Carnosic acid ameliorates depressive-like symptoms along with the modulation of FGF9 in the hippocampus of middle carotid artery occlusion-induced Sprague Dawley rats.

The increased survival rate of stroke patients has led to the higher incidences of post-stroke depression. Carnosic acid has the ability to cross blood brain barrier with good neuro-modulatory actions. Recently, inclined level of fibroblast growth factor 9 (FGF9) in the postmortem brain of the depressed patients was noted. Therefore, in the present study, the effect of carnosic acid on post-stroke depression-like behavior, and the expression of FGF9 were evaluated. After 3 weeks of middle carotid artery occlusion in Sprague Dawley rats, carnosic acid (20 and 40 mg/kg) was administered for 2 weeks. Sucrose preference test, forced swimming test, and open field test were performed and hippocampi were analyzed for FGF9 and FGFR-3. In comparison to post-stroke depressed rats, carnosic acid increased the sucrose preference, and reduced the immobility time of the rats by ~2×. The speed and distance-covered were also increased. At 40 mg/kg, FGF9 was reduced by ~3× while FGFR-3/Actin was increased by ~1.5×. Altogether results suggest anti-depressant-like activity of carnosic acid in post-stroke depressed rats with decreased expression of hippocampal FGF9.

Synthesis of new Enrofloxacin Derivatives as Potential Antibiofilm Drugs Against Staphylococcus Aureus and Klebsiella Pneumoniae.

BACKGROUND: The antimicrobial resistance due to biofilm formation among bacteria is a significant problem in the healthcare and food industries. OBJECTIVE: The current study describes the synthesis of enrofloxacin derivatives 2-17, and the evaluation of their anti-bacterial and anti-biofilm activities. METHODS: Compounds 2-17 were synthesized through the acylation of enrofloxacin with thionyl chloride, followed by reaction with different aromatic amines. The new analogues identified among the sixteen compounds were 2-7, 11, 14, and 17. RESULTS: Compound 2 appeared to be effective against pathogens S. aureus as well as K. pneumonia, whereas, compound 11 was found active against K. pneumonia only. Compound 2 inhibited >75% biofilm formation of S. aureus at 20 µg/mL and K. pneumonia at 10 µg/mL concentrations. These doses are far below the bactericidal concentration of compound 2, suggesting the anti-virulence mechanism of these compounds. Compound 11 inhibited 60% biofilm formation of K. pneumoniae at 70 µg/mL concentration. Compound 5 inhibited the biofilm of K. pneumoniae at 62 µg/mL concentration but also had bactericidal properties at this concentration. Interestingly, compound 2 eradicated the preformed biofilm of both the pathogens at much lower doses as compared to control drug, gentamycin and substrate, enrofloxacin. Cytotoxicity of compounds 2-17 was checked by a standard method using 3T3 normal cell lines (mouse fibroblast), all compounds were found to be noncytotoxic. CONCLUSION: These compounds can be used alone or with FDA approved drugs to overcome biofilm related K. pneumoniae and S. aureus infections.

Tyramine Derivatives as Potent Therapeutics for Type 2 Diabetes: Synthesis and In Vitro Inhibition of α-Glucosidase Enzyme.

BACKGROUND: Tyramine derivatives 3-16 were prepared and tested first time for their α- glucosidase (Sources: Saccharomyces cerevisiae) inhibitory activity by using an in vitro mechanismbased biochemical assay. All the compounds were found to be new, except compounds 3, 10-12 and 16. OBJECTIVE: In continuation of our research to synthesize and identify potent inhibitors of α-glucosidase enzyme, we intended to synthesize new inhibitors of α-glucosidase enzyme with enhanced efficacy in order to provide the basis for the better treatment of the type-II diabetic. METHODS: Tyramine (1) was allowed to react with a variety of aryl chlorides (2) to yield the corresponding amides. Synthesized compounds were then purified through normal phase column chromatography. Compounds 3-16 were then assessed for their α-glucosidase inhibitory activity in an in vitro biochemical assay. The cytotoxicity of compounds 3-16 was determined by using 3T3 mouse fibroblast cell lines. RESULTS: Compounds 3-5, 8, 13, and 15-16 were found to be more active (IC50 = 103.1±0.46, 37.3±4.51, 56.7±4.2, 23.9±2.31, 43.6±2.88, 55.8±1.73, and 38.2±0.86 µM, respectively) than the acarbose, the standard inhibitor of α-glucosidase enzyme, (IC50= 840.0±1.73 µM). To determine the dissociation constants and mode of inhibition, the kinetic studies were also performed for compounds 4 and 8 (the most potent inhibitors). It was observed that compounds 4 and 8 possess noncompetitive properties as the inhibitors of α-glucosidase. All the compounds were found to be noncytotoxic, except 5 and 12 (IC50= 14.7± 0.24 and 6.6± 0.38 µM, respectively). CONCLUSION: The current study gives the facile synthesis and identification of potent inhibitors of α- glucosidase. The new inhibitors reported here may be investigated further for the designing and development of novel anti-diabetic agents.

Antiglycation Activity of Triazole Schiff's Bases Against Fructosemediated Glycation: In Vitro and In Silico Study.

BACKGROUND: Advanced glycation end products (AGEs) are known to be involved in the pathophysiology of diabetic complications, neurodegenerative diseases, and aging. Preventing the formation of AGEs can be helpful in the management of these diseases. OBJECTIVES: Two classes of previously synthesized traizole Schiff's bases (4H-1,2,4-triazole-4- Schiff's bases 1-14, and 4H-1,2,4-triazole-3-Schiff's bases 15-23) were evaluated for their in vitro antiglycation activity. METHODS: In vitro fructose-mediated human serum albumin (HSA) glycation assay was employed to assess the antiglycation activity of triazole Schiff's bases. The active compounds were subjected to cytotoxicity analysis by MTT assay on mouse fibroblast (3T3) cell line. Molecular docking and simulation studies were carried out to evaluate the interactions and stability of compounds with HSA. Anti-hyperglycemic and antioxidant activities of selected non-cytotoxic compounds were evaluated by in vitro α-glucosidase inhibition, and DPPH free radical scavenging assays, respectively. RESULTS: Compound 1 (IC50=47.30±0.38 µM) from 4H-1,2,4-triazole-4-Schiff's bases has exhibited antiglycation activity comparable to standard rutin (IC50=54.5±0.05 µM) along with a stable RMSD profile in MD simulation studies. Compound 1 also exhibited a potent α-glucosidase inhibitory activity, and moderate antioxidant property. Other derivatives showed a weak antiglycation activity with IC50 values between 248.1-637.7 µM. Compounds with potential antiglycation profile were found to be non-cytotoxic in a cellular assay. CONCLUSION: The study identifies triazole Schiff's bases active against fructose-mediated glycation of HSA, thus indicates their potential against late diabetic complications due to production of advancedend products (AGEs).

Synthesis of ß-Ketosulfone Derivatives As New Non-Cytotoxic Urease Inhibitors In Vitro.

BACKGROUND: Peptic ulcer and urolithiasis are largely due to infection caused by ureaseproducing bacteria. Therefore, the discovery of urease inhibitors is an important area of medicinal chemistry research. OBJECTIVE: The main aim of the work was to identify novel urease inhibitors with no cytotoxicity. METHODS: During the current study, a series of ß-ketosulfones 1-26 was synthesized in two steps and evaluated for their in vitro urease inhibition potential. RESULTS: Out of twenty-six compounds, seventeen have shown good to significant urease inhibitory activity with IC50 values ranging between 49.93-351.46 µM, in comparison to standard thiourea (IC50 = 21 ± 0.11 µM). Moreover, all compounds found to be non-cytotoxic against normal 3T3 cell line. CONCLUSION: This study has identified ß-ketosulfones as novel and non-cytotoxic urease inhibitors.

2-Mercapto Benzothiazole Derivatives: As Potential Leads for the Diabetic Management.

BACKGROUND: Results of our previous studies on antiglycation activity, and the noncytotoxicity of 2-mercapto benzothiazoles, encouraged us to further widen our investigation towards the identification of leads against diabetes mellitus. METHODS: 33 derivatives of 2-mercapto benzothiazoles 1-33 were evaluated for in vitro α- glucosidase inhibitory activity. Mode of inhibition was deduced by kinetic studies. To predict the interactions of 2-mercapto benzothiazole derivatives 1-33 with the binding pocket of α-glucosidase enzyme, molecular docking studies were performed on the selected inhibitors. RESULTS: Compounds 2-4, 6-7, 9-26, 28 and 30 showed many folds potent α-glucosidase inhibitory activity in the range of IC50 = 31.21-208.63 µM, as compared to the standard drug acarbose (IC50 = 875.75 ± 2.08 µM). It was important to note that except derivative 28, all other derivatives were also found previously to have antiglycating potential in the range of IC50 = 187.12-707.21 µM. CONCLUSION: A number of compounds were identified as dual nature as antiglycating agent and α- glucosidase inhibitors. These compounds may serve as potential lead candidates for the management of diabetes mellitus.

Effect of Sideritis leptoclada against HT-144 human malignant melanoma.

Sideritis leptoclada O. Schwarz et P.H. Davis extracts were evaluated for its singlet oxygen production capacity using spectrophotometric method. The extracts producing singlet oxygen were then evaluated for cytotoxicity against malignant melanoma cancer (HT-144) and fibroblast (3T3) cell lines using the 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. The photocytotoxicity against the HT-144 human melanoma cell line in the presence of illumination (∼≥400 nm) was also evaluated. In the standard MTT assay, the ethanol extract of S. leptoclada (100 µg/ml) showed 83.49±3.33% inhibition of HT-144 cancer cells, whereas in the illuminated MTT assay, it showed 77.46±1.97% inhibition of HT-144 cancer cells. The effects of ethanol extract on reactive oxygen species production, apoptosis, and tumor necrosis factor-α secretion were also evaluated on HT-144 cell lines. The extract triggered an increase in intracellular reactive oxygen species production and tumor necrosis factor-α secretion compared with the respective controls. Thus, the ethanol extract may cause apoptosis. The LC-MS/MS analyses of S. leptoclada ethanolic extract showed that it has quinic acid (137213±11.25 µg/g extract), malic acid (1468±0.16 µg/g extract), chlorogenic acid (881.7±0.06 µg/g extract), and apigetrin (223.2±0.13 µg/g extract) as major constituents. The ethanolic extract of S. leptoclada should be further investigated as a potential treatment for malignant melanoma cancer.

Crystal Structure of Mistletoe Lectin I (ML-I) from Viscum album in Complex with 4-N-Furfurylcytosine at 2.85 Å Resolution.

BACKGROUND: Viscum album (the European mistletoe) is a semi-parasitic plant, which is of high medical interest. It is widely found in Europe, Asia, and North America. It contains at least three distinct lectins (i.e. ML-I, II, and III), varying in molecular mass and specificity. Among them, ML-I is in focus of medical research for various activities, including anti-cancer activities. To understand the molecular basis for such medical applications, a few studies have already addressed the structural and functional analysis of ML-I in complex with ligands. In continuation of these efforts, we are reporting the crystal structure of ML from Viscum album in complex with the nucleic acid oxidation product 4-N-furfurylcytosine (FC) refined to 2.85 Å resolution. FC is known to be involved in different metabolic pathways related to oxidative stress and DNA modification. METHODS: X-ray suitable hexagonal crystals of the ML-I/FC complex were grown within four days at 294 K using the hanging drop vapor diffusion method. Diffraction data were collected up to a resolution of 2.85 Å. The ligand affinity was verified by in-silico docking. RESULTS: The high-resolution structure was refined subsequently to analyze particularly the active site conformation and a binding epitope of 4-N-furfurylcytosine. A distinct 2Fo-Fc electron density at the active site was interpreted as a single FC molecule. The specific binding of FC is achieved also through hydrophobic interactions involving Tyr76A, Tyr115A, Glu165A, and Leu157A of the ML-I A-chain. The binding energy of FC to the active site of ML-I was calculated as well to be -6.03 kcal mol-1. CONCLUSION: In comparison to other reported ML-I complexes, we observed distinct differences in the vicinity of the nucleic acid base binding site upon interaction with FC. Therefore, data obtained will provide new insights in understanding the specificity, inhibition, and cytotoxicity of the ML-I A-chain, and related RIPs.

2-Oxo-1,2,3,4-tetrahydropyrimidines Ethyl Esters as Potent ß- Glucuronidase Inhibitors: One-pot Synthesis, In vitro and In silico Studies.

BACKGROUND: Glucuronidation is essential for the metabolism and excretion of toxic substances. ß-Glucuronidase enzyme slows down the process of glucuronidation, and thus plays an important role in the on-set of colorectal carcinoma, and many other diseases. Inhibition of ß- glucuronidase activity is thus identified as an important approach for the treatment of several diseases. OBJECTIVE: Current study was aimed to synthesize a library of 2-oxo-1,2,3,4-tetrahydropyrimidine and to evaluate their ß-glucuronidase inhibitory activity, and their mode of enzyme inhibition. METHOD: We synthesized a series of 2-oxo-1,2,3,4-tetrahydropyrimidines 1-25 by fusing urea, ethyl acetoacetate, and a variety of aldehydes using copper nitrate trihydrate as catalyst. All synthesized compounds were evaluated for their in vitro ß-glucuronidase inhibitory activity. In addition, molecular docking studies were also performed by using MOE docking tools. RESULTS: Eighteen compounds showed inhibitory activity better than the standard D-saccharic acid 1,4-lactone, a well known ß-glucuronidase inhibitor (IC50 = 45.75 ± 2.16 µM). Compound 20 (IC50 = 1.36 ± 0.03 µM) showed an excellent inhibitory activity, thirty-five folds superior to the standard. Docking results highlighted the role of various chemical moieties at different positions on 2- oxo-1,2,3,4-tetrahydropyrimidine skeleton in enzyme inhibitory activity. CONCLUSION: This study has identified a class of potent ß-glucuronidase inhibitors with the potential to be investigated further.

Synthesis of Thiocarbohydrazones and Evaluation of their in vitro Antileishmanial Activity.

BACKGROUND: Leishmaniasis is a protozoan parasitic vector-borne disease which is endemic in 88 tropical countries. Infected sandfly is the main vector of this disease, while there are several other vectors, parasites, and reservoirs involved in the transmission of this disease. Leishmania donovani, L. infantum, and L. chagasi are common disease causing species, transmitted through sandflies. Leishmaniasis is a neglected tropical disease with broad spectrum of clinical manifestations. Cutaneous leishmaniasis is prevalent in many countries, including Pakistan. METHODS: Thiocarbohydrazones (1-20) were synthesized through one pot method by refluxing thiocarbahydrazide with different substituted benzaldehydes in ethanol in the presence of acetic acid as a catalyst. These synthetic compounds were evaluated for their potential antileishmanial activity in vitro against Leishmania major promastigotes. RESULTS: Compounds 5-8, 11, 14, 16, 17, 19 and 20 were reported earlier, while compounds 2-4, 9, 10, 12, 13 and 15 were identified as were derivatives. Compounds 1-20 demonstrated antileishmanial activities with IC50 values between 1.63 ± 0.05 - 64.82 ± 0.17 µM, as compared to the standard drug pentamidine (IC50 = 5.09 ± 0.04 µM). Compounds 2 (IC50 = 1.63 ± 0.05 µM), 11 (IC50 = 2.33 ± 0.01 µM), 4 (IC50 = 11.03 ± 0.20 µM), and 10 (IC50 = 11.63 ± 0.06 µM) displayed comparable antileishmanial activities to the standard drug pentamidine. However, compounds 13, 15-17, and 20 with IC50 values 36.95 ± 0.025, 64.82 ± 0.17, 64.27 ± 0.38, 62.34 ± 0.38, and 40.47 ± 0.05 µM, respectively, showed a moderate antileishmanial activity. In contrast, compounds 1, 3, 5-9, 12, 14, 18, and 19 demonstrated less than 50% growth inhibition of promestigotes of L. major, and thus considered as inactive. CONCLUSION: In thiocarbohydrazone derivatives, different substituents at aryl part may be responsible for a varying degree of antileishmanial activity in vitro. Consequently, these compounds might have a potential for further studies as a new class of antileishmanial agents.

Anthranilic Acid Derivatives: Novel Inhibitors of Protein Glycation and the Associated Oxidative Stress in the Hepatocytes.

BACKGROUND: Anthranilic acid derivatives are important pharmacophores in drug discovery. Several of them are currently being used, such as mefenamic acid and meclofenamates, possess analgesic, anti-inflammatory and antipyretic activities. Some anthranilic acid-based scaffolds have also been reported for the management of metabolic disorders. OBJECTIVES: The aim of the current study was to investigate the antiglycation potential of 2-anilino benzoic acid derivatives against (N-phenylanthranilic acid) fructose- human serum albumin (HSA) glycation. The study also analyzed the effects of newly identified antiglycation inhibitors on AGEs-mediated intracellular reactive oxygen species production, and associated impaired proliferation of the hepatocytes. METHODS: The present study focuses on the antiglycation activity of 2- anilinobenzoic acid derivatives 1-18 in in-vitro human serum albumin (HSA)- fructose model. These derivatives were also identified as non-toxic to 3T3 mouse fibroblast cell-line using metabolic assay. The effect of the most promising derivative 1, 2- (2, 4- dinitroanilino)benzoic acid, was studied in a dose dependent manner, co-incubated with fructose-derived AGEs (0- 200 µg/mL), on rat hepatocytes proliferation and associated intracellular generation of ROS via MTT assay and DCFH-DA technique, respectively. RESULTS: We found that derivative 1 ameliorates the elevated intracellular oxidative stress and associated diminished proliferation of the hepatocytes in response to AGEs. CONCLUSION: In conclusion, we identify novel 2- anilino benzoic acid derivatives as antiglycation agents through in-vitro and cellular-based models.

Xanthine Oxidase Inhibitory and Molecular Docking Studies on Pyrimidones.

BACKGROUND: Xanthine oxidase is an important enzyme which catalyzes the production of uric acid and superoxide anion from xanthine. The over-production of these products leads to different disease conditions. For instance, uric acid is responsible for hyperuricemia, gout, and arthritis, while superoxide anion contributes to the oxidative stress, and related diseases. Hence XO is an important pharmacological target for the treatment of a range of diseases. METHODS: Based on the structural resemblance of pyrimidines with xanthine, a series of previously synthesized ethyl 6- methyl-2-oxo-1, 2, 3, 4-tetrahydro-5-pyrimidinecarboxylate derivatives were evaluated for XO inhibitory activity. RESULTS: Among 25 pyrimidone derivatives, 22 were found to be good to weak inhibitors with IC50 values in the range of 14.4 - 418 µM. Compounds 3, 14, 15, 18, and 21-23 were significant inhibitors, and thus analyzed for their kinetic parameters. Among them compounds 14, 15, 18, and 23 were competitive, 21 and 22 showed non-competitive, while 23 was a mixed-type of inhibitor. Molecular docking studies highlighted the interactions of these inhibitors with critical amino acids of XO, such as Val1011, Phe649, Lys771, and others. Moreover, the cytotoxicity studies on these selected inhibitors showed all these compounds to be non-cytotoxic. CONCLUSION: These non-cytotoxic, significant XO inhibitors can thus be further investigated for the treatment of hyperuricemia, and gout.

High Resolution NMR Spectroscopy as a Structural and Analytical Tool for Unsaturated Lipids in Solution.

Mono- and polyunsaturated lipids are widely distributed in Nature, and are structurally and functionally a diverse class of molecules with a variety of physicochemical, biological, medicinal and nutritional properties. High resolution NMR spectroscopic techniques including 1H-, 13C- and 31P-NMR have been successfully employed as a structural and analytical tool for unsaturated lipids. The objective of this review article is to provide: (i) an overview of the critical 1H-, 13C- and 31P-NMR parameters for structural and analytical investigations; (ii) an overview of various 1D and 2D NMR techniques that have been used for resonance assignments; (iii) selected analytical and structural studies with emphasis in the identification of major and minor unsaturated fatty acids in complex lipid extracts without the need for the isolation of the individual components; (iv) selected investigations of oxidation products of lipids; (v) applications in the emerging field of lipidomics; (vi) studies of protein-lipid interactions at a molecular level; (vii) practical considerations and (viii) an overview of future developments in the field.

In vitro α-Glucosidase Inhibition by Non-sugar based Triazoles of Dibenzoazepine, their Structure-Activity Relationship, and Molecular Docking.

BACKGROUND: α-Glucosidase inhibitors (AGIs) have been reported for their clinical potential against postprandial hyperglycemia, which is responsible for the risks associated with diabetes mellitus 2 and cardiovascular diseases (CVDs). Besides, a number of compounds have been reported as potent AGIs, several side effects are associated with them. METHODS: The aim of present work is to explore new and potent molecules as AGIs. Therefore, a library of dibenzoazepine linked triazoles (1-15) was studied for their in vitro α-glucosidase inhibitory activity. The binding modes of potent compounds in the active site of α-glucosidase enzyme were also explored through molecular docking studies. RESULTS AND CONCLUSION: Among the reported triazoles, compounds 3-9, 11, and 13 (IC50 = 6.0 ± 0.03 to 19.8 ± 0.28 µM) were found to be several fold more active than the standard drug acarbose (IC50 = 840 ± 1.73 µM). Compound 5 (IC50 = 6.0 ± 0.03 µM) was the most potent AGIs in the series, about 77- fold more active than acarbose. Therefore, dibenzoazepine linked-triazoles described here can serve as leads for further studies as new non-sugar AGIs.

Dinuclear Cyclam Complex as a Non-Cytotoxic, Anti-Hyperurecemic Lead: In vitro to In vivo Studies.

BACKGROUND: Uric acid is the end product of purine metabolism in humans and its increased level in serum leads to hyperuricemia. Among the different regulatory factors to control the level of uric acid in humans, xanthine oxidase (XO) is a well-established pharmacological target, as it is directly involved in uric acid production. METHODS: The aim of the study was to present a systematic approach to analyze the xanthine oxidase inhibition studies from in vitro leading to in vivo. RESULTS: Initially, dinuclear cyclam complex 1 was evaluated for in-vitro XO inhibitory activity using a spectrophotometric assay. Significant results were obtained in XO inhibition assay (IC50 = 3.70 ± 0.07 µM), in comparison to the standard drug, allopurinol (IC50 = 2.00 ± 0.01 µM). Complex 1 showed a non-competitive type of inhibition in kinetic studies. Complex 1 was also found to be non-cytotoxic in MTT assay, as it did not affect the viability of 3T3-cell line. Based on these results, compound 1 was further evaluated for the in-vivo xanthine oxidase inhibitory activity. An in-vivo model was used to evaluate the XO inhibitory activity in plasma samples of male Wistar rats. Complex 1 showed a significant inhibition of xanthine oxidase activity (50%), in comparison to the standard inhibitor allopurinol (100%). Therefore, non-cytotoxic compound 1 could be considered as an anti-hyperurecemic lead for further studies. CONCLUSION: Our studies concluded that complex 1 is a non-cytotoxic inhibitor that decreases the activity of XO in a non-competitive manner. It can serve as a potential anti-hyperurecemic lead after further pre-clinical and clinical studies.

Derivatives of 6-Nitrobenzimidazole Inhibit Fructose-Mediated Protein Glycation and Intracellular Reactive Oxygen Species Production.

BACKGROUND: Benzimidazoles are important pharmacophores in drug discovery, and currently its derivatives such as flubendazole, omeprazole, and astemizole are used for the treatment of anthelmintic, ulcerative, and histaminic diseases, respectively. OBJECTIVES: The aim of the current study was to investigate the antiglycation activity of nitrobenzimidazole derivatives against fructose-mediated human serum albumin (HSA) glycation. The study was also aimed at investigating the effects of newly identified antiglycation inhibitors on AGEsinduced intracellular reactive oxygen species (ROS) production, and associated impaired proliferation of the hepatocytes. METHODS: The present study focuses on the antiglycation activity of 6-nitrobenzimidazole derivatives 1-13 in in-vitro human serum albumin (HSA)- fructose model. These derivatives were also identified as non-toxic against 3T3 mouse fibroblast cell-line in MTT-based assay. The effect of the most promising derivative 5, 4-(6-nitro-1H-benzimidazol-2-yl)-1,2,3-benzenetriol, was studied in a dose dependent manner, co-incubated with fructose-derived AGEs (0- 200 µg/mL) on rat hepatocytes proliferation and associated intracellular generation of ROS via MTT-based assay and DCFHDA technique, respectively. RESULTS: We found that derivative 5 ameliorates the elevated intracellular oxidative stress and associated diminished proliferation of the hepatocytes in response to AGEs. CONCLUSION: In conclusion, we identified novel 6-nitrobenzimidazole derivatives as antiglycation agents through in-vitro, and cell-based models.

Harmaline and its Derivatives Against the Infectious Multi-Drug Resistant Escherichia coli.

BACKGROUND: Multidrug resistance (MDR) is a major challenge in the treatment of infectious diseases. The MDR in urinary tract infection causing bacteria, such as Escherichia coli, has made treatment of UTI very difficult. OBJECTIVE: The aims of the current study were to synthesize a library of harmaline derivatives, and to evaluate their activity against various strains of multi-drug resistance (MDR) E. coli. METHOD: Harmaline derivatives were synthesized by the reaction of harmaline (1) with various acid halides and anhydrides. These compounds were subjected to susceptibility determination by in vitro MTT assay. The changes in morphology of the bacterial cells after the treatment with harmaline (1) and its new derivatives 2 and 3 were studied through scanning electron, atomic force and fluorescence microscopy. Effect of harmaline and its derivatives on the production of Reactive Oxygen Species (ROS) in MDR E. coli was assessed through lucigenin chemiluminescence assays. RESULTS: The selected compounds assisted the fluorescently labeled dye DiBAC4(3) to bind to the lipid rich intra-cellular entities, and thus produced a sharp green fluorescence by easily penetrating into the compound-induced depolarized membrane of MDR E. coli. These compounds have also triggered a significant generation of ROS from bacterial cells as compared to the conventional antibiotics. The current study demonstrated that harmaline (1), and its derivatives 2 and 3 were identified as anti-MDR agents against MDR strains of E. coli. Antibacterial effect of compounds 1-3 on MDR E. coli is possibly due to membrane depolarization due to ROS-induced damage to the bacterial cell membrane. CONCLUSION: Harmaline and its derivatives were identified as anti-MDR agents against various highly resistant and Pakistani MDR clinical isolates of E. coli. These compounds may serve as the leads for further studies towards the development of treatment against the infections caused by MDR E. coli.

In vitro antiplasmodial and antioxidant activities of bisbenzylisoquinoline alkaloids from Alseodaphne corneri Kosterm.

OBJECTIVE: To study antiplasmodial and antioxidant activities of the isolation of alkaloids from the active dichloromethane extract of Alseodaphne corneri. METHODS: Phytochemical studies of the crude extract led to the isolation of six alkaloids using recycle high performance liquid chromatography and preparative thin layer chromatography. The antiplasmodial activity of the isolated compounds was evaluated using the histidine-rich protein II assay. The isolated alkaloids were also tested for their antioxidant activity using three different assays; DPPH, ferric reducing ability of plasma and metal chelating assays. RESULTS: Malaria infection caused the formation of free radicals which subsequently led to oxidative stress and apoptosis. The antioxidant properties of the alkaloids under investigation revealed that in addition to the antiplasmodial activity, the alkaloids could also prevent oxidative stress. (+)-laurotetanine and (+)-norstephasubine exhibited strong antiplasmodial activities with IC50 values of 0.189 and 0.116 µM, respectively. CONCLUSIONS: Interestingly, the two most potent compounds that exhibit antiplasmodial activity also exhibit good antioxidant activities. The crude dichloromethane extract and the isolated compounds exert substantial antiplasmodial and antioxidative activities which in turn suppress oxidative stress and cause less damage to the host.

Synthesis, Molecular Structure Optimization, and Cytotoxicity Assay of a Novel 2-Acetyl-3-amino-5-[(2-oxopropyl)sulfanyl]-4-cyanothiophene.

A novel thiophene-containing compound, 2-acetyl-3-amino-5-[(2-oxopropyl)sulfanyl]-4-cyanothiophene (4) was synthesized by reaction of malononitrile with CS2 in the presence of K2CO3 under reflux in DMF and the subsequent reaction with chloroacetone followed by cyclization. This compound has been characterized by means of FT-IR, ¹H-NMR, (13)C-NMR, and mass spectrometry as well as elemental analysis. In addition, the molecular structures of compound 4 was determined by X-ray crystallography. The geometry of the molecule is stabilized by an intramolecular interaction between N1-H1···O1 to form S6 graf set ring motif. In the crystal, molecules are linked via N1-H2···O1 and C7-H7A···N2 interactions to form a three-dimensional network. Molecular structure and other spectroscopic properties of compound 4 were calculated using DFT B3LYP/6-31G (d,p) method. Results revealed a good agreement between the optimized geometric parameters and the observed X-ray structure. Furthermore, and by employing the natural bond orbital (NBO) method, the intramolecular charge transfer (ICT) interactions along with natural atomic charges at different sites, were calculated; results indicated strong n→π* ICT from LP(1)N5→BD*(2)C15-C16 (63.23 kcal/mol). In addition, the stabilization energy E(2) of the LP(2)O3→ BD*(1)N5-H6 ICT (6.63 kcal/mol) indicated the presence of intramolecular N-H···OH bonding. Similarly, calculations of the electronic spectra of compound 4 using, TD-DFT revealed a good agreement with the experimental data. Finally, compound 4 was evaluated for its in vitro cytotoxic effect against PC-3 and HeLa cell lines, as an anticancer agent, and found to be nontoxic.

2-Arylquinazolin-4(3H)-ones: Inhibitory Activities Against Xanthine Oxidase.

2-Arylquinazolin-4(3H)-ones (1-25) were synthesized, and evaluated for their xanthine oxidase inhibitory activity. Significant to moderate activities were exhibited by the compounds 1-3, 7, 9, 13-15, 19-21, and 23 with IC50 between 2.80 - 28.13 µM as compared to the standard allopurinol (IC50 (IC50 = 2.01 ± 0.01 µM). Compounds 4-6, 8, 11-12, 16-18, 22, and 24 demonstrated a weak activity with IC50 values 44.60 - 112.60 µM. Nonetheless, compounds 10 and 25 did not show any activity. Amongst all derivatives, compound 2, containing a C-4´ dimethylamino group, was the most potent inhibitor of the enzyme with an IC50 value comparable to the standard. Kinetics studies on the most active compounds (2, 7, 9, 14, 15, 19, and 20) were conducted in order to determine their modes of inhibition and dissociation constants Ki. Some of the compounds of 2-arylquinazolin-4(3H)-one series were thus identified as potential leads for further studies towards the treatment of hyperuricemia and gout.