Synergistic antimicrobial activity of melittin with clindamycin on the expression of encoding exfoliative toxin in Staphylococcus aureus

Potentiality of raloxifene loaded melittin functionalized lipidic nanovesicles against pancreatic cancer cells

Pancreatic cancer (PC) frequency and incidence have grown rapidly in recent years. One of the most serious problems with PC is the existence of asymptotic manifestations, which frequently delays early detection, and until the diagnosis is established, tumor cells progress to the metastatic stage. Another significant concern with PC is the scarcity of well-defined pharmacotherapeutic drugs. The aim of this study was to develop an efficient nanocarrier system to augment the efficacy of raloxifene (RLX) against PC cells. As a result, the current investigation was carried out in order to give an effective treatment method, in which an optimum RLX loaded phospholipid-based vesicles with melittin (PL-MEL) was chosen using experimental design software, with particle size, zeta potential and entrapment efficiency % as dependent variables. Furthermore, anticancer activity against PANC1 cells was assessed. The optimized nanovesicle parameters were 172.5 nm for the measured size, zeta potential of -0.69 mV, and entrapment efficiency of 76.91% that were in good agreement with the expected ones. RLX-raw, plain formula, and optimized RLX-PL-MEL showed IC50 concentrations of 26.07 ± 0.98, 9.166 ± 0.34, and 1.24 ± 0.05 µg/mL, respectively. Furthermore, cell cycle analysis revealed that the nanovesicle was most effective in the G2-M phase, whereas Bax, and Bcl-2 estimates revealed that optimized RLX formula had the highest apoptotic activity among treatments investigated. However, as compared to RLX alone or plain formula alone, the optimized formula demonstrated higher expression of TNFα and Bax while a significant reduction of Bcl-2 and NF-κB expression was observed. mitochondrial membrane potential (MMP) analysis confirmed the apoptosis as well as the anticancer effect of the optimized formula. Thus, the present study results showed an improvement in the anti-PC effects of the RLX with phospholipid conjugated melittin, making it a novel treatment approach against PC.

Hybrid nanoparticulate system of Fluvastatin loaded phospholipid, alpha lipoic acid and melittin for the management of colon cancer

As a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, Fluvastatin (FLV) is used for reducing low-density lipoprotein (LDL) cholesterol as well as to prevent cardiovascular problems. FLV showed cell line cytotoxicity and antitumor effect. Melittin (MEL) exhibits antineoplastic activity and is known to be promising as a therapeutic option for cancer patients. The aim of this work was to investigate the combination of FLV with MEL loaded hybrid formula of phospholipid (PL) with alpha lipoic acid (ALA) nanoparticles to maximize anticancer tendencies. This study examines the optimization of the prepared formulation in order to minimize nanoparticles size and maximize zeta potential to potentiate cytotoxic potentialities in colon cancer cells (Caco2), cell viability, cell cycle analysis and annexin V were tested. In addition to biological markers as P53, Bax, bcl2 and Caspase 3 evaluation The combination involving FLV PL ALA MEL showed enhanced cytotoxic potentiality (IC50 = 9.242 ± 0.35 µg/mL), about twofold lower, compared to the raw FLV (IC50 = 21.74 ± 0.82 µg/mL). According to studies analyzing cell cycle, optimized FLV PL ALA MEL was found to inhibit Caco2 colon cancer cells more significantly than other therapeutic treatments, wherein a higher number of cells were found to accumulate over G2/M and pre-G1 phases, whereas G0/G1/S phases witnessed the accumulation of a lower number of cells. The optimized formulation may pave the way for a novel and more efficacious treatment for colon cancer.

Mastoparans: A Group of Multifunctional α-Helical Peptides With Promising Therapeutic Properties

Biologically active peptides have been attracting increasing attention, whether to improve the understanding of their mechanisms of action or in the search for new therapeutic drugs. Wasp venoms have been explored as a remarkable source for these molecules. In this review, the main findings on the group of wasp linear cationic α-helical peptides called mastoparans were discussed. These compounds have a wide variety of biological effects, including mast cell degranulation, activation of protein G, phospholipase A₂, C, and D activation, serotonin and insulin release, and antimicrobial, hemolytic, and anticancer activities, which could lead to the development of new therapeutic agents.

Effects of citronellal on growth and enterotoxins production in Staphylococcus aureus ATCC 29213

Staphylococcus aureus (S. aureus) is known to be one of the most common foodborne pathogens capable of secreting a wide range of exotoxins such as enterotoxin, which severely threatens the health of consumers. Over the past few years, the development of safe and effective strategies in inhibiting the growth and enterotoxins generation of S. aureus in food turns out to be the research focus and emphasis. This research explores citronellal (CIT), a native compound with extensive existence in spices, which could effectively inhibit the growth and enterotoxins generation of S. aureus (ATCC 29213). Results from minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill curves, showed that CIT could tremendously inhibit the growth of S. aureus. Analysis on hemolysin showed that CIT at sub-MIC could significantly (p < 0.05) inhibit the hemolytic activity of S. aureus. As revealed by the results of ELISA, the production of enterotoxins in the culture supernatant and pork meat decreased significantly (p < 0.05) after exposure to CIT at sub-MIC. Furthermore, a significant (p < 0.05) decrease in dose-dependent was found in the transcription levels of virulence-related genes. In all, CIT proved to be a possible inhibitor of the growth and enterotoxins production of S. aureus with highly promising application in the food industry.

Screening of secondary metabolites and antioxidant potential of endophytic fungus Penicillium citrinum and host Digitaria bicornis by spectrophotometric and electrochemical methods

Perennial grasses are hosts to an extremely diverse assemblage of endophytic fungi, but their significance is still underexplored. In the present study, an endophytic fungus was isolated from the aerial regions of Digitaria bicornis (Lam.) Roem. & Schult. and was characterized by morphological and molecular methods (ITS rDNA region), as Penicillium citrinum Thom. The crude extracts of endophytic fungus and host were recovered and evaluated for their antioxidant potential by spectrophotometric and electrochemical methods. The present study was also an attempt to compare the anti-radical power of extracts by spectrophotometric (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), hydrogen peroxide and nitric oxide radical scavenging assay) and electrochemical (cyclic voltammetry) methods and suggested that cyclic voltammetry could be used routinely instead of assaying by more number of spectrophotometric methods. The results indicated that the ethyl acetate extract of P. citrinum and methanolic extract of D. bicornis has potential compounds with antioxidant and other pharmaceutical activities. Nine and 17 antioxidant biomolecules, respectively, in P. citrinum and D. bicornis extracts were detected by OHR-LC-MS and the presence of function group of the bioactive compounds was confirmed by FTIR spectroscopy. Finally, the study also reported that the extracts of P. citrinum and D. bicornis have several bioactive compounds with application in commercial pharmaceutical industries.

Antibiotics and ECMO in the Adult Population-Persistent Challenges and Practical Guides

Extracorporeal membrane oxygenation (ECMO) is an emerging treatment modality associated with a high frequency of antibiotic use. However, several covariables emerge during ECMO implementation, potentially jeopardizing the success of antimicrobial therapy. These variables include but are not limited to: the increased volume of distribution, altered clearance, and adsorption into circuit components, in addition to complex interactions of antibiotics in critical care illness. Furthermore, ECMO complicates the assessment of antibiotic effectiveness as fever, or other signs may not be easily detected, the immunogenicity of the circuit affects procalcitonin levels and other inflammatory markers while disrupting the immune system. We provided a review of pharmacokinetics and pharmacodynamics during ECMO, emphasizing practical application and review of patient-, illness-, and ECMO hardware-related factors.

Development of Novel Peptides for the Antimicrobial Combination Therapy against Carbapenem-Resistant Acinetobacter baumannii Infection

Carbapenem-resistant Acinetobacter baumannii (CRAB) infection has a high mortality rate, making the development of novel effective antibiotic therapeutic strategies highly critical. Antimicrobial peptides can outperform conventional antibiotics regarding drug resistance and broad-spectrum activity. PapMA, an 18-residue hybrid peptide, containing N-terminal residues of papiliocin and magainin 2, has previously demonstrated potent antibacterial activity. In this study, PapMA analogs were designed by substituting Ala¹⁵ or Phe¹⁸ with Ala, Phe, and Trp. PapMA-3 with Trp¹⁸ showed the highest bacterial selectivity against CRAB, alongside low cytotoxicity. Biophysical studies revealed that PapMA-3 permeabilizes CRAB membrane via strong binding to LPS. To reduce toxicity via reduced antibiotic doses, while preventing the emergence of multi-drug resistant bacteria, the efficacy of PapMA-3 in combination with six selected antibiotics was evaluated against clinical CRAB isolates (C1–C5). At 25% of the minimum inhibition concentration, PapMA-3 partially depolarized the CRAB membrane and caused sufficient morphological changes, facilitating the entry of antibiotics into the bacterial cell. Combining PapMA-3 with rifampin significantly and synergistically inhibited CRAB C4 (FICI = 0.13). Meanwhile, combining PapMA-3 with vancomycin or erythromycin, both potent against Gram-positive bacteria, demonstrated remarkable synergistic antibiofilm activity against Gram-negative CRAB. This study could aid in the development of combination therapeutic approaches against CRAB.