Comparative toxicological evaluation of carvacrol, acetylcarvacrol anda fipronil-based pesticide in human blood cells Isaac Filipe Moreira Konig, Aline Chaves Reis, Mariana Aparecida Braga, Dirceu De Sousa Melo, Erika Aparecida Oliveira, et al. Drug and Chemical Toxicology, 2024 Plant-derived chemicals are promising substances to control arthropod pests, although synthetic ones are still the most frequently used. Thus, comparative toxicological studies are needed to determine if natural substances are safe alternatives to replace the use of synthetic chemicals. This study aimed to compare the toxicity of carvacrol (natural origin), acetylcarvacrol (semi-synthetic) and a fipronil-based pesticide (synthetic). We assessed the effects of these chemicals on hemolytic activity, erythrocytes morphology and leucocyte viability using whole blood from human subjects. Additionally, DNA damage was evaluated through comet and DNA fragmentation assays. Fipronil and carvacrol caused hemolysis at concentrations ranging from 0.5 to 2.0%, whereas acetylcarvacrol did not cause hemolysis at 0.5 and 0.75%. Fipronil and carvacrol caused severe alterations in erythrocytes’ morphology at 2%, such as ghost erythrocytes, elliptocyte-like shape and rouleau-like shape, presenting only 3.3 and 8.3% normal cells, respectively, at this concentration. However, 73.3% erythrocytes incubated with 2% acetylcarvacrol exhibited normal morphology. Fipronil considerably reduced leucocytes viability, decreasing it to 78% at 2%. Carvacrol and acetylcarvacrol showed no differences in leucocyte viability for 0.5 to 1.0%, but a decrease was observed for 2% carvacrol. The comet assay showed similar DNA damage for fipronil and carvacrol, but it was significantly lower for 1 and 2% acetylcarvacrol. Incubation with genomic DNA showed that only fipronil caused fragmentation of this molecule. Thus, we conclude that carvacrol and fipronil can present similar toxicity at higher concentrations. However, acetylation of carvacrol significantly reduced its toxicity to human blood cells compared with the other chemicals.
Intense Caloric Restriction from Birth Prevents Cardiovascular Aging in Rats Dirceu de Sousa Melo, Liliane Costa Pereira, Carina Sousa Santos, Bruno Ferreira Mendes, Isaac Filipe Moreira Konig, et al. Rejuvenation Research, 2023 We previously demonstrated that a 50% caloric restriction from birth improves several cardiometabolic risk factors in young rats. In this study, we investigated in middle-aged rats the consequences of a 50% caloric restriction (CR) from birth on cardiometabolic risk factors, heart function/morphology, ventricular arrhythmia, and fibrillation incidence, and cardiac intracellular proteins involved with redox status and cell survival. From birth to the age of 18 months, rats were divided into an Ad Libitum group (AL18), which had free access to food, and a CR18 group, which had food limited to 50% of that consumed by the AL18. Resting metabolic rate, blood pressure, and heart rate were recorded, and oral glucose and intraperitoneal insulin tolerance tests were performed. Blood was collected for biochemical analyses, and visceral fat and liver were harvested and weighed. Hearts were harvested for cardiac function, histological, redox status, and western blot analyses. The 50% CR from birth potentially reduced several cardiometabolic risk factors in 18-month-old rats. Moreover, compared with AL18, the CR18 group showed a ~50% increase in cardiac contractility and relaxation, nearly 3-5 times less incidence of ventricular arrhythmia and fibrillation,~18% lower cardiomyocyte diameter, and ~60% lower cardiac fibrosis. CR18 hearts also improved biomarkers of antioxidant defense and cell survival. Collectively, these results reveal several metabolic and cardiac anti-aging effects of a 50% CR from birth in middle-aged rats.
Non-Lactic Probiotic Beverage Enriched with Microencapsulated Red Propolis: Microorganism Viability, Physicochemical Characteristics, and Sensory Perception Iara Ferreira, Dirceu de Sousa Melo, Marly Silveira Santos, Disney Ribeiro Dias, Carolina Oliveira de Souza, et al. Fermentation, 2023 This work aimed to develop a non-dairy functional beverage fermented with probiotic strains and fortified with Brazilian red propolis (microencapsulated and extracted). The non-dairy matrix consisted of oats (75 g), sunflower seeds (175 g), and almonds (75 g). It was fermented by a starter co-culture composed of Lactiplantibacillus plantarum CCMA 0743 and Debaryomyces hansenii CCMA 176. Scanning electron microscopy analysis was initially performed to verify the integrity of the microcapsules. The viability of the microorganisms after fermentation and storage, chemical composition (high performance liquid chromatography (HPLC) and gas chromatography coupled to mass spectrometry (GC-MS) analyses), rheology, antioxidant activity, and sensory profile of the beverages were determined. After fermentation and storage, the starter cultures were well adapted to the substrate, reducing the pH (6.50 to 4) and cell count above 7.0 log CFU/mL. Lactic acid was the main organic acid produced during fermentation and storage. In addition, 39 volatile compounds were detected by gas chromatography coupled to mass spectrometry (GC-MS), including acids, alcohols, aldehydes, alkanes, alkenes, esters, ethers, phenols, terpenes, and others. The addition of propolis extract increased the antioxidant and phenolic activity and the presence of volatile esters but reduced the beverage’s acceptability. The addition of microencapsulated propolis was more associated with the presence of higher alcohols and had similar acceptance to the control beverage. The combination of a non-dairy substrate, a starter co-culture, and the addition of propolis led to the development of a probiotic beverage with great potential for health benefits.
A Little Helper: Beneficial Bacteria with Growth-Promoting Mechanisms Can Reduce Asian Soybean Rust Severity in a Cell-Free Formulation Victor Hugo Buttrós, Neílton Antônio Fiusa Araújo, Vinícius de Abreu D’Ávila, Maysa Mathias Alves Pereira, Dirceu de Sousa Melo, et al. Agronomy, 2022 Growth-promoting bacteria are already used in sustainable agricultural systems in Brazil. The market is dominated by inoculants and biological pesticides, which do not reach the full potential of this tool in the agricultural sector. This study aimed to evaluate four bacterial strains for the presence of growth promotion mechanisms, as well as the reduction of Asian rust severity in soybean plants and its effects on three antioxidant enzymes during pathogenesis. The plants were treated using the bacterial cells and/or their biosurfactants before inoculation of the pathogen (IOP). Severity was measured based on a diagrammatic scale at 14, 18 and 21 days after IOP, and the activities of the enzymes SOD, CAT, and APX were evaluated 21 days after IOP. Treatments containing only bacterial cells were not efficient in reducing the severity, with losses of leaf area reaching 15%, while the addition of biosurfactants led to a result that is similar to the biofungicide, based on Bacillus subtilis (Serenade®). The presence of direct growth promotion mechanisms can be observed in all isolates, as well as the role of bacterial metabolites, especially lipopeptides, in the biological control of diseases and the modulation of the plant’s immune response.
