Synthesis and α-Glucosidase Inhibitory Activity of Ursolic Acid,Lupeol, and Betulinic Acid Derivatives

Chemistry of Natural Compounds - Seven synthetic derivatives of ursolic acid, lupeol, and betulinic acid (1a–1b, 2a–2b, and 3a–3c) were synthesized to study their...     

Synthesis and Inhibitory Effect of Some Indole-Pyrimidine Based Hybrid Heterocycles on α-Glucosidase and α-Amylase as Potential Hypoglycemic Agents

The Michael addition reaction of barbituric acid with chalcones incorporating the indole scaffold was achieved by using a highly efficient bimetallic Iron–palladium catalyst in the presence of acetylacetone (acac). This catalytic approach produced the desired products in a simple operation and low catalyst loading with acceptable yield of the new hybrids. All tested compounds were subjected for biological activity on α-glucosidase and α-amylase. The results revealed that all synthesized compounds exhibited very good activity against both enzymes when compared to positive control (acarbose). Moreover, compound 5o showed the best activity whereas its IC₅₀ (μM) are 13.02+0.01 and 21.71+0.82 for α-glucosidase and α-amylase respectively. Both compounds 5o and 5l exhibited high similarity in binding mode and pose with amylase protein (4UAC). The obtained data may be used for developing potential hypoglycemic agents.     

Inhibitory Activities on α-Glucosidase and Composition Analysis of Different Fractions of Ethanol Extracts from Actinidia chinensis Radix

Tlie inhibitory actions of ethyl acetate,n-butanol and water fractions from Actinidia chinensis Radix (A. chinensis Radix) ethanol extracts on glucosidase were investigated. We found that the inhibitory activity of different ethanol extract fractions on α-glucosidase is concentration-dependent. At the same concentration, the ethyl acetate and n-butaiiol fractions showed higher inliibitory activities on gglucosidase in comparison witli acarbose. We then determined the chemical constituents of tlie ethyl acetate and n-butanol fractions through ultra performance liquid cliromatography-triple-time of flight/mass spectrometry(UPLC-Triple-TOF/MS). Based on the mass spectrometry analysis and the databases Scitinder and Reaxys, 21 compoiinds(A1-A21) were identified from the ethyl acetate fraction. In addition, 11 of those compounds(A2, A3, A5, A6, A8, A10, A11, A13, A15, A19, A20) were identified for the first time from A. chinensis Radix. We also identified 14 compounds(A22-A32 and A4-A6) from tlie w-butanol fraction and compound A29 is a new natural product. From the n-butanol fraction, 7 additional compounds (A22, A25, A27, A28, A30-A32) were identified from A. chinensis Radix for the first time.     

Synthesis and Acid-Base Properties of α-Aminophosphoryl Compounds

-Aminophosphoryl compounds of the phosphonate, phosphine oxide, and ,-bis(phosphine oxide) series and some of their thiophosphoryl analogs were synthesized. Potentiometric measurements of the pK_a of the conjugate acids revealed an insignificant effect of variation of substituents on the phosphorus, nitrogen, and -carbon atoms on the basicity of the phosphorylated amines. The latter are weak bases. Organophosphorus groups decrease the basicity of the amines by almost 5 pK _a units. The role of the hydrophobic effect and intramolecular H-bonding in the obtained substances was discussed.     

Synthesis and Properties of Phosphorylated and Silylated α-Mercaptocarbonyl Compounds

Abstract

Phosphorylation and silylation of α -mercaptooarbonyl compounds have been investigated. A novel type of 1.4 S-O migration trimethylsilyl and P(III) groups has been discovered. The thiophosphite-thiophosphonate rearrangement when exposed to oxygen as well as heterocyclization with the formation of 1,3,2-oxathiaphospholenes and 1,3,2-oxathiasilalenes were also found. Some regularities of these processes and the properties of heterocycles synthesized have also been brought out.     

α-Glucosidase Inhibition and Antioxidant Properties of Streptomyces sp.: In Vitro

Streptomyces strain isolated from the soil sediment was studied for its in vitro α-glucosidase and antioxidant properties. Morphological characterization and 16S rRNA partial gene sequencing were carried out to confirm that the strain Loyola AR1 belongs to genus Streptomyces sp. Modified nutrient glucose broth was used as the basal medium for growth and metabolites production. Ethyl acetate extract of Loyola AR1 (EA-Loyola AR1) showed 50 % α-glucosidase inhibition at the concentration of 860.50?±?2.68 μg/ml. Antioxidant properties such as total phenolic content of EA-Loyola AR1 was 176.83?±?1.17 mg of catechol equivalents/g extracts. EA-Loyola AR1 showed significant scavenging activity on 2,2-diphenyl-picrylhydrazyl (50 % inhibition (IC₅₀), 750.50?±?1.61 μg/ml), hydroxyl (IC₅₀, 690.20?±?2.38 μg/ml), nitric oxide (IC₅₀, 850.50?±?1.77 μg/ml), and superoxide (IC₅₀, 880.08?±?1.80 μg/ml) radicals, as well as reducing power. EA-Loyola AR1 showed strong suppressive effect on lipid peroxidation (IC₅₀, 670.50?±?2.52 μg/ml). Antioxidants of β-carotene linoleate model system reveals significantly lower than butylated hydroxyanisole.     

Antioxidant and Cytotoxic Phenolic Compounds of Areca Nut（Areca catechu）

<正>1 Introduction Areca catechu L.(Palmae), commonly known as an important economical seed crop, is widely culti-vated in tropical and subtropical areas, including India, Southeast Asia, East Africa and New Guinea. Areca nut(frequently known as betel nut) is the ripe fruit of     

Chemo- and Enantioselective Oxidative α-Azidation of Carbonyl Compounds

We report high-performance I⁺/H₂O₂ catalysis for the oxidative or decarboxylative oxidative α-azidation of carbonyl compounds by using sodium azide under biphasic neutral phase-transfer conditions. To induce higher reactivity especially for the α-azidation of 1,3-dicarbonyl compounds, we designed a structurally compact isoindoline-derived quaternary ammonium iodide catalyst bearing electron-withdrawing groups. The nonproductive decomposition pathways of I⁺/H₂O₂ catalysis could be suppressed by the use of a catalytic amount of a radical-trapping agent. This oxidative coupling tolerates a variety of functional groups and could be readily applied to the late-stage α-azidation of structurally diverse complex molecules. Moreover, we achieved the enantioselective α-azidation of 1,3-dicarbonyl compounds as the first successful example of enantioselective intermolecular oxidative coupling with a chiral hypoiodite catalyst.     

Antioxidant and anticancer activities of α-aminophosphonates containing thiadiazole moiety

In the current study, α-aminophosphonates containing thiadiazole moiety (1–4) was synthesized, characterized and their antioxidant and anticancer activities were carried out. The compounds (1–4) were synthesized from the reaction of 2-amino-5-methyl-1,3,4-thiadiazole with various aldehydes, triphenylphosphite and mixed valence Cu(I)/Cu(II) inorganic coordination polymer as a catalyst. The elucidation of compounds structures were carried out using different spectroscopic techniques. The antioxidant properties were carried out using radical scavenging methods (DPPH) which exhibited excellent scavenging activity particularly with compound 3. The cytotoxic effects of the five compounds on the human hepato cellular carcinoma (HepG2) and breast adeno carcinoma (MCF7) cell lines were evaluated using MTT assay which revealed the presence of cytotoxic effect with highest activity for compound 3 on HepG2 and compound 1 on MCF7. This suggests that these five compounds, particularly compounds 1 and 3, have antioxidant and anticancer effect and could be used as novel chemotherapeutic compounds but this needs further in vivo investigation to confirm our in vitro results.     

Bivalent Organophosphorus Compounds—Synthesis and Acetylcholinesterase Inhibitory Activity

Abstract

A series of novel symmetric S,S′-2,2′-(ethane-1,2-diylbis(azanediyl)) bis(2-oxoethane-2,1-diyl) O,O,O′,O′-tetraethyl diphosphorodithioate derivatives (12) was designed and synthesized based on the cluster effect and the multiple binding sites of acetylcholinesterase (AChE). The structures of all the newly synthesized title compounds were characterized by ¹ Choi, S. K. Synthetic Multivalent Molecules: Concepts and Biomedical Application, 20–21. New Jersey: John Wiley & Sons, Inc. 2004, chapter 1 [Google Scholar]H and ¹³ Tang, H., Zhao, L. Z., Zhao, H. T., Huang, S. L., Zhong, S. M., Qin, J. K., Chen, Z. F., Huang, Z. S. and Liang, H. 2011. Euro. J. Med. Chem., 46: 4970–4979. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]C NMR as well as elemental analyses. Their inhibitory activities against AChE were tested, and compound 12b exhibited the best activity (6.60-fold higher than ethion). The results suggested that the compound would bind to the catalytic center and the narrow gorge of the AChE simultaneously.

Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional table.     

Isolation and Identification of α-Glucosidase and Protein Glycation Inhibitors from Stereospermum colais

Stereospermum colais (family Bignoniaceae) is a well-known pharmacologically potent medicinal plant reported in traditional systems of medicine. Phytochemical investigation of the roots of S. colais resulted in the isolation of seven compounds, and the metabolites were screened for its α-glucosidase enzyme inhibition and anti-glycation property. The compounds identified were β-sitosterol (1), 2-(4′-hydroxyphenyl) ethyl undecanoate (2), 2-(4′-hydroxyphenyl)ethyl pentadecanoate (3), 5α-ergosta-7,22-dien-3β-ol (4), ursolic acid (5), lapachol (6), and pinoresinol (7). Ursolic acid, lapachol, and pinoresinol possessed IC₅₀ values of 119.01, 130.29, and 125.62 nM, respectively, compared to standard ascorbic acid with an IC₅₀ value of 201.01 nM. The other compounds failed to show the activity. Results of the current study showcased the possible exploration of this medicinal plant for the treatment of type 2 diabetes in line with the development of phytopharmaceutical industry.     

Synthesis and 125Te NMR Spectroscopy of α-Tellurocarbonyl Compounds and Derivatives

The reaction of lithium alkyl-, alkenyl-, alkynyl-, and aryl tellurolates with α-bromocarobonlyl compounds in anhydrous tetrahydrofuan gives the title compounds in yields ranging from 55–92%. The ¹²⁵Te NMR chemical shift range for these compounds is 405–1024 ppm.     

α-Glucosidase Inhibitory Constituents from Trichosanthis Radix

Chemistry of Natural Compounds - One new compound, β-D-apiofuranosyl-(1→6)-1-ethyl-O-β-D-glucopyranoside (1), and 11 known compounds were isolated from Trichosanthis Radix. Their...     

Phosphorylated,Silylated, and Stannylated Derivatives of α-Mercaptocarbonyl Compounds

The authors are summing up their research in the field of phosphorylation, silylation, and stannylation of -mercaptocarbonyl compounds. Synthetic methods were developed for a series of new saturated and unsaturated organosilicon(tin) reagents that were applied to organophosphorus syntheses. Representatives of new classes of heterocyclic compounds were prepared: 1,3,2-oxathiaphospholenes with four- and five-coordinate phosphorus. A new thiophosphite-thiophosphate rearrangement initiated by molecular oxygen was discovered.     

Nucleophilicities of Cyclic α-Diazo Carbonyl Compounds

The one-bond nucleophilic reactivities of seven cyclic α-diazo carbonyl compounds in dichloromethane were determined by analyzing the kinetics of their reactions with benzhydrylium ions (one-bond reference electrophiles) at 20 °C according to the Mayr-Patz equation. Though not calibrated for pericyclic reactions, the identified nucleophilicities also reflect relative reactivities of the α-diazo carbonyl compounds in 1,3-dipolar cycloadditions with dimethyl acetylenedicarboxylate. These (3+2)-cycloadditions primarily gave spirocyclic 3H-pyrazoles, which underwent thermal [1,5]-sigmatropic (van Alphen-Hüttel) rearrangements to furnish 1H-pyrazole-fused tricyclic products.     

Austin Meroterpenoids from Mangrove-Derived Fungus Penicillium sp. MGP11 with α-Glucosidase Inhibitory Activity

Chemistry of Natural Compounds -     

A Proline-Based Aminophosphinic Acid Ligand and It’s Vanadyl Complex: Synthesis,Characterization and In Vitro Inhibitory Effects on α-Amylase And α-Glucosidase

Abstract

A proline-based aminophosphinic acid ligand and it's vanadium complex have been synthesized and characterized by spectroscopic techniques. The inhibitory activity on pancreatic α-amylase and Baker's yeast α-glucosidase has been examined in vitro. The novel complex showed more inhibitory potency against pancreatic α-amylase and Baker's yeast α-glucosidase compared to acarbose as an antidiabetic drug.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.