Many antimicrobial compounds have been seeking to protect the human body against pathogenic microbial infections. In recent times, there has been considerable growth of pathogens resistant to existing drugs due to the inappropriate use of antibiotics. In the present study, bacteria isolated from the honey of stingless bees native to the Amazon called Scaptotrigona aff. postica and Apis mellifera were used to determine their potential antimicrobial properties and characterize the medium cultivated with isolated bacteria. The results showed inhibition of nine isolates. Among these isolates, SCA12, SCA13, and SCA15 showed inhibitory activity similar to that of vancomycin, which was used as a positive control. The SCA13 strain obtained the best results with antimicrobial extract against the tested pathogens; the species was identified as Enterococcus faecalis, and its lyophilized extract was characterized by temperature, pH, and trypsin, in which they showed antimicrobial activity. This work shows that bacteria isolated from the stingless bee honey, Scaptotrigona aff. postica, have the potential to produce antimicrobial substances.

Wound healing is a complex and coordinated process involving interactions between cells and various messenger systems. This study conducted in vivo tests to determine the healing effect of propolis (PR)-based cream derived from the Amazon stingless bee, Scaptotrigona aff. postica, reared in açaí (Euterpe oleracea) monoculture, on induced wounds in rats. Data were obtained by monitoring injuries on 14 Wistar rats, divided into three groups (G1, G2 and G3), each receiving specific treatments: propolis-based cream (PR), collagenase (PC) and neutral cream (NC). Over the seven days of treatment, the lesions were measured using photographic records and ImageJ software to evaluate the healing effectiveness of the test cream. ImageJ software version 1.53g was used to compare the wound diameters for each treatment. After seven days, histopathological analyses of the induced lesions were performed. It was observed that collagenase (PC) and the test cream (PR) did not differ significantly in terms of wound diameter reduction. However, the propolis-based cream directly influenced the lesion maturation process and exhibited a milder inflammatory response compared to the positive control (PC). This effect is possibly associated with antimicrobial and anti-inflammatory compounds identified by GC/MS analysis in the propolis. Notably, this is the first report describing propolis of Scaptotrigona aff. postica obtained from açaí monocultures with strong healing potential, highlighting the identification of a high concentration of phenolic compounds that aid directly in wound repair.

Manganese (Mn²⁺) is an abundant chemical element in the earth’s crust and is present in soil, water, and industrial environments, including mining, welding, and battery manufacturing. Manganese (Mn) is an essential metal needed as a cofactor for many enzymes to maintain proper biological functions. Excessive exposure to Mn in high doses can result in a condition known as manganism, which results in disorders of the neurological, cardiac, and pulmonary systems. The aim of this study was to assess cardiac susceptibility to manganese intoxication in Colossoma macropomum subjected to a fixed concentration of 4 mg/mL for a period of up to 96 h. This study used 45 Tambaquis (30.38 ± 3.5 g) divided into five groups of 9 animals/treatment. The treated groups were exposed to the manganese concentration for a period of 24, 48, 72, and 96 h, after which the animals’ ECGs were recorded, showing heart rate, R-R interval, P-Q interval, QRS complex duration and S-T interval. The results showed that cardiac activity decreased as the contact time increased, with an increase in the P-Q and S-T intervals. This indicates that the breakdown of circulatory homeostasis in these animals was caused by contact time with manganese.

The biodiversity of Brazil provides an excellent climate and favorable pollination conditions for Apis mellifera L., especially in the Eastern Amazon region, which boasts vast floral wealth, including an abundance of açaí (Euterpe oleracea) flowers and fruits. In the present study, seven types of honey were evaluated: three containing floral nectar from açaí (Açaí honey) collected in the Eastern Amazon region (Açaí honey from Breu Branco (AH1 and AH2) and Açaí honey from Santa Maria (AH3), both from the state of Pará, Brazil) and four honeys from different regions of Brazil (Aroeira honey from Minas Gerais, Cipó-Uva honey from Distrito Federal, Mangue honey from Pará, and Timbó honey from Rio Grande do Sul). The characteristics of these honeys were evaluated by examining their physicochemical properties, melissopalynological aspects, color, antioxidant potential, and their constituent compounds, which were confirmed through GC-MS analysis. Açaí floral nectar honeys presented physicochemical results similar to those of other honeys, aligning with Brazilian legislation norms, but differed in their high values of free acidity, apparent sugars, and lower reducing sugars, which are directly related to their botanical origin. These differences correlate with unique flavor and distinct aroma characteristics. Melissopalynological analysis confirmed the botanical origin of the honeys containing açaí floral nectar, which had a color range from amber to dark amber. The three açaí honeys demonstrated high antioxidant capacity and superior flavonoid and polyphenol content compared to other honeys, particularly the açaí honey from Breu Branco (AH1), which had four times the content to combat free radicals compared to the honey with the highest potential (Aroeira honey). GC-MS analysis confirmed the presence of antioxidant properties as well as potential anti-inflammatory, antibacterial, antimicrobial, and antitumor capabilities in açaí honeys, which have not yet been fully studied.

The honeys produced by stingless bees native to the Amazon (Meliponini) are distinguished by their high moisture and acidity content, along with elevated levels of phenolic acids and flavonoids. They also feature a rich and diverse microbiota, including organisms as Lactobacillus acidophilus, Bifidobacterium animalis, and Saccharomyces spp., setting them apart from honey produced by Apis mellifera L. The internal microbiota contributes to natural fermentation processes that enhance honey’s acidity and unique properties. These honeys exhibit potent antimicrobial activity, effectively inhibiting the growth of pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. This antimicrobial efficacy stems from factors like the presence of hydrogen peroxide, low pH levels, low sugar concentration, and specific antibacterial compounds. Consequently, honey holds promise for therapeutic applications, including the development of novel medical and food products. The microbial biodiversity present also suggests potential for discovering new probiotics that could benefit human health.

Menthol, a natural monoterpene extracted from Mentha species, has gained attention as an alternative sedative and anesthetic in aquaculture. However, its physiological safety range and potential sublethal toxicity remain insufficiently defined. This study investigated the cardiac and behavioral effects of menthol sedation in Oreochromis niloticus , aiming to identify a therapeutic window and elucidate its underlying mechanisms of action. Juvenile fish were exposed to graded concentrations of menthol (100–250 mg L⁻¹) to evaluate induction and recovery times, cardiac rhythm stability, and electrocardiographic parameters, including heart rate, QRS amplitude, and PQ and QT intervals. Additional assays with the GABAAA receptor antagonist flumazenil (1 mg kg⁻¹, i.p.) were performed to determine neurophysiological mediation. Menthol induced a concentration-dependent decrease in heart rate and prolongation of ventricular conduction intervals, characterizing sinus bradycardia without arrhythmia. Concentrations between 100 and 200 mg L⁻¹ provided effective sedation and rapid recovery while maintaining hemodynamic stability, defining a safe therapeutic window. Above 200 mg L⁻¹, pronounced bradycardia and delayed recovery were observed, indicating sublethal cardiac depression. Flumazenil significantly prolonged anesthesia induction, confirming GABAAA-mediated mechanisms in menthol sedation. These findings establish the physiological safety limits for menthol use in Nile tilapia and highlight its ecotoxicological significance, as excessive or environmental exposure may impair cardiac homeostasis in aquatic organisms. The results contribute to defining safe anesthetic practices and to understanding the toxicodynamic implications of natural sedatives in aquatic ecosystems. Graphical Abstract [Insert Fig. 1 about here]