Self-micellizing solid dispersion of thymoquinone with enhanced biopharmaceutical and nephroprotective effects

The present study was designed to develop a self-micellizing solid dispersion (SMSD) containing Thymoquinone (TQM), a phytonutrient obtained from Nigella sativa seeds, aiming to improve its biopharmaceutical and nephroprotective functions. The apparent solubility of TQM in polymer solutions was used to choose an appropriate amphiphilic polymer that could be used to make an SMSD system. Based on the apparent solubility, Soluplus® was selected as an appropriate carrier, and mixing with TQM, SMSD-TQM with different loadings of TQM (5-15%) was made by solvent evaporation and freeze-drying techniques, respectively, and the formulations were optimized. The optimized SMSD-TQM was evaluated in terms of particle size distribution, morphology, release characteristics, pharmacokinetic behavior, and nephroprotective effects in a rat model of acute kidney injury. SMSD-TQM significantly improved the dissolution characteristics (97.8%) of TQM in water within 60 min. Oral administration of SMSD-TQM in rats exhibited a 4.9-fold higher systemic exposure than crystalline TQM. In a cisplatin-induced (6 mg/kg, i.p.) acute kidney-damaged rat model, oral SMSD-TQM (10 mg/kg) improved the nephroprotective effects of TQM based on the results of kidney biomarkers and histological abnormalities. These findings suggest that SMSD-TQM might be efficacious in enhancing the nephroprotective effect of TQM by overcoming biopharmaceutical limitations.

Irrational use of antibiotics and factors associated with antibiotic resistance: Findings from a cross-sectional study in Bangladesh

Background and aims

Irrational antibiotic (AB) usage poses a serious concern to third-world countries because of poor surveillance, lack of information, and patients' propensity for self-medication. Additionally, the unpredictability of the coronavirus disease 2019 (COVID-19) pandemic promoted the abuse of ABs, which accelerated the prevalence of antibiotic resistance (ABR). The primary aim of this study was to assess the pattern of AB usage and irrational use of ABs-related potential factors associated with ABR among the students and teachers of a leading public university of Bangladesh.

Methods

A cross-sectional web-based survey was conducted among the students and teachers (n = 783) of the selected university, from January 1 to February 28, 2022. Descriptive statistics, χ ² test, and logistic regression analysis were employed to analyze the collected data.

Results

The regression analysis supported that male participants had a 34% lower experience of acquiring ABR than female respondents (adjusted odds ratio [AOR] = 0.66, 95% confidence interval [CI] = 0.448, 0.973; p = 0.036). The 1st/2nd-year level students had more than two times higher experience with ABR than the master's or higher-class students (AOR = 2.149, 95% CI = 1.047, 4.412; p = 0.037). The participants who took ABs for 4-6 days showed more than two times ABR experience than those who took ABs for above 10 days (AOR = 2.016, 95% CI = 1.016, 4.003; p = 0.045). Respondents who finished their AB medication (dose completion) had a 57% less chance of acquiring ABR than the participants who did not complete their dose.

Conclusion

This study found that irrational use of ABs is more prevalent among the youth and female participants. At this stage, there is an urgent need for comprehensive statutory AB control rules, as well as measures for appropriate information, education, and surveillance throughout different groups of Bangladesh.

Synthesis of Sugar and Nucleoside Analogs and Evaluation of Their Anticancer and Analgesic Potentials

Chemical modification of sugars and nucleosides has a long history of producing compounds with improved selectivity and efficacy. In this study, several modified sugars (2–3) and ribonucleoside analogs (4–8) have been synthesized from α-d-glucose in a total of 21 steps. The compounds were tested for peripheral anti-nociceptive characteristics in the acetic acid-induced writhing assay in mice, where compounds 2, 7, and 8 showed a significant reduction in the number of writhes by 56%, 62%, and 63%, respectively. The compounds were also tested for their cytotoxic potential against human HeLa cell line via trypan blue dye exclusion test followed by cell counting kit-8 (CCK-8) assay. Compound 6 demonstrated significant cytotoxic activity with an IC50 value of 54 µg/mL. Molecular docking simulations revealed that compounds 2, 7, and 8 had a comparable binding affinity to cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes. Additionally, the bridged nucleoside analogs 7 and 8 potently inhibited adenosine kinase enzyme as well, which indicates an alternate mechanistic pathway behind their anti-nociceptive action. Cytotoxic compound 6 demonstrated strong docking with cancer drug targets human cytidine deaminase, proto-oncogene tyrosine-protein kinase Src, human thymidine kinase 1, human thymidylate synthase, and human adenosine deaminase 2. This is the first ever reporting of the synthesis and analgesic property of compound 8 and the cytotoxic potential of compound 6.

Antimicrobial Diterpenes: Recent Development From Natural Sources

Antimicrobial resistance has been posing an alarming threat to the treatment of infectious diseases over the years. Ineffectiveness of the currently available synthetic and semisynthetic antibiotics has led the researchers to discover new molecules with potent antimicrobial activities. To overcome the emerging antimicrobial resistance, new antimicrobial compounds from natural sources might be appropriate. Secondary metabolites from natural sources could be prospective candidates in the development of new antimicrobial agents with high efficacy and less side effects. Among the natural secondary metabolites, diterpenoids are of crucial importance because of their broad spectrum of antimicrobial activity, which has put it in the center of research interest in recent years. The present work is aimed at reviewing recent literature regarding different classes of natural diterpenes and diterpenoids with significant antibacterial, antifungal, antiviral, and antiprotozoal activities along with their reported structure–activity relationships. This review has been carried out with a focus on relevant literature published in the last 5 years following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 229 diterpenoids from various sources like plants, marine species, and fungi are summarized in this systematic review, including their chemical structures, classification, and significant antimicrobial activities together with their reported mechanism of action and structure–activity relationships. The outcomes herein would provide researchers with new insights to find new credible leads and to work on their synthetic and semisynthetic derivatives to develop new antimicrobial agents.

Status of psychological health of students following the extended university closure in Bangladesh: Results from a web-based cross-sectional study

Students' severe affective mental distress has emerged as significant public health attention globally because of the disastrous effects of coronavirus disease 2019 (COVID-19). The current study aimed at exploring the prevalence of two alarming psychological distresses, depression and anxiety, among university students following a prolonged shutdown of educational institutions in Bangladesh. A cross-sectional online-based study was conducted by deploying two standard scales to assess the depression and anxiety among Bangladeshi students from various universities amid the 2nd stream of the COVID-19 pandemic. A total of 568 Bangladeshi university students participated in this questionnaire-based survey through various social media platforms. Frequency and percentage distribution as univariate, chi-square (χ2) test as bivariate, and logistic regression as multivariate analyses were applied to investigate the prevalence of depression and anxiety and their associated various sociodemographic factors. After cleaning and eliminating the partial data, we analyzed 465 responses, where 42% were female and 64.3% were from public universities. Both mental disorders were prevalent in more than 50% of Bangladeshi university students. The students from the private universities were two times and 2.7 times more depressed and anxious, respectively than the students from the public universities. In addition, the students who became incomeless had significantly more anxiety (adjusted odds ratio [AOR] = 1.711; p = 0.018) than those who did not lose income source during the COVID-19 lockdown. The present study revealed that more than 50% of Bangladeshi university students were suffering from depression and anxiety. Several effective measures must be assured by the concerted efforts of university authorities, educationalists, and the Government to alleviate these distressing mental health burdens.

Recommendation and Roadmap of Mass Vaccination against Coronavirus Disease 2019 Pandemic in Bangladesh as a Lower-Middle-Income Country

Low-income countries (LICs) and lower-middle-income countries (LMICs) are still deprived of the optimum doses of coronavirus disease 2019 (COVID-19) vaccines for their population, equal access and distribution, as well as mass immunization roadmaps to be implemented for achieving herd immunity and protection from the ongoing pandemic. In this short report, we are interacting with the world public health experts, as well as national and global leaders for warranting the mass vaccination drive to be more progressive against COVID-19 with equitable access of vaccines to LICs or LMICs to save the lives of the poorest country people and refugees. From several scientific databases, such as Google Scholar, PubMed, as well as national and international news websites, the data were collected data by utilizing appropriate keywords regarding the topic. Bangladesh might be exemplified in this brief communication as the representative of LMIC. As of October 14, 2021, 48% of the world's people have received at least one dose of the COVID-19 vaccine. In contrast, only 2.5% of people from LICs have come in under COVID-19 vaccination for at least a single shot. Both LICs and LMICs need far more vision and ambition, including political, administrative, and diplomatic progress along with enhancing the vaccination drive for their population to be immunized through simultaneous mass vaccination progress of other countries with implementing public health safety measures against the COVID-19 pandemic.

A Comprehensive Account on Recent Progress in Pharmacological Activities of Benzimidazole Derivatives

Nowadays, nitrogenous heterocyclic molecules have attracted a great deal of interest among medicinal chemists. Among these potential heterocyclic drugs, benzimidazole scaffolds are considerably prevalent. Due to their isostructural pharmacophore of naturally occurring active biomolecules, benzimidazole derivatives have significant importance as chemotherapeutic agents in diverse clinical conditions. Researchers have synthesized plenty of benzimidazole derivatives in the last decades, amidst a large share of these compounds exerted excellent bioactivity against many ailments with outstanding bioavailability, safety, and stability profiles. In this comprehensive review, we have summarized the bioactivity of the benzimidazole derivatives reported in recent literature (2012-2021) with their available structure-activity relationship. Compounds bearing benzimidazole nucleus possess broad-spectrum pharmacological properties ranging from common antibacterial effects to the world's most virulent diseases. Several promising therapeutic candidates are undergoing human trials, and some of these are going to be approved for clinical use. However, notable challenges, such as drug resistance, costly and tedious synthetic methods, little structural information of receptors, lack of advanced software, and so on, are still viable to be overcome for further research.

Synthesis, in vivo and in silico analgesic and anti-inflammatory studies of α-D-ribofuranose derivatives

Five α-D-ribofuranose analogues (2, 3, 4, 5 and 6) were synthesized in good yields from 3-O-benzyl-4-C-(hydroxymethyl)-1, 2-O-isopropylidene-α-D-ribofuranose (1). The synthesized compounds were then subjected to analgesic, anti-inflammatory, antimicrobial and antioxidant assays. Compound 3 demonstrated 79.74% (P < 0.001) writhing inhibition and highest reaction time of 2.55 ± 0.13 min (P < 0.001) after 30 min of oral administration in peripheral and central analgesic assay, respectively, at 50 mg/kg dose. Compound 2 and 6 exhibited significant anti-inflammatory activity at 100 mg/kg dose with paw edema inhibition of 91.15% (P < 0.001) and 95.13% (P < 0.001), respectively, in 4th hour. The synthesized analogues did not show notable antioxidant and antibacterial properties. Molecular docking study revealed higher binding affinity of −8.1 kcal/mol and −8.9 kcal/mol of compound 3 towards cyclooxygenase-1 and phospholipase A_2, respectively, compared to −7.7 and −7.6 kcal/mol respectively for corresponding native ligands. Compound 2 demonstrated binding affinity of −9.1 kcal/mol towards interleukin-1 receptor-associated kinase-4 compared to −8.7 kcal/mol of the native ligand. The molecular properties related to drug likeness of compounds were found to be within acceptable range. Synthesized D-ribofuranose analogues demonstrated promising analgesic and anti-inflammatory activities and further development may lead to new potent analgesic and anti-inflammatory agents.

Therapeutic Effectiveness and Safety of Repurposing Drugs for the Treatment of COVID-19: Position Standing in 2021

COVID-19, transmitted by SARS-CoV-2, is one of the most serious pandemic situations in the history of mankind, and has already infected a huge population across the globe. This horrendously contagious viral outbreak was first identified in China and within a very short time it affected the world's health, transport, economic, and academic sectors. Despite the recent approval of a few anti-COVID-19 vaccines, their unavailability and insufficiency along with the lack of other potential therapeutic options are continuing to worsen the situation, with valuable lives continuing to be lost. In this situation, researchers across the globe are focusing on repurposing prospective drugs and prophylaxis such as favipiravir, remdesivir, chloroquine, hydroxychloroquine, ivermectin, lopinavir-ritonavir, azithromycin, doxycycline, ACEIs/ARBs, rivaroxaban, and protease inhibitors, which were preliminarily based on in vitro and in vivo pharmacological and toxicological study reports followed by clinical applications. Based on available preliminary data derived from limited clinical trials, the US National Institute of Health (NIH) and USFDA also recommended a few drugs to be repurposed i.e., hydroxychloroquine, remdesivir, and favipiravir. However, World Health Organization later recommended against the use of chloroquine, hydroxychloroquine, remdesivir, and lopinavir/ritonavir in the treatment of COVID-19 infections. Combining basic knowledge of viral pathogenesis and pharmacodynamics of drug molecules as well as in silico approaches, many drug candidates have been investigated in clinical trials, some of which have been proven to be partially effective against COVID-19, and many of the other drugs are currently under extensive screening. The repurposing of prospective drug candidates from different stages of evaluation can be a handy wellspring in COVID-19 management and treatment along with approved anti-COVID-19 vaccines. This review article combined the information from completed clinical trials, case series, cohort studies, meta-analyses, and retrospective studies to focus on the current status of repurposing drugs in 2021.

Synthesis, in vitro bioassays, and computational study of heteroaryl nitazoxanide analogs

Antiprotozoal drug nitazoxanide (NTZ) has shown diverse pharmacological properties and has appeared in several clinical trials. Herein we present the synthesis, characterization, in vitro biological investigation, and in silico study of four hetero aryl amide analogs of NTZ. Among the synthesized molecules, compound 2 and compound 4 exhibited promising antibacterial activity against Escherichia coli (E. coli), superior to that displayed by the parent drug nitazoxanide as revealed from the in vitro antibacterial assay. Compound 2 displayed zone of inhibition of 20 mm, twice as large as the parent drug NTZ (10 mm) in their least concentration (12.5 µg/ml). Compound 1 also showed antibacterial effect similar to that of nitazoxanide. The analogs were also tested for in vitro cytotoxic activity by employing cell counting kit-8 (CCK-8) assay technique in HeLa cell line, and compound 2 was identified as a potential anticancer agent having IC50 value of 172 µg which proves it to be more potent than nitazoxanide (IC50  = 428 µg). Furthermore, the compounds were subjected to molecular docking study against various bacterial and cancer signaling proteins. The in vitro test results corroborated with the in silico docking study as compound 2 and compound 4 had comparatively stronger binding affinity against the proteins and showed a higher docking score than nitazoxanide toward human mitogen-activated protein kinase (MAPK9) and fatty acid biosynthesis enzyme (FabH) of E. coli. Moreover, the docking study demonstrated dihydrofolate reductase (DHFR) and thymidylate synthase (TS) as probable new targets for nitazoxanide and its synthetic analogs. Overall, the study suggests that nitazoxanide and its analogs can be a potential lead compound in the drug development.

Repurposing therapeutic agents against SARS-CoV-2 infection: most promising and neoteric progress

INTRODUCTION

The pathogenic and highly transmissible etiological agent, SARS-CoV-2, has caused a serious threat COVID-19 pandemic. WHO has declared the epidemic a public health emergency of international concern owing to its high contagiosity, mortality rate, and morbidity. Till now, there is no approved vaccine or drug to combat the COVID-19 and avert this global crisis.

AREAS COVERED

In this narrative review, we summarized the updated results (January to August 2020) of the most promising repurposing therapeutic candidates to treat the SARS-CoV-2 viral infection. The repurposed drugs classified under four headlines like antivirals, anti-parasitic, immune-modulating, and miscellaneous drugs were discussed with their in vitro efficacy to recent clinical advancements against COVID-19.

EXPERT OPINION

Currently, palliative care, ranging from outpatient management to intensive care, including oxygen administration, ventilator support, intravenous fluids therapy, with some repurposed drugs, are the primary weapons to fight against COVID-19. Until a safe and effective vaccine is developed, an evidence-based drug repurposing strategy might be the wisest option to save people from this catastrophe. Several existing drugs are now under clinical trials, and some of them are approved in different places of the world for emergency use or as adjuvant therapy in COVID-19 with standard of care.

Synthesis and evaluation of pharmacological activities of some 3-O-benzyl-4-C-(hydroxymethyl)-1,2-O-isopropylidene-α-D-ribofuranose derivatives as potential anti-inflammatory agents and analgesics

Background and purpose:

α-D-ribofuranose analogues are reported to have multifarious biological properties such as analgesic, anti-inflammatory, and antiviral activities. The present study aims to synthesize some α-D- ribofuranose derivatives and investigate their biological properties.

Experimental approach:

Four derivatives (2a, 2b, 3, and 4) were synthesized from the starting material 3-O- benzyl-4-C-(hydroxymethyl)-1,2-O-isopropylidene-α-D-ribofuranose via subsequent benzylation, tosylation, and acetylation reactions in good yields. The compounds were confirmed by spectroscopic methods such as Fourier-transform infrared (FTIR) and proton nuclear magnetic resonance (¹HNMR), and then evaluated for various pharmacological activities using standard in vitro and in vivo procedures.

Findings / Results:

Compound 2a (50 mg/kg) exhibited both central and peripheral analgesic activity in the tail immersion test (2.52 ± 0.14 min tail flicking reaction time after 30 min from administration, P < 0.001) and the acetic acid-induced writhing test (65.33 ± 2.06% reduction in abdominal writhing, P < 0.001) respectively. In the anti-inflammatory assay, percent paw edema inhibition of carrageenan-induced rats for compounds 2a and 4 (100 mg/kg) after 4 h of administration were 82.6% (P < 0.001) and 87.6% (P < 0.001), respectively. The compounds were also tested for antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, antimicrobial property in disk diffusion assay, and cytotoxicity in HeLa cell line; however, no significant results were observed in any of those tests.

Conclusion and Implications:

Our study indicated that some of the synthesized compounds exhibited promising analgesic and anti-inflammatory effects and may serve as potential lead compounds.

Effective syntheses of 2',4'-BNANC monomers bearing adenine, guanine, thymine, and 5-methylcytosine, and the properties of oligonucleotides fully modified with 2',4'-BNANC

We efficiently synthesized 2'-O,4'-C-aminomethylene-bridged nucleic acid (2',4'-BNA^NC) monomers bearing the four nucleobases, guanine, adenine, thymine, and 5-methylcytosine and incorporated these monomers into oligonucleotides. Initially, we carried out the transglycosylation reaction on several 2'-O-substituted 5-methyluridines to evaluate the effects of 2'-substitutions on this reaction. Under the optimized conditions, purine nucleobases were successfully introduced, and 2',4'-BNA^NC monomers bearing adenine or guanine were obtained over several steps. In addition, the improved synthesis of the 2',4'-BNA^NC monomers bearing thymine or 5-methylcytosine was also achieved. The obtained 2',4'-BNA^NC monomers were subsequently incorporated into oligonucleotides and the duplex-forming abilities of the modified oligonucleotides were investigated. Duplexes containing 2',4'-BNA^NC monomers in both or either strands were found to possess excellent thermal stabilities.

Synthesis, Characterization and Comparison of Local Analgesic, Anti-Inflammatory, Anti-Ulcerogenic Activity of Copper and Zinc Complexes of Indomethacin

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAID) exert gastrointestinal upset by inhibiting mucosal cyclooxygenase (COX) activity and complexation technique with metals has been adopted to overcome this drawback.

OBJECTIVE

The study aimed to overcome the gastrointestinal side effects associated with indomethacin treatment by synthesizing copper (Cu) and zinc (Zn) complexes of indomethacin along with assessing potential pharmacological effects of these complexes.

METHOD

The characterization of synthesized complexes was done by FT-IR, XRD, UV-Vis, Atomic Absorption Spectroscopy (AAS) and Differential Scanning Calorimetry (DSC). Biological properties as local analgesic activity, anti-inflammatory activity and antiulcerogenic activity were evaluated following radiant heat tail flick, inhibition of rat hind paw edema and inhibition of NSAID induced gastroenteropathy method respectively.

RESULTS

0.3 ml of indomethacin-copper complex demonstrated prominent analgesia at 25 &micro;g/ml dose and 0.3 ml of indomethacin-zinc complex, after 30, 60 and 90 minutes of oral administration, shown significant local analgesia at 25, 50 and 100 µg/ml dose. In antiinflammatory activity assay, indomethacin-copper exhibited significant inhibition at 20 mg/kg dose after 2nd, 3rd and 4th hour of administration whereas indomethacin-zinc illustrated significant inhibition at 10 mg/kg dose after 2nd, 3rd and 4th hour of administration. Anti-ulcerogenic activity study of the complexes exhibited no macroscopic damage to the stomach and intestine, except minor microscopic damage.

CONCLUSION

In view of the results, the copper and zinc complexes of indomethacin may be used as better substitutes of the parent indomethacin owing to their minimal side effects with additional pharmacological effects.

Evaluation of antinociceptive and antidiarrhoeal properties of Manilkara zapota leaves in Swiss albino mice

Context Manilkara zapota (L.). P. Royen. (Sapotaceae) has been used in folk medicine to treat pain, diarrhoea, inflammation, arthralgia, and other disorders. Objective Screening of Manilkara zapota leaves ethanol extract and its different solvent soluble fractions for possible antinociceptive and antidiarrhoeal activities in Swiss albino mice. Materials and methods The extract and various fractions (200 and 400 mg/kg body weight; p.o.) were tested for peripheral and central antinociceptive activity by acetic acid-induced writhing and radiant heat tail-flick method, respectively; castor oil-induced diarrhoeal model was used to evaluate antidiarrhoeal activity at both doses. All the samples were administered once in a day and the duration of study was approximately 5 h. Results Ethanol extract (400 mg/kg), petroleum ether fraction (400 mg/kg), and ethyl acetate fraction (400 mg/kg) showed significant peripheral antinociceptive activity having 59.89, 58.24, and 46.7% (p < 0.001) of writhing inhibition, respectively, which is comparable with that of standard diclofenac (59.34% inhibition). The ethanol extract (400 mg/kg) and petroleum ether fraction (400 mg/kg) also showed promising central analgesic activity having 74.15 and 82.15% (p < 0.001) elongation of reaction time, respectively, at 90 min after administration of sample which is also similar to that obtained by morphine (85.84% elongation). In antidiarrhoeal activity screening, ethanol extract (200 and 400 mg/kg) showed significant inhibition of defecation by 53.57 and 60.71%, respectively (p < 0.001) compared with that of loperamide (71.42%). Discussion and conclusion The findings of the studies demonstrated antinociceptive and antidiarrhoeal activities of M. zapota leaves which could be the therapeutic option against pain and diarrhoeal disease.

Transition Metal Complexes of Naproxen: Synthesis, Characterization, Forced Degradation Studies, and Analytical Method Verification

The aim of our current research was to synthesize some transition metal complexes of Naproxen, determine their physical properties, and examine their relative stability under various conditions. Characterizations of these complexes were done by 1H-NMR, Differential Scanning Calorimetry (DSC), FT-IR, HPLC, and scanning electron microscope (SEM). Complexes were subjected to acidic, basic, and aqueous hydrolysis as well as oxidation, reduction, and thermal degradation. Also the reversed phase high-performance liquid chromatography (RP-HPLC) method of Naproxen outlined in USP was verified for the Naproxen-metal complexes, with respect to accuracy, precision, solution stability, robustness, and system suitability. The melting points of the complexes were higher than that of the parent drug molecule suggesting their thermal stability. In forced degradation study, complexes were found more stable than the Naproxen itself in all conditions: acidic, basic, oxidation, and reduction media. All the HPLC verification parameters were found within the acceptable value. Therefore, it can be concluded from the study that the metal complexes of Naproxen can be more stable drug entity and offer better efficacy and longer shelf life than the parent Naproxen.

Analgesic and antidepressant activities of Brassica rapa subspecies chinensis (L.) Hanelt on Swiss-albino mice model

Bangladesh being a subtropical country provides varieties of herbs and vegetables. Brassica is a broad genus available in Bangladesh and it encompasses a lot of nutritive herbs. Among these, Brassica rapa subspecies chinensis (L.) Hanelt (Family-Brassicaceae) is popular in many parts of the world. In the quest of medicinal property, this plant was investigated here for observing analgesic and antidepressant activities in Swiss-albino mice model. The herb was extracted well with methanol and then assayed by acetic acid-induced writhing and tail immersion methods for analgesic action. Besides, thiopental sodium induced sleeping time test, tail suspension test and forced swim test were conducted for the evaluation of its antidepressant activity. The plant extract was orally administered to the mice at 200 and 400 mg/kg body weight and it exhibited significant analgesic and antidepressant activities in compare to the controlled groups. This is the first time comprehensive report for analgesic and antidepressant activities of this plant.

Crispene E, a cis-clerodane diterpene inhibits STAT3 dimerization in breast cancer cells

Crispene E inhibited STAT3 dimerization in a cell-free fluorescent polarization assay and was found to have significant toxicity against STAT3-dependent MDA-MB 231 breast cancer cell line and selectively inhibited the expression of STAT3 and STAT3 target genes.

Hybridizing ability and nuclease resistance profile of backbone modified cationic phosphorothioate oligonucleotides

Various stereochemically pure cationic phosphorothioate oligonucleotides bearing aminoalkyl moieties were synthesized, and their duplex-forming ability against single-stranded DNA (ssDNA), single-stranded RNA (ssRNA) and triplex-forming ability against double-stranded DNA (dsDNA) were evaluated by UV melting experiments. The cationic Rp stereoisomers showed improved duplex-forming ability against ssDNA, triplex-forming ability against dsDNA and nuclease stability.

Interrupted 2'-o,4'-C-aminomethylene bridged nucleic acid modification enhances pyrimidine motif triplex-forming ability and nuclease resistance under physiological condition

Due to instability of pyrimidine motif triplex DNA at physiological pH, triplex stabilization at physiological pH is crucial in improving its potential in various triplex formation-based strategies in vivo, such as regulation of gene expression, mapping of genomic DNA, and gene-targeted mutagenesis. To this end, we investigated the effect of our previously reported chemical modification, 2'-O,4'-C-aminomethylene bridged nucleic acid (2',4'- BNA(NC)) modification, introduced into interrupted and continuous positions of triplex-forming oligonucleotide (TFO) on pyrimidine motif triplex formation at physiological pH. The interrupted 2',4'-BNA(NC) modifications of TFO increased the binding constant of the triplex formation at physiological pH by more than 10-fold, and significantly increased the nuclease resistance of TFO. On the other hand, the continuous 2',4'-BNA(NC) modification of TFO showed lower ability to promote the triplex formation at physiological pH than the interrupted 2',4'-BNA(NC) modifications of TFO, and did not significantly change the nuclease resistance of TFO. Selection of the interruptedly 2',4'-BNA(NC)-modified positions in TFO was more favorable for achieving the higher binding affinity of the pyrimidine motif triplex formation at physiological pH and the higher nuclease resistance of TFO than that of the continuously 2',4'-BNA(NC)-modified positions in TFO. We conclude that the interrupted 2',4'-BNA(NC) modification of TFO could be a key chemical modification to enhance pyrimidine motif triplex-forming ability and nuclease resistance under physiological condition, and may eventually lead to progress in various triplex formation-based strategies in vivo.

2'-O,4'-C-aminomethylene-bridged nucleic acid modification with enhancement of nuclease resistance promotes pyrimidine motif triplex nucleic acid formation at physiological pH

Due to the instability of pyrimidine motif triplex DNA at physiological pH, triplex stabilization at physiological pH is crucial in improving its potential in various triplex-formation-based strategies in vivo, such as gene expression regulation, genomic DNA mapping, and gene-targeted mutagenesis. To this end, we investigated the thermodynamic and kinetic effects of our previously reported chemical modification, 2'-O,4'-C-aminomethylene-bridged nucleic acid (2',4'-BNA(NC)) modification of triplex-forming oligonucleotide (TFO), on triplex formation at physiological pH. The thermodynamic analyses indicated that the 2',4'-BNA(NC) modification of TFO increased the binding constant of the triplex formation at physiological pH by more than 10-fold. The number and position of the 2',4'-BNA(NC) modification in TFO did not significantly affect the magnitude of the increase in the binding constant. The consideration of the observed thermodynamic parameters suggested that the increased rigidity and the increased degree of hydration of the 2',4'-BNA(NC)-modified TFO in the free state relative to the unmodified TFO may enable the significant increase in the binding constant. Kinetic data demonstrated that the observed increase in the binding constant by the 2',4'-BNA(NC) modification resulted mainly from the considerable decrease in the dissociation rate constant. The TFO stability in human serum showed that the 2',4'-BNA(NC) modification significantly increased the nuclease resistance of TFO. Our results support the idea that the 2',4'-BNA(NC) modification of TFO could be a key chemical modification to achieve higher binding affinity and higher nuclease resistance in the triplex formation under physiological conditions, and may lead to progress in various triplex-formation-based strategies in vivo.

Promotion of triplex formation by 2'-O,4'-C-aminomethylene bridged nucleic acid (2',4'-BNA NC) modification

We examined the effect of 2'-O,4'-C-aminomethylene bridged nucleic acid (2',4'-BNA(NC)) backbone modification of triplex-forming oligonucleotide (TFO) on the pyrimidine motif triplex formation at neutral pH, a condition where pyrimidine motif triplexes are unstable. The melting temperature of the pyrimidine motif triplex at pH 6.8 with 2',4'-BNA(NC) modified TFO was significantly higher than that observed with unmodified TFO. The 2',4'-BNA(NC) modification of TFO increased the thermal stability of the pyrimidine motif triplex at neutral pH. The present results certainly support the idea that the 2',4'-BNA(NC) backbone modification of TFO could be a key chemical modification and may eventually lead to progress in therapeutic applications of the antigene strategy in vivo.

Promotion of triplex formation by 3'-amino-2'-O,4'-C-methylene bridged nucleic acid modification

We examined the effect of 3'-amino-2'-O,4'-C-methylene bridged nucleic acid (3'-amino-2',4'-BNA) backbone modification of triplex-forming oligonucleotide (TFO) on the pyrimidine motif triplex formation at neutral pH, a condition where pyrimidine motif triplexes are unstable. The melting temperature of the pyrimidine motif triplex at pH 6.8 with 3'-amino-2',4'-BNA modified TFO was significantly higher than that observed with unmodified TFO. The 3'-amino-2',4'-BNA modification of TFO increased the thermal stability of the pyrimidine motif triplex at neutral pH. The present results certainly support the idea that the 3'-amino-2',4'-BNA modification of TFO could be a key chemical modification and may eventually lead to progress in therapeutic applications of the antigene strategy in vivo.

RNA interference with 2',4'-bridged nucleic acid analogues

In this study, a number of 2',4'-BNA- and 2',4'-BNA(NC)-modified siRNAs were designed and synthesized. Their thermal stability, nuclease resistance and gene silencing properties against cultured mammalian cells were evaluated and compared with those of natural siRNAs. The 2',4'-BNA- and 2',4'-BNA(NC)-modified siRNAs (named siBNA and siBNA(NC), respectively) showed very high T(m) values, were remarkably stable in serum sample and showed promising RNAi properties equal to those exhibited by natural siRNAs. Thermally stable siBNAs composed of slightly modified sense and antisense strands were capable of suppressing gene expression equal to that of natural siRNA. A number of modifications on the sense strand by 2',4'-BNA or 2',4'-BNA(NC), either consecutively or separated by natural RNA nucleotides, is tolerable in RNAi machinery. Modifications at the Argonauate (Ago2) cleavage site of the sense strand (9-11th positions from the 5'-end of the sense strand) produced variable results depending on siRNA composition. Mostly, modification at the 10th position diminished siRNA activity. In moderately modified siRNAs, modification at the 11th position displayed usual RNAi activity, while modification at the 9th position showed variable results depending on siRNA composition.

Synthesis and properties of 3'-amino-2',4'-BNA, a bridged nucleic acid with a N3'-->P5' phosphoramidate linkage

The synthesis and properties of a bridged nucleic acid analogue containing a N3'-->P5' phosphoramidate linkage, 3'-amino-2',4'-BNA, is described. A heterodimer containing a 3'-amino-2',4'-BNA thymine monomer, and thymine and methylcytosine monomers of 3'-amino-2',4'-BNA and their 5'-phosphoramidites, were synthesized efficiently. The dimer and monomers were incorporated into oligonucleotides by conventional 3'-->5' assembly, and 5'-->3' reverse assembly phosphoramidite protocols, respectively. Compared to a natural DNA oligonucleotide, modified oligonucleotides containing the 3'-amino-2',4'-BNA residue formed highly stable duplexes and triplexes with single-stranded DNA (ssDNA), single-stranded RNA (ssRNA), and double-stranded DNA (dsDNA) targets, with the average increase in melting temperature (T(m)) against ssDNA, ssRNA and dsDNA being +2.7 to +4.0 degrees C, +5.0 to +7.0 degrees C, and +5.0 to +11.0 degrees C, respectively. These increases are comparable to those observed for 2',4'-BNA-modified oligonucleotides. In addition, an oligonucleotide modified with a single 3'-amino-2',4'-BNA thymine residue showed extraordinarily high resistance to nuclease degradation, much higher than that of 2',4'-BNA and substantially higher even than that of 3'-amino-DNA and phosphorothioate oligonucleotides. The above properties indicate that 3'-amino-2',4'-BNA has significant potential for antisense and antigene applications.

2',4'-BNA(NC): a novel bridged nucleic acid analogue with excellent hybridizing and nuclease resistance profiles

Oligonucleotides modified with 2 ',4 '-BNA(NC) (N-H)/(N-Me) monomers exhibited excellent hybridizing and nuclease resistance properties. Duplex and triplex thermal stabilities were greatly enhanced by incorporating 2',4'-BNA(NC) (N-H) and (N-Me) monomers and nuclease resistance was tremendously higher than that of natural oligonucleotide.

Design, synthesis, and properties of 2',4'-BNA(NC): a bridged nucleic acid analogue

The novel bridged nucleic-acid analogue 2',4'-BNA(NC) (2'-O,4'-C-aminomethylene bridged nucleic acid), containing a six-membered bridged structure with an N-O linkage, was designed and synthesized efficiently, demonstrating a one-pot intramolecular NC bond-forming key reaction to construct a perhydro-1,2-oxazine ring (11 and 12). Three monomers of 2',4'-BNA(NC) (2',4'-BNA(NC)[NH], [NMe], and [NBn]) were synthesized and incorporated into oligonucleotides, and their properties were investigated and compared with those of 2',4'-BNA (LNA)-modified oligonucleotides. Compared to 2',4'-BNA (LNA)-modified oligonucleotides, 2',4'-BNA(NC) congeners were found to possess: (i) equal or higher binding affinity against an RNA complement with excellent single-mismatch discriminating power, (ii) much better RNA selective binding, (iii) stronger and more sequence selective triplex-forming characters, and (iv) immensely higher nuclease resistance, even higher than the S(p)-phosphorthioate analogue. 2',4'-BNA(NC)-modified oligonucleotides with these excellent profiles show great promise for applications in antisense and antigene technologies.

High-affinity RNA mimicking binding of 2',4'-BNANC towards complementary strands: a comparative study with 2',4'-BNA/LNA

2',4'-BNA(NC), a bridged nucleic acid analogue, which was designed and synthesized in our laboratory, showed very high binding affinity towards complementary RNA and DNA strands. Its duplex-forming ability towards a single-stranded RNA was similar to or slightly higher than that of 2',4'-BNA and the overall triplex-forming ability against a double-stranded DNA was also better than that of 2',4'-BNA. 2',4'-BNA(NC) exhibited higher RNA selectivity than 2',4'-BNA.

N-Methyl substituted 2',4'- BNANC: a highly nuclease-resistant nucleic acid analogue with high-affinity RNA selective hybridization

Oligonucleotides modified with a novel BNA analogue, 2', 4'-BNA(NC)[N-Me], were synthesized, and in comparison to 2',4'-BNA (LNA), have similarly high RNA affinity, better RNA selectivity and much higher resistance to nuclease degradation, suggesting that the novel BNA analogue may be particularly useful for antisense approaches.

Synthesis and properties of 2',4'-BNA(NC), a second generation BNA

We have recently designed and synthesized a novel bridged nucleic acid analogue 2',4'-BNA(NC), bearing an N-O bridged structure, which furnished both higher duplex and triplex-forming abilities and sequence selectivity towards complementary RNA and/or DNA, respectively, and showed excellent resistance against nuclease degradation. Duplex and triplex-forming abilities were slightly higher or similar to those of 2',4'-BNA and nuclease resistance was as high as that of S-oligo.

Novel Synthesis of Bridged Phenylthienylethenes and Dithienylethenes via Pd-Catalyzed Double-Cyclization Reactions of Diarylhexadienynes

[reaction: see text] Bridged phenylthienylethenes and dithienylethenes were synthesized via Pd-catalyzed double-cyclization reactions of (Z,Z)-1,6-diaryl-1,5-hexadien-3-ynes. Pd-catalyzed as well as photoinduced Z/E isomerization of the products were also investigated.

High cholesterol diet results in increased expression of interleukin-6 and caspase-1 in the brain of apolipoprotein E knockout and wild type mice

Inflammation in the central nervous system is an early hallmark of many neurodegenerative diseases including Alzheimer's disease (AD). Recently, increasing evidence suggests that hypercholesterolemia during midlife and abnormalities in the cholesterol metabolism could have an important role in the pathogenesis of AD. In the present study, we have evaluated the effect of high cholesterol (HC) diet on the expression of interleukin-6 (IL-6), a cytokine involved in neurodegeneration, and caspase-1, that is responsible for the cleavage of the precursors of interleukin-1 beta (IL-1 beta) and interleukin-18 (IL-18) in the brain of apolipoprotein E (Apo E) knock-out (KO) and wild type (WT) mice. The density of IL-6-positive cells was increased in the hippocampus (p<0.0001) and the dorsal part of the cortex (p<0.001) of KO and WT mice on HC diet (KOHC and WTHC mice, respectively) compared to KO and WT mice on ND (KOND and WTND mice, respectively). KOHC mice had increased caspase-1 positive cells and staining intensity in the hippocampus in comparison with WTHC mice (p<0.01). In the hippocampus, the density of caspase-1 positive cells was also higher in KOHC compared to KOND mice (p<0.05) and KOHC compared with WTHC mice (p<0.01). There was a major increase in caspase-1 immunoreactivity and cell density in both the dosal part of the cortex (p<0.001) and the lateral part of the cortex (p<0.005) in KO and WT mice on HC diet compared to ND. The findings of the present study indicate that chronic exposure to HC diet increases the expression of the two important inflammatory mediators IL-6 and caspase-1 in the brain of KO and WT mice. In the case of caspase-1, we report a major difference in the effect of HC diet on the KO mice compared to WT mice in the hippocampus. Increased expression of inflammatory mediators involved in neurodegeneration could be a potential mechanism by which hypercholesterolemia and HC diet increase the risk of AD.

Evaluation of scopadulciol-related molecules for their stimulatory effect on the cytotoxicity of acyclovir and ganciclovir against Herpes simplex virus type 1 thymidine kinase gene-transfected HeLa cells

Herpes simplex virus type 1 thymidine kinase (HSV TK) is involved in both antiherpetic therapy and cancer gene therapy with acyclovir (ACV) and ganciclovir (GCV). Enhanced sensitivity to these drugs is advantageous in their clinical use. In the present study, scopadulciol (SDC) and its related compounds were evaluated for their stimulatory effect on the cytotoxicity of ACV and GCV by determination of selective toxicities against HSV TK-expressing HeLa cells. Although SDC remarkably potenciated the cytotoxicity of ACV and GCV, the other tested compounds showed only weak selectivity, except for compound 34.

Effects of high cholesterol diet on gliosis in apolipoprotein E knockout mice. Implications for Alzheimer's disease and stroke

Hypercholesterolemia has been suggested as a risk factor for Alzheimer's disease (AD). A genetic risk factor for AD is the E4 allele of apolipoprotein E (apoE). ApoE is the major lipoprotein transporter in the brain, and is mainly produced by glial cells. The present study is focussed on analysing the effects of high cholesterol (HC) diet, duration 9 months, on glial activation in the brain, both in wild type (WT) mice and in mice with a null mutation in the apoE gene (knock-out, KO) mice. The activation of astrocytes and microglia was analysed after immunohistochemical labelling of glial fibrillary acidic protein (GFAP), and F4/80, respectively. In addition, the expression of the antioxidant enzyme NAD(P)H:quinone oxidoreductase (NQO1) was analysed. There was a marked stimulation of astrocyte and microglial activation as well as induced expression of NQO1 in the hippocampus and cerebral cortex upon HC diet. Furthermore, there was significant astrocyte activation in the apoE KO mice, as compared to the WT mice, on ND. The long time exposure to HC diet combined with apoE deficiency resulted in a synergistic effect on the expression of NQO1 in the brain.

Efficient synthesis of biindenylidene derivatives via a domino-Heck-type double cyclization of diaryldienynes

[reaction: see text] Synthesis of aromatic ring substituted (E)-1,1'-biindenylidene derivatives was achieved by a domino-Heck type double cyclization of (Z,Z)-1,6-diaryl-1,5-hexadien-3-ynes.