Evaluation of the Ameliorative Potential of 3,5-bis(2-hydroxyethyl)-1,3,5-thiadiazinane-2-thione against Scopolamine-Induced Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder, marked by cognitive impairment. Currently, the available treatment provides only symptomatic relief and there is a great need to design and formulate new drugs to stabilize AD. In the search for a new anti-Alzheimer's drug, 3,5-bis(2-hydroxyethyl)-1,3,5-thiadiazinane-2-thione (THTT), a tetrahydro-2H-1,3,5-thiadiazine-2-thione derivative, was investigated against a scopolamine-induced Alzheimer's model. The selected test compound was administered intraperitoneally in three doses (15 mg/kg, 30 mg/kg, and 45 mg/kg). The test compound exhibited an IC50 value of 69.41 µg/mL, indicating its ability to inhibit the acetylcholinesterase enzyme. An antioxidant DPPH assay revealed that the IC50 value of the test compound was 97.75 µg/mL, which shows that the test compound possesses antioxidant activity. The results of behavior tests including the Y-maze and elevated plus maze (EPM) show that the test compound improved short-term memory and spatial memory, respectively. Furthermore, in the Morris water maze (MWM) and light/dark model, the test compound shows improvements in learning and memory. Moreover, the results of histological studies show that the test compound can protect the brain against the harmful effects of scopolamine. Overall, the findings of our investigation suggest that our chosen test compound has disease-modifying and neuroprotective activities against the scopolamine-induced Alzheimer's model. The test compound may be beneficial, subject to further elaborate investigation for anti-amyloid disease-modifying properties in AD.

Blocking the major inflammatory pathways by newly synthesized thiadiazine derivatives via in-vivo, in-vitro and in-silico mechanism.

A series of new thiadiazine derivatives including 2-(5-alkyl/aryl-6-thioxo-1,3,5-thiadiazinan-3-yl) propanoic acids (a) and 4-methyl-2-(5-alkyl/aryl-6-thioxo-1,3,5-thiadiazinan-3-yl) pentanoic acids (b) were synthesized by reacting primary alkyl/aryl amines with CS2, followed by reaction with formaldehyde and amino acids. The chemical structures of synthesized compounds were confirmed by 13C- NMR and 1H- NMR techniques. The inhibitory potential of major inflammatory enzymes, COX-2 and 5-LOX was examined. Moreover, anti-nociceptive and anti-inflammatory activities were evaluated in the in vivo thermally induced nociceptive, and carrageenan induced paw edema models in mice. The in-vitro results reflect that these compounds exhibited concentration dependent inhibition of COX-2 and 5-LOX. The tested compounds at 50 mg/kg showed significant effect on thermally induced pain, and reduced latency time (seconds) as compared to the vehicle treated animals. Moreover, tested compounds exhibited percent inhibition of paw edema in the carrageenan induced paw edema model in mice. Furthermore, the binding modes of the most active COX-2 and 5-LOX inhibitors were determined through computational methods. The computational study reflects that the docked compounds have high binding affinities for COX-2 and 5-LOX enzymes, which leads to inhibition of these enzymes.

One pot domino synthesis of new 3,5-disubstituted-tetrahydro-2H-1,3,5-thiadiazine-2-thiones (THTTs) as anti-inflammatory and antinociceptive candidates: A proof from in-vivo to in-vitro and in-silico mechanistic studies.

A series of alkyl/aryl/aralkylamines or amino acids appended tetrahydro-2H-1,3,5-thiadiazine-2-thiones (4a-i, 5a-g, 6 and 7) were synthesized via one pot domino synthesis. The synthesis involved reacting alkyl/aryl/aralkylamines or amino acids with carbon disulfide employing basic aqueous medium and further cyclization with formaldehyde and alkyl/aryl/aralkylamines or amino acids. In addition, the carboxy-functionalized 1,3,5-thiadiazine-2-thione 6 was further subjected to esterification. All the structures were confirmed through spectral techniques i.e IR, 1H NMR, 13C NMR, and MS analysis. Furthermore, the newly synthesized compounds were biologically assessed via in vitro COX-2 and 5-LOX assays, in vivo anti-nociceptive and anti-inflammatory activities. Among the screened compounds, 6, 5f, and 7 exhibited highest inhibitory potency against COX-2 with IC50 values of 11.96, 13.54, and 13.93 µM, respectively. Moreover, compounds 6 and 7 exhibited excellent inhibitory potential against 5-LOX with IC50 values of 14.01 and 14.13 µM. The in-vivo anti-inflammatory bioassay studies showed that compounds 6, 7 and 5f dramatically reduced the paw edema size at 1 h and 3 h time intervals. In the anti-nociceptive activity, compound 6 showed pain protection comparative to Tramadol in all tested time intervals. In addition, studies of molecular docking revealed the compounds binding modes in the allosteric site of COX-2 and active site of 5-LOX, where these compounds exhibited higher binding scores and good binding interactions.

Antiproliferative activity of 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine thione (THTT) derivatives and evaluation as potential prodrug.

Four series of tetrahydro-2H-1,3,5-thiadiazine thione derivatives were screened for their in vitro antiproliferative activities against two human cancerous PC3 and HeLa cell lines. The cytotoxicity of all the compounds (series A-D) was also determined on mammalian mouse fibroblast 3T3 cells. Most of the compounds showed significant anticancer potential against both cancer cell lines within the range of IC50 = 6.4-29.9 and 2.4-23.8 M respectively when compared with standard doxorubicin (IC50 = 0.3 M). All compounds demonstrated a notable selectivity for Hela cells and found either non-toxic or relatively less toxic for 3T3 cell lines model. The structure-activity relationship indicated that antiproliferative activity mainly influenced by the nature and position of substituents at thidiazine nucleus. In general, the presence of aryl groups for example 3,4-(OMe) 2.Bzl and CH(Ph)Me at N-3 position resulted in a significant activity. Under enzymatic hydrolysis, complete conversion (100%) of ester derivative of thiadiazine thione (10a) into its acidic counterpart (7c) was achieved during 20 min which indicated that these types of THTT ester derivatives can be a possible lead for future investigations as prodrug anticancer probes.

Attenuation of vincristine-induced neuropathy by synthetic cyclohexenone-functionalized derivative in mice model.

Vincristine (VCR) is a well-known anticancer drug which frequently induced painful neuropathy and impairs the quality of life of patients. The present study was designed to investigate the alleviative potential of a novel cyclohexenone derivative (CHD), i.e., ethyl 6-(4-methoxyphenyl)-2-oxo-4-phenylcyclohexe-3-enecarboxylate, against VCR-induced neuropathic pain in mice model. VCR was administered intraperitoneally for 10 days in two cycles to induce neuropathic pain. Static and dynamic mechanical allodynia was evaluated using von Frey hair filaments and cotton buds, respectively. Paw thermal hyperalgesia was determined through a hot plate analgesiometer. The tail cold immersion hyperalgesia and paw cold allodynia were determined by available standard protocols. The formalin nociception was induced via subplantar injection of formalin. The antioxidant potential was evaluated via 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity. The outcome of this study revealed that CHD (30-45 mg/kg) and gabapentin (75 mg/kg) significantly enhanced the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) in static and dynamic allodynia, respectively, and increased the PWL in thermal hyperalgesia and tail withdrawal latency (TWL) as compared to the VCR-treated group. CHD significantly augmented the paw withdrawal duration (PWD) in paw cold allodynia, while the same compound only increased the paw elevation and paw licking in the delayed phase of formalin nociception. Moreover, CHD significantly inhibited the DPPH free radical scavenging action (IC50 = 56), butylated hydroxytoluene (BHT) (IC50 = 39), and ascorbic acid (IC50 = 2.93). In conclusion, CHD exhibited a profile of potential attenuative effect against the VCR-induced neuropathic pain which might be attributed to its possible antinociceptive and antioxidant effect.

Antileishmanial, insecticidal and phytotoxic potential of leaves and stems of Rumex nervosus Vahl.

Biological assays including; phytotoxicity, brine shrimp lethality, antileishmanial and insecticidal activities were carried out on crude methanolic extracts of stems and leaves of R. nervosus and their fraction namely; n-Hexane, CHCl3, EtOAc, and MeOH fractions. The highest significant phytotoxicty activity showed by chloroform, n-hexane fractions and crude extract of leaves, the growth regulation were (95%, 90% and 90%) respectively against Lemna minor, while ethyl acetate fraction and n-hexane fractions of stems displayed significant phytotoxicty (100% and 90%) respectively against Lemna minor at high dose (1000µg/ml). The results obtained from cytotoxicity assays revealed that none of the fractions are cytotoxic. The chloroform fraction of stems was showed good antileishmanial activity against L. major with LC50±S.D: 70.3±1.2 at µg/ml. The crude methanolic extracts of leaves, chloroform fraction and ethyl acetate fraction exhibited low mortality against tested insect Rhyzopertha dominica while, the rest of extracts were found almost inactive against insects species.

Effects of temperature and storage on the antioxidant potential, polyphenols and Vitamin-C contents of azadirachta indica leave aqueous extract.

The aim of the study was to investigate the effects of effects of storage and temperature on the antioxidant potential, vitamin-C contents, total as well as selected individual phenolic acids and flavonoids of fresh aqueous leaves extract of Azadirachta Indica. The antioxidant activity of Azadirachta Indica leaves aqueous extract was determined by scavenging of DPPH free radical, while the phenolic compounds and vitamin-C contents by HPLC method. The analyses were carried out on crude extract of fresh leaves and after storage time of 1, 2 and 3 month at temperature of 20, 30 and 50°C. Storage for longer duration and rise in temperature caused decreasing the phenolic acids and vitamin C contents as well as antioxidant potential. Vitamin C contents were decreased up to 91% upon storage for 3 months at 50°C, while the anti-oxidant potential was decreased 29 %. The effect of storage time and temperature on individual phenolic acid and flavonoids were also remarkable, except ferulic acid which increased upon storage and rise in temperature.

Chemical composition and vascular and intestinal smooth muscle relaxant effects of the essential oil from Psidium guajava fruit.

CONTEXT: Psidium guajava L. (Myrtaceae) is widely used in traditional medicine for the treatment of various ailments including cardiovascular and gastrointestinal disorders. OBJECTIVES: The current study investigated the chemical composition and cardiovascular and gastrointestinal effects of the essential oil of P. guajava. MATERIALS AND METHODS: The chemical composition of the essential oil was investigated using gas chromatography-mass spectrometry (GC-MS) technique. The biological activity of the essential oil was tested on rabbit aorta and jejunum. All changes in isometric tension were recorded through a force transducer coupled with a bridge amplifier data acquisition system. RESULTS AND DISCUSSION: GC-MS analysis showed the presence of butanoic acid methyl ester, 3-methyl glutaric anhydride, 1-butanol, 3-hexenal, cinnamyl alcohol, 1-hexanol and hexane as the major components. In isolated rabbit aorta preparations, the essential oil showed vasorelaxation at doses of 3-10 mg/mL against high K+ and phenylephrine pre-contractions with EC50 values of 5.52 (5-6.04) and 6.23 mg/mL (5.0-7.46). The essential oil inhibited spontaneous and high K+ induced contractions in isolated rabbit jejunum with EC50 values of 0.84 (0.3-1.38) and 0.71 mg/mL (0.3-1.12) and shifted Ca + 2 concentration curves to the right, similar to verapamil, suggesting spasmolytic activity mediated possibly through Ca + 2 channel blockade. CONCLUSIONS: In summary, the data indicated the presence of seven different phytoconstituents in the essential oil of P. guajava and calcium channel blocking activity, which provides a pharmacological base to the traditional use of P. guajava in cardiovascular and gastrointestinal disorders. Further studies are suggested to explore the molecular nature of these effects.

Development of HPLC method by UV-VIS detection for the quantification of phenolic acids in different Ocimum sanctum Linn. extracts.

A simple and rapid chromatographic method has been developed for the simultaneous determination of five phenolic acids including Gallic acid, Chloroganic acid, Syringic acid, Benzoic acid and Vanillic acid by HPLC with UV-VIS detector. These Phenolic acids were separated by analytical column Intersil ODS-3 C18, a gradient elution system of ACN and acidified water solution with 1ml/min flow rate and quantified in a total run of 30 minutes at 210nm wavelength. In the quantitative analysis of these compounds showed good regression (0.995-0.999). The limit of detection [LOD] and limit of quantification [LOQ] of these compounds were in the range of 0.15-0.46 and 0.42-2.47 ßg/mL. The average recoveries were between 95.8-103.1% and their RSD values were less than 3.34%. By the proposed method Gallic acid, Chloroganic acid and Syringic acid were found and quantified in Methanolic, Ethanolic and Acetonic extract of Ocimum sanctum Linn. leaves. While the two other phenolic acids benzoic acid and vanillic acid was not found in the extracts of Ocimum sanctum Linn. leaves.

Removal of hydrocarbon pollutants from refinery wastewater using N-hexadecylchitosan as an efficient adsorptive platform.

The negative impact of refinery wastewater is of great concern to the aquatic, terrestrial, and aerial environment. In this study, N-hexadecylchitosan (NHDC) was successfully synthesized to deal with low mechanical strength, poor adsorption capacity, and limited selectivity of native chitosan. The NHDC was characterized by fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-Ray diffraction analysis (XRD) to study its composition, morphology, and structural attributes. The adsorption of hydrocarbon pollutants from refinery wastewater was studied in batch mode experiments. The results indicated that the removal of COD attained by chitosan and NHDC was 21 and 63%, respectively. COD removal was found to be maximal, i.e., 96% using 0.08 g of NHDC at 60 min in a solution of pH 6.5 maintained at 60 °C. Furthermore, kinetic data revealed that the adsorption system followed pseudo-second order kinetics, whereas equilibrium studies supported both monolayer and multilayer adsorption mechanisms. The designed adsorption platform was able to capture hydrocarbon pollutants under very mild optimized conditions. Furthermore, NHDC demonstrated long term stability when subjected to five successive cycles, which contributed to the sustainability of water treatment systems. On the basis of the outcome of this work, it is advocated that new biobased NHDC can be used as an efficient adsorbent for the remediation of organic contaminants laden wastewater streams generated from oil refineries.

Potent bioactive metabolites from Olea ferruginea.

Seven known (1-7) and one new compound (8) were isolated and identified from the stem of Olea ferruginea. The species has been recognised as a new source for six of the known metabolites (1, 3, 4, 5, 6, and 7). Based on detailed spectroscopic analyses, these compounds were identified as scopoletin (1), 8-ketosetosterol (2), (+)-cycloolivil (3), (+)-africanal (4), isovanilic acid (5), hydroxytyrosol acetate (6), vanillic acid (7), and cycloolivil A (8). The crude extracts and purified compounds were analysed for their Leishmanicidal, anti-glycation, anti-cancer, and anti-inflammatory activities. n-Hexane fraction was found to be the most active (among all the fractions), against Leishmania parasites, exhibiting 97.85% inhibition at 15 µg/mL. However, none of the extracts showed any significant anti-glycation or anti-cancer potential, all the fractions, except the aqueous layer, displayed moderate to low anti-inflammatory activity. Compound 1 was found to have strong anti-inflammatory activity, exhibiting 96.7% stimulation at 25 µg/mL.

Identification of Novel Antileishmanial Chemotypes By High-Throughput Virtual and In Vitro Screening.

BACKGROUND: Leishmaniasis is a deadly protozoan parasitic disease and a significant health problem in underdeveloped and developing countries. The global spread of the parasite, coupled with the emergence of drug resistance and severe side effects associated with existing treatments, has necessitated the identification of new and potential drugs. OBJECTIVE: This study aimed to identify promising compounds for the treatment of leishmaniasis by targeting two essential enzymes of Leishmania donovani: trypanothione reductase (Try-R) and trypanothione synthetase (Try-S). METHODS: High-throughput virtual and in vitro screening of in-house and commercial databases was conducted. A pharmacophore model with seven features was developed and validated using the Guner-Henery method. The pharmacophore-based virtual screening yielded 690 hits, which were further filtered through Lipinski's rule, ADMET analysis, and molecular docking against Try-R and Try-S. Molecular dynamics studies were performed on selected compounds, and in vitro experiments were conducted to evaluate their activity against the promastigote and amastigote forms of L. donovani. RESULTS: The virtual screening and subsequent analysis identified 33 promising compounds. Molecular dynamics studies of two compounds (comp-1 and comp-2) demonstrated stable binding interactions with the target enzymes and high affinity. In vitro experiments revealed that 13 compounds exhibited moderate activity against both the promastigote (IC50, 41 µM-76 µM) and the amastigote (IC50, 44 µM-72 µM) forms of L. donovani. Compounds 1 and 2 showed the highest percent inhibition and the lowest IC50 values. CONCLUSION: The identified compounds demonstrated significant inhibitory activity against Leishmania donovani and stable interactions with target enzymes. These findings suggest that the compounds could serve as promising leads for developing new treatments for leishmaniasis.

Comparative assessment of phenolic composition profile and biological activities of green extract and conventional extracts of Salvia sclarea.

In recent years, there have been an attempt to develop safe and environmental friendly solvents to replace conventional solvents, and use for extraction bioactive compounds from natural sources. A current investigation involved the preparation of green, methanolic, and ultrasonic extracts of S. sclarea, and compared their phenolic profiling using HPLC-DAD, antibacterial, antioxidant, and enzyme inhibition activities. The HPLC-DAD analysis revealed that Rosmarinic acid was the main content in all extracts, with Ellagic acid only present in the green extract. The green extract exhibited superior anti-biofilm activity against S. Aureus and E. Faecalis compared to the other extracts at MIC concentration. Furthermore, the green extract also displayed the highest inhibition of swarming motility in P. Aeruginosa with inhibition range 68.0 ± 2.1 (MIC) to 19.5 ± 0.6 (MIC/4). and better enzyme inhibitory activity against BChE (with IC50 = 131.6 ± 0.98 µg/mL) and AChE (with inhibition 47.00 ± 1.50%) compared to the other extracts; while, the ultrasonic extract showed strong inhibition of violacein production by C. Violaceum with a inhibition range 05.5 ± 0.1 (MIC/32) to 100 ± 0.00 (MIC), followed by the green extract with a inhibition range 15.0 ± 0.5 (MIC/8) to 100 ± 0.00 (MIC), additionally, the ultrasonic and methanoic extracts showed significant activity against urease enzyme with (IC50 = 171.6 ± 0.95 µg/mL and IC5 0 = 187.5 ± 1.32 µg/mL) respectively. Both the green and methanolic extracts showed considerable antioxidant activities, as ß-carotene-linoleic acid (IC50 = 5.61 ± 0.47 µg/mL and 5.37 ± 0.27 µg/mL), DPPH· (IC50 = 19.20 ± 0.70 µg/mL and 16.31 ± 0.23 µg/mL), ABTS·+(IC50 = 8.64 ± 0.63 µg/mL and 6.50 ± 0.45 µg/mL) and CUPRAC (A0.5 = 17.22 ± 0.36 µg/mL and 12.28 ± 0.12 µg/mL) respectively, likewise the green extract performing better in metal chelating compared to the other extracts. The green extraction is reported as a cost effective and solvent free method for extracting natural products that produces compounds free of toxic chemicals. This could be the method to be used in the industries as a renewable method.

One pot synthesis of 5-hydroxyalkylated thiadiazine thiones: Implication in pain management and bactericidal properties.

The synthesis of a new series of thiadiazine thiones including 5-(2-hydroxyethyl)-3-alkyl/aryl-1, 3, 5-thiadiazine-2-thiones (1-5), 5-(2-hydroxypropyl)-3-alkyl/aryl-1, 3, 5-thiadiazine-2-thiones (6-8), 3,5-dipropyl-1, 3, 5-thiadiazine-2-thione (9) and (2-(5-alkyl/aryl-6-thioxo-1, 3, 5-thiadiazine-3-yl) alkyl acetate/benzoate) (10-17) was accomplished via one pot reaction. The structures of the synthesized compounds were characterized through NMR and Mass spectrometry. The anti-nociceptive activity of compounds was performed on BALB/C mice by hot plate method, where compounds 3, 5 (50 µg/kg), and 8 (50, 100 µg/kg) exhibited significant effect (P < 0.01, P < 0.05) in latency time of 15, 30, and 60 min, while compounds 6 and 16 (100 µg/kg) exhibited significant effect (P < 0.01, P < 0.05) in latency time interval of 15 and 30 min. Compounds 1, 12-13, and 15 showed moderate activity. Among the tested hits, compounds 5 (17.3 ± 2.2), 11 (16.2 ± 2.1), and 8 (16.1 ± 2.1) showed significant anti-nociceptive potential. Molecular docking studies on the most active anti-nociceptive hits indicated that the activity might be attributed to the ability of the compounds to target µ-opioid receptor (µOR) effectively. Furthermore, compounds 14 and 11 showed anti-bacterial activity against Pseudomonas aeruginosa and MSRA with MIC of 40.97 and 54.77 µg/mL, respectively. In addition, the predicted ADMET profile of 5, 9, and 11 indicates that these molecules follow the drug-likeness criteria, and their activity can be enhanced through structural optimization.

Involvement of the Opioidergic Mechanism in the Analgesic Potential of a Novel Indazolone Derivative: Efficacy in the Management of Pain, Neuropathy, and Inflammation Using In Vivo and In Silico Approaches.

Indazolones possess interesting pharmacological activities. The search for indazole and indazolone-containing nuclei as drugs is an important research area of medicinal chemistry. The current work aims to evaluate a novel indazolone derivative against in vivo and in silico targets of pain, neuropathy, and inflammation. An indazolone derivative (ID) was synthesized and characterized using advanced spectroscopic techniques. Well-established animal models of abdominal constriction, hot plate, tail immersion, carrageenan paw edema, and Brewer's yeast-induced pyrexia were employed for evaluating the potential of the ID at different doses (20-60 mg kg-1). Nonselective GABA antagonists, opioid antagonist naloxone (NLX) and pentylenetetrazole (PTZ), were employed to assess the potential role of GABAergic and opioidergic processes. The antineuropathic potential of the drug was evaluated using a vincristine-induced neuropathic pain model. In silico studies were performed to assess any possible interactions of the ID with pain target sites like cyclooxygenases (COX-I/II), GABAA, and opioid receptors. This study revealed that the selected ID (doses of 20-60 mg kg-1) efficiently hampered chemically and thermally induced nociceptive responses, producing significant anti-inflammatory and antipyretic effects. These effects produced by the ID were dose-dependent (i.e., 20-60 mg kg-1 and p range of 0.001-0.01) and significant in comparison to standards (p < 0.001). Antagonistic studies with NLX (1.0 mg kg-1) and PTZ (15.0 mg kg-1) revealed the involvement of the opioidergic mechanism rather than the GABAergic mechanism. The ID showed promising anti-static allodynia effects as well. In silico studies revealed preferential binding interactions of the ID with cyclooxygenases (COX-I/II), GABAA, and opioid receptors. According to the results of the current investigation, the ID may serve in the future as a therapeutic agent for the treatment of pyrexia, chemotherapy-induced neuropathic pain, and nociceptive inflammatory pain.

Thiadiazine thione derivatives as anti-leishmanial agents: synthesis, biological evaluation, structure activity relationship, ADMET, molecular docking and molecular dynamics simulation studies.

During last decades, 3,5-disubstituted-tetrahydro-2H-thiadiazine-2-thione scaffold remains the center of interest due to their ease of preparation, diverse range substituents at N-3 and N-5 positions, and profound biological activities. In the current study, a series of 3,5-disubstituted-tetrahydro-2H-thiadiazine-2-thiones were synthesized in good to excellent yield, and the structure of the compounds were confirmed by various spectroscopic techniques such as FTIR, 1H-NMR, 13C-NMR and Mass spectrometry, and finally evaluated against Leishmania major. Whereas, all the evaluated compounds (1-33), demonstrate potential leishmanicidal activities with IC50 values in the range of (1.30- 149.98 uM). Among the evaluated compounds such as 3, 4, 6, and 10 exhibited excellent leishmanicidal activities with IC50 values of (2.17 µM), (2.39 µM), (2.00 µM), and (1.39 µM), respectively even better than the standard amphotericin B (IC50 = 0.50) and pentamidine (IC50 = 7.52). In order to investigate binding interaction of the most active compounds, molecular docking study was conducted with Leishmania major. Further molecular dynamic simulation study was also carried out to assess the stability and correct binding of the most active compound 10, within active site of the Leishamania major. Likewise, the physiochemical properties, drug likeness, and ADMET of the most active compounds were investigated, it was found that none of the compounds violate Lipiniski's rule of five, which show that this class of compounds had enough potential to be used as drug candidate in near future.Communicated by Ramaswamy H. Sarma.

Small molecule activators of proteasome-related HslV peptidase.

The HslVU is the proteasome-related two component system composed of HslV peptidase and HslU chaperone. It is involved in the degradation of an array of intracellular proteins. The presence of HslVU homologs in pathogenic microbes and its absence in human makes it an antimicrobial drug target. The functional HslVU complex forms when HslV dodecamer is flanked at both ends by HslU hexamers. In the HslVU complex, eight residues at the carboxy termini of HslU subunits intercalate into a clefts between two adjacent HslV subunits causing a conformational change in the active site of HslV which in turn results in the allosteric activation of HslV peptidase. Here, we report small molecules capable of activating HslV peptidase in the absence of its natural activator HslU ATPase. For this purpose, virtual screening of an in-house library of synthetic and natural compounds was performed to find out ligands mimicking the interaction of HslU carboxy terminus with HslV dodecamer. The benzimidazole, quinazoline and chromone derivatives were suggested by ligand docking to bind at the HslU carboxy termini intercalation pockets in the HslV dodecamer. This was confirmed by HslV activation and isothermal titration calorimetry assays with these compounds that gave ED(50) in sub-micromolar range (0.6-1.5µM). The results showed for the first time that small, extracellular non-peptidic molecules can allosterically activate the peptide hydrolytic activity of HslV which in turn would initiate intracellular proteolysis.

Antioxidant activity of mulberry fruit extracts.

Phenolic compounds were extracted from the fruits of Morus nigra and Morus alba using methanol and acetone. The sugar-free extracts (SFEs) were prepared using Amberlite XAD-16 column chromatography. All of the SFEs exhibited antioxidant potential as determined by ABTS (0.75-1.25 mmol Trolox/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) (EC(50) from 48 µg/mL to 79 µg/mL), and reducing power assays. However, a stronger activity was noted for the SFEs obtained from Morus nigra fruits. These extracts also possessed the highest contents of total phenolics: 164 mg/g (methanolic SFE) and 173 mg/g (acetonic SFE). The presence of phenolic acids and flavonoids in the extracts was confirmed using HPLC method and chlorogenic acid and rutin were found as the dominant phenolic constituents in the SFEs.

Analagesic and Anti-Inflammatory Potentials of a Less Ulcerogenic Thiadiazinethione Derivative in Animal Models: Biochemical and Histochemical Correlates.

Purpose: Gastric ulcer induced by NSAIDs is the major medical concern and researchers are utilizing several approaches to combat this medical issue. In the current study, we investigated the efficacy of thiadiazinethione derivative (2,2'(2-thioxo-1,3,5-thiadiazinane-3,5-diyl) diacetic acid, as new less ulcerogenic compound. Methods: 2,2'(2-thioxo-1,3,5-thiadiazinane-3,5-diyl) diacetic acid was evaluated using standard animal models including hot plate, writhing test and formalin induced nociceptive models. Anti-inflammatory activity was assessed via carrageenan-induced paw oedema model. Involvement of opioidergic nociceptive mechanism was confirmed via naloxone administration in hot plat assay. The gastro-ulcerogenic potential of test and standard compounds were evaluated via NSAID-induced pyloric ligation model followed by standard histopathological and biochemical analysis. Results: In acetic acid-induced writhing test, our compound significantly reduced abdominal constrictions at the tested doses of 15 (p < 0.05), 30 (p < 0.01) and 45 mg kg-1 (p < 0.001) as compared to control (p < 0.001). In hot plate test, after 30 min of administration, our test compound showed significant anti-nociceptive potential (p < 0.05 at 15 and 30 mg kg-1 and p < 0.01 at 45 mg kg-1) and tramadol (p ˂ 0.001) at 30 mg kg-1 dose. After 60 min tramadol (30 kg-1) and test sample (30, 45 mg kg-1) exhibited significant anti-nociceptive activity p < 0.001. In Formalin-induced nociceptive response, a significant decline (p ˂ 0.001) was observed for aspirin and test compound during acute and chronic phases. Decline in the anti-nociceptive potential of tramadol and test sample via administration of naloxone indicate the involvement of opioidergic mechanism. Our compound exhibited significant anti-inflammatory activity in second phase of carrageenan induced paw oedema model. Histological and biochemical parameters exhibited less ulcerogenic potential as compared to aspirin. Conclusion: Our findings suggests that our test compound has desirable anti-nociceptive and anti-inflammatory potentials with less propensity to cause gastric ulcer.