VARIOUS BIOLOGICAL ACTIVITIES OF COUMARIN AND OXADIAZOLE DERIVATIVES

In this review article data is collected regarding the various derivatives of coumarin and oxadiazole as both these have wide range of biological activities and they can be further modified to synthesize more effective and potent drugs. Coumarin class of organic compounds consists of 1,2-benzopyrone ring system as a basic parent scaffold. These benzopyrones are subdivided into alpha-benzopyrones and gamma benzopyrones; with coumarin class of compounds belonging to alpha-benzopyrones. Since the last few years, coumarins were synthesized in many of their derivative forms. Their pharmacological, therapeutic and biochemical properties depend upon their pattern of substitution. Coumarins exhibit a wide range of pharmacological activities, which includes anti-diabetic, anti-viral, anti-microbial, anticancer, anti-oxidant, anti-parasitic, anti-helminthic, anti-proliferative, anti-convulsant, anti-inflammatory and antihypertensive activities. 1,3,4-Oxadiazole is a heterocyclic compound containing an oxygen atom and two nitrogen atoms in a five-membered ring. It is derived from furan by substitution of two methylene groups (=CH) with two pyridine type nitrogens (-N=). There are three known isomers: 1,2,4-oxadiazole, 1,2,3-oxadiazole and 1,2,5- oxadiazole. Oxadiazole moiety shows antimicrobial, anticancer and anti-inflammatory activity and suitably substituted 1,3,4-oxadiazole having biological activities like antimicrobial, anticancer and other biological activities

Therapeutic potentials of black tea medicaments

Tea; a product of Camellia Sinensis plant is the most broadly used beverage in the world. Tea phytochemicals have been studied for the prevention of various chronic diseases, such as cancer, obesity, diabetes, jaundice, hypertension and inflammation related disorders. Whereas many studies have revealed the potential efficiency of tea for the prevention of these physiological disorders, the underlying mechanisms remain unclear. In this work, we evaluated the evidence and discussed the significance of proposed mechanisms for the prevention of the diseases such as Alzheimer’s, obesity, diabetes mellitus type II, hypertension and asthma by tea. Molecular docking method was used to explore the ability of tea phytochemicals to inhibit the key enzymes. The three dimensional structure of target enzymes were either retrieved from protein data bank or modelled using swiss model. Autodock4.2 software was used for molecular docking that applies Lamarckian Genetic Algorithm. The ligand structures were retrieved from PubChem and KNApSAcK-3D database. PreADMET web server was used for Toxicity and ADME predictions. Based on this analysis, it has been found that theaflavin, rutin and 8-c-ascorbyl epigallocatechin could be the potential lead molecules as they act as inhibitor for most of the target enzymes and has a good drug score and also qualifies the toxicity and ADME test. Further the tea extract is loaded in liposomal drug delivery system and pectin-HEMA hydrogel system to analyse their drug delivery potential and it was found that liposomal system is best suitable for delivery to brain and hydrogel system better serve as colon specific delivery system. We concluded that these phytochemicals or their derivatives can be used for further in-vitro and in-vivo studies to produce valuable lead drug candidates

Radiopharmaceuticals for PET imaging of neuroinflammation - Les radiopharmaceutiques pour l’imagerie TEP de la neuroinflammation

Abstract Recently, accumulating evidence has revealed that neuroinflammation appears to be the cornerstone of many neurological diseases including stroke, multiple sclerosis, Alzheimer's disease or Parkinson's disease. Neuroinflammation causes neuronal damages by activation of numerous cells and molecular mediators in diseases involving the inflammatory process. In this article, we focus on noninvasive molecular imaging of radioligands that target inflammatory cells and molecules involved in neuroinflammation. PET is in fact one of the most promising imaging techniques to visualize and quantify neuroinflammation in vivo. We have also summarized the potential neuroinflammation imaging targets and corresponding PET radioligands. Résumé Des données scientifiques récentes et de plus en plus nombreuses ont mis en évidence le rôle central joué par le processus de neuroinflammation dans la physiopathologie de nombreuses maladies neurologiques, telles que l’accident vasculaire cérébral, la sclérose en plaques, la maladie d’Alzheimer ou encore la maladie de Parkinson. Dans ces maladies impliquant le processus inflammatoire, la neuro-inflammation cause en effet des dommages neuronaux par activation de nombreuses cellules et médiateurs moléculaires. L’imagerie par tomographie par émission de positons (TEP) apparaît comme une approche prometteuse pour visualiser et quantifier in vivo la neuro-inflammation de façon non invasive, grâce en particulier au développement de radioligands ciblant spécifiquement diverses molécules impliquées dans cette réaction inflammatoire cérébrale. Dans cette revue sont présentés les cibles moléculaires potentielles pour l’imagerie TEP de la neuro-inflammation ainsi que les médicaments radiopharmaceutiques correspondants

Biological evaluation, molecular docking, and sar studies of novel 2-(2,4-dihydroxyphenyl)- 1H- benzimidazole analogues

In the present study, new 4-(1H-benzimidazol-2-yl)-benzene-1,3-diols, modified in both rings, have been synthesized and their efficacies as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors have been determined. The modified Ellman’s spectrophotometric method was applied for the biological evaluation. The compounds showed strong $IC_{50}$ 5-0.2 $\mu$ M AChE and moderate ($IC_{50}$ 5-0.2 M) BuChE inhibition in vitro. Some compounds were e ective toward AChE/BuChE, exhibiting high selectivity ratios versus BuChE, while the other compounds were active against both enzymes. The structure–activity relationships were discussed. The compounds inhibited also in vitro self-induced A$\beta$ (1-42) aggregation and exhibited antioxidant properties. The docking simulations showed that the benzimidazoles under consideration interact mainly with the catalytic site of AChE and mimic the binding mode of tacrine

E. coli immunosensori arendus ja rakendamine

Väitekirja elektrooniline versioon ei sisalda publikatsiooneIga aastaga muutuvad keskkonna kvaliteet ja puhtus maailmas aina olulisemaks. Üks tähtsamaid küsimusi on inimeste ligipääs puhtale veele. Kui tavaliselt mõeldakse selle all eelkõige joogivett, siis sama oluline on ka suplusvee puhtus ja ohutus. Üheks vee kvaliteedi parameetriks on tema mikrobioloogiline ohutus, mille hindamiseks kasutatakse teatud bakteriliike, ehk indikaatorliike, mille olemasolu ja arvukuse järgi hinnatakse vee kvaliteeti. Üheks levinumaks indikaatorliigiks vees on Escherichia coli ehk soolekepike. Mõned E. coli tüved võivad olla ka patogeensed. Tavaliselt hinnatakse E. coli arvukust mikrobioloogilistel meetoditel, kultiveerides proove spetsiaalsetel söötmetel, kuid see on aeganõudev. Molekulaarsed meetodid (PCR) on küll kiiremad, kuid nõuavad keeruka aparatuuri kasutamist ning on tundlikud võimaliku saastuse ja proovide maatriksist tuleneva inhibitsiooni suhtes. Doktoritöö eesmärgiks oli välja töötada immunobiosensorsüsteem E. coli tuvastamiseks ning testida selle biosensori rakendamise võimalusi looduslike veeproovide ja kliiniliste uriiniproovide analüüsil. Kasutatud biosensori bioloogiline äratundmiskomponendina kasutati fluorestsentsmärgisega konjugeeritud anti - E. coli ankeha. Analüüsi kõrge tundlikkus saavutati tänu proovis leiduva E. coli sidumisele ühekordse kasutusega mikrokolonnile ning seondunud bakterite spetsiifilisele detekteerimisele. Erinevatest allikatest pärinevates proovides saadud analüüsitulemusi võrreldi alternatiivsete E. coli määramismeetodite, mikrobioloogilise külvi ja kvantitatiivse PCR abil saadud tulemustega. Nimetatud metoodikad võimaldavad küll kõik hinnata E. coli arvukust, kuid mõõdavad erinevaid rakku iseloomustavaid suurusi. Mikrobioloogiliste külvide meetod võtab arvesse elusaid kultiveeritavid rakke; kvantitatiivne PCR hindab E. coli genoomse DNA kogust (elusad + mitte-kultiveeritavad ja surnud rakud), ning biosensor mõõdab E. coli mebraanivalkude kontsentratsiooni proovis. Mõõtes näiteks ühte ja sama veeproovi kirjeldatud meetoditega selgus, et oodatult kõige madalama tulemuse andis mikrobioloogiline meetod (40 korda madalam, kui biosensor), ning ka qPCR meetod andis keskmiselt 4 korda madalama tulemuse kui biosensor. Töö selgitati välja põhjused, mis selliseid erinevusi põhjustasid. Esiteks, biosensoris põhjustasid mõõdetava signaali ka rakkude mehhaanilisel ja keemilisel töötlemisel saadud rakumembraanide fragmendid. Teise olulise tulemusena selgus, et biosensoris kasutatava antikeha äratundmisreaktsioon oli komplekses mikrobioloogilises keskkonnas eeldatust vähem selektiivne. Lisaks E. coli´le on looduslikes keskkondades palju sarnaseid bakteriliike (kolivormseid), millest mõnedel on potentsiaalselt afiinsus immunosensoris kasutatud E. coli antikeha suhtes. Kuna selliste bakterite üldhulk looduslikes vetes võib olla kõrge, siis tuleb biosensori mõõtetulemuste interpreteerimisel arvestada ka nende poolt genereeritava signaaliga. Arvestades erinevate rakufragmentide ning kolivormsete rakkude poolt põhjustatud signaali osakaalu, siis elusate kultiveeritavate E. coli rakkude poolt tingitud signaali osakaal on immunosensori kogusignaalist 10%. E. coli immunosensorit kasutati ka uropatogeense E. coli tuvastamiseks ja kvantiteerimiseks kliinilistes uriiniproovides, kus biosensoriga saadud analüüsitulemused langesid kokku mikrobioloogiliste ja molekulaarsete (qPCR) meetoditega saadud tulemustega. Väljatöötatud biosensorsüsteem võimaldas määrata E. coli sisalduse vee- või uriiniproovides vahemikus 7-107 rakku milliliitris 20 minuti jooksul, mis loob eelduse E. coli automaatseks kohapealseks määramiseks, vältides vajadust proovide transpordiks laborisse ning analüüsile eelnevaks töötluseks.The quality of water is among the major global problems usually associated with drinking water. However, problems with the physical, chemical, and biological pollution of bathing water are increasing. The biological pollution is commonly assessed using microbiology methods by identifying and quantifying microbial indicator organisms. The most common indicator species for water analysis is Escherichia coli – gram-negative, rod-shaped bacteria generally found in the guts of warm-blooded animals. Most E. coli strains are harmless, but there is also a group of E. coli strains, which are human pathogens Uropathogenic E. coli (UPEC) is the main human urinary tract pathogen. The most common method for E. coli enumeration is still microbiological cultivation. This method is reliable and simple, but the analysis time is long, the sensitivity is quite poor and the cultivation requires special lab conditions. In addition, E. coli can be detected with qPCR. A good alternative for E. coli indication and enumeration are biosensor-based systems, which can provide short analysis time, high specificity, and sensitivity. Biosensors also offer options for automation and on-site analysis required to meet modern requirements for data collection. The objective of this thesis was the design and production of an E. coli-specific immunosensor, its testing for potential applications in environmental monitoring and clinical laboratory analysis, and validation of the biosensor results. The proposed E. coli immunosensor integrates the use of polyclonal E. coli antibodies for bio-recognition and single-use microcolumn analysis system for the rapid detection of E. coli from bathing water and urine samples. The immunosensor the detection limit was below 10 cells/ml, and the working range was between 10…108 cells/ml. In urine, there was no inference other bacterial species present in urine to the biosensor signal, as there is a small probability of the presence of dead and/or fragmented E. coli cells in urine. The E. coli biosensor results were in the same range as those obtained with qPCR and cultivation methods. The analysis of the biosensor signal in bathing water samples revealed that the signal was strongly affected by dead cells, cell fragments, and different coliforms, which are abundant in natural waters. The proportion of cultivable E. coli cells in the immunosensor entire signal was only about 10%. The signal of non-cultivable E. coli cells (measured by qPCR) formed 30% of the immunosensor signal and the majority of the measured signal, 60%, was most likely generated by different forms of coliform bacteria and E. coli cell fragments. Using renewable, single-use E. coli immunosensor is an excellent alternative to time-consuming microbiological and molecular methods for analyzing complex natural samples. These immunosensors can significantly shorten the time required to determine and quantify E. coli. It could be used for automated analyses, as quick identification of E. coli allows to take timely measures to minimize potential health risks.https://www.ester.ee/record=b550784

The hepatoprotective capacity of selected natural products from South Africa

Drug-induced liver injury (DILI) is recognized as a significant clinical problem, which may account for up to 50% of all cases of acute liver failure. DILI is initiated by the bioactivation of parent drug molecules to produce chemically reactive metabolites. These reactive intermediates induce mitochondrial dysfunction and oxidative stress leading to glutathione (GSH) depletion and damage to cellular proteins, lipids and nucleic acids, which eventually culminates in necrotic cell death. The principal objective of this study is to establish an in vitro screening platform to identify potential hepatoprotective natural products (plants and mushrooms) from South Africa (SA). Aqueous plant extracts (Cyclopia intermedia, Opuntia ficus indica and Kigelia africana), and aqueous and ethanolic macrofungal extracts (Ganoderma lucidum, Russula capensis, Pleurotus ostreatus and Lenzites elegans) were prepared and screened against HepG2 and VERO cells to assess their safety using Hoechst 33342-PI dual labelling. A drug-induced hepatotoxic model was established, using the dietary supplement menadione (vitamin K3). Hoechst 33342- PI, -CellROX® Orange and -TMRE dual labelling was used for necrosis, oxidative stress and mitochondrial membrane potential depolarization (ΔΨm) detection, respectively. The accuracy of the hepatoprotection model was confirmed through HepG2 cellbased assays (Hoechst 33342- PI, -CellROX® Orange and -TMRE dual labelling) that measured the protective effects of natural products against the menadione-induced toxicity, anti-oxidant assays (DPPH, NO, ORAC, CAPe and FRAP) that measured their anti-oxidant potential and enzyme assays (βglucuronidase, carboxylesterase and CYP450 isoform 3A4) that measured their effects on drug metabolism. Silymarin was used as a positive control for each assay. Menadione displayed significant cell death, increased oxidative stress and decreased ΔΨm at an elevated concentration of 100 μM; confirming the hepatotoxicity model, where necroptosis was suspected to be menadione’s cell death mode. Only ethanolic G. lucidum was cytotoxic. All three aqueous plant extracts demonstrated strong anti-oxidant capacities out of all the tested extracts; where C. intermedia displayed the most promising DPPH, NO, ORAC, CAPe and FRAP activity, followed by aqueous G. lucidum. Aqueous plant and ethanolic macrofungal extracts (C. intermedia, O. ficus indica, K. africana, and ethanolic P. ostreatus, R. capensis) displayed decreased menadione-induced ROS production and protected against menadione-induced ΔΨm depolarization, posing them and aqueous G. lucidum potential therapeutic interventions for DILI. Ethanolic L. elegans demonstrated the highest enzyme inhibition for each assay and presented genotoxicity, ruling it out as a therapeutic strategy against DILI. Together these assays addressed several aspects relating to DILI and hepatoprotection, and served as a good starting point in evaluating the therapeutic value of natural products from South Africa

Quinoline Heterocycles: Synthesis and Bioactivity

Among heterocyclic compounds, quinoline is a privileged scaffold that appears as an important construction motif for the development of new drugs. Quinoline nucleus is endowed with a variety of therapeutic activities, and new quinolone derivatives are known to be biologically active compounds possessing several pharmacological activities. Many new therapeutic agents have been developed by using quinoline nucleus. Hence, quinoline and its derivatives form an important class of heterocyclic compounds for the new drug development. Numerous synthetic routes have been developed for the synthesis of quinoline and its derivatives due to its wide range of biological and pharmacological activities. The article covers the synthesis as well as biological activities of quinoline derivatives such as antimalarial, anticancer, antibacterial, anthelmintic, antiviral, antifungal, anti-inflammatory, analgesic, cardiovascular, central nervous system, hypoglycemic, and miscellaneous activities

Anticancer prodrugs for targeted therapy

Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2019Nos tempos que correm, o cancro é a segunda maior causa de morte globalmente, sendo uma doença com uma grande expressão e fisiopatologia complexa. Existem diversos tipos de tratamentos anti cancro como, por exemplo, cirurgia e radioterapia porém, quando o tumor se encontra distribuído e com desenvolvimento de metástases, surge a quimioterapia. Apesar da sua ação ser focada no decréscimo da proliferação de células cancerígenas, a maioria dos fármacos citotóxicos não está apta a localizar, seletivamente, o local do tumor, o que leva a variados efeitos adversos indesejados. Por este motivo, tornou-se urgente a procura de novas soluções que possam otimizar o tratamento anti cancro e a terapia localizada, com a utilização de pró fármacos, é uma das potenciais estratégias. Em comparação com os tecidos ditos normais, as células cancerígenas são caracterizadas por únicos e anormais marcadores e, por isso, a estratégia baseada no uso de pró fármacos irá explorar essas diferenças, de modo a afetar somente o tumor, sem causar dano aos tecidos saudáveis. As células cancerígenas são, então, caracterizadas pelo seu microambiente específico com baixos valores de pH, elevada concentração de espécies reativas de oxigénio e glutationa e, ainda, por uma elevada expressão de certas enzimas e antigénios específicos. Esta última característica está relacionada com abordagens mais experimentais focando-se em anticorpos monoclonais ou terapia genómica. Deste modo, estão a ser desenvolvidas estratégias centradas nos mecanismos e singularidades do cancro e alguns exemplos já se encontram disponíveis, incluindo não só pró fármacos que já se encontram no mercado, mas também aqueles que ainda se encontram em estados mais primordiais do seu desenvolvimento. Consequentemente, esta monografia irá focar-se não só no design de pro fármacos mas na tentativa de ter uma maior perceção de todos estes métodos através de vários exemplos detalhados de alguns dos pro fármacos já comercializados ou ainda em desenvolvimento.In the current times, cancer is the second leading cause of death globally, being a wide spread disease with a complex physiopathology. There are various types of cancer treatment, such as surgery and radiotherapy but, when the tumor is well spread with the development of metastases, chemotherapy comes to picture. Although its action is focused on decreasing the proliferation of cancer cells, the majority of antitumor drugs cannot selectively localize the cancer site, leading to several undesired side effects. So, it has become urgent to find new solutions that can optimize the anticancer treatment and targeted therapy, using prodrugs, is one potential strategy. In comparison with normal tissues, cancer cells are characterized by unique abnormal markers, thus the prodrug strategy will exploit these differences, in order to kill solely the cancer tissues without damaging the healthy ones. Cancer cells are, then, characterized of its specific microenvironment with low pH levels, elevated ROS or high levels of GSH, unique overexpressed enzymes and also specific antigens. This last characteristic is related to more experimental approaches focusing on mAb or gene therapy. Therefore, strategies are being developed focusing on the cancer mechanisms and singularities and some proven examples are already coming to light, regarding non only prodrugs that are already in the market, but also the ones that are still in earlier stages of development. Hence, this review will be focused not only on the prodrug design but also in trying to have a better understanding of all these methods with given detailed examples of some prodrugs already on the market or still in development.Hospital Curry Cabral e Farmácia Lusitan