Metabolic profiling and antibacterial activity of Eryngium pristis Cham. & Schltdl. - prospecting for its use in the treatment of bacterial infections

Morbidity and mortality of the infected patients by multidrug-resistant bacteria have increased, emphasizing the urgency of fight for the discovery of new innovative antibiotics. In this sense, natural products emerge as valuable sources of bioactive compounds. Among the biodiversity, Eryngium pristis Cham. & Schltdl. (Apiaceae Lindl.) is traditionally used to treat thrush and ulcers of throat and mouth, as diuretic and emmenagogue, but scarcely known as an antimicrobial agent. With this context in mind, the goals of this study were to investigate the metabolic profile and the antibacterial activity of ethanolic extract (EE-Ep) and hexane (HF-Ep), dichloromethane (DF-Ep), ethyl acetate (EAF-Ep) and butanol (BF-Ep) fractions from E. pristis leaves. Gas Chromatography-Mass Spectrometry (GC-MS) was performed to stablish the metabolic profile and revealed the presence of 12 and 14 compounds in EAF-Ep and HF-Ep, respectively. β-selinene, spathulenol, globulol, 2-methoxy-4-vinylphenol, α-amyrin, β-amyrin, and lupeol derivative were some of phytochemicals identified. The antibacterial activity was determined by Minimal Inhibitory Concentration (MIC) using the broth micro-dilution against eight ATCC® and five methicillin-resistant Staphylococcus aureus (MRSA) clinical strains. HF-Ep was the most effective (MIC ≤ 5,000 µg/µL), being active against the largest part of tested Gram-positive and Gram-negative bacterial strains, including MRSA, with exception of Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 9027) and (ATCC 27853). These results suggest that E. pristis is a natural source of bioactive compounds for the search of new antibiotics which can be an interesting therapeutic approach to recover patients mainly infected by MRSA strains.

COVID-19 immunologic and toxicological implication: Innate immune sensor and immune escape

Related COVID-19 and new Variant and treatment like vaccine it is relevant to deeply verify the immunologic implication and in a special way regarding the innate immune sensor system and the evasion of the immune system. This can be crucial to search for new strategies to fight this severe disease under a Toxicology-antidotes point of view. The rapid emergence of a new variant is under study by researchers because some of these show different responses to antibodies as reported in literature (vaccine efficacy?). In this article after a review part it is submitted a collection of hypothesis of solution to contrast COVID-19. Spread and mortality and project hypothesis. A new toxicological approach also in a viral respiratory disease can be a novelty to adequately fight this severe condition and this focusing not only towards specific immunity but also a specific measures. A toxicological approach in drug- vaccine like products designing makes it possible to get the clinical outcomes needed.

Production and characterization of staphylokinase enzyme from Staphylococcus aureus ASIA4

Six clinical Staphylococcus aureus strains isolated from different clinical samples. Isolates ASIA1 and ASIA2 isolated from urine samples of urinary tract infected patients; ASIA3 isolated from swab samples of burn abscess patients at Assiut University hospital as well as ASIA4, ASIA5 and ASIA6 obtained from blood samples of different cancer patients at South Egypt Cancer Institute. All isolates showed varied abilities to produce halo zones of hydrolysis with different diameters on blood agar, heated plasma agar, casein agar and skim milk agar plates along with different clot lyses percent. Staphylococcus aureus ASIA3, ASIA4 and ASIA6 produced 4.83, 5.98 and 2.08 U/mL of staphylokinase on tryptone soy broth reduced to 1.95, 2.08 and 1.70 U/mL on casein hydrolysate yeast extract broth, respectively. On the other hand, Staphylococcus aureus ASIA1, ASIA2 and ASIA5 gave 2.20, 2.93 and 3.65 U/mL on CYEB compared to 2.10, 1.88 and 3.41 U/mL on TSB as production medium. The staphylokinase yielded from the hyperactive producer Staphylococcus aureus ASIA4 was increased for 7.64-fold (from 2.08 U/mL to 15.88 U/mL) on the optimized fermentation medium composed of 5.0 g sucrose as carbon source, 10.0 g soy bean as nitrogen source, 5.0 g NaCl, K2HPO4 5.0 g and pH 7.0 that inoculated with isolate ASIA4 and incubated for 24 h at 35 °C. Moreover, Staphylokinase activity reached its peak at the optimal enzymatic reaction conditions which were reaction time 25 min, casein as substrate, reaction pH 8.0, reaction temperature 40 °C. In addition it retained 100% of its activity at temperature ranged between 15 and 45 °C and pH ranged from pH 6.0 to 9.0. EDTA inhibited the enzyme activity by 3.0% to 32.2% with increasing its values from 30.0 to 90.0 mM. MgCl2 at a concentration of 30 mM increased the enzyme activity by 4% and then slightly decreased at higher concentrations but NaCl was potent staphylokinase activator at concentrations lower than 90 mM.