Solid-phase Synthesis Strategy Research Articles

Minute-level synthesis of tunable carbon dots-based phosphorescence materials for information encryption and light-emitting diodes

The emergence of carbon dots has broadened the design and application of new room-temperature phosphorescence materials, but the mass production of long-lived color-tunable carbon dots-based phosphorescence materials (CDPMs) is still hindered by solvent dependence and time-consuming. In this work, a minute-level solid-phase synthesis strategy was proposed for the preparation of a series of CDPMs through pyrolyzing the mixture of boric acid and pimelic acid. By tuning the mass ratio of boric acid and pimelic acid, CDPMs with different room-temperature phosphorescence characterises can be obtained within 7 min. Preferably, the CDPMs-60 synthesized from the mass ratio of boric acid and pimelic acid of 60:1 exhibits a long afterglow length up to 10 s and has obvious phosphorescence chromatic aberrations following excitation at 254 and 365 nm, and phosphorescence lifetimes of CDPMs-60 in the blue and green band can reach 1030 ms and 555 ms, respectively. The CDPMs were further successfully applied for the information encryption and fabricating light emitting diodes based on their simple synthesis process, exceptional optical properties and low-toxicity. This study may provide a valuable reference for the facile synthesis and suitable commercial application of room temperature phosphorescence materials.

Solid-phase peptide synthesis in 384-well plates.

Newer solid-phase peptide synthesis and release strategies enable the production of short peptides with high purity, allowing direct screening for desired bioactivity without prior chromatographic purification. However, the maximum number of peptides that can currently be synthesized per microplate reactor is 96, allowing the parallel synthesis of 384 peptides in modern devices that have space for 4 microplate reactors. To synthesize larger numbers of peptides, we modified a commercially available peptide synthesizer to enable the production of peptides in 384-well plates, which allows the synthesis of 1,536 peptides in one run (4× 384 peptides). We report new hardware components and customized software that allowed for the synthesis of 1,536 short peptides in good quantity (average > 0.5μmol), at high concentration (average > 10 mM), and decent purity without purification (average > 80%). The high-throughput peptide synthesis, which we developed with peptide drug development in mind, may be widely used for peptide library synthesis and screening, antibody epitope scanning, epitope mimetic development, or protease/kinase substrate screening.

Nonthreaded Isomers of Sungsanpin and Ulleungdin Lasso Peptides Inhibit H1299 Cancer Cell Migration.

Lasso peptides are a structurally distinct class of biologically active natural products defined by their short sequences with impressively interlocked tertiary structures. Their characteristic peptide [1]rotaxane motif confers marked proteolytic and thermal resiliency, and reports on their diverse biological functions have been credited to their exceptional sequence variability. Because of these unique properties, taken together with improved technologies for their biosynthetic production, lasso peptides are emerging as a designable scaffold for peptide-based therapeutic discovery and development. Although the defined structure of lasso peptides is recognized for its remarkable properties, the role of the motif in imparting bioactivity is less understood. For example, sungsanpin and ulleungdin are natural lasso peptides that similarly exhibit encouraging cell migration inhibitory activities in A549 lung carcinoma epithelial cells, despite sharing only one-third of the sequence homology. We hypothesized that the shape of the lasso motif is beneficial for the preorganization of the conserved residues, which might be partially retained in variants lacking the threaded structure. Herein, we describe solid-phase peptide synthesis strategies to prepare acyclic, head-to-side chain (branched), and head-to-tail (macrocyclic) cyclic variants based on the sungsanpin (Sun) and ulleungdin (Uln) sequences. Proliferation assays and time-lapse cell motility imaging studies were used to evaluate the cell inhibitory properties of natural Sun compared with the synthetic Sun and Uln isomers. These studies demonstrate that the lasso motif is not a required feature to slow cancer cell migration and more generally show that these nonthreaded isomers can retain similar activity to the natural lasso peptide despite the differences in their overall structures.

Precise solid-phase synthesis of CoFe@FeOx nanoparticles for efficient polysulfide regulation in lithium/sodium-sulfur batteries

Complex metal nanoparticles distributed uniformly on supports demonstrate distinctive physicochemical properties and thus attract a wide attention for applications. The commonly used wet chemistry methods display limitations to achieve the nanoparticle structure design and uniform dispersion simultaneously. Solid-phase synthesis serves as an interesting strategy which can achieve the fabrication of complex metal nanoparticles on supports. Herein, the solid-phase synthesis strategy is developed to precisely synthesize uniformly distributed CoFe@FeOx core@shell nanoparticles. Fe atoms are preferentially exsolved from CoFe alloy bulk to the surface and then be carburized into a FexC shell under thermal syngas atmosphere, subsequently the formed FexC shell is passivated by air, obtaining CoFe@FeOx with a CoFe alloy core and a FeOx shell. This strategy is universal for the synthesis of MFe@FeOx (M = Co, Ni, Mn). The CoFe@FeOx exhibits bifunctional effect on regulating polysulfides as the separator coating layer for Li-S and Na-S batteries. This method could be developed into solid-phase synthetic systems to construct well distributed complex metal nanoparticles.

Ternary Rare Earth Alloy Pt3-xIrxSc Nanoparticles Modulate Negatively Charged Pt via Charge Transfer To Facilitate pH-Universal Hydrogen Evolution.

Rare earth (RE) elements possess electronic configurations that can provide additional pathways for tailoring the electronic structures of active elements through alloying, making it an important area of exploration in electrocatalysis. However, the large negative redox potential between RE and Pt has hindered the development of RE nanoalloys. In this study, a solid-phase synthesis strategy was employed to synthesize ternary Pt3-xIrxSc nanoparticles (NPs). By leveraging the electronegativity difference between Pt (2.28), Ir (2.20), and Sc (1.36), a charge-balance strategy was implemented to stabilize and enhance the catalytic performance of the alloy. The electron transfer from Sc to Pt/Ir results in the latter being negatively charged, and the Ir modifies the electron density of Pt, enabling favorable adsorption of active H species during the hydrogen evolution reaction (HER). Pt2IrSc exhibits enhanced HER activity at all pH values, achieving low overpotentials at 10 mA cm-2 of only 13, 18, and 25 mV in 0.5 M H2SO4, 1 M PBS, and 1 M KOH, respectively. This electrocatalyst also exhibits robust electrocatalytic stability even after 20,000 cycles. This work represents an application of the charge balance strategy to RE nanoalloys, and it is expected to inspire the design and synthesis of highly reactive RE nanoalloys.

Ternary sulfide nanoparticles anchored in carbon bubble structure for oxygen evolution reaction

The synergistic effect and unique interfacial structure of ternary transition metal (Co, Ni, Fe) sulfides are significant in improving the catalytic performance of oxygen evolution reaction (OER). Herein, the ultrathin Co0.3Ni0.3Fe0.2S ternary sulfide nanoparticles (Co0.3Ni0.3Fe0.2S NPs) anchored in carbon bubble structure with rich pore structures (Co0.3Ni0.3Fe0.2S NPs/C) were firstly constructed via a cost-effective and general solid-phase synthesis strategy. Co0.3Ni0.3Fe0.2S NPs/C has a crystalline structure of Co1−xS, accompanying the shift of diffraction peaks, which indicate the doping of nickel and iron atoms into Co1−xS lattice. Co0.3Ni0.3Fe0.2S NPs/C catalyst has good OER activity with a low overpotential of 322 mV at 100 mA cm−2 in 1.0 M KOH electrolyte, superior to single metal sulfide synthesized at the same conditions. More importantly, the Co0.3Ni0.3Fe0.2S NPs/C catalyst possesses excellent stability with a low current density decrease in the continuous 336 h I-t test. The good catalytic intrinsic activity may originate from the synergistic effect among the highly exposed Fe, Co, and Ni sulfide grown on the porous carbon bubbles and the unique reconstruction structure formed during the OER process. This work provides some reference significance for the systematic study of the synergistic effects between multicomponents and the relationship between interfacial modulation and OER.

Chemical Synthesis of Alpha-Synuclein Proteins via Solid-Phase Peptide Synthesis and Native Chemical Ligation.

Alpha-Synuclein (α-Synuclein) is a 140 amino acid protein implicated in neurodegenerative disorders known as synucleino-pathies, where it accumulates in proteinaceous inclusions in the brain. The normal physiological function of α-Synuclein remains obscure, as it exists in several non-neuronal cells in which its function has not been studied. Given the tremendous interest in studying α-Synuclein, and the existing limitations in the production of modified forms of the protein, we developed a method for the chemical synthesis of α-Synuclein by combining peptide fragment synthesis via automated microwave-assisted solid-phase peptide synthesis and ligation strategies. Our synthetic pathway enables the synthesis of protein variants of interest, carrying either mutations or posttranslational modifications, for further investigations of the effects on the structure and aggregation behavior of the protein. Ultimately, our study forms the foundation for future syntheses and studies of other custom-made α-Synuclein variants with a single or several modifications, as necessary.

Rational Optimizations of the Marine-Derived Peptide Sungsanpin as Novel Inhibitors of Cell Invasion.

Cancer metastasis, including cell invasion, is a major cause of poor clinical outcomes and death in numerous cancer patients. In recent years, many efforts have been made to develop potent therapeutic molecules from naturally derived peptides. Sungsanpin is a naturally derived lasso peptide that inhibits A549 cell invasion. We aimed to evaluate the potential of sungsanpin derivatives as candidates for anti-invasion drugs. We synthesized an analog of sungsanpin (Sun A) using a solid-phase peptide synthesis strategy (SPPS) and further modified its structure to improve its anti-invasion activity. All peptides were tested for their proliferative inhibition and anti-invasion activities in the A549 cell lines. Octapeptide S3 and cyclooctapeptide S4 upregulated the expression of TIMP-1 and TIMP-2 mRNA effectively and thus improved the inhibitory effect on the invasion of A549 cells. The two peptides can inhibit the invasion of A549 cells by up to 60 %, suggesting that they have potential as lead molecules for the development of peptide inhibitors.

Total stepwise solid-phase synthesis of peptide-oligonucleotide conjugates using side-chain Boc/tBu protecting groups.

A practical strategy for the total stepwise solid-phase synthesis of peptide-oligonucleotide conjugates was developed. In this strategy, the Boc/tBu protecting groups are utilized for the side chains of Trp, His, Arg, Asp, and Glu, and is deprotected in borate buffer at 90 °C to avoid depurination of the oligonucleotide caused by strong acid treatment. The advantage of this strategy is that the abovementioned amino acids are readily available in the market and the side reaction of deguanidination of the Arg residue can be avoided. This side-chain Boc/tBu protection strategy will expand the applicability of total stepwise synthesis in the preparation of peptide-oligonucleotide conjugates.

Total Synthesis and Bioactivity Evaluation of Hydrophobic Microcionamide-Inspired Peptides.

In this report, we describe the facile synthesis of four microcionamide-inspired peptides where the atypical 2-phenylethylenamine (2-PEA) functional group in the marine natural product, microcionamide A, was replaced with a similarly-aromatic but more easily incorporated tryptophan (Trp) residue. Compounds 1-4 were synthesized using a standard Fmoc-based solid-phase synthesis strategy followed by iodine-mediated on-resin cyclization for disulfide-bridged compounds 1-3. Compound 1 showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, with minimum inhibitory concentrations (MICs) of 9.1 μM and 15 μM, respectively. The inactivity of alanine analogs 2-4 against these pathogens suggests that the N-terminal Val, the cyclic scaffold, the contiguous Ile residues, and consequently, the hydrophobicity of compound 1 are essential for antibacterial activity. Compound 1 also favorably exhibited minimal cytotoxicity against normal mammalian cell lines. In summary, we have synthesized an analog of microcionamide A where replacement of the 2-PEA moiety with a Trp residue retained the antibacterial activity and with favorably low cytotoxicity.

Hierarchical porous graphite-like carbon nanosheet cooperated with Fe/Fe3C@Fe-N-C nanocomposites toward catalytic oxidation process

In this work, Fe, N co-doped hierarchical porous graphite-like carbon with carbon-encapsulated Fe/Fe3C@ Fe-N-C was synthesized by a facile solid-phase synthesis strategy, and was employed as an efficient catalyst to activate peroxymonosulfate (PMS) for oxidation of tetracycline (TC). The optimal Fe-N/C 800 outlined a highly catalytic performance in activating peroxymonosulfate (PMS) with TC decomposition rate reaching 89.2 % in 20 min at ultra-low catalyst dosage. Meanwhile, the effect of operating parameters was also investigated in order to evaluate the potential of using Fe-N/C 800 in practical applications. In addition, the characterization analysis and experiments results elucidated that graphitic N, pyridinic N, CO, Fe3C, Fe0 and FeN4 were considered as the main reactive species promoting the PMS activation to generate reactive oxygen species (ROS) (including singlet oxygen (1O2), sulfate radical (SO4•-) and hydroxyl radical (•OH)). The electron paramagnetic resonance (EPR) experiments and radicals quenching analyses further demonstrated that the non-radical species singlet oxygen (1O2) was the dominant reactive oxygen species. Moreover, the TC degradation pathways were presented by LC-MS. Ultimately, the toxicity of the intermediate products were also investigated by ECOSAR system.

Solid phase synthesis Ni3N and N-CNT synergetic corn-like multifunctional electrocatalyst

Nickel nitride (Ni3N) based catalysts have been studied extensively as oxygen evolution and hydrogen evolution reaction (OER/HER) catalysts because of good stability in alkaline solution. However, relatively poor electrical conductivity of Ni3N seriously restricted electron transfer from the Ni3N nanoparticles surfaces to inner substrates for highly efficient water splitting. In this work, solid phase synthesis strategy is implemented to prepare Ni3N/N-CNT composite. Ni3N/N-CNT shows impressive onset potential (0.81 V) and half wave (0.70 V) in oxygen reduction reaction (ORR), respectively. The higher limiting diffusion current of Ni3N/N-CNT shows the faster ORR kinetics. Ni3N was anchored on N-CNT, which displayed an outstanding OER and HER performance. The low OER overpotential (0.40 V) indicated that the Ni3N nanoparticles on N-CNT has significant enhancement of the OER activity. Significantly, Ni3N/N-CNT displays an excellent HER activity with preferable current density and low overpotential of 259 mV at 10 mA cm−2. The excellent multifunctional catalytic property is due to the electronic interaction between Ni3N and N-CNT which is beneficial for the mass and electron transfer. The conclusion broadens our understanding for exploit multifunctional catalysts.

Solid-Phase Synthesis of Titanium Dioxide Micro-Nanostructures.

Titanium dioxide (TiO2) micro-nanostructures are widely utilized in photochemical applications due to their unique band gaps and are of huge demand in scientific research and industrial manufacture. Herein, this work reports a controllable, facile, economical, and green solid-phase synthesis strategy to prepare TiO2 with governable morphologies containing 1D nanorods, 3D microbulks, and irregular thick plates. Specifically, Ti powders are transformed into TiO2 micro-nanostructures through dispersing them into a solid NaOH/KOH mixture with a low eutectic point, followed by grinding, heating, ion exchange, and calcination. As no solvents are utilized in the alkali treatment process, the usage of solvents is decreased and high vapor pressure is avoided. Moreover, the band gaps of TiO2 micro-nanostructures can be regulated from 3.02 to 3.34 eV through altering the synthetic parameters. Notably, the as-prepared TiO2 micro-nanostructures exhibit high photocatalytic activities in the degradation of rhodamine B and methylene blue under simulated solar light illumination. It is believed that the solid-phase synthesis strategy will be of huge demand for the synthesis of TiO2 micro-nanostructures.

Solid phase radiosynthesis of an olaparib derivative using 4-[18F] fluorobenzoic acid and in vivo evaluation in breast and prostate cancer xenograft models for PARP-1 expression

IntroductionSolid-phase synthesis and conjugation reactions of acids and amines using coupling reagents are common in organic synthesis, but rare in 18F radiochemistry. 4-[18F]Fluorobenzoic acid (FBA) is a useful building block, but is seldom used directly with coupling reagents for the preparation of 18F radiopharmaceuticals. To overcome the inconveniences associated with using [18F]FBA in conjugation reactions, we have developed a non-covalent solid-phase synthesis (SPS) strategy for the radiosynthesis of [18F]PARPi, a derivative of olaparib as a Poly (ADP-ribose) polymerase-1 (PARP-1) radioligand. MethodsFluoro-, bromo- and iodo-benzoic derivatives of olaparib were synthesized, and their PARP-1 affinities were measured using a recently developed cell culture-based competitive assay. To produce [18F]PARPi, [18F]FBA was radiosynthesized and purified using a cation-exchange cartridge, and then trapped by an anion-exchange resin cartridge, on which the solid-phase radiosynthesis was carried out to produce the desired product. [18F]PARPi was evaluated in vivo in breast and prostate xenograft tumor models by microPET imaging, biodistribution and autoradiography. ResultsThe best derivatives of olaparib were identified as compound 4, 7 and 8. [18F]4 ([18F]PARPi) was radiosynthesized in high radiochemical yield, high molar activity and high radiochemical purity using this SPS strategy. The in vivo evaluation of [18F]PARPi demonstrates the PARP-1 specific uptake of [18F]PARPi in the animal models. ConclusionsThis method is simple and efficient, having great potential for the synthesis of radiopharmaceuticals starting from [18F]FBA or other radiolabeled aromatic acids. Using [18F]PARPi prepared by this method, we demonstrated the promise of [18F]PARPi in the nuclear imaging of PARP-1 expression.

Solvent-free synthesis of Co@NC catalyst with Co—N species as active sites for chemoselective hydrogenation of nitro compounds

Metal-organic frameworks (MOFs) derived Co-based catalysts have received extensive attention in the chemoselective hydrogenation of nitroarenes, while they usually require a lot of solvent during the synthesis and identification of active species. This study explores a solid-phase synthesis strategy to obtain MOF precursors without using any solvent, which is then foamed and pyrolyzed to synthesize the Co@NC-X catalyst. It was found that a nitrogen-doped graphene shell can well encapsulate the Co nanoparticles. The resulting catalyst, which was pyrolyzed at 800°C, exhibited ~100% conversion for the hydrogenation of 3-nitrostyrene and >99% selectivity to 3-vinylaniline. This catalyst also showed excellent stability and good substrate universality for the hydrogenation of extensive substituted nitroarenes. Various characterizations revealed a positive relationship between the catalytic performance and the content of Co—N species tuned by pyrolysis temperature. This work provides a novel and green strategy to design an efficient Co-based catalyst for chemoselective hydrogenation.

Solid phase synthesis of oxidized sodium alginate-tobramycin conjugate and its application for infected wound healing

Although sodium alginate possesses excellent biocompatibility, moisture retention and easy availability, it cannot be directly applied for infected wound treatment. Herein, a solid phase synthesis strategy was proposed to fabricate oxidized sodium alginate-tobramycin conjugate (OSA-TOB) for anti-infection dressing development. 13C nuclear magnetic resonance spectra indicated that the oxidization process does not change the ratio of β-D-mannuronic acid (M) / α-L-guluronic acid (G) in OSA and the oxidization reaction shows no stereoselectivity. Elemental analysis disclosed that the graft ratio of tobramycin in OSA-TOB is 13.8 %. Antibacterial test indicated that OSA-TOB can effectively inhibit four prevalent pathogenic bacterial S.epidermidis, P. aeruginosa, S. aureus and E. coli via a different antibacterial mechanism compared to the original TOB. Hemolysis and cytotoxicity assays shown that OSA-TOB have superior hemocompatibility and cytocompatibility. Infected wound healing assay shown that the healing rate of OSA-TOB is the highest. Further analysis indicated that OSA-TOB can reduce the local inflammatory response, accelerate the form of epithelium and collagen deposition. In conclusions, OSA-TOB synthesized in solid phase can be potentially applied as a promising anti-infection wound dressing.

Synthesis, Radiolabeling, and Preclinical Evaluation of 68Ga/177Lu-Labeled Leuprolide Peptide Analog for the Detection of Breast Cancer.

Objectives: The expansion of novel and potent tumor receptor binding peptides is a promising approach for the precise targeting of various cancer. Leuprolide is a 9-residue peptide analog of gonadotropin-releasing hormone and is extensively used in the treatment of sex hormone-dependent tumors, including prostate, breast, and ovarian cancer. This preclinical study was undertaken to prepare a new radiolabeled leuprolide peptide for the detection of breast carcinoma. Methods: A 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-coupled 9-amino acid leuprolide peptide was synthesized after typical 9-fluorenylmethyl-oxycarbonyl-based solid-phase peptide synthesis and radiolabeled with both 68Ga and 177Lu radionuclides for theranostic use. The systemic pharmacokinetics was done in healthy balb/c mice. The in vitro tumor cell binding affinity was determined on MCF7, T47D, and MDA-MB-231 breast cancer cell lines. In vivo tumor targeting and micro positron-emission tomography imaging was performed on nude mice with MCF7 breast tumor xenografts. Results: The leuprolide peptide was conveniently synthesized by solid-phase synthesis strategy and its identity and purity were validated by mass spectrometry and high-performance liquid chromatography. The peptide radiolabeled efficiently (˃94%) with both diagnostic (68Ga) and therapeutic (177Lu) radionuclides and displayed nanomolar binding potency to all three tested MCF7, T47D, and MDA-MB-231 cell lines. Fast and favorable pharmacokinetics was observed for 68Ga/177Lu-leuprolide in healthy Balb/c mice. In nude mice, 68Ga-leuprolide peptide exhibited rapid clearance from the blood circulation with low to moderate (up to 5% ID/g) uptake/retention by the major body organs. The accumulation in the estrogen receptor-positive MCF7 tumor was 2.24% ± 0.62% ID/g at 45 min p.i, with good tumor to blood and muscle uptake ratios. The radiolabeled peptide was excreted primarily through the renal pathway. Conclusion: The encouraging results of this initial study demonstrate that additional testing of this leuprolide peptide seems to be indicated because of its convincing potential to be a new agent for the management of breast carcinoma.

Potent Bactericidal Antimycobacterials Targeting the Chaperone ClpC1 Based on the Depsipeptide Natural Products Ecumicin and Ohmyungsamycin A.

Ohmyungsamycin A and ecumicin are structurally related cyclic depsipeptide natural products that possess activity against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Herein, we describe the design and synthesis of a library of analogues of these two natural products using an efficient solid-phase synthesis and late-stage macrolactamization strategy. Lead analogues possessed potent activity against Mtb in vitro (minimum inhibitory concentration 125-500 nM) and were shown to inhibit protein degradation by the mycobacterial ClpC1-ClpP1P2 protease with an associated enhancement of ClpC1 ATPase activity. The most promising analogue from the series exhibited rapid bactericidal killing activity against Mtb, capable of sterilizing cultures after 7 days, and retained bactericidal activity against hypoxic non-replicating Mtb. This natural product analogue was also active in an in vivo zebrafish model of infection.

Solid phase synthesis of metal-free perovskite crystalline materials

Metal-free perovskites, a new class of perovskite materials, show attractive piezoelectric, ferroelectric and pyroelectric properties because of their intrinsic structural properties. The introduction of organic components also leads to desirable properties such as structural adjustability, high mechanical flexibility, environmentally friendly processing conditions and low treatment temperatures. However, explorations of new metal-free perovskite materials suffer from the drawbacks of their previous liquid phase synthesis method, such as high time cost and poor experimental reproducibility. Here, we reported the first solid-phase synthesis of metal-free perovskite crystalline materials. Using the optimized ball milling method, we found that the starting materials were fully converted to pure metal-free perovskite DABCO-NH4Br3 (DABCO ​= ​N,N′-diazabicyclo [2.2.2] octonium) in the size of 5–10 ​μm. This solid phase synthesis strategy was successfully applied to the synthesis of MDABCO-NH4I3 (MDABCO ​= ​N-methyl-N′-diazabicyclo [2.2.2] octonium), demonstrating the great potential for the preparation and exploration of metal-free perovskite materials via solid phase synthesis.

Inhibition of jack bean urease by amphiphilic peptides

In the current study, amphiphilic peptides were designed and screened against Jack bean urease by using computer aided drug discovery approach. The result showed that out of thirty-eight amphiphilic peptides 1, 3, 12, 18, 30, and 33 exhibit stronger binding affinity with the active site of the enzyme through chelation of charged amino acids with the nickel ions i.e., Ni+2 841 and Ni+2 842 as well as hydrophobic contacts of the nonpolar tail with the nonpolar residues in the active site. The selected amphiphilic peptides were synthesized by solid-phase peptide synthesis strategy, characterized by fast atomic bombardment mass spectroscopy (FAB-MS) and nuclear magnetic resonance spectroscopy (1H and 13C-NMR) and in vitro urease inhibitory activity of amphiphilic peptides was studied. Amphiphilic peptides 12 and 33 showed excellent urease inhibitory activity, (p < 0.001) with IC50 values 20.5 ± 0.01, and 28.1 ± 0.03 µM respectively, which was considerably better than thiourea used as positive control.