An organic solvent-tolerant lipase of Streptomyces pratensis MV1 with the potential application for enzymatic improvement of n6/n3 ratio in polyunsaturated fatty acids from fenugreek seed oil.

Lipase-catalyzed esterification is an efficient technique in the production of polyunsaturated fatty acid (PUFA) concentrates which are applied for nutrition and health purposes. In this project, a solvent-tolerant lipase from Streptomyces pratensis MV1 was immobilized and purified by a hydrophobic support. The purified lipase revealed enhanced activity and stability towards chemicals, organic solvents, and a broad range of pH values. The production of lipase was enhanced to 7.0 U/mL after optimization by a central composite design. Acylglycerols (AGs) rich in α-linolenic acid (45%, w/w) were produced and a favorable n-6/n-3 free fatty acid (FFA) ratio of 1.1 was achieved in fenugreek seed oil using the immobilized lipase. The ability of S. pratensis lipase in ester synthesis and the improvement of n6/n3 FFA ratio make it a suitable candidate in food production industries.

Design and synthesis of new imidazo[1,2-b]pyrazole derivatives, in vitro α-glucosidase inhibition, kinetic and docking studies.

A new series of imidazo[1,2-b]pyrazole derivatives 4a-o was designed, synthesized, and screened for in vitro α-glucosidase inhibitory activity. All compounds showed high inhibitory activity in the range of IC50 = 95.0 ± 0.5-372.8 ± 1.0 µM as compared to standard drug acarbose (IC50 = 750 ± 1.5 µM) and were also found to be non-cytotoxic. Among the synthesized compounds, the most potent compound was compound 4j with eightfold higher inhibitory activity compared to acarbose. Like acarbose, compound 4j inhibited α-glucosidase in a competitive mode. Molecular modeling studies of the most potent compounds 4j, 4f, 4o, and 4c were also conducted.

Design and synthesis of new fused carbazole-imidazole derivatives as anti-diabetic agents: In vitro α-glucosidase inhibition, kinetic, and in silico studies.

Twenty three fused carbazole-imidazoles 6a-w were designed, synthesized, and screened as new α-glucosidase inhibitors. All the synthesized fused carbazole-imidazoles 6a-w were found to be more active than acarbose (IC50 = 750.0 ±â€¯1.5 µM) against yeast α-glucosidase with IC50 values in the range of 74.0 ±â€¯0.7-298.3 ±â€¯0.9 µM. Kinetic study of the most potent compound 6v demonstrated that this compound is a competitive inhibitor for α-glucosidase (Ki value = 75 µM). Furthermore, the in silico studies of the most potent compounds 6v and 6o confirmed that these compounds interacted with the key residues in the active site of α-glucosidase.

Design, synthesis, in vitro, and in silico studies of novel diarylimidazole-1,2,3-triazole hybrids as potent α-glucosidase inhibitors.

In this work, new derivatives of diarylimidazole-1,2,3-triazole 7a-p were designed, synthesized, and evaluated for their in vitro α-glucosidase inhibitory activity. All compounds showed potent inhibitory activity in the range of IC50 = 90.4-246.7 µM comparing with acarbose as the standard drug (IC50 = 750.0 µM). Among the synthesized compounds, compounds 7b, 7c, and 7e were approximately 8 times more potent than acarbose. The kinetic study of those compounds indicated that they acted as the competitive inhibitors of α-glucosidase. Molecular docking studies were also carried out for compounds 7b, 7c, and 7e using modeled α-glucosidase to find the interaction modes responsible for the desired inhibitory activity.

Design and synthesis of novel quinazolinone-1,2,3-triazole hybrids as new anti-diabetic agents: In vitro α-glucosidase inhibition, kinetic, and docking study.

A novel series of quinazolinone-1,2,3-triazole hybrids 10a-p were designed, synthesized, and evaluated for their in vitro α-glucosidase inhibitory activity leading to efficient anti-diabetic agents. All synthesized compounds exhibited good inhibitory activity against yeast α-glucosidase (IC50 values in the range of 181.0-474.5 µM) even much more potent than standard drug acarbose (IC50 = 750.0). Among them, quinazolinone-1,2,3-triazoles possessing 4-bromobenzyl moiety connected to 1,2,3-triazole ring (10g and 10p) demonstrated the most potent inhibitory activity towards α-glucosidase. Compound 10g inhibited α-glucosidase in a competitive manner with Ki value of 117 µM. Furthermore, the binding modes of the most potent compounds 10g and 10p in the α-glucosidase active site was studied through in silico docking studies. Also, lack of cytotoxicity of compounds 10g and 10p was confirmed via MTT assay.

Design, synthesis and in vitro α-glucosidase inhibition of novel dihydropyrano[3,2-c]quinoline derivatives as potential anti-diabetic agents.

A novel series of dihydropyrano[3,2-c]quinoline derivatives 6a-q were synthesized and evaluated for their in vitro α-glucosidase inhibitory activities. All newly synthesized compounds displayed potent α-glucosidase inhibitory activity in the range of 10.3 ±â€¯0.3 µM-172.5 ±â€¯0.8 µM against the yeast α-glucosidase enzyme when compared to the standard drug acarbose (IC50 = 750.0 ±â€¯1.5 µM). Among these compounds, compounds 6e and 6d displayed the most potent α-glucosidase inhibitory activity (IC50 = 10.3 ±â€¯0.3 and 15.7 ±â€¯0.5 µM, respectively). The kinetic analysis of the most potent compounds 6e and 6d revealed that compound 6e inhibited α-glucosidase in an uncompetitive manner (Ki = 11 µM) while compound 6d was a non-competitive inhibitor (Ki = 28 µM) of the enzyme. Then, the cytotoxicity of the most potent compounds (i.e., compounds 6a, 6d, 6e, 6 g, 6j, and 6l) were evaluated for toxicity using the breast cancer cell lines MDA-MB231, MCF-7, and T-47D by using a MTT assay, and no toxicity was observed.

Design, synthesis, docking study, α-glucosidase inhibition, and cytotoxic activities of acridine linked to thioacetamides as novel agents in treatment of type 2 diabetes.

A novel series of acridine linked to thioacetamides 9a-o were synthesized and evaluated for their α-glucosidase inhibitory and cytotoxic activities. All the synthesized compounds exhibited excellent α-glucosidase inhibitory activity in the range of IC50 = 80.0 ±â€¯2.0-383.1 ±â€¯2.0 µM against yeast α-glucosidase, when compared to the standard drug acarbose (IC50 = 750.0 ±â€¯1.5 µM). Among the synthesized compounds, 2-((6-chloro-2-methoxyacridin-9-yl)thio)-N-(p-tolyl) acetamide 9b displayed the highest α-glucosidase inhibitory activity (IC50 = 80.0 ±â€¯2.0 µM). The in vitro cytotoxic assay of compounds 9a-o against MCF-7 cell line revealed that only the compounds 9d, 9c, and 9n exhibited cytotoxic activity. Cytotoxic compounds 9d, 9c, and 9n did not show cytotoxic activity against the normal human cell lines HDF. Kinetic study revealed that the most potent compound 9b is a competitive inhibitor with a Ki of 85 µM. Furthermore, the interaction modes of the most potent compounds 9b and 9f with α-glucosidase were evaluated through the molecular docking studies.

Characterization of Probiotic Pichia sp. DU2-Derived Exopolysaccharide with Oil-in-Water Emulsifying and Anti-biofilm Activities.

Probiotic-derived exopolysaccharides are considered as promising sources of carbohydrate with extensive applications in many industries. In the current study, yeast strains were isolated from chicken ingluvies and gizzard samples. According to molecular identification, EPS-producing yeast (Pichia sp. DU2) showed the most similarity to Pichia cactophila (99.67%). Pichia sp. DU2 showed probiotic properties. EPS of Pichia sp. DU2 showed emulsifying activity. The formed emulsions showed 53% (colza oil) and 100% (p-xylene) stability after 24 h. These emulsions were oil-in-water and have stability in the presence of NaCl, KCl, and also acidic and basic conditions. Also, the EPS showed anti-biofilm (29.7-47.6% and 19.06-55.26% against B. cereus and Y. enterocolitica, respectively) and flocculating activities (31.4%). FT-IR showed the presence of various functional groups in EPS structure. Also, its heteropolysaccharide nature was revealed in 1H-NMR and HPLC analysis. This emulsifying EPS showed significant thermal stability and negative zeta potential, which make it a promising carbohydrate for various industries. Finally, according to the predicted model, the maximal EPS production was achieved at reaction time 36 h, pH 6, yeast extract concentration 1.0%, and sucrose concentration 5%. Pichia sp. DU2 with probiotic properties and producing EPS with emulsifying, anti-biofilm, and flocculating activities can be considered as promising yeast strain in various industries like food and pharmaceutical industries.

Immobilization of lipase on the modified magnetic diatomite earth for effective methyl esterification of isoamyl alcohol to synthesize banana flavor.

The present study was designed to propose a simple, cost-effective, and efficient method for the preparation of a biocompatible composite made from magnetic diatomaceous earth (mDE) coated by aminopropyltriethoxysilane (APTES) and its application for immobilization of porcine pancreatic lipase (PPL). The produced mDE-APTES was instrumentally characterized and the obtained results of FTIR analysis and scanning electron microscopy equipped by energy-dispersive X-ray spectroscopy (SEM-EDS) showed successful coating of APTES on mDE surface. PPL was then immobilized onto mDE to obtain the biocatalyst of PPL@mDE (immobilization yield and efficiency of 78.0 ± 0.3% and 80.1 ± 0.6, respectively) and the presence of enzyme was confirmed by EDS method. The attained results of the reusability of PPL@mDE revealed that 57% of the initial activity was retained after 11 cycles of biocatalyst application. PPL@mDE demonstrated higher storage stability than the free enzyme at 4 °C, 25 °C, and 37 °C. The apparent K m (2.35 ± 0.12 mM) and V max (13.01 ± 0.64 µmol/min) values for the immobilized enzyme were considerably altered compared to those of the free enzyme (p > 0.05). PPL@mDE was subsequently employed for the synthesis of banana flavor (isoamyl acetate) in n-hexane, which yields an esterification percentage of 100 at 37 °C after 3 h. However, it merits further investigations to find out about large-scale application of the as-synthesized biocatalyst for esterification.

Pyrano[3,2-c]quinoline Derivatives as New Class of α-glucosidase Inhibitors to Treat Type 2 Diabetes: Synthesis, in vitro Biological Evaluation and Kinetic Study.

BACKGROUND: Pyrano[3,2-c]quinoline derivatives 6a-n were synthesized via simple two-step reactions and evaluated for their in vitro α-glucosidase inhibitory activity. METHODS: Pyrano[3,2-c]quinoline derivatives 6a-n derivatives were prepared from a two-step reaction: cycloaddition reaction between 1-naphthyl amine 1 and malonic acid 2 to obtain benzo[h]quinoline-2(1H)-one 3 and reaction of 3 with aryl aldehydes 4 and Meldrum's acid 5. The anti- α-glucosidase activity and kinetic study of the synthesized compounds were evaluated using α-glucosidase from Saccharomyces cerevisiae and p-nitrophenyl-a-D-glucopyranoside as substrate. The α-glucosidase inhibitory activity of acarbose was evaluated as positive control. RESULTS: All of the synthesized compounds, except compounds 6i and 6n, showed more inhibitory activity than the standard drug acarbose and were also found to be non-cytotoxic. Among the synthesized compounds, 1-(2-bromophenyl)-1H-benzo[h]pyrano[3,2-c]quinoline-3,12(2H,11H)-dione 6e displayed the highest α-glucosidase inhibitory activity (IC50 = 63.7 ± 0.5 µM). Kinetic study of enzyme inhibition indicated that the most potent compound, 6e, is a non-competitive inhibitor of α-glucosidase with a Ki value of 72 µM. Additionally, based on the Lipinski rule of 5, the synthesized compounds were found to be potential orally active drugs. CONCLUSION: Our results suggest that the synthesized compounds are promising candidates for treating type 2 diabetes.

Enzymatic hydrolysis of inulin by an immobilized extremophilic inulinase from the halophile bacterium Alkalibacillus filiformis.

Bacterial inulinases are the key enzymes in the enzymatic hydrolysis of inulin and production of fructooligosaccharides (FOSs) and high fructose syrup (HFS). An extremophilic inulinase was purified from Alkalibacillus filiformis using 80% ethanol precipitation, ultrafiltration, and Q-Sepharose anion exchange chromatography. The purified inulinase was highly active in a wide range of pH, temperature, chemical reagents, and NaCl concentrations. The enzyme immobilization on cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) was carried out by carrier binding method with covalent linkage and showed improved stability and reusability within a broad temperature and pH range, compared with the free enzyme. Using free and immobilized inulinases from A. filiformis, 122 g L-1 and 160 g L-1 fructose with 61% and 80% conversion, respectively, were obtained, with inulin as the substrate. The enzymatic properties, such as notable stability under extreme conditions, make the inulinase from A. filiformis a promising candidate for related biotechnological applications.

Enzymatic esterification of acylglycerols rich in omega-3 from flaxseed oil by an immobilized solvent-tolerant lipase from Actinomadura sediminis UTMC 2870 isolated from oil-contaminated soil.

Polyunsaturated fatty acids (PUFAs) are essential to human health and can be produced by enzymatic esterification. Actinomadura sediminis UTMC 2870 isolated from oil-contaminated soil contained a lipase that was stable at varying pH and in various solvents, salts, and chemicals. This lipase exhibited high efficiency for omega-3 (n-3), and its production was optimized using a response surface method. Acylglycerols (AGs) rich in n-3 were produced by extraction of the free fatty acids (FFAs) from flaxseed oil, concentration of PUFAs, and enzymatic esterification by the Celite-immobilized lipase. The resulting product contained 50% (w/w) PUFAs, including 42% (w/w) α-linolenic and 9.7% (w/w) linoleic acid. The n-6/n-3 ratio in the product was 0.24, which differed markedly from the high values for this ratio in seed oils. Therefore, the A. sediminis lipase appears to be a good candidate enzyme for ester synthesis and especially for production of n-3-rich AGs for food industries.

New 6-amino-pyrido[2,3-d]pyrimidine-2,4-diones as novel agents to treat type 2 diabetes: A simple and efficient synthesis, α-glucosidase inhibition, molecular modeling and kinetic study.

A new series of 6-amino-pyrido[2,3-d]pyrimidine-2,4-dione derivatives 3a-3s were prepared via a facile and efficient reaction from α-azidochalcones and 6-amiouracils. The reactions were performed under mild conditions to produce the corresponding compounds in good to excellent yields. Obtained derivatives 3a-3s were evaluated for α-glucosidase inhibitory activity and all of them exhibited excellent in vitro yeast α-glucosidase inhibition with IC50 values ranging from 78.0 ±â€¯2.0 to 252.4 ±â€¯1.0 µM. For example, the most active compound 3o was around 10-fold more potent than acarbose, a standard drug (IC50 = 750.0 ±â€¯1.5 µM). Kinetic study of compound 3o revealed that it inhibited α-glucosidase in a competitive mode. Molecular modeling studies of the most active compounds 3o, 3i, 3e and 3m were also performed.

Molecular, chemical and biological screening of soil actinomycete isolates in seeking bioactive peptide metabolites.

BACKGROUND AND OBJECTIVE: Due to the evolution of multidrug-resistant strains, screening of natural resources, especially actinomycetes, for new therapeutic agents discovery has become the interests of researchers. In this study, molecular, chemical and biological screening of soil actinomycetes was carried out in order to search for peptide-producing actinomycetes. MATERIALS AND METHODS: 60 actinomycetes were isolated from soils of Iran. The isolates were subjected to molecular screening for detection NRPS (non-ribosomal peptide synthetases) gene. Phylogenic identification of NRPS containing isolates was performed. Chemical screening of the crude extracts was performed using chlorine o-dianisidine as peptide detector reagent and bioactivity of peptide producing strains was determined by antimicrobial bioassay. High pressure liquid chromatography- mass spectrometry (HPLC-MS) with UV-visible spectroscopy was performed for detection of the metabolite diversity in selected strain. RESULTS: Amplified NRPS adenylation gene (700 bp) was detected among 30 strains. Phylogenic identification of these isolates showed presence of rare actinomycetes genera among the isolates and 10 out of 30 strains were subjected to chemical screening. Nocardia sp. UTMC 751 showed antimicrobial activity against bacterial and fungal test pathogens. HPLC-MS and UV-visible spectroscopy results from the crude extract showed that this strain has probably the ability to produce new metabolites. CONCLUSION: By application of a combined approach, including molecular, chemical and bioactivity analysis, a promising strain of Nocardia sp. UTMC 751 was obtained. This strain had significant activity against Staphylococcus aureus and Pseudomonas aeruginosa. Strain Nocardia sp. UTMC 751 produce five unknown and most probably new metabolites with molecular weights of 274.2, 390.3, 415.3, 598.4 and 772.5. This strain had showed 99% similarity to Nocardia ignorata DSM 44496 T.