Sweet tea extract encapsulated by different wall material combinations with improved physicochemical properties and bioactivity stability.

Aim: To prepare sweet tea extract microcapsules (STEMs) via a spray-drying by applying different wall material formulations with maltodextrin (MD), inulin (IN), and gum arabic (GA). Methods: The microcapsules were characterised by yield, encapsulation efficiency (EE), particle size, sensory evaluation, morphology, attenuated total reflectance-Fourier transform infra-red spectroscopy and in vitro digestion studies. Results: The encapsulation improved the physicochemical properties and bioactivity stability of sweet tea extract (STE). MD5IN5 had the highest yield (56.33 ± 0.06% w/w) and the best EE (e.g. 88.84 ± 0.36% w/w of total flavonoids). MD9GA1 obtained the smallest particle size (642.13 ± 4.12 nm). MD9GA1 exhibited the highest retention of bioactive components, inhibition of α-glucosidase (96.85 ± 0.55%), α-amylase (57.58 ± 0.99%), angiotensin-converting enzyme (56.88 ± 2.20%), and the best antioxidant activity during in vitro gastrointestinal digestion. Conclusion: The encapsulation of STE can be an appropriate way for the valorisation of STE with improved properties.

Hypoglycemic peptide-enriched hydrolysates of Corbicula fluminea and Chlorella sorokiniana possess synergistic hypoglycemic activity through inhibiting α-glucosidase and dipeptidyl peptidase-4 activity.

BACKGROUND: The prevalence of diabetes mellitus worldwide has increased in recent decades. Maintaining the level of blood glucose is the most basic and important issue for diabetics. This study aimed to investigate the hypoglycemic activity of a combination of hypoglycemic peptide-enriched hydrolysates of Corbicula fluminea (ACH) and Chlorella sorokiniana (PCH). RESULTS: Combined supplementation of ACH and PCH synergistically inhibited α-glucosidase and DPP4 activities in vitro. After 4 weeks of treatment with ACH and/or PCH, the plasma glucose concentration and insulin, homeostasis model assessment-estimated insulin resistance (HOMA-IR), total cholesterol (TC) and triglyceride (TG) levels significantly decreased. The hypoglycemic peptides in ACH and PCH were purified and assayed for α-glucosidase and DPP4 activity. The hypoglycemic peptides in ACH and PCH effectively decreased α-glucosidase and DPP4 activities. In silico assays showed that these two peptide types have different docking poses, which determined their inhibitory effect against α-glucosidase and DPP4 activity. CONCLUSION: Combined treatment with hypoglycemic peptide-enriched ACH and PCH could modulate blood glucose by synergistically inhibiting α-glucosidase and DPP4 activities. © 2021 Society of Chemical Industry.

Comprehensive chemical and metabolic profiling of anti-hyperglycemic active fraction from Clerodendranthi Spicati Herba.

Extensive pharmacological research has demonstrated that Clerodendranthi Spicati Herba has an obvious anti-hyperglycemic effect via α-glucosidase inhibitory activity. However, the anti-hyperglycemic active fraction and its metabolic behavior in vivo have not been elaborated clearly. In this study, ultra-high-performance liquid chromatography coupled to quadrupole time of flight tandem mass spectrometry with data filtering strategy, including mass defect screening, diagnostic product ions and neutral loss identification, was established for chemical and metabolic profiling of anti-hyperglycemic active fraction from Clerodendranthi Spicati Herba. A total of 28 methoxylated flavonoids and 61 diterpenoids were rapidly identified. Four main known methoxylated flavonoids were purified and unambiguously identified by nuclear magnetic resonance analysis. Thirty-one absorbed diterpenoids, 12 absorbed methoxylated flavonoids, and 56 methoxylated flavonoids metabolites were identified in rat plasma, urine, bile, and feces after oral administration of anti-hyperglycemic active fraction. The methoxylated flavonoids were predominantly metabolized by demethylation, sulfation, and glucuronidation. Glucuronidation metabolites found in bile and urine after demethylation were dominant metabolites. Diterpenoids were absorbed into the blood mainly in the form of prototypes and excreted through bile and urine. These results indicated that methoxylated flavonoids and diterpenoids were responsible for α-glucosidase inhibitory activity, which might provide novel drug candidates for the management of diabetes mellitus.

Safety of a Novel Weight Loss Combination Product Containing Orlistat and Acarbose.

The safety of a novel modified-release oral capsule with orlistat and acarbose (MR-OA) was investigated in 67 obese middle-aged White men with a body mass index of 32 to 40 kg/m2 or 30 to 32 kg/m2 plus waist circumference >102 cm. The purpose of this investigation was to compare MR-OA with the existing conventional orlistat regarding systemic safety defined as plasma orlistat concentration at the end of the treatment period of 14 days. Participants took the MR-OA fixed-dose combination formulation 3 times a day together with a major meal. Three different doses of MR-OA were evaluated-60/20, 90/30, and 120/40 (mg orlistat/mg acarbose)-as well as 1 reference group who received the conventional orlistat, Xenical, with 120 mg of orlistat. Blood plasma was sampled on days 1 and 14. The orlistat plasma concentrations of the MR-OA dose showed a delayed absorption and were lower compared with conventional orlistat at the end of the study. All doses were safe and well tolerated without any unexpected adverse events and no serious adverse events. The delay in the rise of orlistat plasma concentration indicates that the modified-release properties of the MR-OA formulation are effective. The systemic exposure of orlistat resulting from MR-OA was similar, albeit a bit lower than the conventional orlistat with 120 mg of orlistat. We can therefore assume that the safety profile regarding the orlistat moiety of MR-OA is comparable to the conventional orlistat and a promising approach for weight control in obese patients. Further clinical evaluation is underway.

Evaluation of the Bioequivalence of Acarbose in Healthy Chinese People.

The purpose of this study was to determine whether the reference formulation and test formulation of acarbose are bioequivalent among healthy Chinese subjects based on evaluation of the pharmacodynamic end point. Two clinical trials with acarbose were conducted: study A, a pilot study (n = 12; 50 and 100 mg), and study B, a pivotal study (n = 60; 50 mg). In study A, there was a dose-dependent relationship between 50 mg acarbose and 100 mg acarbose and a significant difference compared with sucrose alone. In study B, after logarithmic conversion, a linear mixed-effects model was used to analyze the maximum serum glucose value and area under the serum glucose-time curve from 0 to 2 hours. The geometric mean ratios (test formulation/reference formulation) were 92.68% and 95.70%, with 90% confidence intervals of 84.08%-102.17% and 84.21%-108.76%, respectively, falling between 80.00% and 125.00%. According to the geometric least-squares mean, the test formulation (or reference formulation) was statistically significantly different as a single sucrose (P < .001). The effective dose of acarbose in healthy Chinese volunteers was 50 mg. The reference and test formulations were bioequivalent.

Pharmacodynamic comparison of acarbose tablets in Chinese healthy volunteers under chewing and swallowing conditions.

WHAT IS KNOWN AND OBJECTIVE: Acarbose can efficiently block glucose absorption in the intestine as an alpha-glucosidase inhibitor. It is currently manufactured in several oral dosage forms, with the most common types being tablets and chewable tablets. The acarbose tablet (Glucobay® , 50 mg, Bayer) package insert gives instructions for either directly swallowing or chewing then swallowing. This study compared the pharmacodynamic effects of a single formulation of acarbose tablets under these two different administration routes. METHODS: This randomized, crossover study enrolled 24 healthy subjects who were instructed to chew (C group) or swallow (S group) the acarbose tablet. Glucose levels were monitored in subjects for up to 4 h following administration of 75 g of sucrose to establish a baseline firstly, after which subjects in the C and S groups were administered 50- or 100- mg of acarbose along with 75 g of sucrose. Then, subjects entered a 1-week washout period before being crossed over to the alternate dosing route. RESULTS AND DISCUSSION: Compared with the S group, the C group had a lower maximum concentration of serum glucose (Cmax ) and areas under the concentration-time curve (AUC0-2 , AUC0-1.5 ). In addition, the maximum reduction in serum glucose (ΔCmax ) and the reduction in the AUC (AUEC0-1.5 ) were both increased in the S group. This occurred at both the 50 mg and 100 mg dosages. These results indicate that fluctuations in blood glucose were lower following chewing of the acarbose tablet. Both administration routes exhibited similar safety and tolerance profiles. WHAT IS NEW AND CONCLUSION: In summary, chewing acarbose tablets appears to induce a superior glycaemic-controlling effect compared with swallowing them directly, at least with a single dose. It will be important to inform both clinicians and patients about these differences between the two administrations so that informed clinical decisions can be made, as numerous patients with diabetes are inclined to directly swallow acarbose tablets for convenience.

Polyphenol fingerprinting and hypoglycemic attributes of optimized Cycas circinalis leaf extracts.

BACKGROUND: Cycas circinalis leaves are used to treat diabetes mellitus in local medicinal systems without any scientifically proved information on their medicinal potential and phytochemicals. In this study, the total phenolic contents, total flavonoid contents, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and inhibitory effects on α-glucosidase and α-amylase were determined for optimized hydroethanolic leaf extracts. Secondary metabolites were identified using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS). In vivo studies on diabetic albino mice were also carried out to evaluate the impact of the most active extract on their blood glucose levels. RESULTS: The 60% ethanolic extract showed the highest extract yield (209.70 ± 0.20 g kg-1 ) and total phenolic (154.24 ± 3.28 mg gallic acid equivalent) and flavonoid (78.52 ± 1.65 mg rutin equivalent per gram dried extract) contents and exhibited the maximum DPPH scavenging activity (IC50 = 59.68 ± 2.82 µg mL-1 ). The IC50 values for inhibition of α-glucosidase (58.42 ± 2.22 µg mL-1 ) and α-amylase (74.11 ± 1.70 µg mL-1 ) were also significant for the 60% ethanolic extract. The untargeted UHPLC-QTOF-MS/MS-based metabolite profiling confirmed the presence of iridoid glucoside, gibberellin A4, O-ß-d-glucosyl-4-hydroxy-cinnamate, 3-methoxy-2-phyenyl-4H-furo[2,3-h]chromen-4-one, kaempferol, withaferin A, amentoflavone, quercitin-3-O-(6″-malonyl glucoside), ellagic acid, and gallic acid. Plant extract at a dose of 500 mg kg-1 body weight reduced the blood glucose level by a considerable extent and also improved the lipid profile of diabetic mice after a 28-day trial. CONCLUSION: The findings revealed the medicinal potential of C. circinalis leaves to treat diabetes mellitus and provided the nutraceutical leads for functional food development. © 2020 Society of Chemical Industry.

Structural characterization and stability study of green synthesized starch stabilized silver nanoparticles loaded with isoorientin.

Isoorientin (Iso) is a natural flavonoid, the effect of metal nanoparticles loaded with it was unknown. In this study, silver nanoparticles (AgNPs) were synthesized by corn starch and sodium citrate with the green synthesis method, and the structural characterization and stability of AgNPs loaded with Iso (AgNPs-Iso) were examined by UV-vis spectroscopy and zetasizer. Results showed that AgNPs (65 ± 0.87 nm, spheres) successfully loaded with Iso (117 ± 2.13 nm, loading efficiency: 76.60%). There are no significant changes of the stability of AgNPs and AgNPs-Iso in pH 5-9 and 0-0.30 M of NaCl solution. AgNPs-Iso was more stable than AgNPs in the simulated gastrointestinal digestion in vitro. Furthermore, AgNPs-Iso showed the lower erythrocytes hemolysis ratio and cytotoxicity, and exhibited a notably inhibitive effect on α-glucosidase and pancreatic lipase. Therefore, this study could provide the basic support for the further development of highly stable and lowly cytotoxic AgNPs-Iso on Type II diabetes and obesity.

Efficacy and Safety of Miglitol- or Repaglinide-Based Combination Therapy with Alogliptin for Drug-Naïve Patients with Type 2 Diabetes: An Open-Label, Single-Center, Parallel, Randomized Controlled Pilot Study.

BACKGROUND: Combination therapy with an alpha-glucosidase inhibitor or glinide plus a dipeptidyl peptidase-4 inhibitor is thought to be effective for glycemic control because of its effects on postprandial hyperglycemia. However, no studies have directly compared these two combination therapies in relation to efficacy and safety. METHODS: Eighteen patients with type 2 diabetes were studied. All had diabetes not adequately controlled with diet and exercise therapy, an HbA1c level of ≥7.5%, and were not receiving any medication for diabetes. The patients were randomized to either miglitol- or repaglinide-based combination therapy with alogliptin. Patients received miglitol or repaglinide monotherapy for 3 months (the miglitol and repaglinide groups, respectively), after which alogliptin was added to each group as combination therapy for 3 months. A meal tolerance test (MTT) was performed before the start of treatment and at the end of monotherapy and combination therapy. RESULTS: During the study period, decreases in HbA1c and glycated albumin were significantly greater in the repaglinide group than in the miglitol group; however, there was no significant difference between treatment groups at the end of the study. At the end of monotherapy, insulin secretion relative to glucose elevation (ISG0-30: area under the curve of insulin from 0 to 30 min during MTT [AUC0-30 of IRI]/AUC0-30 of plasma glucose) was significantly higher only in the repaglinide group; ISG0-30 did not significantly increase in either group after the addition of alogliptin. CONCLUSIONS: The addition of alogliptin to repaglinide monotherapy did not cause glucose-independent inappropriate insulin secretion and did not appear to increase the incidence of hypoglycemia.

Acarbose bioequivalence: Exploration of eligible protocol design.

WHAT IS KNOWN AND OBJECTIVE: Acarbose is a poorly absorbed α-glucosidase inhibitor that acts locally in the intestinal tract. Therefore, the evaluation of its bioequivalence (BE) should be based on pharmacodynamic (PD) rather than pharmacokinetic (PK) endpoints. Currently, there is no consensus on the best method for acarbose BE evaluation. The optimal protocol design regarding dosing time/dose and PD parameters requires further exploration. The aim of the study was to identify an optimum protocol for establishing acarbose BE in healthy Chinese volunteers using PD endpoints. METHODS: Three pilot studies were conducted in healthy Chinese subjects. Study 1 was an open, randomized, two-period crossover study using the reference (R) drug at the dose of 1 × 50 mg. Study 1 aimed to determine appropriate dosing time by comparing the PD effect of acarbose between two administration methods. One method was concomitant administration of sucrose and acarbose, and another method was acarbose administration 10 min before sucrose. Study 2 was an open, randomized, three-period crossover study. Subjects were given the R drug at the dose of 1 × 50 mg, 2 × 50 mg or 3 × 50 mg in a random sequence. The aim of Study 2 was to identify a reasonable dose of acarbose in the BE study. Study 3 was conducted with an open, randomized, three-period crossover design using the test (T) or R drug in an R-T-R sequence at the dose of 2 × 50 mg. Study 3 aimed to compare the BE between the R and T drug and determine intra-individual variation. Twelve subjects were recruited in Study 1, Study 2 and Study 3, respectively, with a one-week washout period. Serum glucose and insulin concentrations were determined after sucrose administration (baseline) and sucrose/acarbose co-administration. RESULTS AND DISCUSSION: In Study 1, no significant differences in PD parameters were found between the two administration methods. The results of Study 2 revealed that the optimal dose was between 1 × 50 mg and 2 × 50 mg. The comparison of PD parameters indicated that the rectifying method could distinguish between different formulations. Study 3 showed that the geometric mean ratios of Cmax, r , AUC0-2 h, r and AUC0-4 h, r were 90.06%, 84.55% and 84.21%, respectively, using the rectifying method. The 90% CIs of Cmax, r were within acceptance limits (80.00%-125.00%), whereas that of AUC0-2 h, r and AUC0-4 h, r were out of the range. The intra-individual variation was approximately 21% for R formulation. Based on the variation, the number of subjects needed to identify formulation differences in the pivotal study would be 55 with 90% power at the 5% level of significance. WHAT IS NEW AND CONCLUSION: The results from our study manifested that a randomized, balanced, two-way crossover design was eligible to evaluate acarbose BE. The appropriate dosing time was concomitant administration of sucrose and acarbose, and the optimal dose was 2 × 50 mg. The rectifying method exhibited preferable sensitivity and applicability in acarbose BE evaluation. A practical sample size of the pivotal study would be 55. These results may help to provide new insights into the protocol design of acarbose BE study.

Design of oral intestinal-specific alginate-vitexin nanoparticulate system to modulate blood glucose level of diabetic rats.

Vitexin of Ficus deltoidea exhibits intestinal α-glucosidase inhibitory and blood glucose lowering effects. This study designs oral intestinal-specific alginate nanoparticulate system of vitexin. Nanospray-dried alginate, alginate/stearic acid and alginate-C18 conjugate nanoparticles were prepared. Stearic acid was adopted to hydrophobize the matrix and minimize premature vitexin release in stomach, whereas C-18 conjugate as immobilized fatty acid to sustain hydrophobic effect and drug release. Nanoparticles were compacted with polyethylene glycol (PEG 3000, 10,000 and 20,000). The physicochemical, drug release, in vivo blood glucose lowering and intestinal vitexin content of nanoparticles and compact were determined. Hydrophobization of alginate nanoparticles promoted premature vitexin release. Compaction of nanoparticles with PEG minimized vitexin release in the stomach, with stearic acid loaded nanoparticles exhibiting a higher vitexin release in the intestine. The introduction of stearic acid reduced vitexin-alginate interaction, conferred alginate-stearic acid mismatch, and dispersive stearic acid-induced particle breakdown with intestinal vitexin release. Use of PEG 10,000 in compaction brought about PEG-nanoparticles interaction that negated initial vitexin release. The PEG dissolution in intestinal phase subsequently enabled particle breakdown and vitexin release. The PEG compacted nanoparticles exhibited oral intestinal-specific vitexin release, with positive blood glucose lowering and enhanced intestinal vitexin content in vivo.

Effects of hot­water extracts from 26 herbs on α­glucosidase activity.

α­glucosidase is a key enzyme that plays a role in glucose absorption in the gastrointestinal tract, and the inhibition of its activity induces the prevention of postprandial hyperglycemia. Several α­glucosidase inhibitors have been used as medicines for type 2 diabetes, but a similar effect is observed in natural resources, including traditional herbs and their phytochemicals. To identify the presence of the α­glucosidase inhibitory activity in herbs, in which various functional effects have been known to occur, the present study investigated the effects of hot­water extracts of 26 types of herbs on α­glucosidase activity in an in vitro assay. The results indicated significant increases in the inhibition of α­glucosidase activity in 1,000 µg/ml olive (P<0.01), white willow (P<0.01) and red rooibos hot­water extracts. Furthermore, ≥50% inhibition of α­glucosidase activity was determined to be significant in 1,000 µg/ml coltsfoot, green tea and bearberry hot­water extracts. In addition, the effects of bearberry, green tea and coltsfoot hot­water extracts on α­glucosidase activity in vivo were evaluated according to the blood glucose levels (BGLs) in maltose and glucose load model rats. It was indicated that the administration of these three herb extracts significantly reduced the increasing BGLs after maltose loading until 0.5 h compared with the control group. However, only coltsfoot extract significantly reduced the increasing BGLs after glucose loading until 0.5 h compared with the control group. Thus, the present results may facilitate the understanding of a novel functionality in traditional herbs, which could be useful for the prevention of disease onset and progression, such as in hyperglycemia and type 2 diabetes.

An overview on the role of bioactive α-glucosidase inhibitors in ameliorating diabetic complications.

Recently the use of bioactive α-glucosidase inhibitors for the treatment of diabetes have been proven to be the most efficient remedy for controlling postprandial hyperglycemia and its detrimental physiological complications, especially in type 2 diabetes. The carbohydrate hydrolysing enzyme, α-glucosidase, is generally competitively inhibited by the α-glucosidase inhibitors and results in the delayed glucose absorption in small intestine, ultimately controlling the postprandial hyperglycemia. Here we have reviewed the most recent updates in the bioactive α-glucosidase inhibitors category. This review provides an overview of the α-glucosidase inhibitory potentials and efficiency of controlling postprandial hyperglycemia of various bioactive compounds such as flavonoids, phenolic compound, polysaccharide, betulinic acid, tannins, anthocyanins, steroids, polyol, polyphenols, galangin, procyanidins, hydroxyl-α-sanshool, hydroxyl-ß-sanshool, erythritol, ganomycin, caffeoylquinic acid, resin glycosides, saponins, avicularin, oleanolic acids, urasolic acid, ethanolic extracts etc., from various dietary and non-dietary naturally occurring sources.

Dietary 5,6,7-Trihydroxy-flavonoid Aglycones and 1-Deoxynojirimycin Synergistically Inhibit the Recombinant Maltase-Glucoamylase Subunit of α-Glucosidase and Lower Postprandial Blood Glucose.

1-Deoxynojirimycin (1-DNJ) is the major effective component of mulberry leaves, exhibiting inhibitory activity against α-glucosidase. However, due to the low content of 1-DNJ in mulberry products, its level cannot meet the lowest dose to exhibit its activity. In this study, a combination of dietary 5,6,7-trihydroxy-flavonoid aglycones with 1-DNJ showed synergistic inhibitory activity against maltase of mice α-glucosidase and recombinant C- and N-termini of maltase-glucoamylase (MGAM) and baicalein with 1-DNJ exhibited the strongest synergistic effect. The synergistic effect of the combination was also confirmed by the maltose tolerance test in vivo. Enzyme kinetics, molecular docking, fluorescence spectrum, and circular dichroism spectrometry studies indicated that the major mechanism of the synergism is that baicalein was a positive allosteric inhibitor and bound to the noncompetitive site of MGAM, causing an increase of the binding affinity of 1-DNJ to MGAM. Our results might provide a theoretical basis for the design of dietary supplements containing mulberry products.

Antihyperglycemic Effects of Annona diversifolia Safford and Its Acyclic Terpenoids: α-Glucosidase and Selective SGLT1 Inhibitiors.

Annona diversifolia Safford and two acyclic terpenoids were evaluated to determine their antihyperglycemic activity as potential α-glucosidase and selective SGLT-1 inhibitiors. Ethanolic extract (EEAd), chloroformic (CHCl3Fr), ethyl acetate (EtOAcFr), aqueous residual (AcRFr), secondary 5 (Fr5) fractions, farnesal (1), and farnesol (2) were evaluated on normoglycemic and streptozocin-induced diabetic mice. EEAd, CHCl3Fr, Fr5, (1) and (2) showed antihyperglycemic activity. The potential as α-glucosidase inhibitors of products was evaluated with oral sucrose and lactose tolerance (OSTT and OLTT, respectively) and intestinal sucrose hydrolysis (ISH) tests; the potential as SGLT-1 inhibitors was evaluated using oral glucose tolerance (OGTT), intestinal glucose absorption (IGA), and urinary glucose excretion (UGE) tests. In OSTT and OLTT, all treatments showed significant activity at two and four hours. In ISH, half maximal effective concentrations (CE50) of 565, 662 and 590 µg/mL, 682 and 802 µM were calculated, respectively. In OGTT, all treatments showed significant activity at two hours. In IGA, CE50 values of 1059, 783 and 539 µg/mL, 1211 and 327 µM were calculated, respectively. In UGE Fr5, (1) and (2) showed significant reduction of the glucose excreted compared with canagliflozin. These results suggest that the antihyperglycemic activity is mediated by α-glucosidase and selective SGLT-1 inhibition.

Targeting Endoplasmic Reticulum α-Glucosidase I with a Single-Dose Iminosugar Treatment Protects against Lethal Influenza and Dengue Virus Infections.

Influenza and dengue viruses present a growing global threat to public health. Both viruses depend on the host endoplasmic reticulum (ER) glycoprotein folding pathway. In 2014, Sadat et al. reported two siblings with a rare genetic defect in ER α-glucosidase I (ER Glu I) who showed resistance to viral infections, identifying ER Glu I as a key antiviral target. Here, we show that a single dose of UV-4B (the hydrochloride salt form of N-(9'-methoxynonyl)-1-deoxynojirimycin; MON-DNJ) capable of inhibiting Glu I in vivo is sufficient to prevent death in mice infected with lethal viral doses, even when treatment is started as late as 48 h post infection. The first crystal structure of mammalian ER Glu I will constitute the basis for the development of potent and selective inhibitors. Targeting ER Glu I with UV-4B-derived compounds may alter treatment paradigms for acute viral disease through development of a single-dose therapeutic regime.

In Vitro and In Vivo Medicinal Value of Culinary-Medicinal Lung Oyster Mushroom Pleurotus pulmonarius var. stechangii (Agaricomycetes).

Pleurotus pulmonarius var. stechangii is a culinary-medicinal mushroom commonly cultivated in subtropical countries in Asia. In this study, the in vitro antixanthine oxidase, antihyperglycemic, and in vivo anti-inflammatory activities of a methanol extract (ME) of P. pulmonarius var. stechangii fruiting bodies were evaluated. The xanthine oxidase inhibitory activity of the ME of P. pulmonarius var. stechangii was lower than that of allopurinol, a xanthine oxidase inhibitor used as a positive control. Eleven phenolic compounds were identified from the fruiting bodies of P. pulmonarius var. stechangii by HPLC analysis. The inhibitory effects of ME on α-amylase and α-glucosidase were moderate and lower than that of acarbose, a positive control. The ME inhibited the production of nitric oxide (NO) and nitric oxide synthases (iNOS) protein expression in lipopolysaccharide-induced RAW 264.7 macrophages. It also exhibited an inhibitory effect on carrageenan-induced hind paw edema in a rat model. Taken together, our experimental results demonstrated that the fruiting bodies of P. pulmonarius var. stechangii might be a good natural source to promote human health through its antixanthine oxidase, antihyperglycemia, and anti-inflammatory activities.

Utilizing the Combination of Binding Kinetics and Micro-Pharmacokinetics Link in Vitro α-Glucosidase Inhibition to in Vivo Target Occupancy.

Many compounds with good inhibitory activity (i.e., high affinity) within in vitro experiments failed in vivo studies due to a lack of efficacy from limited target occupancy (TO) in the drug discovery process. Recently, it was found that rate constants of the formation and dissociation of the binary drug-target complex, rather than affinity, often govern in vivo efficacy. Therefore, the binding kinetics (BK) properties of compound-target interaction are emerging as a pivotal parameter. However, it is obvious that BK rate constants of the compound against target would not be directly linked to the in vivo TO unless the compound concentration in the target vicinity at any time point (TPK) can be evaluated. Here, we developed a novel simulation model to quantitate the dynamic change of target engagement over time in rat with a combined use of BK and TPK features of Epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) on the basis of α-glucosidase (AGH). Analysis of the results displayed that the percent of maximum AGH occupancies by the ECG were varied significantly from 48.9 to 95.3% and by the EGCG slightly from 96 to 99.8%; that the time course of above 70% engagement by ECG spanned a range from 0 to 0.64 h and by EGCG a range of 1.5 to 8.9 h in four different intestinal segments of the rat. It was clearly analyzed how each parameter in the simulation model effected on the in vivo the AGH engagement by ECG and EGCG. Our results provide a novel approach for assessing the potential inhibitory activity of the compounds against AGH.

A randomized, crossover study of the acute effects of acarbose and gastric distension, alone and combined, on postprandial blood pressure in healthy older adults.

BACKGROUND: Postprandial hypotension (PPH) occurs frequently in the elderly and patients with type 2 diabetes, and lacks a satisfactory treatment. Gastric distension and the α-glucosidase inhibitor, acarbose, may attenuate the postprandial fall in blood pressure (BP) by complementary mechanisms. We aimed to determine whether gastric distension and acarbose have additive effects to attenuate the fall in BP induced by oral sucrose. METHODS: Ten healthy older adults (74.0 ± 1.4 yr) had measurements of BP and superior mesenteric artery (SMA) blood flow for 120 min after receiving either (i) the 'study drink' of 100 g sucrose in 300 mL of water (control treatment), (ii) a 300 mL water 'preload' 15 min before the 'study drink' (distension treatment), (iii) 100 mg acarbose dissolved in the 'study drink' (acarbose treatment) or (iv) a 300 ml water 'preload' 15 min before 100 mg acarbose dissolved in the 'study drink' (acarbose and distension treatment). RESULTS: The area under the curve (AUC)0-120min for mean arterial pressure (MAP) was greater (P = 0.005) and the maximum fall in MAP was less (P = 0.006) during treatments with acarbose. Gastric distension did not affect the MAP-AUC0-120min response to acarbose (P = 0.44) and there was no effect of gastric distension alone (P = 0.68). Both acarbose treatments attenuated the rise in SMA blood flow (P = 0.003), whereas gastric distension had no effect. CONCLUSIONS: In healthy older adults, acarbose (100 mg), but not gastric distension, attenuates the fall in BP and rise in SMA blood flow after oral sucrose. The observations support the use of acarbose, but not gastric distension, to attenuate a postprandial fall in BP. TRIAL REGISTRATION: The study was retrospectively registered at ( ACTRN12618000152224 ) on February 02nd 2018.