Novel ammonium phosphinates containing peptide moiety: Synthesis, structure, and in vitro antimicrobial activity

Covalent Graft of Lipopeptides and Peptide Dendrimers to Cellulose Fibers

Introduction: Bacterial proliferation in health environments may lead to the development of specific pathologies, but can be highly dangerous under particular conditions, such as during chemotherapy. To limit the spread of infections, it is helpful to use gauzes and clothing containing antibacterial agents. As cotton tissues are widespread in health care environments, in this contribution we report the preparation of cellulose fibers characterized by the covalent attachment of lipopeptides as possible antimicrobial agents. Aim: To covalently link peptides to cotton samples and characterize them. Peptides are expected to preserve the features of the fabrics even after repeated washing and use. Peptides are well tolerated by the human body and do not induce resistance in bacteria. Materials and Methods: A commercially available cotton tissue (specific weight of 150 g/m2, 30 Tex yarn fineness, fabric density of 270/230 threads/10 cm in the warp and weft) was washed with alkali and bleached and died. A piece of this tissue was accurately weighed, washed with methanol (MeOH) and N,N-dimethylformamide (DMF), and air-dried. Upon incubation with epibromohydrin, followed by treatment with Fmoc-NH-CH2CH2-NH2 and Fmoc removal, the peptides were synthesized by incorporating one amino acid at a time, beginning with the formation of an amide bond with the free NH2 of 1,2–diaminoethane. We also linked to the fibers a few peptide dendrimers, because the mechanism of action of these peptides often requires the formation of clusters. We prepared and characterized seven peptide-cotton samples. Results: The new peptide-cotton conjugates were characterized by means of FT-IR spectroscopy and X-ray Photoelectron Spectroscopy (XPS). This latter technique allows for discriminating among different amino acids and thus different peptide-cotton samples. Some samples maintain a pretty good whiteness degree even after peptide functionalization. Interestingly, these samples also display encouraging activities against a Gram positive strain. Conclusions: Potentially antimicrobial lipopeptides can be covalently linked to cotton fabrics, step-by-step. It is also possible to build on the cotton Lys-based dendrimers. XPS is a useful technique to discriminate among different types of nitrogen. Two samples displaying some antibacterial potency did also preserve their whiteness index.

Pharmacophores Modeling in Terms of Prediction of Theoretical Physicochemical Properties and Verification by EXPERIMENTAL correlations of Carbacylamidophosphates (CAPh) and Sulfanylamidophosphates (SAPh) Tested as New Carbonic Anhydrase Inhibitors

Background:

The function of Carbonic anhydrase is to facilitate the physiological process i.e. interconversion of CO2 to HCO3 - by hydration. Carbonic anhydrase enzyme plays a vital role in different physiological processes to regulate pH as well as regulate the inner environment of CO2 and secretion of electrolytes.

Methods:

Six representatives of amidophosphate derivatives (L1-L6) were synthesized and evaluated for their biological activities against carbonic anhydrase enzyme.

Results:

Out of six derivatives, L1 (IC50 = 12.5 ± 1.35 µM), and L2 (IC50 = 3.12 ± 0.45 µM) showed potent activity against BCA-II. While (L3, L4 and L5) showed weak inhibitory activity with IC50 values of 24.5 ± 2.25, 55.5± 1.60, and 75.5 ± 1.25 µM, respectively and were found to be weak inhibitors of carbonic anhydrase as compared to acetazolamide (IC50 =0.12± 0.03µM), used as standard inhibitor. A computational Petra/Osiris/Molinspiration/DFT (POM/DFT) based model has been expanded for the determination of physicochemical parameters governing the bioactivity amidophosphate derivatives (L1-L6) containing (O1 --- O2) pharmacophore site. The six compounds (L1-L6) analyzed here were previously experimentally and now virtually screened for their anti-carbonic anhydrase activity.

:

A computational Petra/Osiris/Molinspiration/DFT (POM/DFT) based model has been expanded for the determination of physicochemical parameters governing the bioactivity amidophosphate derivatives (L1-L6) containing (O1 --- O2) pharmacophore site. The six compounds (L1-L6) analyzed here were previously experimentally and now virtually screened for their anti-carbonic anhydrase activity.

Conclusion:

The highest anti-carbonic anhydrase activity was obtained for compound L2, which exhibited excellent bioactivity (% of inhibition = 95%), comparable to acetazolamide (% of inhibition = 89%). The compound L3 represents increased activity as compared to its analogues (L4-L6). The increase of bioactivity from L3 to L4-L6 could be attributed to the presence of a minimum of steric effect of substituents of P=O moiety which plays a decisive template part in the organization of anti-carbonic anhydrase (O1---O2) phramacophore site. Moreover, it is inexpensive, has little side effects and possible inclusions in selective anti-carbonic anhydrase agents design.