Oral Delivery of Teriparatide Using a Nanoemulsion System: Design, in Vitro and in Vivo Evaluation.

PURPOSE: Investigate the possibility of delivering teriparatide orally using nanoemulsion. METHOD: Teriparatide was allowed to interact with chitosan in the presence of HPßCD.The formed polyelectrolyte complex (PEC) was characterized by DSC, FTIR, DLS and for entrapment efficiency. PEC was the incorporated in an oil phase consisting of Oleic Acid, Labrasol and Plurol Oleique to form a nanoemulsion. This preparation was characterized for refractive index, viscosity, pH, conductivity, particle size, and morphology.Bioavailability of the preparation was evaluated using rabbits against SC injection. The efficacy of the formula was tested using ovariectomized rats (an osteoporosis animal model) and mechanical and histological tests were conducted on their bones. The stability of the preparation was evaluated by storing samples at 4o C, 25o C and 40o C for three months. RESULTS: PEC testing demonstrate a complex formation with particle size of 208 nm, zeta potential of +17 mV and entrapment efficiency of 49%. For the nanoemulsion, the results demonstrate the formation of a nano-sized dispersed system (108 nm) with a drug loading of 98% and a percent protection of 90% and 71% in SGF and SIF respectively. Bioavailability results showed a sustained release profile was achieved following the oral formulation administration. Efficacy studies showed improvement in the strength, thickness and connectivity of bones. Short-term stability study demostrated that the nanoemulsion is mostly stable at 4o C. CONCLUSION: These findings demonstrate the ability of delivering Teriparatide orally using oleic acid based dispersion in combination with chitosan PEC.

Multi-Armed 1,2,3-Selenadiazole and 1,2,3-Thiadiazole Benzene Derivatives as Novel Glyoxalase-I Inhibitors.

Glyoxalase-I (Glo-I) enzyme was established to be a valid target for anticancer drug design. It performs the essential detoxification step of harmful byproducts, especially methylglyoxal. A robust computer-aided drug design approach was used to design and validate a series of compounds with selenium or sulfur based heterorings. A series of in-house multi-armed 1,2,3-selenadiazole and 1,2,3-thiadiazole benzene derivatives were tested for their Glo-I inhibitory activity. Results showed that these compounds bind Glo-I active sites competitively with strong potential to inhibit this enzyme with IC50 values in micro-molar concentration. Docking poses revealed that these compounds interact with the zinc atom at the bottom of the active site, which plays an essential role in its viability.

Computational and experimental exploration of the structure-activity relationships of flavonoids as potent glyoxalase-I inhibitors.

Hit, Lead & Candidate Discovery Glyoxalase-I (Glo-I) enzyme has emerged as a potential target for cancer treatment. Several classes of natural products including coumarins and flavonoids have shown remarkable Glo-I inhibitory activity. In the present study, computational and experimental approaches were used to explore the structure-activity relationships of a panel of 24 flavonoids as inhibitors of the Glo-1 enzyme. Scutellarein with an IC50 value of 2.04 µM was identified as the most potent inhibitor among the series studied. Di- or tri-hydroxylation of the benzene rings A and B accompanied with a C2/C3 double bond in ring C were identified as essential structural features for enzyme inhibition. Moreover, the ketol system showed a minor role in the inhibitory power of these compounds. The structure-activity relationships revealed in this study had deepened our understanding of the Glo-I inhibitory activities of flavonoids and opened the door for further exploration of this promising compound class.

A3, a Scorpion Venom Derived Peptide Analogue with Potent Antimicrobial and Potential Antibiofilm Activity against Clinical Isolates of Multi-Drug Resistant Gram Positive Bacteria.

Current research in the field of antimicrobials is focused on developing novel antimicrobial agents to counteract the huge dilemma that the human population is mainly facing in regards to the rise of bacterial resistance and biofilm infections. Host defense peptides (HDPs) are a promising group of molecules for antimicrobial development as they display several attractive features suitable for antimicrobial activity, including their broad spectrum of activity and potency against bacteria. AamAP1 is a novel HDP that belongs to the venom of the North African scorpion Androctonus amoeruxi. In vitro antimicrobial assays revealed that the peptide displays moderate activity against Gram-positive and Gram-negative bacteria. Additionally, the peptide proved to be highly hemolytic and displayed significantly high toxicity against mammalian cells. In our study, a novel synthetic peptide analogue named A3 was synthetically modified from AamAP1 in order to enhance its activity and toxicity profile. The design strategy depended on modifying the amino acid sequence of AamAP1 in order to alter its net positive charge, percentage helicity and modify other parameters that are involved theoretically in HDPs activity. Accordingly, A3 was evaluated for its in vitro antimicrobial and anti-biofilm activity individually and in combination with four different types of conventional antibiotics against clinical isolates of multi-drug resistant (MDR) Gram-positive bacteria. A3 was also evaluated for its cytotoxicity against mammalian cells. A3 managed to selectively inhibit the growth of a wide range of resistant strains of Gram-positive bacteria. Our results also showed that combining A3 with conventional antibiotics caused a synergistic antimicrobial behavior that resulted in decreasing the MIC value for A3 peptide as low as 0.125 µM. At the concentrations needed to inhibit bacterial growth, A3 displayed minimal mammalian cell toxicity. In conclusion, A3 exhibits enhanced activity and selectivity when compared with the parent natural scorpion venom peptide. The combination of A3 with conventional antibiotics could provide researchers in the antimicrobial drug development field with a potential alternative for conventional antibiotics against MDR bacteria.

Generation of the first structure-based pharmacophore model containing a selective "zinc binding group" feature to identify potential glyoxalase-1 inhibitors.

Within this study, a unique 3D structure-based pharmacophore model of the enzyme glyoxalase-1 (Glo-1) has been revealed. Glo-1 is considered a zinc metalloenzyme in which the inhibitor binding with zinc atom at the active site is crucial. To our knowledge, this is the first pharmacophore model that has a selective feature for a "zinc binding group" which has been customized within the structure-based pharmacophore model of Glo-1 to extract ligands that possess functional groups able to bind zinc atom solely from database screening. In addition, an extensive 2D similarity search using three diverse similarity techniques (Tanimoto, Dice, Cosine) has been performed over the commercially available "Zinc Clean Drug-Like Database" that contains around 10 million compounds to help find suitable inhibitors for this enzyme based on known inhibitors from the literature. The resultant hits were mapped over the structure based pharmacophore and the successful hits were further docked using three docking programs with different pose fitting and scoring techniques (GOLD, LibDock, CDOCKER). Nine candidates were suggested to be novel Glo-1 inhibitors containing the "zinc binding group" with the highest consensus scoring from docking.

The design and evaluation of the antimicrobial activity of a novel conjugated penta-ultrashort antimicrobial peptide in combination with conventional antibiotics against sensitive and resistant strains of S. aureus and E. coli.

Background and purpose: Antimicrobial resistance still constitutes a major health concern to the global human population. The development of new classes of antimicrobial agents is urgently needed to thwart the continuous emergence of highly resistant microbial pathogens. Experimental approach: In this study, we have rationally designed a novel conjugated ultrashort antimicrobial peptide. The peptide named naprolyginine was challenged against representative strains of wild-type and multidrug-resistant bacteria individually or in combination with individual antibiotics by employing standard antimicrobial and checkerboard assays. Findings / Results: Our results displayed that the peptide exhibits potent synergistic antimicrobial activity against resistant strains of gram-positive and gram-negative bacteria when combined with individual antibiotics. Additionally, the peptide was evaluated for its hemolytic activity against human red blood cells and displayed negligible toxicity. Conclusion and implications: Naprolyginine could prove to be a promising candidate for antimicrobial drug development.

The Design of Alapropoginine, a Novel Conjugated Ultrashort Antimicrobial Peptide with Potent Synergistic Antimicrobial Activity in Combination with Conventional Antibiotics.

(1) Background: Antimicrobial resistance represents an urgent health dilemma facing the global human population. The development of novel antimicrobial agents is needed to face the rising number of resistant bacteria. Ultrashort antimicrobial peptides (USAMPs) are considered promising antimicrobial agents that meet the required criteria of novel antimicrobial drug development. (2) Methods: Alapropoginine was rationally designed by incorporating arginine (R), biphenylalanine (B), and naproxen to create an ultrashort hexapeptide. The antimicrobial activity of alapropoginine was evaluated against different strains of bacteria. The hemolytic activity of alapropoginine was also investigated against human erythrocytes. Finally, synergistic studies with antibiotics were performed using the checkerboard technique and the determination of the fractional inhibitory index. (3) Results: Alapropoginine displayed potent antimicrobial activities against reference and multi-drug-resistant bacteria with MIC values of as low as 28.6 µg/mL against methicillin-resistant S. aureus. Alapropoginine caused negligible toxicity toward human red blood cells. Moreover, the synergistic studies showed improved activities for the combined conventional antibiotics with a huge reduction in their antimicrobial concentrations. (4) Conclusions: The present study indicates that alapropoginine exhibits promising antimicrobial activity against reference and resistant strains of bacteria with negligible hemolytic activity. Additionally, the peptide displays synergistic or additive effects when combined with several antibiotics.

Immunodiagnosis of cattle fascioliasis using a 27 kDa Fasciola gigantica antigen.

BACKGROUND AND AIM: Diagnosis of fascioliasis depends on clinical symptoms and routine laboratory tests. Recently, antibodies and circulating antigens of Fasciola were used for detecting active infections. Therefore, this study aimed to identify Fasciola gigantica antigens in the sera of infected cattle using Western blotting and enzyme-linked immunosorbent assay (ELISA) for an accurate diagnosis of cattle infected with F. gigantica. MATERIALS AND METHODS: Serum samples were obtained from 108, 23, and 19 cattle infected with Fasciola gigantica, Paramphistomum cervi, and Strongylids, respectively, including 57 non-infected cattle that were used as healthy cattle for the study. Western blotting and ELISA were then used to detect circulating Fasciola antigens at 27 kDa. RESULTS: The target epitope was detected in an F. gigantica adult-worm antigen preparation, excretory/secretory products, and serum from cattle infected with F. gigantica. However, it was absent in sera from P. cervi, Strongylids, and healthy cattle. The purified 27 kDa F. gigantica (FPA-27) antigen was also detected in cattle serum using ELISA with high degrees of sensitivity and specificity (94% and 82%, respectively), and the area under the receiver operating characteristic curve was 0.89 with a highly significant correlation of p<0.0001. CONCLUSION: The FPA-27 is proposed to be a promising candidate for the serodiagnosis of fascioliasis in cattle.

Ellagic acid: A potent glyoxalase-I inhibitor with a unique scaffold.

The glyoxalase system, particularly glyoxalase-I (GLO-I), has been approved as a potential target for cancer treatment. In this study, a set of structurally diverse polyphenolic natural compounds were investigated as potential GLO-I inhibitors. Ellagic acid was found, computationally and experimentally, to be the most potent GLO-I inhibitor among the tested compounds which showed an IC50 of 0.71 mmol L-1. Its binding to the GLO-I active site seemed to be mainly driven by ionic interaction via its ionized hydroxyl groups with the central Zn ion and Lys156, along with other numerous hydrogen bonding and hydrophobic interactions. Due to its unique and rigid skeleton, it can be utilized to search for other novel and potent GLO-I inhibitors via computational approaches such as pharmacophore modeling and similarity search methods. Moreover, an inspection of the docked poses of the tested compounds showed that chlorogenic acid and dihydrocaffeic acid could be considered as lead compounds worthy of further optimization.

Pretreatment with Salvadora persica L. (Miswak) aqueous extract alleviates paracetamol-induced hepatotoxicity, nephrotoxicity, and hematological toxicity in male mice.

BACKGROUND AND AIM: Paracetamol (PCM) ingestion is one of the most frequent global causes of toxicity. Salvadora persica L. is a plant that among many other effects exhibits potent antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. In this study, we investigated the possible protective effect of S. persica aqueous extract in the PCM overdose-induced liver and kidney injury and hematological changes in a mice model. MATERIALS AND METHODS: Mice were given PCM with and without S. persica pretreatment. Blood cell counts and liver and kidney function biomarkers were measured. Liver and kidney samples were histologically examined. RESULTS: A single overdose of PCM caused significant elevations of alanine and aspartate transaminases, alkaline phosphate, bilirubin, urea, uric acid, and creatinine compared with the control group. In addition, PCM toxicity significantly lowered red blood cell count but insignificantly increased both white blood cell and platelet counts in comparison to the control mice. Pretreatment with S. persica significantly prevented PCM-induced changes in hepatic and renal biomarkers. S. persica also caused marked reversal of hematological changes. Histologically, the liver and kidney showed inflammation and necrosis after PCM treatment, which were significantly reduced in mice pretreated with S. persica. CONCLUSION: Taken together, S. persica significantly inhibited PCM-induced renal, hepatic, and hematological toxicity, pointing to its possible use in the treatment of liver and renal disorders.

Budget Impact Analysis of Switching to Rituximab's Biosimilar in Rheumatology and Cancer in 13 Countries Within the Middle East and North Africa.

INTRODUCTION: Biosimilars of monoclonal antibodies are being rapidly developed and approved by public health regulatory authorities worldwide. These biosimilars are expected to bring significant budgetary savings to national governments and consequently increase patients' accessibility to biological therapy. Rituximab has been used extensively for the treatment of cancer and rheumatoid disorders over the past two decades. New biosimilars of Rituximab have been developed and introduced into clinical practice. We have analyzed the budgetary impact and savings outcome of introducing Rituximab's biosimilar into 13 countries within the Middle East and North Africa through the implementation of a budget impact analysis model. METHODS: Our model was based on a 1-year full uptake and switch scenario of the Rituximab's biosimilar CT-P10. The model calculated the total number of patients based on the total national consumption of Rituximab per country. Accordingly, the model produced savings per each indication which were translated into the additional number of patients that would be permitted access to Rituximab's therapy as a result of these savings. RESULTS: In our modeling scenario, the total projected savings that will result from the uptake of Rituximab's biosimilar within the MENA region were estimated to be 46.59 million dollars. The cumulative savings in all 13 countries would allow access of Rituximab's therapy for a total of 6589 patients which is equivalent to a 14% increase in the number of patients benefiting from Rituximab's therapy. CONCLUSION: The introduction of Rituximab's biosimilar within the Middle East and North Africa region is associated with significant budgetary savings that will allow public national health authorities to reinvest such economic gains either in expanding access to Rituximab therapy or other costly lifesaving biologicals.

Production, immunogenicity, stability, and safety of a vaccine against Clostridium perfringens beta toxins.

BACKGROUND AND AIM: The beta toxin is causing the most severe Clostridium perfringens-related diseases. This work was dedicated to developing a vaccine against beta toxin using C. perfringens type C (NCTC 3180). MATERIALS AND METHODS: The crude toxoid harvest contained 710 limits of flocculation (Lf)/mL. The vaccine was formulated. Each 1 mL of the final vaccine product contained at least 50 Lf/mL of beta toxoids, 0.2 mL 3% aluminum hydroxide gel (equivalent to 5.18 mg of aluminum), <0.001% W/V thiomersal, formaldehyde <0.05% W/V, and ~0.7 mL phosphate-buffered saline (pH 7.2). The efficacy of the vaccine was evaluated by potency, stability, and safety tests. RESULTS: The vaccine demonstrated 24.36 IU/mL (standard deviation, ±0.56) and 14.74 IU/mL (±0.36) of neutralizing antibodies in rabbits and cattle, respectively. Indeed, these levels were above the minimum recommended by international protocols since the obtained antibody levels had 2.43- and 1.47-fold increase in both rabbits and cattle, respectively, over the minimum antitoxin level suggested by the United States Department of Agriculture. Interestingly, our formulation was capable of inducing 1.65-fold higher immune responses in rabbits than that stimulated in cattle (65% increase) with a significant difference (p<0.0001). The vaccine was stable up to 30 months. The vaccinated rabbits were suffered from a temporarily slight increase in temperatures in the first 10 h without any significant difference (p>0.05). CONCLUSION: The research showed a procedure for the manufacturing process of the vaccine against C. perfringens beta toxins with a feasible quantity and the vaccine described here showed to be effective in eliciting levels of neutralizing antibodies higher than required by international standards. In addition, The vaccine was stable up to 30 months. Thus, it may represent an effective and safe for preventing C. perfringens-related diseases in rabbits and cattle, although further studies to prove its efficacy in the field on other farm animals are still needed.

Functional Characterization of a Novel Hybrid Peptide with High Potency against Gram-negative Bacteria.

BACKGROUND: Multi-drug resistant infections are a growing worldwide health concern. There is an urgent need to produce alternative antimicrobial agents. OBJECTIVE: The study aimed to design a new hybrid antimicrobial peptide, and to evaluate its antimicrobial activity alone and in combination with traditional antibiotics. METHODS: Herein, we designed a novel hybrid peptide (BMR-1) using the primary sequences of the parent peptides Frog Esculentin-1a and Monkey Rhesus cathelicidin (RL-37). The positive net charge was increased, and other physicochemical parameters were optimized. The antimicrobial activities of BMR-1 were tested against control and multi-drug resistant gram-negative bacteria. RESULTS: BMR-1 adopted a bactericidal behavior with MIC values of 25-30 µM. These values reduced by over 75% upon combination with conventional antibiotics (levofloxacin, chloramphenicol, ampicillin, and rifampicin). The combination showed strong synergistic activities in most cases and particularly against multi-drug resistance P. aeruginosa and E. coli. BMR-1 showed similar potency against all tested strains regardless of their resistant mechanisms. BMR-1 exhibited no hemolytic effect on human red blood cells with the effective MIC values against the tested strains. CONCLUSION: BMR-1 hybrid peptide is a promising candidate to treat resistant infectious diseases caused by gramnegative bacteria.

The evaluation of the synergistic antimicrobial and antibiofilm activity of AamAP1-Lysine with conventional antibiotics against representative resistant strains of both Gram-positive and Gram-negative bacteria.

Background and purpose: Antimicrobial resistance toward antibiotics is reaching historical unprecedented levels. There is an urgent and imminent need to develop novel antimicrobial alternatives. Antimicrobial peptides could prove to be a successful group of antimicrobials for drug development. Recently, we have designed a novel synthetic peptide named AamAP1-Lysine. The peptide displayed potent wide-spectrum antimicrobial activities against Gram-positive and Gram-negative bacteria. The purpose of this study is to evaluate the antimicrobial effect of combining AamAP1-Lysine with five different conventional antibiotics each representing a distinct mechanism of action in order to explore the possibility of producing a synergistic mode of action against a resistant strain of Gram-positive and a resistant strain of Gram-negative bacteria. Methodology: The antimicrobial activity of AamAP1-Lysine in combination with five different antibiotics were evaluated for their antimicrobial activity employing standard antimicrobial assays, the synergistic activity of the peptide-antibiotic combinations were evaluated using checkerboard technique in addition to real-time time-kill assays. For the antibiofilm studies, the MBEC values were determined by employing the Calgary device. Results: The combination strategy displayed potent synergistic activities against planktonic bacteria in a significant number of peptide-antibiotic combinations. The synergistic activity managed to reduce the effective minimum inhibitory concentration (MIC) concentrations dramatically with some combinations exhibiting a 64-fold decrease in the effective MIC of AamAP1-Lysine individually. Additionally, the combined synergistic activities of the peptide antibiotics were evaluated, and our results have identified two peptide antibiotic combinations with potent synergistic activities against biofilm growing strains of resistant bacteria. Conclusion: Our results clearly indicate that peptide-antibiotic combinations could prove to be a very effective strategy in combatting multidrug-resistant bacteria and biofilm caused infections.

Synergism of cationic antimicrobial peptide WLBU2 with antibacterial agents against biofilms of multi-drug resistant Acinetobacter baumannii and Klebsiella pneumoniae.

PURPOSE: The activity of the cationic antimicrobial peptide WLBU2 was evaluated against planktonic cells and biofilms of multi-drug resistant (MDR) Acinetobacter baumannii and Klebsiella pneumoniae, alone and in combination with classical antimicrobial agents. METHODS: Control American Type Culture Collection (ATCC) strains and MDR clinical isolates of A. baumannii and K. pneumoniae were utilized. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of WLBU2 alone and in combination with antimicrobials were determined by classical methods. The Calgary biofilm device was used to determine the minimum biofilm eradication concentration (MBEC). The MTT assay was used to determine the cytotoxicity of agents on eukaryotic cells. The electrophoretic mobility shift assay was used to evaluate the ability of WLBU2 to bind bacterial DNA. RESULTS: The WLBU2 MIC and MBC values were identical indicating bactericidal activity. The MIC/MBC values ranged from 1.5625 to 12.5 µM. At these concentrations, Vero cells and human skin fibroblasts were viable. The MBEC of WLBU2 ranged from 25 to 200 µM. A significant loss of eukaryotic cell viability was observed at the MBEC range. The combination of sub-inhibitory concentrations of WLBU2 with amoxicillin-clavulanate or ciprofloxacin for K. pneumoniae, and with tobramycin or imipenem for A. baumannii, demonstrated synergism, leading to a significant decrease in MIC and MBEC values for some isolates and ATCC strains. However, all combinations were associated with considerable loss in eukaryotic cells' viability. WLBU2 did not demonstrate the ability to bind bacterial plasmid DNA. CONCLUSION: WLBU2 in combination with antimicrobials holds promise in eradication of MDR pathogens.

Design and characterization of a new hybrid peptide from LL-37 and BMAP-27.

Background and purpose: The world is heading to a post-antibiotic era where the treatment of bacterial infections will not be possible even with well-known last-line antibiotics. Unfortunately, the emergence of multidrug resistant bacterial strains is uncontrollable, and the humanity will face a life-threatening fate unless new antimicrobial agents with new bacterial target sites are promptly developed. Herein, we design a hybrid antimicrobial peptide (B1) from helical parts taken from the parent peptides: LL-37 and BMAP-27. The purpose of this design is to improve the potency and enhance the toxicity profile of the parent peptides. Methods: Rational design was used to hybridize two antimicrobial peptides, in which two helical parts from the bovine analog BMAP-27, and the human cathelicidin LL-37 were used to generate a novel peptide (B1). The physicochemical properties were checked using in silico methods. The antimicrobial activities were tested against nine control and resistant strains of Gram-positive and Gram-negative bacteria. On the other hand, the antibiofilm activities were tested against four resistant strains. The cytotoxicity on mammalian cells was tested using HEK293, and the hemolysis activity was also investigated on human blood. Finally, synergistic studies were performed with four conventional antibiotics against four resistant strains of Gram-positive and Gram-negative bacteria. Results: The new peptide B1 exhibited broad-spectrum activities against all tested strains. The concentration against planktonic cells ranged between 10 and 20 µM. However, 40-60 µM were needed to eradicate the biofilms. B1 showed reduced toxicity toward mammalian cells with minimal hemolysis risk. On the other hand, the synergistic studies showed improved activities for the combined conventional antibiotics with a huge reduction in their minimum inhibitory concentration values. The concentrations of B1 peptide combined with the tested antibiotics were also decreased markedly down to 0.5 µM in some cases. Conclusion: B1 is a hybrid peptide from two cathelicidin peptides. It showed an improved activity compared to parent peptides. The hybridization was successful in this study. It generated a new potent broad-spectrum antimicrobial. The toxicity profile was improved, and the synergism with the convention antibiotics showed promising results.

Combination of pharmacophore modeling and 3D-QSAR analysis of potential glyoxalase-I inhibitors as anticancer agents.

Glyoxalase system is an ubiquitous system in human cells which has been examined thoroughly for its role in different diseases. It comprises two enzymes; Glyoxalase I (Glo-I) and Glyoxalase II (Glo-II) which perform detoxifying endogenous harmful metabolites, mainly methylglyoxal (MG) into non-toxic bystanders. In silico computer Aided Drug Design approaches were used and ninety two diverse pharmacophore models were generated from eighteen Glyoxalase I crystallographic complexes. Subsequent QSAR modeling followed by ROC evaluation identified a single pharmacophore model which was able to predict the expected Glyoxalase I inhibition. Screening of the National Cancer Institute (NCI) database using the optimal pharmacophore Hypo(3VW9) identified several promising hits. Thirty eight hits were successfully predicted then ordered and evaluated in vitro. Seven hits out of the thirty eight tested compounds showed more than 50% inhibition with low micromolar IC50.

Recent Advances in Glyoxalase-I Inhibition.

Glyoxalase system is a ubiquitous system in human cells which has been examined thoroughly for its role in different disease conditions. It is composed of Glyoxalase-I (Glo-I) and Glyoxalase- II which perform an essential metabolic process inside the cell by detoxifying endogenous harmful metabolites, mainly methylglyoxal (MG) into non-toxic D-lactic acid. Tumor cells are well-known for their high metabolic rate which results in elevated levels of toxic metabolites. The over-expression of Glo-I in tumor cells makes this enzyme a pivotal target for anticancer drug development. Glo-I is metalloenzyme with two polypeptide chains and encompasses two active sites with an integral zinc atoms at their center. This review aims to highlight the important role of Glo-I in different pathogenic conditions, and more importantly, it provides a thorough discussion of all known human Glo-I inhibitors since its discovery, a hundred years ago, up to date. It embraces the different classes they belong to, their design and chemical structures. We believe this review will help guide the design of novel and potent human Glo-I inhibitors by providing a handy reference for interested researchers in this target.

In vivo antimicrobial activity of the hybrid peptide H4: a follow-up study.

BACKGROUND: The consistent upsurge in antimicrobial resistance globally is threatening the world population with the prospect of facing the post-antibiotic era. Dry pipelines and a drastic decrease of antimicrobial drug development accompany this rise in antimicrobial resistance. Governments and health authorities are calling for the development of novel classes of antimicrobial agents that would tackle this problem. Antimicrobial peptides represent a promising group of molecules for antimicrobial drug development due to their potency and rapid mode of killing. However, several obstacles, such as high mammalian cell toxicity and lack of target selectivity, have challenged the development of such agents. METHODS: We have recently designed a novel hybrid peptide named H4 that exhibits potent antimicrobial activity and low toxicity in vitro. In order to confirm the potential therapeutic efficacy and safety of the peptide, we evaluated the in vivo activity and toxicity of H4 against Staphylococcus aureus peritonitis mice model. RESULTS: Our results indicate that H4 is highly potent in eradicating bacterial infections in vivo with an effective dose50 value of 4.55±0.89 mg/kg. Additionally, the acute systemic toxicity results indicate that the peptide exhibits a high therapeutic index with no significant negative effects on the function of major body organs. CONCLUSION: H4 is a novel hybrid peptide with great potential for antimicrobial drug development.

Hybridization and antibiotic synergism as a tool for reducing the cytotoxicity of antimicrobial peptides.

INTRODUCTION: As the development of new antimicrobial agents faces a historical decline, the issue of bacterial drug resistance has become a serious dilemma that threatens the human population worldwide. Antimicrobial peptides (AMPs) represent an attractive and a promising class of antimicrobial agents. AIM: The hybridization of AMPs aimed at merging two individual active fragments of native peptides to generate a new AMP with altered physicochemical properties that translate into an enhanced safety profile. MATERIALS AND METHODS: In this study, we have rationally designed a new hybrid peptide via combining two individual α-helical fragments of both BMAP-27 and OP-145. The resultant peptide, was evaluated for its antimicrobial and antibiofilm activity against a range of microbial strains. The resultant peptide was also evaluated for its toxicity against mammalian cells using hemolytic and anti proliferative assays. RESULTS: The antimicrobial activity of H4 revealed that the peptide is displaying a broad spectrum of activity against both Gram-positive and Gram-negative bacteria including standard and multidrug-resistant bacterial strains in the range of 2.5-25 µM. The new hybrid peptide displayed potent activity in eradicating biofilm-forming cells, and the reported minimum biofilm eradication concentrations were equal to the minimum inhibitory concentration values reported for planktonic cells. Additionally, H4 exhibited reduced toxicity profiles against eukaryotic cells. Combining H4 peptide with conventional antibiotics has led to a dramatic enhancement of the antimicrobial activity of both agents with synergistic or additive outcomes. CONCLUSION: Overall, this study indicates the success of both the hybridization and synergism strategy in developing AMPs as potential antimicrobial therapeutics with reduced toxicity profiles that could be efficiently employed to eradicate resistant bacterial strains and enhance the selectivity and toxicity profiles of native AMPs.