An Efficient Synthesis Of Acyclic N7- and N9-Adenine Nucleosides Via Alkylation With Secondary Carbon Electrophiles to Introduce Versatile Functional Groups At the C-1 Position of Acyclic Moiety

The introduction of versatile functional groups, allyl and ester, at the C-1 position of the acyclic chain in acyclic adenine nucleosides was achieved for the first time directly by alkylation of adenine and N⁶-protected adenine. Thus, the C-1′-substituted N⁹-adenine acyclic nucleoside, adenine-9-yl-pent-4-enoic acid ethyl ester (11), was prepared by direct alkylation of adenine with 2-bromopent-4-enoic acid ethyl ester (6), while the corresponding N⁷-regioisomer, 2-[6, (dimethylaminomethyleneamino)-purin-7-yl]-pent-4-enoic acid ethyl ester (10), was obtained in one step by the coupling of N,N-dimethyl-N′- (9H-purin-6-yl)-formamidine (9) with 2-bromopent-4-enoic acid ethyl ester (6). The functional groups, ester and allyl, were converted to the desired hydroxymethyl and hydroxyethyl groups, and subsequently to phosphonomethyl derivatives and corresponding pyrophosphorylphosphonates.     

Interactome Analysis of Human Phospholipase D and Phosphatidic Acid-Associated Protein Network

Mammalian phospholipase D (PLD) enzyme family consists of six members. Among them, PLD1/2/6 catalyzes phosphatidic acid (PA) production, while PLD3/4/5 has no catalytic activities. Deregulation of the PLD-PA lipid signaling has been associated with various human diseases including cancer. However, a comprehensive analysis of the regulators and effectors for this crucial lipid metabolic pathway has not been fully achieved. Using a proteomic approach, we defined the protein interaction network for the human PLD family of enzymes and PA and revealed diverse cellular signaling events involving them. Through it, we identified PJA2 as a novel E3 ubiquitin ligase for PLD1 involved in control of the PLD1-mediated mammalian target of rapamycin signaling. Additionally, we showed that PA interacted with and positively regulated sphingosine kinase 1. Taken together, our study not only generates a rich interactome resource for further characterizing the human PLD-PA lipid signaling but also connects this important metabolic pathway with numerous biological processes.     

Recombinant complement receptor 2 radiolabeled with [99mTc(CO)3]+: a potential new radiopharmaceutical for imaging activated complement

We describe the design and synthesis of a new Tc-99m labeled bioconjugate for imaging activated complement, based on Short Consensus Repeats 1 and 2 of Complement Receptor 2 (CR2), the binding domain for C3d. To avoid non specific modification of CR2 and the potential for modifying lysine residues critical to the CR2/C3d contact surface, we engineered a new protein, recombinant CR2 (rCR2), to include the C-terminal sequence VFPLECHHHHHH, a hexahistidine tag (for site-specific radiolabeling with [(99m)Tc(CO)(3)(OH(2))(3)](+)). The protein was characterized by N-terminal sequencing, SDS-PAGE and size exclusion chromatography. To test the function of the recombinant CR2, binding to C3d was confirmed by enzyme-linked immunosorbent assay (ELISA). The function was further confirmed by binding of rCR2 to C3d(+) red blood cells (RBC) which were generated by deposition of human or rat C3d and analyzed by fluorescence microscopy and flow cytometry. The affinity of rCR2 for C3d(+), in presence of 150 mM NaCl, was measured using surface plasma resonance giving rise to a K(D)≈500 nM. Radiolabeling of rCR2 or an inactive mutant of rCR2 (K41E CR2) or an unrelated protein of a similar size (C2A) with [(99m)Tc(CO)(3)(OH(2))(3)](+) at gave radiochemical yields >95%. Site-specifically radiolabeled rCR2 bound to C3d to C3d(+) RBC. Binding of radiolabeled rCR2 to C3d was inhibited by anti-C3d and the radiolabeled inactive mutant K41E CR2 and C2A did not bind to C3d(+) RBCs. We conclude that rCR2-Tc(99m) has excellent radiolabeling, stability and C3d binding characteristics and warrants in vivo evaluation as an activated complement imaging agent.     

Bovine serum albumin functionalized blue emitting Ti3C2 MXene quantum dots as a sensitive fluorescence probe for Fe3+ ion detection and its toxicity analysis

In the present work, an improved class of protein functionalized fluorescent 2D Ti₃C₂ MXene quantum dots (MXene QDs) was prepared using a hydrothermal method. Exfoliated 2D Ti₃C₂ sheets were used as the starting precursor and transport protein bovine serum albumin (BSA) was used to functionalize the MXene QDs. BSA-functionalized MXene QDs exhibited excellent photophysical property and stability at various physiological parameters. High-resolution transmission electron microscopy analysis showed that the BSA@MXene QDs were quasispherical in shape with a size of ~2 nm. The fluorescence intensity of BSA@MXene QDs was selectively quenched in the presence of Fe³⁺ ions. The mechanism of fluorescence quenching was further substantiated using time-resolved fluorescence and Stern–Volmer analysis. The sensing assay showed a linear response within the concentration range 0–150 μM of Fe³⁺ ions with excellent limit of detection. BSA@MXene QDs probe showed good selectivity toward ferric ions even in the presence of other potential interferences. The practical applicability of BSA@MXene QDs was further tested in real samples for Fe³⁺ ion quantification and the sensor had good recovery rates. The cytotoxicity studies of the BSA@MXene QDs toward the human glioblastoma cells revealed that BSA@MXene QDs are biocompatible at lower doses and showed significant cytotoxicity at higher dosages.     

A Menthol-Based Solid Dispersion Technique for Enhanced Solubility and Dissolution of Sulfamethoxazole from an Oral Tablet Matrix

A menthol-based solid dispersion was designed to improve the intrinsic solubility of the poorly soluble sulfamethoxazole- a class II drug molecule of Biopharmaceutics Classification System (BCS) displaying widespread antibacterial activity. Solid dispersions of menthol and sulfamethoxazole were compressed with hydroxypropyl methylcellulose (HPMC) into suitable sulfamethoxazole-loaded matrix tablets for oral drug delivery. The sulfamethoxazole-loaded solid dispersions and compressed tablets were characterized for their physicochemical and physicomechanical properties such as changes in crystallinity, melting point, molecular transitions, and textural analysis for critical analysis of their effects on the solubility and dissolution of sulfamethoxazole. The formulations were further evaluated for swelling, degradation, solubility, and in vitro drug release behavior. In vitro drug release from the sulfamethoxazole-loaded matrix tablets displayed a minimum and maximum fractional release of 0.714 and 0.970, respectively. The tablets further displayed different release rate profiles over the study periods of 12, 16, 48, and 56 h which were attributed to the varying concentrations of menthol within each formulation. Menthol was determined as a suitable hydrophilic carrier for sulfamethoxazole since it functioned as a solubilizing and release-retarding agent for improving the solubility and dissolution of sulfamethoxazole as well as controlling the rate at which it was released.KEY WORDS: crystallinity, menthol, oral solubility and dissolution, solid dispersion, sulfamethoxazole     

Characterization of Probiotic Properties of Antifungal Lactobacillus Strains Isolated from Traditional Fermenting Green Olives

The aim of this work is to characterize the potential probiotic properties of 14 antifungal Lactobacillus strains isolated from traditional fermenting Moroccan green olives. The molecular identification of strains indicated that they are composed of five Lactobacillus brevis, two Lactobacillus pentosus, and seven Lactobacillus plantarum. In combination with bile (0.3%), all the strains showed survival rates (SRs) of 83.19–56.51% at pH 3, while 10 strains showed SRs of 31.67–64.44% at pH 2.5. All the strains demonstrated high tolerance to phenol (0.6%) and produced exopolysaccharides. The autoaggregation, hydrophobicity, antioxidant activities, and surface tension value ranges of the strains were 10.29–41.34%, 15.07–34.67%, 43.11–52.99%, and 36.23–40.27 mN/m, respectively. Bacterial cultures exhibited high antifungal activity against Penicillium sp. The cell-free supernatant (CFS) of the cultures showed important inhibition zones against Candida pelliculosa (18.2–24.85 mm), as well as an antibacterial effect against some gram-positive and gram-negative bacteria (10.1–14.1 mm). The neutralized cell-free supernatant of the cultures displayed considerable inhibitory activity against C. pelliculosa (11.2–16.4 mm). None of the strains showed acquired or horizontally transferable antibiotic resistance or mucin degradation or DNase, hemolytic, or gelatinase activities. Lactobacillus brevis S82, Lactobacillus pentosus S75, and Lactobacillus plantarum S62 showed aminopeptidase, β-galactosidase, and β-glucosidase activities, while the other enzymes of API-ZYM were not detected. The results obtained revealed that the selected antifungal Lactobacillus strains are considered suitable candidates for use both as probiotic cultures for human consumption and for starters and as biopreservative cultures in agriculture, food, and pharmaceutical industries.

     

Fighting against the second wave of COVID-19: Can honeybee products help protect against the pandemic?

Coronavirus Disease (COVID-19) has infected people in 210 nations and has been declared a pandemic on March 12, 2020 by the World Health Organization (WHO). In the absence of effective treatment and/or vaccines for COVID-19, natural products of known therapeutic and antiviral activity could offer an inexpensive, effective option for managing the disease. Benefits of products of honey bees such as honey, propolis, and bee venom, against various types of diseases have been observed. Honey bees products are well known for their nutritional and medicinal values, they have been employed for ages for various therapeutic purposes. In this review, promising effects of various bee products against the emerging pandemic COVID-19 are discussed. Products of honey bees that contain mixtures of potentially active chemicals, possess unique properties that might help to protect, fight, and alleviate symptoms of COVID-19 infection.     

Moringa peregrina leaf extracts produce anti-obesity,hypoglycemic, anti-hyperlipidemic,and hepatoprotective effects on high-fat diet fed rats

This present research investigated the anti-obesity and hepatoprotective effects of ethanolic Moringa peregrina leaf (MPLE) and bark extracts (MPBE), in the rats fed with a high-fat diet (HFD). Healthy male rats (n = 48) were randomly distributed to six groups (n = 8): control AIN-93 diet; HFD; HFD + MPBE bark extracts ((300 mg/kg); HFD + MPBE (600 mg/kg); HFD + MPLE (300 mg/kg); HFD + MPLE (600 mg/kg). HFD-fed rats in the Moringa peregrina (MP) treatment groups received orally administered MP leaf or bark extract daily for eight weeks. The results revealed that both doses of MP leaf extract significantly reduced HFD-induced increases in their food intake and the gained body weight, fat pad weights (visceral, subcutaneous, and epididymal), glucose and insulin plasma levels, and leptin and resistin serum levels in HFD-fed rats. Concomitantly, MP leaf extract improved glucose levels after oral or intraperitoneal glucose tolerance tests, reduced serum cholesterol, triglycerides, and the low-density lipoprotein LDL concentration, reduced hepatic triglycerides and cholesterol levels, and increased serum high-density lipoproteins HDL levels and triglycerides and cholesterol levels in fecal. Moreover, the administration of MPLE to HFD-fed rats improved liver architecture, reduced fat accumulation, reduced hepatic malondialdehyde, tumor necrosis factor-α, and interleukin-6 levels. Hepatic glutathione peroxidase, superoxide dismutase, and catalase activities were significantly increased. All observed effects were more pronounced in HFD-fed rats treated with a 600 mg/kg MP dose. However, neither dose of MPBE altered the measured markers in the HFD-fed rats. In conclusion, MPLE showed potential anti-obesity and hepatoprotective activity in HFD-induced obese rats, mediated by reduced lipid absorption, anti-hyperlipidemic effects, and hepatic antioxidant effects.     

Lipomas as an Extremely Rare Cause for Brachial Plexus Compression: A Case Series and Systematic Review

Introduction  Brachial plexus lipomas are extremely rare benign tumors that may cause slow progression of neurological deficits leading to thoracic outlet syndrome. Up to now, surgery remains challenging. The aim of this study is to present our surgical treatment regime and long-term neurological outcome in three cases of giant brachial plexus lipomas and to show results of systematic review. Patients and Methods  Retrospective analysis of our database “peripheral nerve lesion” to identify patients suffering from brachial plexus lipomas between January 1, 2012, and December 31, 2019. Systematic review was performed for literature published until March 31, 2020, analyzing PubMed, Google Scholar, Scopus, and the Cochrane Collaboration Library independently by two authors. Results  Over the past years, three patients suffering from giant brachial plexus lipomas attended to our neurosurgical department. All patients underwent preoperative magnetic resonance imaging (MRI), ultrasound examinations, and electrophysiological testing. Tumors were removed microsurgically via anterior/posterior, supraclavicular/infraclavicular, and combined approaches. The patients were accessed postoperatively by MRI and clinical follow-up. Systematic review of the literature revealed 22 cases, which were analyzed in regard to demographics, surgical treatment, and neurological outcome. Conclusion  Brachial plexus lipomas are an extremely rare cause for brachial plexus compression. Total microsurgical removal with intraoperative electrophysiological monitoring is the treatment of choice with excellent long-term MRI and clinical outcome.