Synthesis of New Chiral ß-Carbonyl Selenides with Antioxidant and Anticancer Activity Evaluation-Part I.

A series of unsymmetrical phenyl ß-carbonyl selenides with o-amido function substituted on the nitrogen atom with chiral alkyl groups was obtained. The compounds form a series of enantiomeric and diastereomeric pairs and present the first examples of this type of chiral Se derivatives. All obtained selenides were further evaluated as antioxidants and anticancer agents to define the influence of the particular stereochemistry of the attached functional groups on the bioactivity of the molecules. The highest H2O2 reduction potential was observed for N-(cis-2-hydroxy-1-indanyl)-2-((2-oxopropyl)selanyl)benzamide, and the best radical scavenging properties for N-(-1-hydroxy-2-butanyl)-2-((2-oxopropyl)selanyl)benzamide. Also, both enantiomers of the N-(1-hydroxy-2-butanyl) selenide expressed the highest cytotoxic potential towards human promyelocytic leukemia HL-60 cell line with similar IC50 values 14.4 ± 0.5 and 16.2 ± 1.1 µM, respectively. On the other hand, breast cancer cell line MCF-7 was most sensitive to N-((R)-(-)-1-hydroxy-2-butanyl)- 2-((2-oxopropyl)selanyl)benzamide (IC50 of 35.7 ± 0.6 µM). The structure-activity dependence of the obtained Se derivatives was discussed, and the most potent compounds were selected.

Evaluation of Antimicrobial Activities against Various E. coli Strains of a Novel Hybrid Peptide-LENART01.

Finding the ideal antimicrobial drug with improved efficacy and a safety profile that eliminates antibiotic resistance caused by pathogens remains a difficult task. Indeed, there is an urgent need for innovation in the design and development of a microbial inhibitor. Given that many promising antimicrobial peptides with excellent broad-spectrum antibacterial properties are secreted by some frog species (e.g., bombesins, opioids, temporins, etc.), our goal was to identify the antimicrobial properties of amphibian-derived dermorphin and ranatensin peptides, which were combined to produce a hybrid compound. This new chimera (named LENART01) was tested for its antimicrobial activity against E. coli strains K12 and R1-R4, which are characterized by differences in lipopolysaccharide (LPS) core oligosaccharide structure. The results showed that LENART01 had superior activity against the R2 and R4 strains compared with the effects of the clinically available antibiotics ciprofloxacin or bleomycin (MIC values). Importantly, the inhibitory effect was not concentration dependent; however, LENART01 showed a time- and dose-dependent hemolytic effect in hemolytic assays.

Facile synthesis of chiral phenylselenides as novel antioxidants and cytotoxic agents.

Organoselenium compounds are well-known for their unique biological properties, including antioxidant, anticancer and anti-inflammatory. They result from the presence of a particular Se-moiety enclosed in a structure that provides physicochemical features necessary for effective drug-target interactions. Looking for a proper drug design that considers the influence of each structural element has to be conducted. In this paper, we have synthesized a series of chiral phenylselenides, possessing an additional N-substituted amide moiety, and evaluated their antioxidant and anticancer potential. The presented derivatives, as a group of enantiomeric and diastereomeric pairs, enabled a thorough investigation of the 3D structure-activity dependence in correlation with the presence of the phenylselanyl group as the potential pharmacophore. The N-indanyl derivatives possessing a cis- and trans-2-hydroxy group were selected as the most promising antioxidants and anticancer agents.

Poly(amidoamine) Dendrimer/Camptothecin Complex: From Synthesis to In Vitro Cancer Cell Line Studies.

Camptothecin (CPT), an alkaloid with potent anticancer activity, is still not used in clinical practice due to its high hydrophobicity, toxicity, and poor active-form stability. To address these shortcomings, our research focuses on the encapsulation of this drug in the poly(amidoamine) (PAMAM) dendrimer macromolecule. The PAMAM dendrimer/CPT complex was synthesized and thoroughly characterized. The in vitro drug release study revealed that the drug was released in a slow and controlled manner in acidic and physiological conditions and that more than 80% of the drug was released after 168 h of incubation. Furthermore, it was demonstrated that CPT was released with first-order kinetics and non-Fickian transport. The studies on the hemolytic activity of the synthesized complex indicated that it is hemocompatible for potential intravenous administration at a concentration ≤ 5 µg/mL. Additionally, the developed product was shown to reduce the viability of non-small-cell lung cancer cells (A549) in a concentration- and time-dependent manner, and cancer cells were more susceptible to the complex than normal fibroblasts. Lastly, molecular modeling studies revealed that the lactone or carboxylic forms of CPT had a significant impact on the shape and stability of the complex and that its formation with the lactone form of CPT was more energetically favorable for each subsequent molecule than the carboxylic form. The report represents a systematic and structured approach to develop a PAMAM dendrimer/CPT complex that can be used as an effective drug delivery system (DDS) for the potential treatment of non-small-cell lung cancer.

The Role of a Natural Amphibian Skin-Based Peptide, Ranatensin, in Pancreatic Cancers Expressing Dopamine D2 Receptors.

Despite the progress in early diagnostic and available treatments, pancreatic cancer remains one of the deadliest cancers. Therefore, there is an urgent need for novel anticancer agents with a good safety profile, particularly in terms of possible side-effects. Recently dopaminergic receptors have been widely studied as they were proven to play an important role in cancer progression. Although various synthetic compounds are known for their interactions with the dopaminergic system, peptides have recently made a great comeback. This is because peptides are relatively safe, easy to correct in terms of the improvement of their physicochemical and biological properties, and easy to predict. This paper aims to evaluate the anticancer activity of a naturally existing peptide-ranatensin, toward three different pancreatic cancer cell lines. Additionally, since there is no sufficient information confirming the exact character of the interaction between ranatensin and dopaminergic receptors, we provide, for the first time, binding properties of the compound to such receptors.

Fruits of Hippophaë rhamnoides in human leukocytes and Caco-2 cell monolayer models-A question about their preventive role in lipopolysaccharide leakage and cytokine secretion in endotoxemia.

Preparations from Hippophaë rhamnoides L. (sea buckthorn) have been traditionally used in the treatment of skin and digestive disorders, such as gastritis, gastric and duodenal ulcers, uterine erosions, as well as oral, rectal, and vaginal mucositis, in particular in the Himalayan and Eurasian regions. An influence of an aqueous extract from the fruits of H. rhamnoides (HR) on leakage of lipopolysaccharide (LPS) from Escherichia coli through gut epithelium developed from the human colorectal adenocarcinoma (Caco-2) monolayer in vitro and glucose transporter 2 (GLUT2) translocation were the principal objectives of the study. Additionally, the effect of HR on the production of pro- and anti-inflammatory cytokines (interleukins: IL-8, IL-1ß, IL-10, IL-6; tumor necrosis factor: TNF-α) by the Caco-2 cell line, human neutrophils (PMN), and peripheral blood mononuclear cells (PBMC) was evaluated. The concentration of LPS on the apical and basolateral sides of the Caco-2 monolayer was evaluated with a Limulus Amebocyte Lysate (LAL) assay. GLUT2 translocation was evaluated using an immunostaining assay, whereas secretion of cytokines by cell cultures was established with an enzyme-linked immunosorbent (ELISA) assay. HR (500 µg/ml) significantly inhibited LPS leakage through epithelial monolayer in vitro in comparison with non-treated control. The treatment of Caco-2 cells with HR (50-100 µg/ml) showed GLUT2 expression similar to the non-treated control. HR decreased the secretion of most pro-inflammatory cytokines in all tested models. HR might prevent low-grade chronic inflammation caused by metabolic endotoxemia through the prevention of the absorption of LPS and decrease of chemotactic factors released by immune and epithelial cells, which support its use in metabolic disorders in traditional medicine.

Anticancer efficacy of endo- and exogenous potent ligands acting at dopaminergic receptor-expressing cancer cells.

Cancer is one of the most common and dreaded diseases affecting the vastness of society. Unfortunately, still some people die especially when cancer is not diagnosed and thus caught early enough. On the other hand, using available chemo- or radiotherapy may result in serious side effects. Therefore, cancer-specific medications seem to be the most desired and safe therapy. Knowing that some cancers are characterized by overexpression of specific receptors on the cell surface, target-mediated drugs could serve as a unique and effective form of therapy. In line with this, recently dopaminergic receptors were presented important in cancer therapy as several dopaminergic ligands revealed their efficacy in tumor growth reduction as well as in apoptosis mediation. Unfortunately, the indication of whether DA receptor agonists or antagonists are the best choices in cancer treatment is quite difficult, since both of them may exert either pro- or anticancer effects. In this review, we analyze the therapeutic efficacy of compounds, both of exogenous and endogenous origin, targeting dopaminergic receptor-expressing cancers.

Attachment of Chiral Functional Groups to Modify the Activity of New GPx Mimetics.

A series of new chiral benzisoselenazol-3(2H)-ones and their corresponding diselenides bearing an o-amido function substituted on the nitrogen atom with various aliphatic and aromatic moieties were synthesized. All derivatives representing pairs of enantiomers or diastereoisomers were obtained to thoroughly evaluate the three-dimensional structure-activity correlation. First, bensisoselenazol-3(2H)-ones were synthesized by reacting 2-(chloroseleno)benzoyl chloride with an appropriate enantiomerically pure amine. Then, the Se-N bond was cleaved by a reduction-oxidation procedure using sodium borohydride and then air oxidation to obtain the corresponding diselenides. All derivatives were tested as antioxidants and anticancer agents. In general, the diselenides were more reactive peroxide scavengers, with the highest activity observed for 2,2'-diselenobis[N-(1S,2S)-(-)-trans-2-hydroksy-1-indanylbezamide]. The most cytotoxic derivative towards human promyelocytic leukemia HL-60 and breast cancer MCF-7 cell lines was N-[(1S,2R)-(-)-cis-2-hydroksy-1-indanyl]-1,2-benzizoselenazol-3(2H)-one. The structure-activity relationship of the obtained organoselenium derivatives was discussed.

Electrophoretic Determination of Trimethylamine (TMA) in Biological Samples as a Novel Potential Biomarker of Cardiovascular Diseases Methodological Approach.

In competitive athletes, the differential diagnosis between nonpathological changes in cardiac morphology associated with training (commonly referred to as "athlete's heart") and certain cardiac diseases with the potential for sudden death is an important and not uncommon clinical problem. The use of noninvasive, fast, and cheap analytical techniques can help in making diagnostic differentiation and planning subsequent clinical strategies. Recent studies have demonstrated the role of gut microbiota and their metabolites in the onset and the development of cardiovascular diseases. Trimethylamine (TMA), a gut bacteria metabolite consisting of carnitine and choline, has recently emerged as a potentially toxic molecule to the circulatory system. The present work aims to develop a simple and cost-effective capillary electrophoresis-based method for the determination of TMA in biological samples. Analytical characteristics of the proposed method were evaluated through the study of its linearity (R2 > 0.9950) and the limit of detection and quantification (LOD = 1.2 µg/mL; LOQ = 3.6 µg/mL). The method shows great potential in high-throughput screening applications for TMA analysis in biological samples as a novel potential biomarker of cardiovascular diseases. The proposed electrophoretic method for the determination of TMA in biological samples from patients with cardiac disease is now in progress.

Keratin Scaffolds Containing Casomorphin Stimulate Macrophage Infiltration and Accelerate Full-Thickness Cutaneous Wound Healing in Diabetic Mice.

Impaired wound healing is a major medical challenge, especially in diabetics. Over the centuries, the main goal of tissue engineering and regenerative medicine has been to invent biomaterials that accelerate the wound healing process. In this context, keratin-derived biomaterial is a promising candidate due to its biocompatibility and biodegradability. In this study, we evaluated an insoluble fraction of keratin containing casomorphin as a wound dressing in a full-thickness surgical skin wound model in mice (n = 20) with iatrogenically induced diabetes. Casomorphin, an opioid peptide with analgesic properties, was incorporated into keratin and shown to be slowly released from the dressing. An in vitro study showed that keratin-casomorphin dressing is biocompatible, non-toxic, and supports cell growth. In vivo experiments demonstrated that keratin-casomorphin dressing significantly (p < 0.05) accelerates the whole process of skin wound healing to the its final stage. Wounds covered with keratin-casomorphin dressing underwent reepithelization faster, ending up with a thicker epidermis than control wounds, as confirmed by histopathological and immunohistochemical examinations. This investigated dressing stimulated macrophages infiltration, which favors tissue remodeling and regeneration, unlike in the control wounds in which neutrophils predominated. Additionally, in dressed wounds, the number of microhemorrhages was significantly decreased (p < 0.05) as compared with control wounds. The dressing was naturally incorporated into regenerating tissue during the wound healing process. Applied keratin dressing favored reconstruction of more regular skin structure and assured better cosmetic outcome in terms of scar formation and appearance. Our results have shown that insoluble keratin wound dressing containing casomorphin supports skin wound healing in diabetic mice.

Seleninic Acid Potassium Salts as Water-Soluble Biocatalysts with Enhanced Bioavailability.

Organoselenium compounds are well-known glutathione peroxidase (GPx) mimetics that possess antioxidants/prooxidant properties and are able to modulate the concentration of reactive oxygen species (ROS), preventing oxidative stress in normal cells or inducing ROS formation in cancer cells leading to apoptosis. The purpose of this study was the synthesis of potent GPx mimics with antioxidant and anticancer activity along with improved bioavailability, as a result of good solubility in protic solvents. As a result of our research, glutathione peroxidase (GPx) mimetics in the form of water-soluble benzeneseleninic acid salts were obtained. The procedure was based on the synthesis of 2-(N-alkylcarboxyamido)benzeneselenenic acids, through the oxidation of benzisoselenazol-3(2H)-ones or analogous arenediselenides with an amido group, which were further converted to corresponding potassium salts by the treatment with potassium tert-butanolate. All derivatives were tested as potential antioxidants and anticancer agents. The areneseleninic acid salts were significantly better peroxide scavengers than analogous acids and the well-known organoselenium antioxidant ebselen. The highest activity was observed for the 2-(N-ethylcarboxyamido)benzeneselenenic acid potassium salt. The strongest cytotoxic effect against breast cancer (MCF-7) and human promyelocytic leukemia (HL-60) cell lines was found for 2-(N-cyclohexylcarboxyamido)benzeneselenenic acid potassium salt and the 2-(N-ethylcarboxyamido)benzeneselenenic acid, respectively. The structure-activity correlations, including the differences in reactivity of benzeneseleninic acids and corresponding salts were evaluated.

Evaluation of keratin biomaterial containing silver nanoparticles as a potential wound dressing in full-thickness skin wound model in diabetic mice.

Keratin is a cytoskeletal scaffolding protein essential for wound healing and tissue recovery. The aim of the study was to evaluate the potential role of insoluble fur keratin-derived powder containing silver nanoparticles (FKDP-AgNP) in the allogenic full-thickness surgical skin wound model in diabetic mice. The scanning electron microscopy image evidenced that the keratin surface is covered by a single layer of silver nanoparticles. Data obtained from dynamic light scattering and micellar electrokinetic chromatography showed three fractions of silver nanoparticles with an average diameter of 130, 22.5, and 5 nm. Microbiologic results revealed that the designed insoluble FKDP-AgNP dressing to some extent inhibit the growth of Escherichia coli and Staphylococcus aureus. In vitro assays showed that the FKDP-AgNP dressing did not inhibit fibroblast growth or induce hemolysis. In vivo studies using a diabetic mice model confirmed biocompatible properties of the insoluble keratin dressings. FKDP-AgNP significantly accelerated wound closure and epithelization at Days 5 and 8 (p < .05) when compared with controls. Histological examination of the inflammatory response documented that FKDP-AgNP-treated wounds contained predominantly macrophages, whereas their untreated variants showed mixed cell infiltrates rich in neutrophils. Wound inflammatory response based on macrophages favors tissue remodeling and healing. In conclusion, the investigated FKDP-AgNP dressing consisting of an insoluble fraction of keratin, which is biocompatible, significantly accelerated wound healing in a diabetic mouse model.

Application of micellar electrokinetic chromatography for detection of silver nanoparticles released from wound dressing.

The recent emergence of nanotechnology has provided a new therapeutic modality in case of silver nanoparticles. Dressings containing silver form the basis for the treatment of burns and wounds, either acute or chronic ones. The aim of the study was to examine silver release from the different wound dressings: commercially available (Atrauman Ag, Aquacel Ag) and experimental (FKDP-AgNPs) using MEKC. In order to characterize prepared keratin based wound dressing before and after its modification with AgNPs, a compositional analysis was conducted using energy dispersive X-ray spectroscopy. Nanosilver toxicity was evaluated with the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 sulfophenyl)-2H-tetrazolium test. Silver release from wound dressings was assessed using MEKC. The best separation was observed for MEKC in 20 mM borate buffer at pH 9 with 20 mM SDS addition. In vitro studies showed silver at higher concentration than 10 ppm exerted a toxic effect on fibroblasts isolated from diabetic mice versus. NIH/3T3 and BJ cell lines (p < 0.05). We observed silver was released more gradually from experimental FKDP-AgNPs wound dressing, in compare to commercially available wound dressings. The fast and low-cost method utilizing MEKC can be used in clinical practice to detect silver release from the wound dressings.

Development of a novel keratin dressing which accelerates full-thickness skin wound healing in diabetic mice: In vitro and in vivo studies.

Impaired wound healing is a major medical problem in diabetes. The objective of this study was to determine the possible application of an insoluble fraction of fur-derived keratin biomaterial as a wound dressing in a full thickness surgical skin wound model in mice ( n = 20) with iatrogenically induced diabetes. The obtained keratin dressing was examined in vitro and in vivo. In vitro study showed the keratin dressing is tissue biocompatible and non-toxic for murine fibroblasts. Antimicrobial examination revealed the keratin dressing inhibited the growth of S. aureus and E. coli. In vivo studies showed the obtained dressing significantly ( p < 0.05) accelerated healing during the first week after surgery compared to control wounds. Keratin dressings were incorporated naturally into granulation and regenerating tissue without any visible signs of inflammatory response, which was confirmed by clinical and histopathological analysis. It is one of the first studies to show application of insoluble keratin proteins and its properties as a wound dressing. The obtained keratin dressing accelerated wound healing in mice with iatrogenically induced diabetes. Therefore, it can be considered as a safe and efficient wound dressing. Although future studies are needed to explain the molecular mechanism behind fur-derived keratin effect during the multilayer wound healing process, our findings may open the way for a new class of insoluble fur keratin dressings in chronic difficult to heal wounds treatment.

Bioinspired Amphiphilic Peptide Dendrimers as Specific and Effective Compounds against Drug Resistant Clinical Isolates of E. coli.

Evolution-derived natural compounds have been inspirational for design of numerous pharmaceuticals, e.g., penicillins and tetracyclines. Herein, we present a bioinspired strategy to design peptide dendrimers for the effective therapy of E. coli infections where the selection of appropriate amino acids and the mode of their assembly are based on the information gained from research on membranolytic natural antimicrobial peptides (AMP's). On the molecular level two opposite effects were explored: the effect of multiple positive charges necessary for membrane disintegration was equilibrated by the anchoring role of tryptophanes. Indeed, a series of Trp-terminated dendrimers exhibited high potency against clinical isolates of antibiotic resistant ESBL E. coli strains, stability in human plasma along with very low hemo- and genotoxicity. Investigation of the underlying antimicrobial mechanism indicated that the dendrimers studied at minimal inhibitory concentration showed weak permeability toward membranes. Solid-state 2D NMR studies revealed their presence on and inside the model membranes. Therefore, their biological properties might be explained by targeting of extra- or intracellular receptors. Our results point to a new approach to design novel branched antimicrobials with high therapeutic index.

The effect of wool hydrolysates on squamous cell carcinoma cells in vitro. Possible implications for cancer treatment.

Squamous cell carcinoma of the skin is the second most common cutaneous malignancy. Despite various available treatment methods and advances in noninvasive diagnostic techniques, the incidence of metastatic cutaneous squamous cell carcinoma is rising. Deficiency in effective preventive or treatment methods of transformed keratinocytes leads to necessity of searching for new anticancer agents. The present study aims to evaluate the possibility of using wool hydrolysates as such agents. Commercially available compounds such as 5-fluorouracil, ingenol mebutate, diclofenac sodium salt were also used in this study. The process of wool degradation was based on chemical pre-activation and enzymatic digestion of wool. The effect of mentioned compounds on cell viability of squamous carcinoma cell line and healthy keratinocytes was evaluated. The obtained data show a significantly stronger effect of selected wool hydrolysates compared to commercial compounds (p<0.05) on viability of cells. The wool hydrolysates decreased squamous cell carcinoma cells viability by up to 67% comparing to untreated cells. These results indicate bioactive properties of wool hydrolysates, which affect the viability of squamous carcinoma cells and decrease their number. We hypothesize that these agents may be used topically for treatment of transformed keratinocytes in actinic keratosis and invasive squamous skin cancer in humans.

Opioid Tripeptides Hybridized with trans-1-Cinnamylpiperazine as Proliferation Inhibitors of Pancreatic Cancer Cells in Two- and Three-Dimensional in†vitro Models.

According to the World Health Organization, the mortality rate among patients with pancreatic cancer will increase in the upcoming years. Gemcitabine is the first choice for treatment of pancreatic malignancy, but increasing resistance to this drug is decreasing its overall efficacy. Studies on new therapies that target metabolic pathways, growth factor inhibitors, and tumor stroma or tumor stem cells are currently underway in many research groups. Herein we report the bioactive properties (cytotoxicity and hemolytic activity) of synthetic peptidomimetics containing an opioid tripeptide fragment (Tyr-R1 -R2 -; where R1 is d-Ala or d-Thr, and R2 is Phe or Trp) hybridized with trans-1-cinnamylpiperazine. These compounds are stable in plasma up to 96 h and exhibit low hemotoxicity and good inhibitory effects on cancer cell growth in two- and three-dimensional in vitro models of pancreatic cancer.

Structure-activity relationship study of a small cyclic peptide H-c[Lys-Pro-Glu]-Arg-OH: a potent inhibitor of Vascular Endothelial Growth Factor interaction with Neuropilin-1.

Inhibition of angiogenesis is one of the most promising approaches in anticancer therapy. It was recently suggested that Neuropilin-1 (NRP-1) in tumour cells may serve as a separate receptor for Vascular Endothelial Growth Factor-165 (VEGF165) which is one of the main pro-angiogenic agents in the organism. Therefore molecules inhibiting VEGF165 binding to NRP-1 could be potential candidates for new antiangiogenic and anticancer drugs. Here we present a structure-activity relationship study of the peptide H-c[Lys-Pro-Glu]-Arg-OH which showed high inhibitory effect on VEGF165/NRP-1 binding (IC50=0.18µM) in our previous study. We report the design, synthesis, in vitro assays and docking analysis of four small cyclic peptides (14-,15-membered ring) and one bigger cyclic compound (30-membered ring). Our study shows that both the ring size and configuration of amino acid residues present in the structure are crucial for high inhibitory effect.

Characterization and Optimization of Biosynthesis of Bioactive Secondary Metabolites Produced by Streptomyces sp. 8812.

The nutritional requirements and environmental conditions for a submerged culture of Streptomyces sp. 8812 were determined. Batch and fed-batch Streptomyces sp. 8812 fermentations were conducted to obtain high activity of secondary metabolites. In the study several factors were examined for their influence on the biosynthesis of the active metabolites-7-hydroxy-6-oxo-2,3,4,6-tetrahydroisoquinoline-3-carboxy acid (C10H9NO4) and N-acetyl-3,4-dihydroxy-L-phenylalanine (C11H13NO5): changes in medium composition, pH of production medium, various growth phases of seed culture, amino acid supplementation and addition of anion exchange resin to the submerged culture. Biological activities of secondary metabolites were examined with the use of DD-carboxypeptidase 64-575 and horseradish peroxidase. Streptomyces sp. 8812 mycelium was evaluated under fluorescent microscopy and respiratory activity of the strain was analyzed. Moreover, the enzymatic profiles of the strain with the use of Api ZYM test were analyzed and genetic analysis made. Phylogenetic analysis of Streptomyces sp. 8812 revealed that its closest relative is Streptomyces capoamus JCM 4734 (98%), whereas sequence analysis for 16S rRNA gene using NCBI BLAST algorithm showed 100% homology between these two strains. Biosynthetic processes, mycelium growth and enzyme inhibitory activities of these two strains were also compared.

Design, synthesis and in vitro biological evaluation of a small cyclic peptide as inhibitor of vascular endothelial growth factor binding to neuropilin-1.

Neuropilin-1 (NRP-1) is a co-receptor of VEGFR (vascular endothelial growth factor receptor), but it is also suggested that NRP-1 in tumour cells may serve as a separate receptor for VEGF165. Therefore molecules interfering with VEGF165 binding to NRP-1 seem to be promising candidates as new anti-angiogenic and anti-tumour drugs. Here, we report the design, synthesis, biological evaluation and molecular modelling of the small cyclic peptide, which shows a good inhibitory effect on VEGF165/NRP-1 binding (IC50=0.18µM). The reported compound could be considered as one of the smallest cyclic peptides (MW=510) interfering with VEGF165/NRP-1 binding presented up to now.