Bioactive potential of Eugenia luschnathiana essential oil and extract: antifungal activity against Candida species isolated from oncological patients.

Immunosuppressed individuals, including those undergoing cancer treatment, are more vulnerable to fungal infections, such as oral candidiasis, impacting their quality of life. Given the limitations of current therapies, the discovery of new antifungal agents, including those of natural origin, is crucial for the proper managing of these infections. We investigated the phytochemical profile and antifungal activity of both the essential oil and crude ethanolic extract (CEE) obtained from Eugenia luschnathiana against reference strains and clinical isolates of Candida from oncology patients. Toxicological characterization was also conducted. Gas chromatography coupled to mass spectrometry (GC-MS) and 1H Nuclear Magnetic Resonance (NMR) were used for phytochemical analysis. Antifungal evaluation was conducted to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC); evaluation of potential mechanisms of action; activity on a fungal biofilm; evaluation of the cytotoxic effect on human keratinocytes of the HaCat lineage by the MTT method; determination of lethality for Artemia salina larvae. GC-MS identified a predominance of sesquiterpenes in the essential oil, notably (E)-Caryophyllene. The 1H NMR spectrum identified aliphatic, osidic, and aromatic compounds in the crude ethanolic extract. The essential oil showed no antifungal activity. However, the CEE exhibited fungicidal activity, with MIC and MFC ranging from 1.95 µg/mL to 3.90 µg/mL. The antifungal effect was affected by sorbitol, indicating a possible mechanism targeting fungal cell wall structures. At low concentration (19.5 µg/mL), the CEE inhibited 62,78% of C. albicans biofilm. The CEE demonstrated a promising toxicity profile, with an LC50 of 142.4 µg/mL against Artemia salina. In conclusion, the CEE from Eugenia luschnathiana exhibited potent antifungal activity, likely through cell wall disruption, biofilm inhibition, and a favorable toxicity profile for further exploration.

Chemical characterization of the essential oil from the leaves of Eugenia flavescens DC. (Myrtaceae) and its potential in the treatment of pain, inflammation, and ethanol- and ethanol/HCL-induced gastric ulcers in mice.

Eugenia flavescens is a species cultivated in Brazil for food purposes. Given the potential application of essential oils from plants of the genus Eugenia, this study was carried out to investigate the chemical composition, acute toxicity, antioxidant, antinociceptive, gastroprotective activities, and possible mechanisms of action of the essential oil from the leaves of E. flavescens (EOEf). The EOEf was extracted by hydrodistillation, and the chemical composition was obtained using gas chromatography-mass spectrometry. The antioxidant activity was evaluated, as well as the acute toxicity and the antinociceptive and anti-inflammatory effects in mice. In addition, the gastroprotective effect was investigated using an acute gastric lesion model, considering possible mechanisms of action. The major components found in the EOEf were guaiol (19.97%), germacrene B (12.53%), bicyclogermacrene (11.11%), and E-caryophyllene (7.53%). The EOEf did not cause signs of toxicity in the acute oral toxicity test and showed in vitro antioxidant activity with IC50 ranging from 247.29 to 472.39 µg/mL in the tests ABTS and DPPH. In the nociceptive test, EOEf showed a 72.05% reduction in nociception at a dose of 100 mg/kg. In evaluating the anti-inflammatory effect, the essential oil inhibited paw edema by 95.50% and 97.69% at doses of 50 and 100 mg/kg. The results showed that EOEf has a gastroprotective effect, acting through the sulfhydryl compounds (-SH), nitric oxide (NO), and synthesis PGE2 pathways. The results suggested that EOEf is a promising source of constituents with antioxidant, antinociceptive, anti-inflammatory, and gastroprotective properties with application in the food and pharmaceutical industries.

Mechanism of action and synergistic effect of Eugenia uniflora extract in Candida spp.

The limited arsenal of antifungal drugs have prompted the search for novel molecules with biological activity. This study aimed to characterize the antifungal mechanism of action of Eugenia uniflora extract and its synergistic activity with commercially available antifungal drugs on the following Candida species: C. albicans, C. tropicalis, C. glabrata, C. parapsilosis and C. dubliniensis. In silico analysis was performed to predict antifungal activity of the major compounds present in the extract. Minimal inhibitory concentrations (MICs) were determined in the presence of exogenous ergosterol and sorbitol. Yeast cells were grown in the presence of stressors. The loss of membrane integrity was assessed using propidium iodide staining (fluorescence emission). Synergism between the extract and antifungal compounds (in addition to time kill-curves) was determined. Molecular docking revealed possible interactions between myricitrin and acid gallic and enzymes involved in ergosterol and cell wall biosynthesis. Candida cells grown in the presence of the extract with addition of exogenous ergosterol and sorbitol showed 2 to 8-fold increased MICs. Strains treated with the extract revealed greater loss of membrane integrity when compared to their Fluconazole counterparts, but this effect was less pronounced than the membrane damage caused by Amphotericin B. The extract also made the strains more susceptible to Congo red and Calcofluor white. A synergistic action of the extract with Fluconazole and Micafungin was observed. The E. uniflora extract may be a viable option for the treatment of Candida infections.

How does the life cycle of Clinodiplosis profusa (Cecidomyiidae) adjust to phenological variations of the host plant Eugenia uniflora (Myrtaceae) in sun and shade?

Galls are plant neoformations induced by specialized parasites. Since gall inducers rely on reactive plant sites for gall development, variations in abiotic factors that affect plant phenology are expected to impact the life cycle of gall inducers. To test the hypothesis that different light conditions affect both host plant and gall inducer life cycles, we studied the system Eugenia uniflora (Myrtaceae) - Clinodiplosis profusa (Cecidomyiidae), comparing plants occurring in sunny and shaded environments. We mapped phenological differences among individuals of E. uniflora occurring in the two environments and related them to the influence of luminosity on the life cycle of the gall inducer. Shade plants showed lower intensity of leaf sprouting throughout the year compared to sun-exposed plants, especially during the rainy season. Young and mature galls are synchronized with the peak of leaf sprouting at the beginning of the rainy season, lasting longer in sun-exposed plants - approximately two months longer compared to shade plants. The greater light intensity positively impacts the formation and growth of leaves and galls, with an extended period available for their induction and growth. Thus, light is an important factor for the development of gallers, considering that variations in luminosity influenced not only the phenology of the host plant, but also determined the life cycle of gall inducers. Furthermore, changes in plant-environment interactions are expected to affect the life cycle and richness of other host plant-gall inducer systems.

Oenothein B from Eugenia uniflora leaves exerts pro-angiogenic effects by increasing VEGF and TNF-α levels.

Oenothein B (OeB), a dimeric ellagitannin with a macrocyclic structure, is reported to have beneficial effects, including antioxidant, antitumor, antiviral, and antimutagenic effects, on human health. Despite the remarkable properties of OeB, its role in neovascularization process has not yet been evaluated. Thus, this study aimed to evaluate the angiogenic activity of OeB using a chorioallantoic membrane (CAM) assay at different concentrations (6.25, 12.5, and 25 µg/µL), employing digital imaging and histological analysis. Furthermore, to elucidate the mechanisms by which OeB influences angiogenesis, we assessed the levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α) in CAM using immunohistochemical analysis. All concentrations of OeB significantly increased (p < 0.05) the percentage of vascularization as well as the levels of all the angiogenesis-associated parameters evaluated, indicating the pronounced pro-angiogenic activity of OeB. Our results showed that inflammation was one of the most relevant phenomena observed in CAM histology along with angiogenesis. In addition, a significant increase in VEGF and TNF-α levels was observed in all the CAMs compared to the negative control (p < 0.05). We suggest that OeB may induce the presence of inflammatory cells in CAM, leading to increased VEGF and TNF-α levels that result in the induction of angiogenesis. Therefore, OeB presents a favorable profile that could be further explored for the development of drugs for pro-angiogenic and tissue repair therapies.

The contact toxicity and toxic mechanism of essential oils from Pimenta racemosa and Eugenia caryophyllata against Haemaphysalis longicornis (Acari: Ixodidae).

Haemaphysalis longicornis, which is widely distributed in China, can transmit various tick-borne diseases such as severe fever with thrombocytopenia syndrome, babesiosis, rickettsia disease and so on, and do great harm to human health and the development of animal husbandry. Chemical acaricides are the most traditional tick control method, but because of its many shortcomings, there is an urgent need to find a substitute with high efficiency, environmental protection and low toxicity. It has been found that some plant essential oils (EOs) have good insecticidal activity and environmental safety. In this study, the components of EOs from Pimenta racemosa and Eugenia caryophyllata were analyzed by gas chromatography-mass spectrometry (GC-MS), and their potential for application in the control of Haemaphysalis longicornis were studied. Gas chromatography-mass spectrometry analysis showed that the main components of P. racemosa EO were eugenol (64.07%), those of E. caryophyllata EO were Hexadecanoic acid, 2-methylpropyl ester (51.84%) and eugenol (39.76%). Larval packet test showed that the EOs of P. racemosa and E. caryophyllata had significant acaricidal activity against unfed larvae of H. longicornis, with LC50 values of 1.20 mg/mL and 0.47 mg/mL and LC90 values of 8.76 mg/mL and 2.91 mg/mL, respectively. The P. racemosa EO, E. caryophyllata EO and eugenol showed significant acaricidal activity against unfed nymph H. longicornis, with LC50 values of 1.65 mg/mL, 2.29 mg/mL and 0.93 mg/mL and LC90 values of 5.03 mg/mL, 11.01 mg/mL and 4.77 mg/mL, respectively. The P. racemosa EO, E. caryophyllata EO and eugenol showed significant acaricidal activity against unfed adults H. longicornis, with LC50 values of 0.51 mg/mL, 2.57 mg/mL and 1.83 mg/mL and LC90 values of 2.44 mg/mL, 11.44 mg/mL and 2.54 mg/mL, respectively. Enzyme assays revealed that the E. caryophyllata EO and eugenol significantly inhibited the activity of carboxylesterase (CarE), eugenol significantly inhibited the activity of catalase (CAT), and two EOs and eugenol had no significant effect on acetylcholinesterase (AchE) (p < 0.05). The above results suggest that the essential oils from P. racemosa and E. caryophyllata have great potential for use as alternatives to synthetic acaricides for tick control.

Influence of Major Polyphenols on the Anti-Candida Activity of Eugenia uniflora Leaves: Isolation, LC-ESI-HRMS/MS Characterization and In Vitro Evaluation.

The content of chemical constituents in Eugenia uniflora leaf extracts correlates positively with biological activities. The experimental objective was to carry out the phytochemical screening and purification of the major polyphenols from the leaves of E. uniflora. In addition, the anti-Candida activity of the hydroalcoholic extract, fraction, subfractions and polyphenols purified were evaluated. After partitioning of the extract with ethyl acetate, the fractions were chromatographed on Sephadex® LH-20 gel followed by RP-flash chromatography and monitored by TLC and RP-HPLC. The samples were characterized by mass spectrometry (LC-ESI-QTOF-MS2) and subjected to the microdilution method in 96-well plates against strains of C. albicans, C. auris, and C. glabrata. Myricitrin (93.89%; w/w; m/z 463.0876), gallic acid (99.9%; w/w; m/z 169.0142), and ellagic acid (94.2%; w/w; m/z 300.9988) were recovered. The polyphenolic fraction (62.67% (w/w) myricitrin) and the ellagic fraction (67.86% (w/w) ellagic acid) showed the best antifungal performance (MIC between 62.50 and 500 µg/mL), suggesting an association between the majority constituents and the antifungal response of E. uniflora derivatives. However, there is a clear dependence on the presence of the complex chemical mixture. In conclusion, chromatographic strategies were effectively employed to recover the major polyphenols from the leaves of the species.

Emerging berries from the Brazilian Amazon and Atlantic Forest biomes: new sources of bioactive compounds with potential health benefits.

Brazil has a broad geographic biodiversity spread across its six different biomes. However, it has been suffering from the abusive exploitation of its resources, which poses a threat to the local fauna and flora. The Amazon and Atlantic Forest, for example, are birthplaces to rare and edible native species, such as bacaba (Oenocarpus bacaba, Arecaceae) and camu-camu (Myrciaria dubia, Myrtaceae), and cereja-do-Rio Grande (Eugenia involucrata, Myrtaceae) and grumixama (Eugenia brasiliensis, Myrtaceae), respectively. These plants produce fruits which are sources of macro and micronutrients, including sugars, dietary fibers, vitamins, minerals, and/or lipids. Nutritionally, their consumption have the ability to reach partially or totally the daily recommendations for adults of some nutrients. More recently, these fruits have also been exposed as interesting sources of minor bioactive compounds, such as carotenoids, terpenes, and/or polyphenols, the latter which include anthocyanins, phenolic acids, and tannins. Particularly, bacaba stands out for being a rich source of polyunsaturated fatty acids (around 22%, dry weight) and dietary fibers (6.5-21%, dry weight); camu-camu has very high contents of vitamin C (up to 5000 mg per 100 g of pulp, dry basis); and cereja-do-Rio-Grande and grumixama are abundant sources of anthocyanins. Although they are still underexplored, several in vitro and in vivo studies with different parts of the fruits, including the peel, seed, and pulp, indicate their health potential through anti-oxidative, anti-obesity, antihyperglycemic, antidyslipidemic, antimicrobial, and/or anticancer effects. All things considered, the focus of this research was to highlight the bioactive potential and health impact of native fruits from the Amazon and Atlantic Forest biomes.

Anti-inflammatory naphthoquinone-monoterpene adducts and neolignans from Eugenia caryophyllata.

A phytochemical investigation on the buds of edible medicinal plant, Eugenia carvophyllata, led to the discovery of seven new compounds, caryophones A-G (1-7), along with two biogenetically-related known ones, 2-methoxy-7-methyl-1,4-naphthalenedione (8) and eugenol (9). Compounds 1-3 represent the first examples of C-5-C-1' connected naphthoquinone-monoterpene adducts with a new carbon skeleton. Compounds 4-7 are a class of novel neolignans with unusual linkage patterns, in which the C-9 position of one phenylpropene unit coupled with the aromatic core of another phenylpropene unit. The chemical structures of the new compounds were determined based on extensive spectroscopic analysis, X-ray diffraction crystallography, and quantum-chemical calculation. Among the isolates, compounds (-)-2, 3, 6, and 9 showed significant in vitro inhibitory activities against respiratory syncytial virus (RSV)-induced nitric oxide (NO) production in RAW264.7 cells.

Eugenia uniflora (pitanga) juice as a new alternative vehicle for Limosilactobacillus fermentum ATCC 23271: evaluation of antioxidant and anti-infective effects.

Probiotic-containing foods are among the most appreciated functional foods; however, probiotic-based dairy products cannot be consumed by people who are lactose intolerant, allergic to milk, or vegetarian or vegan individuals. Thus, new non-dairy matrices have been tested for probiotics delivery. This study evaluated the growth and viability of Limosilactobacillus fermentum ATCC 23271 and Lacticaseibacillus rhamnosus ATCC 9595 in Pitanga juice (Eugenia uniflora L.). The effects of the fermentation on the antioxidant and anti-infective properties of the juice were also analyzed. The E. uniflora juice allowed lactobacilli growth without supplementation, reaching rates around 8.4 Log CFU/mL and producing organic acids (pH values < 4) after 72 h of fermentation. The strain remained viable after 35 days of refrigerated storage. Fermentation by these bacteria increases the antioxidant capacity of the juice. The central composite rotational design was employed to evaluate the effects of bacterial inoculum and pulp concentration on growth and organic acids production by L. fermentum ATCC 23271. The strain was viable and produced organic acids in all tested combinations. L. fermentum-fermented juice and its cell-free supernatant significantly increased the survival of Tenebrio molitor larvae infected by enteroaggregative Escherichia coli 042. The results obtained in this study provide more insights into the potential of Pitanga juice to develop a functional non-dairy probiotic beverage with antioxidant and anti-infective properties.

A New Single-Step Approach Based on Supramolecular Solvents (SUPRAS) to Extract Bioactive Compounds with Different Polarities from Eugenia pyriformis Cambess (Uvaia) Pulp.

This work employed supramolecular solvents (SUPRAS) made up of octanoic acid, ethanol, and acidified water (pH ~ 3) to extract and concentrate bioactive compounds from Eugenia pyriformis Cambess (uvaia) pulp. At first, the SUPRAS phase characterization demonstrated the spherical aggregates' formation with an internal hydrophobic structure and an external hydrophilic media. Subsequently, the simultaneous production and extraction (SUPRAS-SPE) method was employed in the solid-liquid extraction (SLE) of uvaia pulp. The extracts were evaluated through Folin-Ciocalteu reducing capacity, antioxidant activity (DPPH assay), total carotenoid content (TCC), and total flavonoid content (TFC). The results showed that reducing the ethanol concentration in the SUPRAS composition boosted the TCC extraction while increasing the ethanol presence, promoting a high TFC yield. Moreover, the SUPRAS-SPE method was compared with the ex situ method (SUPRAS-ES), where the solvent was previously produced and then applied to the SLE. Both methods were evaluated concerning their EE% and thermal degradation. The SUPRAS-SPE method increased the EE% of uvaia pulp bioactive compounds compared to the SUPRAS-SE method, providing a suitable microenvironment to extract, concentrate, and stabilize carotenoids from uvaia pulp, offering a sustainable alternative to obtain valuable compounds.

Multilayer microparticles for programmed sequential release of phenolic compounds from Eugenia stipitata: Stability and bioavailability.

A co-delivery system based on multilayer microparticles was developed and characterized for the sequential release of phenolic compounds (PCs) using different encapsulation processes (spray drying: SD and drying-chilling spray: SDC) and wall materials to improve the stability and bioavailability of PCs. Samples were characterized in terms of process yield (PY%), phenolic retention efficiency (PRE%), chemical structure and crystallinity (NMR, FTIR, DXR), thermal stability (DSC and FT-IR), anti-radical capacity (ORAC and ABTS) and in vitro digestion. PRE% of samples by SD were higher (p < 0.05) than SDC due to the formation of PCs from CRF (cará-roxo flour). NMR, FTIR, DXR confirmed the presence of key components and interactions for the formation of the advanced co-delivery system. The SDC particles showed crystalline regions by XRD and were stable at ∼47 °C. All samples showed good release of PC in the intestinal phase, and antiradical capacity that reached 23.66 µmol TE g-1.

Ripening stage impacts nutritional components, antiglycemic potential, digestibility and antioxidant properties of grumixama (Eugenia brasiliensis Lam.) fruit.

This study aimed to determine the nutritional components (macronutrients ans minerals) and α-amylase inhibition capacity of freeze-dried grumixama (Eugenia brasiliensis Lam) seeds (S) and pulp/peel (P) portions, at ripe and mid-ripe stages. In vitro digestion was also performed on S and P from grumixama to assess the bioaccessibility of total phenolic compound (TPC), flavonoids (TFC), and anthocyanins (TAC), as well as to examine their impact on antioxidant activity (DPPH, ABTS, FRAP). The ripening process impacts the bioactive compounds and individual phenolics of S and P portions. The ripe S was source of myricetin and exhibited higher antioxidant activity, while mid-ripe S was high in flavonoids and cinnamic acid with higher antiglycemic potential. Ripe P showed higher soluble fiber, carbohydrate, TAC, and caffeic acid content, whereas mid-ripe P had increased mineral content (calcium, potassium, manganese), catechin, and TPC. After in vitro digestion, the P portion showed a bioaccessibility of total phenolic content (TPC) and total flavonoid content (TFC) exceeding 40% at intestinal phase. In contrast, the S portions had better release of TPC and TFC and antioxidant activity at gastric phase. Considering the outstanding nutritional and biological properties of grumixama fruit, freeze-dried S and P portions from both ripening stages possess could be explored as valuable sources of nutrients and antioxidant compounds.

The metabolic profiles of Eugenia astringens and E. uniflora (Myrtaceae) sensitive seeds affect desiccation.

Myrtaceae species are abundant in tropical Atlantic rainforests, but 41% of the 5500 species of this family are of extreme conservation concern. Eugenia astringens and E. uniflora are native Brazilian Myrtaceae species that occur in the same habitats and produce desiccation-sensitive (DS) seeds. We hypothesized that their seed desiccation-sensitivity degree is associated with specific metabolic signatures. To test it, we analyzed the germination and metabolic profiles of fresh and desiccated seeds. The water content (WC) at which at least half of the seeds survived desiccation was lower in E. astringens (0.17 g H2 O g-1 DW) than in E. uniflora (0.41 g H2 O g-1 DW). We identified 103 annotated metabolites from 3261 peaks in both species, which differed in their relative contents between E. astringens and E. uniflora seeds. The main differences in seed metabolic profiles include several protective molecules in the group of carbohydrates and organic acids and amino acid contents. The relative contents of monosaccharides and disaccharides, malic and quinic acids, amino acids and saturated fatty acids may have taken part in the distinct DS behaviour of E. astringens and E. uniflora seeds. Our study provides evidence of the relationship between desiccation sensitivity, seed viability and metabolic profile of tropical seeds by comparing two closely related Eugenia species with different DS degrees.

Composition and Anti-Acetylcholinesterase Properties of the Essential Oil of the Ecuadorian Endemic Species Eugenia valvata McVaugh.

Alzheimer's disease is a global health problem due to the scarcity of acetylcholinesterase inhibitors, the basis for symptomatic treatment of this disease; this requires new approaches to drug discovery. In this study, we investigated the chemical composition and anticholinesterase activity of Eugenia valvata McVaugt (Myrtaceae) collected in southern Ecuador, which was obtained as an essential oil (EO) with a yield of 0.124 ± 0.03% (w/w); as a result of the chemical composition analysis, a total of 58 organic compounds were identified-representing 95.91% of the total volatile compounds-using a stationary phase based on 5% phenyl-methylpolysiloxane, as analyzed via gas chromatography coupled to mass spectrometry (GC-MS) and flame ionization detection (GC-FID). The main groups were hydrocarbon sesquiterpenes (37.43%), oxygenated sesquiterpenes (31.08%), hydrocarbon monoterpenes (24.14%), oxygenated monoterpenes (0.20%), and other compounds (3.058%). Samples were characterized by the following compounds: α-pinene (22.70%), α-humulene (17.20%), (E)-caryophyllene (6.02%), citronellyl pentanoate (5.76%), 7-epi-α-eudesmol (4.34%) and 5-iso-cedranol (3.64%); this research was complemented with an enantioselective analysis carried out using 2,3-diethyl-6-tert-butyldimethylsilyl-ß-cyclodextrin as a stationary phase chiral selector. As a result, α-pinene, limonene, and α-cadinene enantiomers were identified; finally, in the search for new active principles, the EO reported strong anticholinesterase activity with an IC50 of 53.08 ± 1.13 µg/mL, making it a promising candidate for future studies of Alzheimer's disease.

Aceite esencial de Arazá (Eugenia stipitata McVaugh) con actividad antibacteriana / Essential oil of Arazá (Eugenia stipitata McVaugh) with antibacterial activity

Introducción: El Perú es uno de los países con mayor biodiversidad en especies botánicas, algunas con propiedades medicinales conocidas. Objetivo: Determinar el efecto antibacteriano del aceite esencial de las hojas de Eugenia stipitata McVaugh frente a Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 y Salmonella enterica sv Enteritidis ATCC 13076. Métodos: Estudio de tipo básico con enfoque cuantitativo y experimental. Las plantas provienen del distrito de Belén, ciudad de Iquitos, Departamento de Loreto. La técnica para la extracción del aceite esencial fue la de arrastre de vapor y la técnica microbiológica para determinar el efecto antimicrobiano la de Kirby Bauer. Se trabajaron las muestras en 4 concentraciones 100, 75, 50 y un 25 por ciento; un control negativo solo con dimetilsulfóxido, se utilizaron 5 repeticiones por cada muestra. Resultados: La muestra a concentración al 100 por ciento tuvo actividad antibacteriana contra Staphylococcus aureus. La actividad del ensayo frente a Escherichia coli demostró ser efectiva en todas las muestras, sin embargo, se observó que los halos de inhibición de mayor diámetro se manifestaron en las muestras al 100 por ciento y 75 por ciento. Además, se evidenció actividad antibacteriana a concentraciones del 100 por ciento, 75 por ciento y un 50 por ciento frente a Salmonella enterica sv Enteritidis. Conclusiones: El aceite esencial de las hojas de Eugenia stipitata McVaugh presenta efecto antibacteriano frente a Staphylococcus aureus, Escherichia coli y Salmonella enterica sv Enteritidis(AU)

Introduction: Peru is one of the countries with the greatest biodiversity in botanical species, some with known medicinal properties. Objective: To determine the antibacterial effect of the essential oil of Eugenia stipitata McVaugh leaves against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Salmonella enterica sv Enteritidis ATCC 13076. Methods: Basic study with a quantitative and experimental approach. Plants came from the district of Belén, city of Iquitos, Department of Loreto. The technique for the extraction of the essential oil was steam dragging and the microbiological technique to determine the antimicrobial effect was Kirby Bauer's technique. The samples were worked in 4 concentrations 100, 75, 50 and 25 percent and a negative control only with dimethyl sulfoxide, using 5 replicates for each sample. Results: The sample at 100 percent concentration had antibacterial activity against Staphylococcus aureus. The activity of the assay against Escherichia coli proved to be effective in all the samples, however, it was observed that the inhibition halos of greater diameter were manifested in the samples at 100 percent and 75 percent. In addition, antibacterial activity was evidenced at concentrations of 100 percent, 75 percent and 50 percent against Salmonella enterica sv Enteritidis. Conclusions: The essential oil of Eugenia stipitata McVaugh leaves has an antibacterial effect against Staphylococcus aureus, Escherichia coli and Salmonella enterica sv Enteritidis(AU)

Larvicidal and Fungicidal Activity of the Leaf Essential Oil of Five Myrtaceae Species.

Myrtaceae is one of the most diverse and abundant botanical families, exhibiting wide diversity in the chemical composition of essential oils (EOs). EOs have various biotechnological applications such as controlling the populations of organisms that negatively impact humans. This study aimed to extract EOs from Myrtaceae species, chemically characterize them, and evaluate their larvicidal and fungicidal effects. EOs were extracted from the leaves of Eugenia brasiliensis, Eugenia uniflora, Psidium cattleyanum, Psidium guajava, and Syzygium cumini by hydrodistillation for 3 h and characterized by chromatographic analysis. Larvaes of Aedes aegypti and colonies of Fusarium oxysporum were subjected to increasing EO concentrations to determine the larvicidal and fungicidal potential. The EOs of Eugenia and Psidium species are primarily composed of sesquiterpenes (>80 %), whereas S. cumini EO is rich in monoterpenes (more than 60 %). The Eugenia species had similar amounts of oxygenated monoterpenes, which may explain their higher larvicidal potential compared to other species, with CL50 of 86.68 and 147.46 PPM, respectively. In addition to these two study species, S. cumini showed a high inhibition of fungal growth, with more than 65 % inhibition. We demonstrated that the actions of five EOs from Myrtaceae with different biological activities are associated with chemical diversity.

Purple pitanga extract (Eugenia uniflora) attenuates oxidative stress induced by MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely used due to its specific and reproducible neurotoxic effect on the nigrostriatal system, being considered a convenient model of dopaminergic neurodegeneration to study interventions therapeutics. The purple pitanga (Eugenia uniflora) is a polyphenol-rich fruit with antioxidant and antidepressant properties, among others. Therefore, this study investigated the effect of purple pitanga extract (PPE) on acute early oxidative stress induced by intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in rats. Male Wistar rats were pre-treated orally with PPE (1000 mg/kg) or vehicle. After 24 h, MPTP (0.1 mg/10µL/nostril) or vehicle was administered bilaterally into the animal's nostrils, and 6 h later, the olfactory bulb (OB), striatum (ST), and substantia nigra (SN) were collected to evaluate the oxidative stress parameters. Our findings revealed that OB and SN were the most affected areas after 6 h of MPTP infusion; an early increase in reactive oxygen species (ROS) levels was observed, while pretreatment with a single dose of PPE prevented this increment. No differences in thiobarbituric acid reactive species (TBARS) and 3-nitrotyrosine (3-NT) formation were observed, although 4-hydroxy-2-nonenal (4-HNE) levels increased, which is the most toxic form of lipid peroxidation, in the MPTP group. The PPE pretreatment could prevent this increase by increasing the NPSH levels previously decreased by MPTP. Furthermore, PPE prevents the Na+/K + ATPase strongly inhibited by MPTP, showing the neuroprotective capacity of the PPE by inhibiting the MPTP-generated oxidation. Thus, we demonstrated for the first time the antioxidant and neuroprotective effects of PPE against the early MPTP neurotoxicity.

Acaricidal activity of a 2-methoxy-clovan-9-ol rich fraction from Eugenia copacabanensis (Myrtaceae) extract on Rhipicephalus microplus (Acari: Ixodidae).

Rhipicephalus microplus (Ixodidae, canestrini, 1888) is an invasive ectoparasite of cattle which causes high economic losses in emerging countries such as Brazil. Phytochemical compounds have been tested as an alternative to synthetic acaricides due to potentially lower mammalian toxicity. This study evaluated the acaricidal activity against R. microplus of the 2-methoxy-clovan-9-ol rich fraction obtained from Eugenia copacabanensis Kiaersk.leaves, a little known Myrtaceae species from the Brazilian Atlantic Forest. This fraction was obtained by maceration with methanol, partition with n-hexane and purification by normal-phase column chromatography. GC-MS, 1H and 13C NMR and IR analysis contributed to the identification of a major compound as the sesquiterpene 2-methoxy-clovan-9-ol, reported for the first time for the Myrtaceae family. The fraction was tested against R. microplus unfed larvae and engorged females and a 93% larval mortality was observed at the concentration of 50 mg mL-1. Lower concentrations of the solution tested demonstrated a significant difference in egg mass weight, hatching and control percentage. Experiments with 50.0 mg mL-1 showed significative results, with lower concentration and maximum efficacy for both assays. The IC50 values for unfed larvae and engorged females were 21.76 and 11.13 mg mL-1, respectively. These results were similar to those obtained in other studies with isolated botanical compounds and essential oils. The lower IC50 for engorged females than for unfed R. microplus larvae had also been described for other plant materials, including plants from the same Myrtaceae family. The present result suggested different mechanisms of action of the compound on the reproductive biology of engorged females, improving its effect against egg viability. These results are important for tick control, suggesting that 2-methoxy-clovan-9-ol could be a potential natural acaricidal product against both R. microplus unfed larvae and engorged females.