Impact of the Water Content in the Therapeutic Deep Eutectic Solvents

Deep eutectic solvent(s) (DES) are the new generation of greener and more sustainable solvents, formulated by the complex of hydrogen bond in the molecules. The solvents allow us to achieve a significantly lower freezing point compared to its components, an affordable formulation and a technology that is typically formulated to improve the bioavailability of a drug. In this research project, we synthesized an ibuprofen-menthol based therapeutic deep eutectic solvent and investigated how water content affects the structure and dynamics of the solvent. For synthesizing the ibuprofen-menthol DES, 2.0629 g of Ibuprofen and 4.6881 g of menthol were placed in a small breaker to achieve a 1:3 molar ratio. The mixer was covered by parafilm paper and was then heated on a hot plate at temperature of 50 ºC with 600 rpm for 30 minutes until a clear liquid was observed. In the infrared spectrum of the DES, a strong C-H stretching is noticed at 2800-2950 cm-1, OH bonds at 3345.57 cm-1 which involves in hydrogen bonding, and a less strong peak for the C=O stretching is detected at 1708.41 cm-1. Raman spectroscopy results showed that 10% and 20 % of water do not interrupt the ibuprofen-menthol’s Raman shift compared to the pure DES, however, significant change is observed while 30% and 40 % water were added to the system

Menthol Based Deep Eutectic Solvents to enhance the Chromatographic Separation of Hydrophobic Antimicrobial Temporin-L Peptide

Peptide therapeutics have grown popular over the past decade because of their wide applications in medicine. One of the problems of peptide therapeutic is the low solubility in water and organic solvents. Poorly soluble peptides have many problems associated to analytical characterization, purification, and applications. In this research, chromatographic separation of the hydrophobic Temporin-L peptide in menthol based deep eutectic solvent (DES) is investigated. Deep eutectic solvent (DES) is the alternative greener solvent and has similar characteristics of ionic liquids, but they are cheaper to synthesis, less toxic and environmentally friendly, recyclable, biodegradable, and are suitable for the biological system. Temporin-L (FVQWFSKFLGRIL) is known to be a very hydrophobic peptide, due to the presence of leucine, isoleucine, and phenylalanine. To assess the impact of menthol-thymol DES on the Temporin L, various samples were prepared by adding 1%, 5%, 10%, and 20% of DES. The Agilent 1290 infinity II UHPLC system equipped with a binary pump, a multisampler and a UV detector excitation at 230 nm was used for all experiments. ZORBAX C18 column (2.1x50 mm, 1.8 Micron) was utilized. Mobile phase consisted of water (A) and acetonitrile (B) with 0.01% TFA. The flow rate was set at 1 mL/min. In menthol-acetic acid- DES, the retention time, peak area, and height of the peptides did not significantly change when DES amount was increased. However, significant changes are noticed for menthol-thymol DES. The peak area and height of the peptide are drastically increased to 11,198 (mAU·s) and 2001 (mAU), respectively when the peptide was dissolved in 1% menthol-thymol DES compared to water (peak area: 537 mAU·s and height: 132 mAU). Moreover, similar trend was also observed when peptide was dissolved in 5%-20% DES. This study discloses that menthol-thymol DES can deliver the best chromatographic separation, recovery, and resolution for the hydrophobic peptides

Scorpion Venom-Based Peptides as Potential Therapeutics Against Bacterial Infections

Many human diseases worldwide are due to bacterial infection, and the current standard of care is antibiotic treatment. One of the biggest and most-pressing problems of the modern medicine is the rapid development of microbial antibiotic resistance. Antibiotic resistance is developed due to short generation cycles, mutation, and improper use of prescribed antibiotics. Without the development of new therapeutic solutions soon, bacterial diseases may become completely resistant to antibiotics and mortality and sickness will increase. Peptide therapeutics have grown popular over the past decade because of their wide applications in medicine and biotechnology. Therefore, developing new effective and specific agents is urgently needed to provide alternate therapeutic molecules to treat bacterial infections. Antimicrobial peptides, isolated from living species, are potential broad-spectrum antibacterial agents. Scorpion venom contains a mixture of peptides and proteins with varied bioactivities and receives great attention due to their potential application in peptide drug design and development. In this research, scorpion venom peptides were chemically synthesized using standard Fmoc-based synthesis protocols and tested their antimicrobial activity against known bacterial and fungal pathogens. The synthesized peptides are purified and characterized by mass spectrometry. AVP1701 peptide was eluted at 4.9 min and showed two intense peaks at m/z 1130.61 and 585.8109 which correspond to [M+H]+ and [M+2H]2+ charge states, respectively. Moreover, AVP2053 peptides was eluted at 5.7 min and showed two intense peaks related to their masses. A highly concentrated solution of peptides (AVP1701 and AVP2053) in various concentrations of DMSO were tested against various bacterial infection diseases using the Kirby-Bauer Disk Diffusion Susceptibility Test. Bacterial inhibition with AVP1701 was observed against the opportunistic pathogen Pseudomonas aeruginosa 01 and Escherichia coli, a common intestinal inhabitant. Broth dilutions and an expansive screen of the peptides against other pathogens is underway which will determine the minimum inhibitory concentration

Evaluating binding and interaction of selected pesticides with serum albumin proteins by Raman, 1H NMR, mass spectrometry and molecular dynamics simulation

Addressing the acute pesticide poisoning and toxicity to humans, is a global challenge of top priority. Serum albumin is the most abundant plasma protein, capable of binding with herbicide and pesticide residues. This study reports multifaceted approaches for in-depth and robust investigation of the molecular interactions of selected pesticides, including propanil (PPL), bromoxynil (BXL), metolachlor (MLR) and glyphosate (GPE) with bovine serum albumin (BSA) proteins using experimental (Raman and FTIR spectroscopy, native mass spectrometry and high field 1H NMR), molecular dynamics (MD) simulation and principal component analysis (PCA). The binding of pesticides with BSA resulted in BSA amide I and amide II Raman spectral shifts. PCA of Raman spectra of serum-pesticide complexes showed the grouping of pesticides on the score plot based on the similarities and differences in pesticides’ chemical structures. Native mass spectrometry results revealed strong adduct formation of the pesticides with the protein. The observed changes in chemical shifts, peak broadening or peak disappearance of characteristic proton signals of the pesticides, indicated altered chemical environments due to binding BSA-pesticides interactions. The results of MD simulation conducted for over 500 ns revealed strong pesticides interaction with LEU197, LEU218, LEU237, TRP213, SER286 and ILE289 residues to the site I of BSA. Free energy landscapes provided insights into the conformational changes in BSA on the binding of pesticides. Overall, the experimental and computational results are in consonant and indicate the binding of pesticides into the site I and site II (sub-domain IIA) of the BSA via hydrogen bonding, non-covalent and hydrophobic interactions. Communicated by Ramaswamy H. Sarma</p