Modification Of Chemical Structure Research Articles

Chitosan and Its Structural Modifications for siRNA Delivery.

The use of RNA interference mechanism and small interfering RNA (siRNA) in cancer gene therapy is a very promising approach. However, the success of gene silencing is underpinned by the efficient delivery of intact siRNA into the targeted cell. Nowadays, chitosan is one of the most widely studied non-viral vectors for siRNA delivery, since it is a biodegradable, biocompatible and positively charged polymer able to bind to the negatively charged siRNA forming nanoparticles (NPs) that will act as siRNA delivery system. However, chitosan shows several limitations such as low transfection efficiency and low solubility at physiological pH. Therefore, a variety of chemical and non-chemical structural modifications of chitosan were investigated in the attempt to develop a chitosan derivative showing the features of an ideal siRNA carrier. In this review, the most recently proposed chemical modifications of chitosan are outlined. The type of modification, chemical structure, physicochemical properties, siRNA binding affinity and complexation efficiency of the modified chitosan are discussed. Moreover, the resulting NPs characteristics, cellular uptake, serum stability, cytotoxicity and gene transfection efficiency in vitro and/or in vivo are described and compared to the unmodified chitosan. Finally, a critical analysis of a selection of modifications is included, highlighting the most promising ones for this purpose in the future.

Isolation of Bioactive Compounds from Fruit Body of Lentinula edodes (Berk.) Pegler and In Silico Approach using Tyrosinase Target Protein Involved in Melanin Production

Traditionally, Lentinula edodes are used in many Asian countries for the treatment of various chronic diseases. In the current study, ethyl acetate fraction of fruit body of Lentinula edodes was obtained by standard bioassay-guided fractionation procedure. This fractionation resulted in the isolation of three bioactive compounds (compound 1 already reported, compound 2 and 3 first time reported from this mushroom) and their structures were characterized using various spectroscopic techniques. Further, all the compounds were studied using molecular docking analysis. Compounds 1, 2, 3 and standard active ingredient used for the treatment of hyperpigmentation i.e. arbutin was prepared as program database files, was docked with the target receptor (tyrosinase, program database ID: 5M8L) which plays a vital role in melanogenesis pathway. The study mainly focuses on better results of compounds as potent tyrosinase inhibitors to down-regulate the melanogenesis pathway. The present study revealed that due to the presence of compound 1 and 3 in the fruit body of Lentinula edodes, it may be preferred as a cosmetic product in extract form to obtain effective skin lightening properties or treatment of melisma. Compounds 2 and 3 was first isolated from Lentinula edodes. The study further concludes that compound 3 could act as a potential lead molecule for the target gene tyrosinase with slight modification or optimization of chemical structure to obtain more effective, less toxic lead molecule and further exhibits remarkable skin lightening properties via inhibiting melanin production.

Effect of gamma irradiation, annealing on spectroscopic and thermal properties of some biopolymers – Gelatin

Modification of chemical structure of gelatin is an important point of research due to its extensive applications in food and package industry. Various methods are prescribed in literature for this purpose. Among them the radiation method is very important due to its easiness and economy. The authors have used gamma irradiation for this purpose and studied the effect of gamma irradiation and annealing on spectroscopic and thermal properties of gelatins. For this purpose spectroscopic (Electron spin resonance (ESR) and Fourier transform infrared (FTIR)), thermal (differential scanning calorimetry) and scanning electron microscope are used. ESR spectra of irradiated gelatin have shown quartet structure at room temperature and the signal is annealed by heating the irradiated gelatin. FTIR spectra of gelatin are recorded under different conditions. After irradiation, change in intensity and shift in band position is observed, which are associated with the chemical changes brought out by radiation. Gamma irradiation brings changes in thermal and surface morphology of gelatin.

Protac: redirigiendo los sistemas de degradación de proteínas a nuevos sustratos

The small molecules development has dominated the design of new drugs until the rise of nucleic acid-based therapies, either by modifying a gene or by preventing it from being effectively transcribed. Taking advantage of this new approaches, the pharmacological intervention in therapeutic targets that are considered unmodifiable up to now with small molecules were allowed. However, these new approaches are not devoid of defects such as low bioavailability due to their stability and pharmacokinetic problems, in addition to being irreversible DNA modifications in many cases, with the subsequent risk of suffering chronic adverse effects. Alternatively, a series of chimeric heterobifunctional compounds, called PROTACs (Protein Targeting Chimeras), have emerged with force in recent years. These PROTACs are able to bring E3 ligases closer with proteins of interest in space to label them with ubiquitin. Finally, it was degraded by the proteasome. This approach enables the generation of different PROTACs structures by rational design and, also, allows the chemical structure modification to improve their stability and pharmacokinetic profile keeping their activity. This review aims to give a comprehensive approach of what PROTACs are, what E3 ligases recruit, relevant factors in PROTAC development, and other approaches similar to this but that use non-proteasomal degradation pathways.

Surface Physicochemistry Modification and Structural Nanoarchitectures of g‐C3N4 for Wastewater Remediation and Solar Fuel Generation

AbstractThe use of graphitic carbon nitride (g‐C3N4) has been widely explored in multiple photocatalytic applications. The design and fabrication of g‐C3N4 are heavily influenced by its overall activity, whereby optical and electronic properties dictate the performance of g‐C3N4. Surface and chemical structural modifications are discussed in length to enhance photocatalytic g‐C3N4. Facile preparation of g‐C3N4 eases structural engineering at a molecular level. This review highlights and recapitulates recent progress on the strategies to enhance both structural and chemical properties of the g‐C3N4 structure via surface functionalization and grafting, defect creation, elemental doping, covalent bonding with nonmetal and heterojunction interfacial formation. The emerging applications of g‐C3N4 in numerous photocatalytic reactions are discussed. The significance of g‐C3N4‐based photocatalyst in various photocatalytic reactions signifies the imminent progress of frontier technologies. Thus, it is integral to overcome lurking challenges and devise superactive photocatalytic activity at a molecular level for sustainable environmental and energy‐related applications.

Effect of the Segmental Structure of Thermoplastic Polyurethane (Hardness) on the Interfacial Adhesion of Textile-Grade Carbon Fiber Composites

In polymer composites, the fiber–matrix interface is primarily influenced by the surface treatment of the fibers and polymer morphology. Previous studies have investigated the effect of surface treatment of carbon fiber on the mechanical properties of the resulting composites. However, very few studies have explored the chemical structural modification of polymer effect on the fiber–matrix adhesion. In this work, the interfaces of soft thermoplastic polyurethane (S-TPU) and hard-segmented TPU (H-TPU) were investigated through surface, thermal, and mechanical characterization. A textile-grade carbon fiber (TCF) with 1% concentration of epoxy sizing (an emerging material for nonaerospace applications with 450 K filament tows) was used as a reinforcement to investigate the structure–property relationship at the interface. Atomic force microscopy results showed 39% higher surface roughness for S-TPU than for H-TPU. X-ray photoelectron spectroscopy results revealed a 550% increase in C═O content, which can provide multiple hydrogen bonding networks in H-TPU, and these C═O bonds can produce a strong chemical bond at the fiber–matrix interface. Dynamic mechanical analysis and differential scanning calorimetry results confirmed the presence of hydrogen bonding that enhances the cross-linked density by 232% in H-TPU compared to S-TPU. The improved mechanical properties of H-TPU composites, such as flexural, impact and tensile by 30, 50, and 130% compared to S-TPU composites, prove that the crystallinity and hydrogen bonding significantly increase the load bearing capacity due to the strong interface. The mechanical properties of TCF–TPU composites validate the formation of chemical bonds through a nucleophilic addition reaction at the interface and improve the bond strength of the composites. Thus, tailoring the polyurethane structure broadens the performance of segmented TPU in conjunction with TCF reinforcement, which has implications for cost-effective, high-strength composites.

Andrographolide and its derivatives: Current achievements and future perspectives.

Natural product andrographolide isolated from the plant Andrographis paniculata shows a plethora of biological activities, including anti-tumor, anti-bacterial, anti-inflammation, anti-virus, anti-fibrosis, anti-obesity, immunomodulatory and hypoglycemic activities. Based on extensive chemical structural modifications, a series of andrographolide derivatives with improved bioavailability and druggability has been developed. Moreover, greater understanding of their mechanisms of action at the molecular and cellular level has been thoroughly investigated. In this review, we give an outlook for the therapeutical potential of andrographolide and its derivatives in diverse diseases and highlighted the drug design, pharmacokinetic and mechanistic studies for the past ten years, together with a brief overview of the pharmacological effects. Notably, we focused to provide a critical enlightenment of the area of andrographolide and its derivatives with the intent of indicating the future perspectives, challenges and limitations. We believe that this review paper will benefit drug discovery where andrographolide was used as a template, shed light on the identification of drug targets for andrographolide and its analogs, as well as increase our knowledge for using them for therapeutic application, including the treatment for various forms of cancers.

A concise review on design and control of structured natural rubber latex particles as engineering nanocomposites

In this article, we review the modification of natural rubber (NR) latex into the engineered particles for make use of them in functional nanocomposites. The review focuses on tuning nano-/microstructure and/or composition of NR latex particles by means of surface chemical functionalization, structural modification and incorporation of inorganic nanoparticles (NPs). Due to their polydispersity in size and non-spherical shape with complicated indigenous stabilizers, i.e., proteins and lipids, we first describe the fundamental and common methods for the modification of synthetic polymer latex which become a practical guideline for engineering of NR particles to a variety of designs. Subsequently, the examples of successfully modified NR latex and the involved parameters in the preparation are discussed. The different nature and properties of the modified NR latex compared to the synthetic latex are then depicted. Finally, specific examples of these systems used in a range of applications including nanofillers, controlled releasing materials, textiles, electronics and coatings are demonstrated. The research on modification of NR latex particles would be beneficial to the field of materials science and engineering for the valorization of naturally abundant colloidal polymer to the advanced functional materials in the broader utilization/commercialization in the future.

Enhancement of O-GlcNAcylation on Mitochondrial Proteins with 2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-d-pyranoside, Contributes to the Mitochondrial Network, Cellular Bioenergetics and Stress Response in Neuronal Cells under Ischemic-like Conditions.

O-GlcNAcylation is a nutrient-driven post-translational modification known as a metabolic sensor that links metabolism to cellular function. Recent evidences indicate that the activation of O-GlcNAc pathway is a potential pro-survival pathway and that acute enhancement of this response is conducive to the survival of cells and tissues. 2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-d-pyranoside (SalA-4g), is a salidroside analogue synthesized in our laboratory by chemical structure-modification, with a phenyl ring containing a para-methoxy group and a sugar ring consisting of N-acetylglucosamine. We have previously shown that SalA-4g elevates levels of protein O-GlcNAc and improves neuronal tolerance to ischemia. However, the specific target of SalA-4g regulating O-GlcNAcylation remains unknown. To address these questions, in this study, we have focused on mitochondrial network homeostasis mediated by O-GlcNAcylation in SalA-4g’s neuroprotection in primary cortical neurons under ischemic-like conditions. O-GlcNAc-modified mitochondria induced by SalA-4g demonstrated stronger neuroprotection under oxygen glucose deprivation and reoxygenation stress, including the improvement of mitochondrial homeostasis and bioenergy, and inhibition of mitochondrial apoptosis pathway. Blocking mitochondrial protein O-GlcNAcylation with OSMI-1 disrupted mitochondrial network homeostasis and antagonized the protective effects of SalA-4g. Collectively, these data demonstrate that mitochondrial homeostasis mediated by mitochondrial protein O-GlcNAcylation is critically involved in SalA-4g neuroprotection.

Chiral Triarylborane-Based Small Organic Molecules for Circularly Polarized Luminescence.

Circularly polarized luminescence (CPL) has shown promising application potentials in 3D display, optical data storage, smart sensors/probers, CPL lasers, and light source for asymmetric photosynthesis. In the last decade, the CPL-active small organic molecules (CPL-SOMs) have attracted rapidly increasing research interest owing to the great advantages of SOMs, such as high luminescence efficiency, facile modification of chemical structure, fine emission wavelength tuning, precise relationships between structure and properties, and as well as easy fabrication. Promoted by the unique effects of boryl group, such as strong electron-accepting ability, great steric effect, and Lewis acidity to bind with Lewis bases, we herein summarized our recent research results about the creation of CPL-SOMs by modification of chiral scaffolds, such as [2.2]paracyclophane, [5]/[7]helicene, and binaphthyl, with boryl group. The preliminary results have well demonstrated that the chiral triarylborane-based SOMs exhibit promising CPL properties, such as intense CPL in combination of high luminescence dissymmetry factor (|glum |) with high fluorescence efficiency, solvent-induced sign inversion, facile emission wavelength tuning, high fluorescence efficiency in the solid, and substituent-induced sign inversion.

Vibronic effect explains ECD spectral shape and tunability of CPL wavelength of two triarylborane-based [5]helicenes derivatives

Substituents and solvent could affect the chiroptical properties of electronic circular dichroism (ECD) and circularly polarized luminescence (CPL) of helicenes. To analyze those effects and unveil all the information carried by the experimental spectra, herein, we report a computational study on optical properties of two optically CPL-active triarylborane-based [5]helicenes derivatives. The pure electronic calculations suggest that the emission wavelength can be tuned by the modification of chemical structure via adjusting the key Molecular Orbital (MO) gaps. However, they alone show expected limitation in reproducing the experimental spectral shape and capturing the fine structures. Thus, more attention is payed on the vibronic effects. To compute vibrationally resolved spectra, the popular, accurate and quite efficient models of Adiabatic Hessian (AH) and Vertical Hessian (VH) are used to build the potential energy surfaces (PESs) in harmonic approximation. Duschinsky mixing, Herzberg-Teller (HT) contribution and temperature effect are considered comprehensively. Cartesian and internal coordinates are compared to express the normal modes since the adopted coordinate can affect the accuracy of the harmonic approximation. Our results show that VH (internal) gives more reliable simulation, predicting with correct sign, reasonable spectral shape, and acceptable spectral width, in very nice agreement with the experiment. We show that HT effect is rather important in capturing the experimental fine structures. What is more, vibronic effect plays a crucial role in revealing the substituent effect on chiroptical properties and solvent effect on CPL maximum frequency.

The dielectric response of phenothiazine-based glass-formers with different molecular complexity

We examined a series of structurally related glass-forming liquids in which a phenothiazine-based tricyclic core (PTZ) was modified by attaching n-alkyl chains of different lengths (n = 4, 8, 10). We systematically disentangled the impact of chemical structure modification on the intermolecular organization and molecular dynamics probed by broadband dielectric spectroscopy (BDS). X-ray diffraction (XRD) patterns evidenced that all PTZ-derivatives are not ‘ordinary’ liquids and form nanoscale clusters. The chain length has a decisive impact on properties, exerting a plasticizing effect on the dynamics. Its elongation decreases glass transition temperature with slight impact on fragility. The increase in the medium-range order was manifested as a broadening of the dielectric loss peak reflected in the lower value of stretching parameter βKWW. A disagreement with the behavior observed for non-associating liquids was found as a deviation from the anti-correlation between the value of βKWW and the relaxation strength of the α-process. Besides, to explain the broadening of loss peak in PTZ with the longest (decyl) chain a slow Debye process was postulated. In contrast, the sample with the shortest alkyl chain and a less complex structure with predominant supramolecular assembly through π–π stacking exhibits no clear Debye-mode fingerprints. The possible reasons are also discussed.

Rapid dynamic quantification of sulfide generation flux in spatially heterogeneous sediments of gravity sewers

Compared with anaerobic pressure sewers, gravity sewers have much more complex operational conditions, such as anaerobic/aerobic spatial variations along variable structures of the pipe network. This greatly complicates the prediction of sulfide generation from spatially heterogeneous sewer sediments. This study proposes a novel quantitative approach for rapidly estimating the sulfide generation flux by understanding the sulfidogenic conversion under complex sewer conditions. Significant anaerobic/aerobic spatial variations were the most critical factor affecting the sulfide production in residential gravity sewers. The dynamic aeration-related process stimulated the growth of sulfide-oxidizing bacteria (SOB) in the surface zone, while the sulfidogenic and methanogenic zone moved into deeper layers. A detailed mechanism model incorporating dynamic alternative anaerobic/aerobic transformation was developed to predict apparent sulfide production, as well as the microscale spatial profiles of chemicals and microbial communities in sediments. The model was evaluated to establish a rapid quantitative approach that only depended on a few key parameters (e.g., flow velocity, pipe diameter, slope, mean hydraulic depth and sulfate concentration), which can provide an important basis for estimating different sulfide generation fluxes under various sewer factors. The identification of sulfide generation hotspots will greatly help determine how to economically control sulfide generation by chemical dosing or pipe structural modification.

An Overview of Methods and Tools for Transfection of Eukaryotic Cells in vitro.

Transfection is a powerful analytical tool enabling studies of gene products and functions in eukaryotic cells. Successful delivery of genetic material into cells depends on DNA quantity and quality, incubation time and ratio of transfection reagent to DNA, the origin, type and the passage of transfected cells, and the presence or absence of serum in the cell culture. So far a number of transfection methods that use viruses, non-viral particles or physical factors as the nucleic acids carriers have been developed. Among non-viral carriers, the cationic polymers are proposed as the most attractive ones due to the possibility of their chemical structure modification, low toxicity and immunogenicity. In this review the delivery systems as well as physical, biological and chemical methods used for eukaryotic cells transfection are described and discussed.

Microbial Degradation of Rubber: Actinobacteria.

Rubber is an essential part of our daily lives with thousands of rubber-based products being made and used. Natural rubber undergoes chemical processes and structural modifications, while synthetic rubber, mainly synthetized from petroleum by-products are difficult to degrade safely and sustainably. The most prominent group of biological rubber degraders are Actinobacteria. Rubber degrading Actinobacteria contain rubber degrading genes or rubber oxygenase known as latex clearing protein (lcp). Rubber is a polymer consisting of isoprene, each containing one double bond. The degradation of rubber first takes place when lcp enzyme cleaves the isoprene double bond, breaking them down into the sole carbon and energy source to be utilized by the bacteria. Actinobacteria grow in diverse environments, and lcp gene containing strains have been detected from various sources including soil, water, human, animal, and plant samples. This review entails the occurrence, physiology, biochemistry, and molecular characteristics of Actinobacteria with respect to its rubber degrading ability, and discusses possible technological applications based on the activity of Actinobacteria for treating rubber waste in a more environmentally responsible manner.

Induction of Divergent Cell Death Pathways by Urea and Carbohydrazide Derivatives.

The complexity of cancer biology and the development of chemotherapy resistance are two main obstacles to cancer treatment and necessitate novel anticancer molecules that target different cell death pathways. Modulation of Endoplasmic Reticulum (ER) stress and subsequent activation of the Unfolded Protein Response (UPR) has been proposed as a potential chemotherapeutic target, as prolonged ER stress can lead to cell death via apoptosis or necrosis. The present study aims to evaluate the molecular mechanism underlying the cytotoxic activity of selected urea and carbohydrazide derivatives. Cell proliferation assays were performed on HeLa, Capan-1, MCF-7, HCC-1937, and MRC-5 cell lines by WST-1 assay. The expression levels of selected ER stress, autophagy, and apoptosis marker proteins were compared by immunoblotting to characterize the underlying mechanism of cytotoxicity. Flow cytometry was used to detect apoptosis. Of the tested cytotoxic compounds, 3a, 4a, 5a, 6a, and 1b dramatically and 5b moderately increased ER stress-related CHOP protein levels. Interestingly, 5b but not 3a, 4a, 5a, 6a, or 1b increased the expression of proapoptotic proteins such as cleaved PARP-1 and cleaved caspase-3 and -7. The flow-cytometry analysis further confirmed that the cytotoxic activity of 5b but not the other compounds is mediated by apoptosis, demonstrated by a significant increase in the percentage of late apoptotic cells (7-AAD/annexin V double-positive cells). Our results suggest that changing a substituent from trifluoromethyl to nitro in urea and carbohydrazide core structure alters the cell death mechanism from apoptosis to an apoptosis-independent cell death pathway. This study shows an example of how such simple modifications of a core chemical structure could cause the induction of divergent cell death pathways.

Graft copolymerization of MA/(TFEA or TFPM) onto cellulosic fibers for surface hydrophobicity

Highly hydrophobicity was imparted to cellulose paper substrate by grafting trifluoroethyl acrylate/methyl acrylate (TFEA/MA) and tetrafluoropropyl methacrylate/methyl acrylate (TFPM/MA) with Fenton reagent initiator (Fe2+–H2O2). The influences of modifications in chemical structure and hydrophobicity were examined. The chemical structure and surface morphology of the modified filter paper was characterized by FT-IR, XPS, solid-state 13C NMR, and SEM. The results from 13C NMR spectroscopy revealed that MA was mainly grafted onto cellulose C6-OH by selecting cellobiose as the model compound of cellulose. The water contact angle of the treated filter paper reached 139° and 145° with MA/TFPM grafting at MA:TFPM = 3:1 ratio and with MA/TFEA grafting at MA:TFEA = 3:1 ratio, respectively. The resulting highly hydrophobic paper was used to separate water from oil/water mixtures. The efficiency of separating water from their mixture with n-hexane, cyclohexane, ethyl acetate, and 1, 2-dichloroethane exceeded 90%.

Biopolymeric Materials Used as Nonviral Vectors: A Review

Bacterial transformation and gene transfection can be understood as being the results of introducing specific genetic material into cells, resulting in gene expression, and adding a new genetic trait to the host cell. Many studies have been carried out to investigate different types of lipids and cationic polymers as promising nonviral vectors for DNA transfer. The present study aimed to carry out a systematic review on the use of biopolymeric materials as nonviral vectors. The methodology was carried out based on searches of scientific articles and applications for patents published or deposited from 2006 to 2020 in different databases for patents (EPO, USPTO, and INPI) and articles (Scopus, Web of Science, and Scielo). The results showed that there are some deposits of patents regarding the use of chitosan as a gene carrier. The 16 analyzed articles allowed us to infer that the use of biopolymers as nonviral vectors is limited due to the low diversity of biopolymers used for these purposes. It was also observed that the use of different materials as nonviral vectors is based on chemical structure modifications of the material, mainly by the addition of cationic groups. Thus, the use of biopolymers as nonviral vectors is still limited to only a few polysaccharide types, emphasizing the need for further studies involving the use of different biopolymers in processes of gene transfer.

Highly selective and antifouling reverse osmosis membrane by crosslinkers induced surface modification

ABSTRACT Post treatment is a very competent and scalable approach to develop the higher water-flux and salt-rejection membrane since it does not require any change in existing manufacturing process. The virgin Thin Film Composite Reverse Osmosis (TFC-RO) membrane was exposed to various concentrations of Poly (ethylene Glycol) diacrylate (PEGDA) and Ethylene glycol dimethacrylate (EGDMA) after activation with sodium hypochlorite for 1 h. Crosslinkers modified membranes were characterized for degree of wettability by contact angle analyses, surface morphology and surface roughness study by Scanning electron micrographs and Atomic force micrographs, chemical structural modifications by Attenuated total reflectance Fourier transform Infrared spectroscopy. These treatments resulted in improved membrane performance. 3500 mg/l PEGDA-treated membrane permeate flux increased by 48.7% and salt-rejection by 3.43%. 2000 mg/l EGDMA treated membrane demonstrated 46.13% increase in water-flux and 3.08% increase in salt-rejection as compared with virgin membrane. Organic fouling study indicated that fouling in PEGDA-treated membrane was significantly lower than virgin membrane. Heavy metal ion removal performances for Zinc and Chromium were also higher for modified membranes. Thus, the surface modification by crosslinkers led to increase in selectivity for certain metal ions and better antifouling performance as compared to virgin membrane.

1,2,4]triazyny – potencjalne leki w chemioterapii nowotworów

Streszczenie Choroby nowotworowe stanowią duże zagrożenie społeczne; w 2018 roku zdiagnozowano prawie 18 milionów nowych przypadków zachorowań na nowotwory. Wybór metody leczenia uzależniony jest od typu nowotworu, a także stopnia zaawansowania choroby w chwili diagnozy. W leczeniu wykorzystuje się przede wszystkim: metody chirurgiczne, radioterapię, immunoterapię, hormonoterapię i chemioterapię. Leki cytostatyczne mogą być stosowane zarówno w monoterapii, jak i w terapii skojarzonej. W latach 2009–2018 Amerykańska Agencja ds. Żywności i Leków (FDA) dopuściła prawie 356 nowych leków w terapii przeciwnowotworowej. Należy jednak zwrócić uwagę, że mimo coraz większej dostępności nowoczesnych leków, choroba ta jest drugą główną przyczyną zgonów na świecie. Badania nad opracowaniem preparatów cytotoksycznych mają na celu zaprojektowanie struktury związku, którego działanie ukierunkowane będzie na komórki nowotworowe przy jednoczesnym braku wpływu na komórki prawidłowe. Strukturę chemiczną o potencjalnym działaniu przeciwnowotworowym mogą tworzyć pochodne triazyny, które są stosowane w terapii onkologicznej już od 1965 roku. W zależności od umiejscowienia atomów azotu w pierścieniu wyróżnia się trzy izomery: [1,2,3]triazyny, [1,2,4]triazyny, [1,3,5]triazyny. Odpowiednia modyfikacja struktury [1,2,4]triazyny ma na celu zapewnienie znacznie silniejszych właściwości cytotoksycznych i ograniczenie działań niepożądanych w porównaniu do obecnie stosowanych leków. Projektowanie nowych preparatów ma także poprawić komfort życia pacjenta. W artykule pokrótce przedstawiono w jaki sposób modyfikacja struktury chemicznej pochodnych [1,2,4]triazyny wpływa na wzrost ich aktywności cytotoksycznej i dlaczego te związki mogą być lepiej tolerowane niż obecnie stosowana terapia.