential lead candidate in developing anti-diabetic therapy.

[Box: see text].

Involvement of heparanase in the pathogenesis of acute pancreatitis: Implication of novel therapeutic approaches.

Acute pancreatitis (AP) is a common gastrointestinal disease with high morbidity and mortality rate. Unfortunately, neither the etiology nor the pathophysiology of AP are fully understood and causal treatment options are not available. Recently we demonstrated that heparanase (Hpa) is adversely involved in the pathogenesis of AP and inhibition of this enzyme ameliorates the manifestation of the disease. Moreover, a pioneer study demonstrated that Aspirin has partial inhibitory effect on Hpa. Another compound, which possesses a mild pancreato-protective effect against AP, is Trehalose, a common disaccharide. We hypothesized that combination of Aspirin, Trehalose, PG545 (Pixatimod) and SST0001 (Roneparstat), specific inhibitors of Hpa, may exert pancreato-protective effect better than each drug alone. Thus, the current study examines the pancreato-protective effects of Aspirin, Trehalose, PG545 and SST0001 in experimental model of AP induced by cerulein in wild-type (WT) and Hpa over-expressing (Hpa-Tg) mice. Cerulein-induced AP in WT mice was associated with significant rises in the serum levels of lipase (X4) and amylase (X3) with enhancement of pancreatic edema index, inflammatory response, and autophagy. Responses to cerulein were all more profound in Hpa-Tg mice versus WT mice, evident by X7 and X5 folds increase in lipase and amylase levels, respectively. Treatment with Aspirin or Trehalose alone and even more so in combination with PG545 or SST0001 were highly effective, restoring the serum level of lipase back to the basal level. Importantly, a novel newly synthesized compound termed Aspirlose effectively ameliorated the pathogenesis of AP as a single agent. Collectively, the results strongly indicate that targeting Hpa by using anti-Hpa drug combinations constitute a novel therapy for this common orphan disease.

Structural insight into sugar-binding modes of microbial ß-amylase.

ß-Amylase, which catalyses the release of ß-anomeric maltose from the non-reducing end of starch, is widely used in the food industry. Increasing its enzyme activity through protein engineering might improve the efficiency of food processing. To obtain detailed structural information to assist rationale design, here the crystal structure of Bacillus cereus ß-amylase (BCB) complexed with maltose was determined by molecular replacement and refined using anisotropic temperature factors to 1.26 Å resolution with Rwork/Rfree factors of 12.4/15.7 %. The structure contains six maltose and one glucose molecules, of which two maltose and one glucose are bound at sites not previously observed in BCB structures. These three new sugar-binding sites are located on the surface and likely to be important in enhancing the degradation of raw-starch granules. In the active site of BCB, two maltose molecules are bound in tandem at subsites -2 âˆ¼ -1 and +1 âˆ¼ +2. Notably, the conformation of the glucose moiety bound at subsite -1 is a mixture of α-anomeric distorted 1,4B boat and 4C1 chair forms, while those at subsites -2, +1 âˆ¼ +2 are all in the 4C1 chair forms. The O1 of the distorted α-glucose residue at subsite -1 occupies the position of the putative catalytic water, forming a hydrogen bond with OE1 of Glu367 (base catalyst), suggesting that this distorted sugar is not involved in catalysis. Together, these findings pave the way for further improving the functionality of microbial ß-amylase enzymes.

Amylase-associated genetic pattern in Xanthomonas euvesicatoria on pepper.

Bacterial leaf spot of pepper (BSP), primarily caused by Xanthomonas euvesicatoria (Xe), poses a significant challenge to pepper production worldwide. Despite its impact, the genetic diversity of this pathogen remains underexplored, which limits our understanding of its population structure. To bridge this knowledge gap, we conducted a comprehensive analysis using 103 Xe strains isolated from pepper in southwest Florida to characterize genomic and type III effector (T3E) variation in this population. Phylogenetic analysis of core genomes revealed a major distinct genetic lineage associated with amylolytic activity. This amylolytic lineage was represented in Xe strains globally. Molecular clock analysis dated the emergence of amylolytic strains in Xe to around 1972. Notably, non-amylolytic strains possessed a single base pair frameshift deletion in the ⍺-amylase gene yet retained a conserved C-terminus. GUS assay revealed the expression of two open reading frames in non-amylolytic strains, one at the N-terminus and another that starts 136 base pairs upstream of the ⍺-amylase gene. Analysis of T3Es in the Florida Xe population identified variation in 12 effectors, including two classes of mutations in avrBs2 that prevent AvrBs2 from triggering a hypersensitive response in Bs2-resistant pepper plants. Knowledge of T3E variation could be used for effector-targeted disease management. This study revealed previously undescribed population structure in this economically important pathogen.IMPORTANCEBacterial leaf spot (BSP), a significant threat to pepper production globally, is primarily caused by Xanthomonas euvesicatoria (Xe). Limited genomic data has hindered detailed studies on its population diversity. This study analyzed the whole-genome sequences of 103 Xe strains from peppers in southwest Florida, along with additional global strains, to explore the pathogen's diversity. The study revealed two major distinct genetic groups based on their amylolytic activity, the ability to break down starch, with non-amylolytic strains having a mutation in the ⍺-amylase gene. Additionally, two classes of mutations in the avrBs2 gene were found, leading to susceptibility in pepper plants with the Bs2 resistance gene, a commercially available resistance gene for BSP. These findings highlight the need to forecast the emergence of such strains, identify genetic factors for innovative disease management, and understand how this pathogen evolves and spreads.

Identification of pancreatin inhibitors from Thai medicinal Piper plants for antidiabetic and anti-obesity activities using high-performance thin-layer chromatography-bioautographic assay.

Exploring the potential of natural products against diabetes and obesity is in demand nowadays. Pancreatic α-amylase and pancreatic lipase are the drug targets to minimize the absorption of glucose from starch and fatty acids from lipids, respectively. In this study, five Piper species, namely P. sarmentosum (Ps), P. wallichii (Pw), P. retrofractum (Pr), P. nigrum (Pn), and P. betle (Pb), which are commonly used as food ingredients and traditional medicines, were evaluated for their inhibitory activities against pancreatin using the microtiter plate method. Additionally, pancreatin inhibitors were identified through a cost-effective high-performance thin-layer chromatography (HPTLC)-bioautography developed using red starch and p-nitrophenyl palmitate, corresponding to anti-amylase and -lipase activities, respectively. Of the 15 samples tested, leaf samples from Pb, which had the highest total phenolic and total flavonoid contents, exhibited remarkable inhibitory activity against pancreatin, with a relative amylase inhibitory capacity (RAIC) ranging between 4.260 × 10-5 and 4.861 × 10-5 and a reciprocal half-maximal inhibitory concentration (1/IC50, PTL) of 0.390-0.510 (mg/mL)-1. Additionally, Ps samples demonstrated the second-ranked anti-pancreatin activity. Principal component analysis indicated that total phenolic content contributed to the anti-pancreatin activities of Pb samples. The anti-pancreatin bands were isolated and identified as caffeic acid, myricetin, genistein, piperine, and eugenol. Myricetin, in the roots of Ps samples, showed notable anti-pancreatin activity, which was consistent with results from the in silico prediction toward pancreatic α-amylase and pancreatic lipase. Caffeic acid and eugenol were present in Pb samples. In conclusion, the developed cost-effective pancreatin HPTLC-bioautography efficiently identified amylase and lipase inhibitors from Piper herbs, which supported the use of these plants for antidiabetes and anti-obesity.

Allosteric mechanism of synergistic effect in α- and ß-amylase mixtures.

Alpha-amylase and beta-amylase coexist as mixtures in industrial production, and the two amylases have active synergistic effects when they approach each other. These effects are due to enhanced enzyme binding affinity for the substrate and the rate of particle hydrolysis. Here, we report the allosteric mechanism of this synergistic effect in α- and ß-amylase mixtures. The assay showed higher activity after mixing α- and ß-amylase. Molecular docking showed that α- and ß-amylase create a stable dual-enzyme complex with high binding energy, and that complex formation does not affect the exposure of respective active sites. ß-Amylase is specifically bound to the B domain of α-amylase, and the dynamic plasticity of the B domain makes it move spatially, and this adjustment leads to a more open conformation in the active site of α-amylase. Because the enzymes binding make the complex more stable, the degree to which the relative activity of the dual-enzyme complex is inhibited is significantly reduced. After enzyme hydrolysis, the products maltose and glucose accumulate and produce competitive inhibition, which explains the relative activity decrease of the later-stage dual-enzyme cooperation. Structural characterization by FT-IR and CD spectroscopy did not reveal significant changes in respective secondary structures after enzyme binding.

Mechanism of inhibition of alpha-amylase by caffeic acid using in-vitro and in-silico techniques.

Type-two diabetes, characterised by insulin resistance or inadequate insulin production, is prevalent among adults. The α-amylase enzyme contributes to carbohydrate digestion, elevating postprandial glucose levels. Natural compounds like caffeic acid offer a solution. This study investigates α-amylase inhibition via in-vitro and in-silico methods, emphasising the connection between phenolic compounds and antidiabetic efficacy for in-silico analysis. Enzyme kinetics, IC50, and molecular docking examine caffeic acid's inhibitory action on α-amylase, comparing it with gallic acid and acarbose. Caffeic acid outperforms acarbose with an IC50 of 4.505 mg/mL versus 16.81 mg/mL, showcasing strong antidiabetic activity. Caffeic acid's superior 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition (90.67%) compared to gallic acid (55.76%) indicates potent antioxidative and antidiabetic properties. Molecular docking reveals hydrogen bonding between caffeic acid and α-amylase. These insights lay the groundwork for phenolic-based diabetic therapies, offering less expensive treatment for diabetes patients.

Evidence of Differential Prediction of Anxiety and Depression by Diurnal Alpha-Amylase and Cortisol in Development.

Research and theory suggest an important role of neuroendocrine function in emotional development, particularly under conditions of elevated stress. We provide empirical data to clarify associations between alpha-amylase (AA) and cortisol as well as test the differential linkages among AA, cortisol, and symptoms of anxiety, depression, and posttraumatic stress in children. Children recruited from a low-income elevated violence community (n = 100; mean age = 10, SD = 0.64; 79% Latino; 67% received free or reduced lunch) were assessed on diurnal levels of AA and cortisol along with assessments of anxiety, depression, and posttraumatic stress symptoms (PTSS). Elevated anxiety symptoms were associated with steeper linear slopes of AA with higher levels of AA in the morning but lower levels of AA in the evening. Depression was associated with differential cubic trajectories of AA when PTSSs were included in the model. Anxiety also predicted differential cubic diurnal trends in cortisol, such that greater anxiety symptoms were associated with relatively higher levels of cortisol in the evening. Again, depression symptoms when PTSS were included predicted diurnal cubic trends with elevated depression associated with lower awakening and midday cortisol that reversed to higher evening cortisol compared to youth with fewer self-reported depression symptoms.

Salivary cortisol and alpha-amylase as stress markers to evaluate an individualized music intervention for people with dementia: feasibility and pilot analyses.

OBJECTIVES: We investigated salivary biomarkers of stress, more specifically, cortisol and alpha-amylase, to evaluate effects of individualized music listening (IML) in people with dementia. METHOD: Participants were N = 64 nursing home residents with dementia (meanage = 83.53 ± 7.71 years, 68.8% female). Participants were randomly assigned to either listening to their favorite music every other day for a period of six weeks (intervention), or standard care (control). Using the Saliva Children`s Swab (SCS), saliva was collected before, after, and 20 min after IML sessions at the beginning and end of the intervention period for the analysis of salivary alpha-amylase and cortisol. RESULTS: Using the SCS was feasible in people with dementia. Nevertheless, there was no effect of IML on salivary stress markers. DISCUSSION: Although using SCS was feasible, active patient engagement is required. Future studies need to corroborate findings in larger samples. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00015641, ISRCTN registry: ISRCTN59052178.

Lipophilic derivatives of EGCG as potent α-amylase and α-glucosidase inhibitors ameliorating oxidative stress and inflammation.

Uncontrolled hyperglycemia leads to increased oxidative stress, chronic inflammation, and insulin resistance, rendering diabetes management harder to accomplish. To tackle these myriads of challenges, researchers strive to explore innovative multifaceted treatment strategies, including inhibiting carbohydrate hydrolases. Herein, we report alkyl-ether EGCG derivatives as potent α-amylase and α-glucosidase inhibitors that could simultaneously ameliorate oxidative stress and inflammation. 4″-C18 EGCG, the most promising compound, showed multifold improvement in glycaemic management compared to acarbose, with 230-fold greater inhibition (competitive) of α-glucosidase (IC50 0.81 µM) and 3-fold better inhibition of α-amylase (IC50 3.74 µM). All derivatives showed stronger antioxidant activity (IC50 6.16-15.76 µM) than vitamin C, while acarbose showed none. 4″-C18 EGCG also downregulated pro-inflammatory cytokines and showed no significant cytotoxicity up to 50 µM in primary human peripheral blood mononuclear cells (PBMC), non-cancerous cell line, 3T3-L1 and HEK 293. The in silico binding affinity analysis of 4″-C18 EGCG with α-amylase and α-glucosidase was found to exhibit a good extent of interaction as compared to acarbose. In comparison to EGCG, 4″-Cn EGCG derivatives were found to remain stable in the physiological conditions even after 24 h. Together, the reported molecules demonstrated multifaceted antidiabetic potential inhibiting carbohydrate hydrolases, reducing oxidative stress, and inflammation, which are known to aggravate diabetes.

Enzymolysis Modes Trigger Diversity in Inhibitor-α-Amylase Aggregating Behaviors and Activity Inhibition: A New Insight Into Enzyme Inhibition.

Inhibitors of α-amylase have been developed to regulate postprandial blood glucose fluctuation. The enzyme inhibition arises from direct or indirect inhibitor-enzyme interactions, depending on inhibitor structures. However, an ignored factor, substrate, may also influence or even decide the enzyme inhibition. In this work, it is innovatively found that the difference in substrate enzymolysis modes, i.e., structural composition and concentration of α-1,4-glucosidic bonds, triggers the diversity in inhibitor-enzyme aggregating behaviors and α-amylase inhibition. For competitive inhibition, there exists an equilibrium between α-amylase-substrate catalytic affinity and inhibitor-α-amylase binding affinity; therefore, a higher enzymolysis affinity and concentration of α-1,4-glucosidic structures interferes the balance, unfavoring inhibitor-enzyme aggregate formation and thus weakening α-amylase inhibition. For uncompetitive inhibition, the presence of macromolecular starch is necessary instead of micromolecular GalG2CNP, which not only binds with active site but with an assistant flexible loop (involving Gly304-Gly309) near the site. Hence, the refined enzyme structure due to the molecular flexibility more likely favors the inhibitor binding with the non-active loop, forming an inhibitor-enzyme-starch ternary aggregate. Conclusively, this study provides a novel insight into the evaluation of α-amylase inhibition regarding the participating role of substrate in inhibitor-enzyme aggregating interactions, emphasizing the selection of appropriate substrates in the development and screening of α-amylase inhibitors.

Isolation and Characterization of Novel Pueroside B Isomers and Other Bioactive Compounds from Pueraria lobata Roots: Structure Elucidation, α-Glucosidase, and α-Amylase Inhibition Studies.

Pueraria lobata (Willd.) Ohwi is a traditional medicinal herb that has been extensively used in Chinese medicine for various therapeutic purposes. In this study, twelve chemical constituents were isolated from the roots of P. lobata, comprising three puerosides (compounds 1-3), six alkaloids (compounds 4-9), and three additional compounds (compounds 10-12). Notably, compound 1 (4R-pueroside B) was identified as a novel compound. The structures of all compounds were elucidated using a range of spectroscopic techniques, including CD spectroscopy for the first-time determination of the absolute configurations of pueroside B isomers (compounds 1 and 2). Enzyme inhibition assays revealed that, with the exception of compound 2, all isolated compounds exhibited varying degrees of α-glucosidase and α-amylase inhibitory activity. Remarkably, compound 12 demonstrated IC50 values of 23.25 µM for α-glucosidase inhibition and 27.05 µM for α-amylase inhibition, which are superior to those of the positive control, acarbose (27.05 µM and 36.68 µM, respectively). Additionally, compound 11 exhibited inhibitory activity against α-glucosidase and α-amylase comparable to the positive control, acarbose. Molecular docking studies indicated that compound 12 interacts with the active sites of the enzymes via hydrogen bonds, van der Waals forces, and hydrophobic interactions, which likely contribute to their inhibitory effects. These findings suggest that the chemical constituents of P. lobata could be potential natural sources of α-amylase and α-glucosidase inhibitors, with compound 12 being particularly promising for further investigation.