Integrated pharmacophore and docking‐based designing of dual inhibitors of aldose reductase (ALR2) and protein tyrosine phosphatase 1B (PTP1B) as novel therapeutics for insulin‐resistant diabetes and its complications

The dual inhibitors against aldose reductase (ALR2) and protein tyrosine phosphatase 1B (PTP1B) may present an anti‐diabetic potency in insulin resistance without risks of serious diabetic complications. Therefore, in the present study, we constructed two separate pharmacophore mapping‐based 3D quantitative structure–activity relationship models for ALR2 (AADRR.1109₃ with standard deviation 0.663, 0.719, F 22.3, root‐mean‐square error 0.705, 0.647, Pearson‐r 0.802) and PTP1B (AARR.15₅ with standard deviation 0.146, 0.945, F 82.70, root‐mean‐square error 0.351, 0.621, Pearson‐r 0.831) employing the dataset of 54 flavonoids as ALR2 inhibitors and 46 naphthoquinones as PTP1B inhibitors to identify structural features necessary for the inhibition of both enzymes. These models were subsequently used as 3D query search for hierarchical virtual screening‐based designing using the PHASE database of 1.5 million compounds. Designed dual inhibitors were further subjected to GLIDE XP docking analysis using high‐resolution 3D structures of ALR2 (1US0, at resolution of 0.66 Å) and PTP1B (2F71 at resolution of 1.55 Å) available in the Protein Data Bank to authenticate identified structural features with important binding interactions necessary for dual inhibition. Copyright © 2014 John Wiley & Sons, Ltd.     

Chemical composition and biological activities of Indigofera hirsuta aerial parts’ methanol fractions

Abstract

Methanol extract of Indigofera hirsuta, was evaluated for its antiradical potential and capacity in inhibiting lipoxygenase and aldose/aldehyde reductase enzymes. The ethyl acetate fraction derived from the methanol extract partition, showed the greatest antioxidant capacity, while the butanol was the strongest inhibitor of lipoxygenase enzyme. All fractions (diethyl ether, ethyl acetate, butanol and the aqueous residue) exhibited strong inhibition capacity of both aldose/aldehyde reductase enzymes, which comes in agreement with the ethnomedicinal plant utilization as an antidiabetic agent. LC-DAD-MS(ESI+) fraction analysis verified the findings above, leading to a conclusion regarding the biological activities attributed to the main compounds. Phytochemical analysis led to the identification of an indolic dimer, cinnamic acids, phenolics, flavonoid glycosides, a cyclic polyol, the rare sugar 1-methyl-β-D-glucopyranoside and glycerol. Many of these compounds were isolated for the first time in Indigofera species while the indolic dimer was isolated for the first time in the Fabaceae family.     

A Diselenide Turn-On Fluorescent Probe for the Detection of Thioredoxin Reductase

We report the first diselenide-based probe for the selective detection of thioredoxin reductase (TrxR), an enzyme commonly overexpressed in melanomas. The probe design involves conjugation of a seminaphthorhodafluor dye with a diselenide moiety. TrxR reduces the diselenide bond, triggering a fluorescence turn-on response of the probe. Kinetic studies reveal favorable binding of the probe with TrxR with a Michaelis–Menten constant (K_m) of 15.89 μm . Computational docking simulations predict a greater binding affinity to the TrxR active site in comparison to its disulfide analogue. In vitro imaging studies further confirmed the diselenide probe exhibited improved signaling of TrxR activity compared to the disulfide analogue.     

Facile Access to Chiral Alcohols with Pharmaceutical Relevance Using a Ketoreductase Newly Mined from Pichia guilliermondii

Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally benign reaction conditions, broad reaction scope, and high stereoselectivity, biocatalytic reduction of prochiral ketones offers significant potential in the synthesis of optically active alcohols. A CmCR homologous carbonyl reductase from Pichia guilliermondii NRRL Y‐324 was successfully overexpressed. Substrate profile characterization revealed its broad substrate specificity, covering aryl ketones, aliphatic ketones and ketoesters. Furthermore, a variety of ketone substrates were asymmetrically reduced by the purified enzyme with an additionally NADPH regeneration system. The reduction system exhibited excellent enantioselectivity (>99% ee) in the reduction of all the aromatic ketones and ketoesters, except for 2‐bromoacetophenone (93.5% ee). Semi‐preparative reduction of six ketones was achieved with high enantioselectivity (>99% ee) and isolation yields (>80%) within 12 h. This study provides a useful guidance for further application of this enzyme in the asymmetric synthesis of chiral alcohol enantiomers.     

QSAR and docking studies on chalcone derivatives for antitubercular activity against M. tuberculosis H37Rv

In our prior studies, we reported some known antitubercular drugs (rifampicin and streptomycin) and newly synthesized chalcone derivatives (16–26) tested in vitro against Mycobacterium tuberculosis H₃₇Rv strain. Most of the tested compounds were efficient antimycobacterial agents showing minimum inhibitory concentration values ranging from 3.5 to 30 µg mL⁻¹. In the present work, a quantitative structure–activity relationship (QSAR) study has been performed on these active chalcone derivatives to correlate their chemical structures with their observed inhibiting activity against M. tuberculosis. A QSAR model that is able to correlate well the antitubercular activity with the chemical structures of active chalcone derivatives 16, 24, 25a, 25c, and 26 has been developed, which is potentially helpful in the design of novel and more potent antitubercular agents. The r² and rCV² of a newly derived QSAR model were 0.89 and 0.84, respectively. The QSAR study indicates that chemical properties, viz. heat of formation (kcal mol⁻¹), lowest unoccupied molecular orbital energy (eV), and amine, hydroxyl, and methyl groups counts, correlate well with the activity. In silico screening results for oral bioavailability and absorption, distribution, metabolism, excretion, and toxicity compliance showed that compounds 25a, 25c, and 24 were found active similar to rifampicin and streptomycin. The docking study for the exploration of mechanism of action showed high binding affinity of active derivatives. Copyright © 2014 John Wiley & Sons, Ltd.     

非达司他的合成新方法

发展一条醛糖还原酶抑制剂非达司他的新合成方法,以价廉、易得的N-苯基马来酰亚胺和对氟苯酚为原料,在碱催化下经Oxo-Michael加成反应、水解、(S)-α-苯乙胺拆分、Friedel-Crafts酰化反应得(S)-6-氟-3,4-二氢-4-氧-2H-1-苯并吡喃-2-羧酸,进一步经Bucherer-Bergs乙内酰脲化反应和氯化4-(4,6-二甲氧基-1,3,5-三嗪-2-基)-4-甲基吗啉盐(DMT-MM)作用下的酰胺化反应得目标物,7步反应总收率22.4%.所有中间体和目标物经1H NMR,13C NMR,HRMS及比旋光度确证并与文献值比较.该方法原料易得、反应条件温和,操作简便,收率良好,产物分离纯化容易,适合大规模制备非达司他.     

Spectroscopic Studies of Mononuclear Molybdenum Enzyme Centers

A concise review is provided of the contributions that various spectroscopic methods have made to our understanding of the physical and electronic structures of mononuclear molybdenum enzymes. Contributions to our understanding of the structure and function of each of the major families of these enzymes is considered, providing a perspective on how spectroscopy has impacted the field.     

Connarus semidecandrus Jack Exerts Anti-Alopecia Effects by Targeting 5α-Reductase Activity and an Intrinsic Apoptotic Pathway

There is a growing demand for hair loss treatments with minimal side effects and recurrence potential. Connarus semidecandrus Jack has been used as a folk medicine for fever in tropical regions, but its anti-alopecia effects remain unclear. In this study, the anti-androgenic alopecia effect of an ethanol extract of Connarus semidecandrus Jack (Cs-EE) was demonstrated in a testosterone-induced androgenic alopecia (AGA) model, in terms of the hair–skin ratio, hair type frequency, and hair thickness. The area of restored hair growth and thickened hair population after Cs-EE treatment showed the hair-growth-promoting effect of Cs-EE. Histological data support the possibility that Cs-EE could reduce hair loss and upregulate hair proliferation in mouse skin by shifting hair follicles from the catagen phase to the anagen phase. Western blotting indicated that Cs-EE reduced the expression of the androgenic receptor. Cs-EE treatment also inhibited programmed cell death by upregulating Bcl-2 expression at the mRNA and protein levels. The anti-alopecia effect of Cs-EE was confirmed by in vitro experiments showing that Cs-EE had suppressive effects on 5-α reductase activity and lymph node carcinoma of the prostate proliferation, and a proliferative effect on human hair-follicle dermal papilla (HDP) cells. Apoptotic pathways in HDP cells were downregulated by Cs-EE treatment. Thus, Cs-EE could be a potential treatment for AGA.