Synthesis and Antioxidant of Some New Pyrazolo[1,5-a]pyrimidine, Pyrazolo[5,1-b]quinazoline and Imidazo[1,2-b]pyrazole Derivatives Incorporating Phenylsulfonyl Moiety

The synthesis and antioxidant of some new pyrazole analogs were described. It is achieved by the reaction of phenyl-4-(phenylsulfonyl)-1H-pyrazole-3,5-diamine (3) with different bifunctional reagents. The free radical-induced damage and the protective effects of the newly synthesized pyrazoles were studied. These new compounds inhibit the free radical-induced oxidative hemolysis of red blood cells effectively. It was found that these compounds effectively inhibit the free radical-induced oxidative hemolysis of red blood cells. Compound 5, which contain phenolic group, and 17, which bear sulfur, nitrogen atoms, and benzothiazole ring, respectively displayed high antioxidant activity. Analogs 15, 11, 10, and 9 were proved to exhibit antioxidative activity. Structures of new pyrazoles were confirmed by spectroscopic and elemental analyses and have been screened for their antioxidant activity.

Antimicrobial, Antioxidant and Antihemolytic Activities of Two Daphne gnidium Leaves Extracts

In this study, Daphne gnidium leaves extracts were screened for their Phenolic content, antimicrobial, antioxidant and antihemolitic activities. Decoction and maceration were used to obtain the aqueous (Aq E) and the ethanolic extract (Et E), respectively. Total phenolic content was determined using Folin–Ciocalteu reagent. Moreover, a disc diffusion assay and inhibition of mycelial growth test were applied to evaluate the antibacterial and antifungal activity. The extracts were also tested for their antioxidant effects in terms of DPPH, OH, H2O2, β-carotene, and ferrous ion chelating assays. To investigate antihemolytic activity, the 2,2,-azobis (2-amidinopropane) dihydrochloride (AAPH) was used to induce erythrocyte oxidative hemolysis. Results indicated that ethanolic extract (Et E) contains the highest polyphenol content (775.25 μg GAE/mg extract). The Et E inhibited the growth of bacterial strains with inhibition zone diameters from 7 to 15 mm. In contrast, no activities have been found against all fungal strains. In antihemolytic test, aqueous and ethanolic extracts showed almost the same effect with an HT50 value of 106 min. Ethanolic extract was found to be more active in DPPH and β-carotene assays (IC50: 5.76 μg/ml and 70% inhibition respectively). However, the aqueous extract showed a greater effect than the ethanolic one in metal chelating activity assay (IC50: 170 μg/ml), OH scavenging effect assay (IC50: 9.67 μg/ml) and H2O2 scavenging assay (IC50: 133.2 μg/ml).

Favism Induced Methemoglobinemia in G6DP Deficient Patients: Case Series and Review of Literature

Introduction: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a well-known cause of hemolysis. It has a notable prevalence in African, Asian, and Mediterranean countries. Favism is a common trigger of oxidative stress in G6PD deficient people, which can lead to hemolysis. Additionally, fava bean ingestion can cause methemoglobinemia (MethHgb), an abnormal variation in the Hgb in which the ferrous (Fe2+) iron in heme is oxidized to the ferric (Fe3+) state. It is rare to have both G6PD deficiency and MethHgb secondary to favism at the same time. The first-line treatment for MethHgb is methylene blue. However, in G6PD deficient patients, it can potentiate hemolysis. Methods: We reviewed the literature using PubMed and Google scholar and found 6 cases of MethHgb secondary to favism in patients with G6PD deficiency. We also analyzed two cases which are still unpublished, making a total of 8 cases. Results: All 8 cases were male with median age of 18 years (1 - 56). 1 patient had a prior diagnosis of G6PD deficiency while 7 were newly diagnosed. Median Hgb was 8.3gm/dL (4.6 - 12.5) and median MetHgb was 7.8 % (3.5 - 35). 1 patient received methylene blue, and 4 received Vitamin C. All of the patients recovered and were discharged [Table 1]. Unpublished case 1: A 56-year-old male presented with MethHgb and hemolytic anemia, secondary to fava bean ingestion. Hgb on admission and lowest recorded were 9.9 and 6.5 gm/dL, respectively. He had an SPO2 of 70% on room air and 101.2 % on ABG. Methylene blue administration worsened the hemolysis as he was G6PD deficient but not diagnosed before. He got better with discontinuation of methylene blue and Vitamin C and was discharged on day 5. Unpublished case 2: A 43-year-old male, known case of G6PD deficiency presented with MethHgb and hemolytic anemia, secondary to fava bean ingestion. Hgb on admission and lowest recorded were 12.5 and 7.4 gm/dL, respectively. He had an SPO2 of 82% on room air and 100 % on ABG. He received IV vitamin C and recovered and was discharged on day 4. Discussion: Methemoglobinemia is usually acquired, secondary to oxidative stress in the body, but can rarely be congenital. Enzyme systems such as NADH methemoglobin reductase, NADPH methemoglobin reductase, ascorbic acid, and glutathione reductase systems keep a check on the accumulation of methemoglobin in the blood. However, these mechanisms can be insufficient to counter the conversion of Hgb to MethHgb, consequently promoting an oxidative state in the body. It can be due to the overproduction of methemoglobin (secondary to exposure to certain drugs, chemicals, or food items, but can sometimes be hereditary) or under conversion to Hgb due to unavailable enzyme mechanisms. One of the causes of the inability to counteract methemoglobin can be secondary to G6PD deficiency. Patients with MetHgb have a low oxygen saturation (SPO2) on pulse oximeters but a falsely high SPO2 on arterial blood gasses (ABG). The treatment depends on symptoms and the level of MethHgb. The first step is to remove any possible precipitator if present. Symptomatic patients (and asymptomatic with a level of methemoglobin >30 %) are treated with methylene blue (1-2mg/kg), which is reduced to leuko-methylene blue via NADPH dependent methemoglobin reductase. This, in turn, reduces methemoglobin back to Hgb, correcting the abnormality [Figure 1]. Rarely, patients can present with co-occurrence of MethHgb and G6PD deficiency. In such cases, caution is required while giving methylene blue as they do not have sufficient levels of NADPH to reduce it. Otherwise, a cascade of oxidative hemolysis ensues secondary to underlying G6PD deficiency, resulting in a vicious cycle of further methemoglobinemia. The most frequent cause of this co-occurrence is the ingestion of fava beans, which can simultaneously induce MethHgb and potentiate G6PD deficiency. One of our patients had a history of favism without developing any symptoms. Only this time, he ate fava beans in a larger amount, leading to hemolysis and MethHgb. Conclusion: Favism is a rare cause of the co-occurrence of methemoglobinemia and hemolysis in G6PD deficient individuals. It is vital to identify G6PD deficiency in patients presenting with MethHgb, as the initiation of methylene blue in such individuals can result in a cascade of oxidative hemolysis. A history of fava beans ingestion without any symptoms does not rule out G6PD deficiency, as it is proportional to the number of beans ingested. Disclosures No relevant conflicts of interest to declare.

Antioxidant Extracts of Three Russula Genus Species Express Diverse Biological Activity

This study explored the biological properties of three wild growing Russula species (R. integra, R. rosea, R. nigricans) from Serbia. Compositional features and antioxidant, antibacterial, antibiofilm, and cytotoxic activities were analyzed. The studied mushroom species were identified as being rich sources of carbohydrates and of low caloric value. Mannitol was the most abundant free sugar and quinic and malic acids the major organic acids detected. The four tocopherol isoforms were found, and polyunsaturated fatty acids were the predominant fat constituents. Regarding phenolic compounds, P-hydroxybenzoic and cinnamic acids were identified in the prepared methanolic and ethanolic extracts, which displayed antioxidant activity through the inhibition of thiobarbituric acid reactive substances (TBARS) formation and oxidative hemolysis; the highest activity was attributed to the R. nigricans ethanolic extract. This is the first report on the antibacterial and antibiofilm potential of the studied species, with the most promising activity observed towards Streptococcus spp. (0.20–0.78 mg/mL as the minimal inhibitory concentration, MIC). The most promising cytotoxic effect was caused by the R. integra methanolic extract on non-small cell lung cancer cells (NCI-H460). Therefore, due to the observed in vitro bioactive properties, the studied mushrooms arise as a source of functional ingredients with potential to be used in novel nutraceutical and drug formulations, which can be used in the treatment of various diseases and health conditions.

The potential of melatonin in the prevention and attenuation of oxidative hemolysis and myocardial injury from cd147 SARS-CoV-2 spike protein receptor binding

The rapid escalation of pandemic health threats associated with the novel, pathogenic SARS-CoV-2 coronavirus poses unprecedented challenges as proven effective vaccines and drugs have yet to be produced. Refractory hypoxemia and myocardial injury have been observed as two of the major causes of fatality in COVID-19 patients. SARS-CoV-2 spike (S) protein binding to broadly expressed CD147 receptors on erythrocytes causes oxidative hemolysis that may result in refractory hypoxemia and myocardial injury. Both of these life-threatening conditions are further exacerbated by imbalance in ACE2 from spike (S) protein receptor binding. Dysregulation in the CD147-cyclophilin A signaling pathway, together with altered calcium signaling from SARS-CoV-2 ion channel activities, may contribute to hypercoagulation, thrombosis, and cardiac remodeling resulting in heart failure. Melatonin is an ancient pleiotropic molecule with recognized antioxidant properties that is essential for the protection of erythrocytes from oxidative hemolysis. Found in erythrocytes, melatonin can reverse hemolytic anemia, normalize heme synthesis, restore lymphocytes and platelet counts, and reduce vessel permeability during an acute hemolytic crisis by maintaining intracellular calcium homeostasis and reduction of oxidative stress. In acute hypoxic conditions, melatonin is cardioprotective via blunting of cardiopulmonary response to hypoxia and suppressing hypoxia pathways. Melatonin normalizes endothelial-dependent nitric oxide production to prevent multiple organ damage from hypercoagulability, thrombosis, and hypertension associated with oxidative hemolysis and ACE2 deficiency, protecting cardiomyocytes from hypertrophy. This review discusses the full potential of melatonin as a safe and effective therapeutic intervention for the prevention and attenuation of hemoglobinopathies, refractory hypoxemia and myocardial injury during critical COVID-19 infections.

Phytochemical Characterization and Bioactive Properties of Cinnamon Basil (Ocimum basilicum cv. ‘Cinnamon’) and Lemon Basil (Ocimum × citriodorum)

The aim of this work was to contribute to the knowledge on the chemical composition and bioactive properties of two species of the Ocimum genus, namely O. basilicum cultivar ’Cinammon’ and O. × citriodorum. For this purpose, samples of these plants grown in Portugal were evaluated for their composition in phenolic and volatile compounds, and the infusion and hydroethanolic extracts were assessed for their in vitro antioxidant, antimicrobial, cytotoxic, and anti-inflammatory activities. In total, the two basil samples showed the presence of seven caffeic acid and derivatives (dimers, trimers, and tetramers) and five flavonoids, mainly glycoside derivatives of quercetin. Despite some qualitative and quantitative differences, in both samples rosmarinic acid was the major phenolic compound, and linalool the predominant volatile compound. In general, the tested extracts provided relevant bioactive properties since both basil species showed higher antioxidant activity in Thiobarbituric Acid Reactive Substances (TBARs) and Oxidative Hemolysis Inhibition (OxHLIA) assays when compared with the positive control Trolox. Despite O. × citriodorum extracts showing slightly better activity against some strains, both types of extracts evidenced similar antimicrobial activity, being more active against Gram-positive bacteria. The extracts also revealed interesting cytotoxicity, particularly the O. × citriodorum hydroethanolic extract which was also the only one exhibiting anti-inflammatory activity.

Evaluation of the Functional Effects of an African American Glucose-6-Phosphate Dehydrogenase (G6PD) Polymorphism (Val68Met) on RBC Hemolytic Propensity and Post-Transfusion Recovery in a Humanized Mouse Model

Background: Growing evidence suggest that donor genetic variation is associated with RBCs storage integrity and post-transfusion recovery. In collaboration with the REDS III program, we performed a large-scale genome-wide association study (GWAS) study in ~13,000 healthy human blood donors, which demonstrated that RBCs with an African American G6PD-deficient A- variant (rs1050828, Val68Met) was associated with higher oxidative hemolysis after cold storage in normal volunteers. Despite a high prevalence of X-linked G6PD mutation in African American population (> 10%), blood donors are not routinely checked for G6PD deficiency and its importance in transfusion medicine is relatively understudied. We hypothesize that G6PD V68M SNP is associated with G6PD deficiency and modulates RBCs in vitro hemolytic propensity and in vivo post-transfusion recovery. Methods and Results: CRISPR-Cas9 technology was used to create non-synonymous human G6PD X-linked SNP (Val68Met) in C57B6 mice, and the desired genotypes were isolated by strategic back-crossing and sequential genotyping to ensure passage of SNP. G6PD enzymatic activity in erythrocytes was measured in fresh collected blood using a colorimetric assay kit. The predisposition of fresh and stored RBCs (after 11 days cold storage) to hemolysis was evaluated by subjecting washed mouse RBCs to selected stress assays, including osmotic fragility, mechanical fragility, and oxidative hemolysis using AAPH, diamide or H2O2. Hemolysis was measured by detection of supernatant cell-free hemoglobin using Drabkin's assay. Hematological values were measured using a Hemavet® 950 Hematology Analyzer System. Reticulocyte count was obtained using thiazole orange staining and analyzed by flow cytometry. We found severe disruption of G6PD enzymatic activity in erythrocytes from G6PD V68M SNP mice compared to WT mice (~5% residual activity in hemizygous male and ~60% in heterozygous female mice). Significant increased oxidative hemolysis was observed in both fresh and stored mouse RBCs with G6PD SNP, consistent with the GWAS study in human. G6PD V68M SNP hemizygous male mice had higher mean corpuscular volume (MCV) and lower mean corpuscular hemoglobin concentration (MCHC) compared to WT mice. However, no difference was observed in storage hemolysis, osmotic fragility, mechanical fragility and reticulocyte counts. Transfusion experiments with stored red blood cells from G6PD hemizygote males into GFP positive recipients will evaluate red blood cell recovery and half-life after standard cold storage and transfusion. Conclusions: We successfully generated a novel mouse strain carrying a "humanized" African American G6PD V68M variant which resembles the phenotype of humans with G6PD deficiency and increased oxidative hemolysis. Studies are undertaken to further investigate the effects of G6PD V68M SNP on RBCs structure, functions and in vivo post-transfusion recovery. Disclosures Gladwin: Bayer Pharmaceuticals: Other: Co-investigator; United Therapeutics: Patents & Royalties: Co-inventor on an NIH government patent for the use of nitrite salts in cardiovascular diseases ; Globin Solutions, Inc: Patents & Royalties: Provisional patents for the use of recombinant neuroglobin and heme-based molecules as antidotes for CO poisoning.