BACKGROUND: Diabetes mellitus (DM) is a chronic metabolic disorder characterized by defects in insulin secretion and action, which can lead to damaged blood vessels and nerves. With respect to ...effective therapeutic approaches to treatment of DM, much effort has being made to investigate potential inhibitors against α-glucosidase and α-amylase from natural products. The edible marine brown alga Ecklonia cava has been reported to possess various interesting bioactivities, which are studied here.RESULTS: In this study, five phloroglucinal derivatives were isolated from Ecklonia cava: fucodiphloroethol G (1), dieckol (2), 6,6'-bieckol (3), 7-phloroeckol (4) and phlorofucofuroeckol A (5); compounds 1, 3 and 4 were obtained from this genus for the first time and with higher yield. The structural elucidation of these derivatives was completely assigned by comprehensive analysis of nuclear magnetic spectral data. The anti-diabetic activities of these derivatives were also assessed using an enzymatic inhibitory assay against rat intestinal α-glucosidase and porcine pancreatic α-amylase. Most of these phlorotannins showed significant inhibitory activities in a dose-dependent manner, responding to both enzymes, especially compound 2, with the lowest IC₅₀ values at 10.8 μmol L⁻¹ (α-glucosidase) and 124.9 μmol L⁻¹ (α-amylase), respectively. Further study of compound 2 revealed a non-competitive inhibitory activity against α-glucosidase using Lineweaver-Burk plots.CONCLUSION: These results suggested that Ecklonia cava can be used for nutritious, nutraceutical and functional foods in diabetes as well as for related symptoms.
Distillation by-products of peppermint have not been considered for the valorization of bioactive compounds. In this study, by-products of peppermint after hydrodistillation, hydrosol and distilled ...leaves, were investigated followed by the most effective fraction was incorporated into ice cream formulations in order to improve the health promoting effects including antioxidant and α-glucosidase inhibition capacities of the ice creams. Distilled leaves of peppermint were subjected to sequential extraction by ethyl acetate and ethanol. HPLC analyses of eriocitrin and total phenolic analysis indicated that hydrosol contained significant amount of phenolics after 2 h hydrodistillation. Extending hydrodistillation from 1 to 2 h had insignificant effects on phenolic content. Distilled leaves of peppermint had extract yield of 7.39 and 7.19 g/100 mL in 1 and 2 h ethyl acetate extraction, respectively. The predominant phenolic of peppermint (eriocitrin) was 917.5 mg/L in hydrosol after 1 h distillation. Four h distillation of peppermint resulted in decrease in the amount of eriocitrin, however, hydrosol contained valuable amount of phenolics (840.1 mg/L). Hydrosols displayed higher antioxidant capacity in all tested methods than distilled leaves. Hydrosols, at equal amount of phenolics, had higher α-glucosidase inhibition capacity (5.92 µg/mL) than ethyl acetate extract (14.62 µg/mL) and ethanol extract (17.04 µg/mL) of deodorized leaves. Hydrosols were spray dried with the aid of maltodextrin in order to increase drying yield and incorporate the spray dried hydrosol (SDH) into ice cream formulations. Among others, ice cream incorporated with 0.5% of SDH was accepted by the panelists without damaging sensorial properties of ice cream.
Studies on aquacultured fish nutrition have focused solely on performance and the activity of the brush-border enzymes, while the molecular aspects have barely been addressed. Nevertheless, the ...expression of genes encoding enzymes and transporters of the brush-border membrane is crucial for the final stages of digestion and absorption of nutrients through the epithelial luminal membrane of the intestine. To establish a molecular tool for such studies, primers for the European sea bass intestinal genes were designed utilizing evolutionarily conserved DNA sequences for the following intestinal enzymes and transporters: maltase, APN, PepT1 and Na
+/K
+-ATPase. The derived European sea bass cDNA fragments showed 64–92% homology to other animal species and enabled us to study the differences in their expression. The mRNA expression of these genes in pyloric caeca and the upper and lower intestinal sections were compared in fed fish vs conditions of food deprivation for 3, 7, 14 and 21 days. The mRNA expression examined using real time PCR of APN, maltase and PepT1 in all the intestinal tract sections, was the highest after 7 days of food deprivation. Na
+/K
+-ATPase showed a different pattern of expression in each section of the intestine. Significant positive linear correlations between APN, maltase and PepT1 mRNA expression were detected in all but day 3 post food deprivation. The cDNA fragments isolated in this study provide a novel molecular tool for revealing new aspects in fish nutrition and can provide additional information regarding the pattern of expression of intestinal genes following long-term fasting in fish.
Plant extracts continue to represent an untapped source of renewable therapeutic compounds for the prevention of illnesses including metabolic disorders such as antihyperglycemia. This study was to ...determine and identify the chemical compounds in leaves and gadung tuber (Dioscorea hispida Dennst), a-glucosidase inhibitory effects of leaves and to test antibacterial activity of tuber against Staphylococcus aureus ATCC 25923 (Gram positive) and Escherichia coli ATCC 25922 (Gram negative). Identification of the chemical compounds was conducted using GC-MS technique, a-glucosidase inhibitory effects test was measured with spectrophotometric and antibacterial activity test was performed in vitro using agar disc diffusion assay. The bioactive compound evaluation of leaves confirmed the presence of dl-chimyl alcohol (11.82%); 10 (E), 12(Z)-conjugated linoleic acid (10.84%); stigmasterol (9.55%); heptadecane (5.94%); campesterol (5.91%). The analysis of gadung tuber revealed the presence of 7-Azabicyclo 4.1.0 heptane, 1-methgyl- (23.16%); n-Hexadecanoic acid (18.85%); 10E, 12(Z)-Conjugated linoleic acid (13.73%); 1, 4, 7, 10, 13, 16 -hexaoxacyclooctadecane (4.34%); 5-Hydroxymethylfurfural (4.07%). IC50 values inhibition of a-glucosidase extract was >300 ppm and glucobay standard was 0.210 ppm. The antimicrobial activity was performed against bacteria, its inhibitory effect. The results concluded that gadung tuber has great potential to invade some human pathogenic bacteria as it showed zone inhibition. Results from this research show that the concentration of gadung tuber compound has a low inhibition of alpha glucosidase activity. Further research is required to fully elucidate the bioactive compounds in this plant using vigorous analytical methods to be potentially responsible for health benefits
Psychotria malayana Jack leaf, known in Indonesia as “daun salung”, is traditionally used for the treatment of diabetes and other diseases. Despite its potential, the phytochemical study related to ...its anti-diabetic activity is still lacking. Thus, this study aimed to identify putative inhibitors of α-glucosidase, a prominent enzyme contributing to diabetes type 2 in P. malayana leaf extract using gas chromatography-mass spectrometry (GC-MS)- and nuclear magnetic resonance (NMR)-based metabolomics, and to investigate the molecular interaction between those inhibitors and the enzyme through in silico approach. Twenty samples were extracted with different solvent ratios of methanol–water (0, 25, 50, 75, and 100% v/v). All extracts were tested on the alpha-glucosidase inhibition (AGI) assay and analyzed using GC-MS and NMR. Multivariate data analysis through a partial least square (PLS) and orthogonal partial square (OPLS) models were developed in order to correlate the metabolite profile and the bioactivity leading to the annotation of the putative bioactive compounds in the plant extracts. A total of ten putative bioactive compounds were identified and some of them reported in this plant for the first time, namely 1,3,5-benzenetriol (1); palmitic acid (2); cholesta-7,9(11)-diene-3-ol (3); 1-monopalmitin (4); β-tocopherol (5); α-tocopherol (6); 24-epicampesterol (7); stigmast-5-ene (8); 4-hydroxyphenylpyruvic acid (10); and glutamine (11). For the evaluation of the potential binding modes between the inhibitors and protein, the in silico study via molecular docking was performed where the crystal structure of Saccharomyces cerevisiae isomaltase (PDB code: 3A4A) was used. Ten amino acid residues, namely ASP352, HIE351, GLN182, ARG442, ASH215, SER311, ARG213, GLH277, GLN279, and PRO312 established hydrogen bond in the docked complex, as well as hydrophobic interaction of other amino acid residues with the putative compounds. The α-glucosidase inhibitors showed moderate to high binding affinities (−5.5 to −9.4 kcal/mol) towards the active site of the enzymatic protein, where compounds 3, 5, and 8 showed higher binding affinity compared to both quercetin and control ligand.
An economical and efficient one step synthesis of a series of 8-(arylidene)-4-(aryl)-5,6,7,8-tetrahydro-quinazolin-2-ylamines and 9-(arylidene)-4-(aryl)-6,7,8,9-tetrahydro-5
...H-cycloheptapyrimidin-2-ylamines by the reaction of
bis-benzylidene cycloalkanones and guanidine hydrochloride in presence of NaH has been developed. All the synthesized compounds were evaluated against
Mycobacterium tuberculosis H
37Rv strain and the α-glucosidase and glycogen phosphorylase enzymes. Few of the compounds have shown interesting
in vitro activity with MIC up to 3.12
μg/mL against
M. tuberculosis and very good inhibition of α-glucosidase and glycogen phosphorylase enzymes. The most potent non toxic compound
40 exhibited about 58%
ex vivo activity at MIC of 3.12
μg/mL. The present study opens a new gate to synthesize antitubercular agents for diabetic TB patients.
In silico docking studies indicate that mycobacterial dihydrofolate reductase is the possible target of these compounds.
BACKGROUND: Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia that occurs due to abnormal insulin secretion, insulin action, or both. Alpha-glucosidase enzyme ...inhibitors are drugs that work by slowing the absorption of carbohydrates in the intestine so that it has an impact on decreasing post-prandial glucose levels.
AIM: The aim of the study was to assess the alpha-glucosidase inhibitory activities of methanolic extracts from different parts of Uncaria gambir Roxb. and Syzygium polyanthum (Wight) Walp. grown in Padang, West Sumatera, Indonesia often used as herbal medicine.
MATERIALS AND METHODS: Methanolic extracts from different parts, fractions, and different drying methods of U. gambir Roxb. and S. polyanthum (Wight) Walp. grown in Padang, West Sumatera, Indonesia, were prepared for alpha-glucosidase inhibitory activities.
RESULT: The proanthocyanidin fraction of U. gambir Roxb. (purity of ≥ 75%) showed a potent alpha-glucosidase inhibitory activities as evidenced by low IC50 at 28,993 ± 1,377 μg/ml, while (+)-catechin at 30,855 ± 0,791 μg/ml (IC50 acarbose: 111,286 ± 2,386 μg/ml). The Butanol fraction of S. polyanthum (Wight) Walp. showed potent alpha-glucosidase inhibitory activities as evidenced by low IC50 at 28,469 ± 1,929 μg/ml.
CONCLUSION: Butanol fraction from U. gambir Roxb.’s oven-dried leaves and S. polyanthum (Wight) Walp. leaves contained proanthocyanidin class compounds. The proanthocyanidin fraction with a purity of > 75% had a stronger alpha-glucosidase inhibitory activity than the acarbose as a positive control.
Valienol-derived allylic C-1 bromides have been used as carbaglycosyl donors for α-xylo configured valienamine pseudodisaccharide synthesis. We synthesised valienamine analogues of the Glc(α1→3)Glc ...and Glc(α1→3)Man disaccharides representing the linkages cleaved by α-Glucosidase II in N-glycan biosynthesis. These (N1→3)-linked pseudodisaccharides were found to have some α-Glucosidase II inhibitory activity, while two other (N1→6)-linked valienamine pseudodisaccharides failed to inhibit the enzyme.
Current theories agree that there appears to be no unique feature responsible for the remarkable heat stability properties of hyperthermostable proteins. A concerted action of structural, dynamic and ...other physicochemical attributes are utilized to ensure the delicate balance between stability and functionality of proteins at high temperatures. We have thoroughly screened the literature for hyperthermostable enzymes with optimal temperatures exceeding 100 °C that can potentially be employed in multiple biotechnological and industrial applications and to substitute traditionally used, high‐cost engineered mesophilic/thermophilic enzymes that operate at lower temperatures. Furthermore, we discuss general methods of enzyme immobilization and suggest specific strategies to improve thermal stability, activity and durability of hyperthermophilic enzymes.
Hyperglycemia and hyperlipidemia have been symptoms of many serious diseases such as diabetes and atherosclerosis overall the world. Thus, drug researchers have focused on new, natural and healthy ...drug alternatives. Marine macroalgae is a great source of hypoglycemic, hypolipidemic or hypocholesterolemic agents. In this study, we investigated that hypoglycemic, hypolipidemic and cytotoxic potentials of 22 marine macroalgae from the Gulf of Izmir. According to our results, the cold methanol extract of
exhibited the highest antioxidant activity (93.6%) compared to BHA (95.3%). Three
species,
(91.9%),
(90.7%),
(89.8%) showed higher α-glucosidase inhibition rates than oral antidiabetic acarbose (79.5%). It has also been observed that same species are potent inhibitors of pancreatic lipase. Cytotoxicity test revealed that these extracts did not cause viability inhibition on MCF-7. The results of maltose- glucose assay indirectly displayed that
cold methanolic extracts inhibited maltose consumption better than acarbose on HT29. The results of this screening study show that these
species may provide non- toxic bioactive agents to control non-communicable diseases (NCDs) such as cardiovascular disease and diabetes mellitus.
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