Exploring antioxidant and α-glucosidase inhibition in Eugenia L. extracts: a comprehensive phytochemical study.

This study analysed extracts obtained from the leaves of Eugenia uniflora, E. involucrata, and E. myrcianthes to determine their chemical composition, antioxidative properties, and α-glucosidase inhibitory capacity. By using liquid chromatography with a diode array detector, we identified chlorogenic acids, flavonoids, tannins, proanthocyanidins, saponins, and triterpenes in the extracts. The antioxidant activities of the extracts were found to be directly related to their total phenolic, flavonoid content and enzyme inhibition. The E. uniflora aqueous extract showed significant inhibition of α-glucosidase (IC50 0.98 µg mL-1), indicating its potential as a non-competitive inhibitor for managing Diabetes Mellitus. This study contributes to the existing knowledge on the chemical and biological aspects of Eugenia genus.

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.

Essential oil of Eugenia stictopetala Mart. ex DC. has antioxidant, antibacterial, and gastrointestinal protective effect.

This work aimed to investigate the chemical composition, antioxidant capacity, antibacterial activity, and intestinal and gastric protective effects, in addition to the acute toxicity of the essential oil of E. stictopetala (EOEs). (E)-caryophyllene (18.01%), ß-pinene (8.84%), and (E)-nerolidol (8.24%), were the components found in higher content in the essential oil. The EOEs showed antioxidant capacity with IC50 values ranging from 220.28 to 283.67 µg/mL, in addition to presenting antibacterial activity against Escherichia coli, Enterobacter aerogenes, Vibrio cholerae, Salmonella enterica, and Listeria monocytogenes. The essential oil showed a gastroprotective effect, with a reduction in the levels of TNF-α, IL-1ß, and IL-6, having multiple pharmacological mechanisms of action. An antidiarrheal effect of EOEs was observed in the castor oil-induced diarrheal model, with reduced intestinal motility. Our findings demonstrate that essential oil can be beneficial in pharmaceutical and therapeutic applications for treating gastrointestinal diseases.

Bioprospecting a Film-Forming System Loaded with Eugenia uniflora L. and Tropaeolum majus L. Leaf Extracts for Topical Application in Treating Skin Lesions.

Natural products can be used as complements or as alternatives to synthetic drugs. Eugenia uniflora and Tropaeolum majus are natives of Brazil and have antimicrobial, anti-inflammatory, and antioxidant activities. This study aimed to develop a film-forming system (FFS) loaded with plant extracts with the potential for treating microbial infections. E. uniflora and T. majus leaf extracts were prepared and characterized, and the individual and combined antioxidant and antimicrobial activities were evaluated. The FFS was developed with different concentrations of polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) and analyzed for physicochemical characteristics. The combination of extracts showed a superior antioxidant effect compared to the individual extracts, justifying the use of the blend. FFS prepared with 4.5% PVA, 4.5% PVP, 7.81% E. uniflora extract, and 3.90% T. majus extract was adhesive, lacked scale formation, presented good malleability, and had a suitable pH for topical application. In addition, the viscosity at rest was satisfactory for maintaining stability; water solubility was adequate; skin permeation was low; and the antimicrobial effect was superior to that of the individual extracts. Therefore, the developed FFS is promising for the differentiated treatment of skin lesions through topical application.

Safety Investigations of Two Formulations for Vaginal Use Obtained from Eugenia uniflora L. Leaves in Female Rats.

Medicinal plants have great prominence in research into the development of new medicines. Eugenia uniflora L. (Myrtaceae) is an edible and medicinal plant with economic value in the northeast region of Brazil. Several preparations from E. uniflora leaves and its fruits are employed as a source of nutrients and bioactive compounds. In this study we evaluated the preclinical toxicology of crude extract and vaginal gel obtained from the leaves of E. uniflora (5%, 10%, and 15%) aiming to provide safety for its use in the treatment of vulvovaginitis. Both formulations were applied to the vaginal cavity for 14 days. Detailed observations of the vaginal region, including pruritus, swelling, irritation, burning, pain, and vaginal secretion, as well as the estrous cycle were evaluated. On the fifth day, blood samples were obtained from the supraorbital plexus for biochemical and hematological analyses. The animals were subsequently euthanized. All animals underwent necropsy and macroscopic examination of the vaginal mucosa and reproductive system. A histological examination was also performed. No clinically significant changes were detected during the entire experimental period. All biochemical, hematological, or histopathological parameters were within the normal range for the species. The data obtained allow us to suggest that the E. uniflora vaginal formulations are safe in this experimental model.

Eugenia uniflora L. Silver and Gold Nanoparticle Synthesis, Characterization, and Evaluation of the Photoreduction Process in Antimicrobial Activities.

Eugenia uniflora linnaeus, known as Brazilian cherry, is widely distributed in Brazil, Argentina, Uruguay, and Paraguay. E. uniflora L. extracts contain phenolic compounds, such as flavonoids, tannins, triterpenes, and sesquiterpenes. The antimicrobial action of essential oils has been attributed to their compositions of bioactive compounds, such as sesquiterpenes. In this paper, the fruit extract of E. uniflora was used to synthesize silver and gold nanoparticles. The nanoparticles were characterized by UV-Vis, transmission electron microscopy, elemental analysis, FTIR, and Zeta potential measurement. The silver and gold nanoparticles prepared with fruit extracts presented sizes of ~32 nm and 11 nm (diameter), respectively, and Zeta potentials of -22 mV and -14 mV. The antimicrobial tests were performed with Gram-negative and Gram-positive bacteria and Candida albicans. The growth inhibition of EuAgNPs prepared with and without photoreduction showed the important functional groups in the antimicrobial activity.

Eugenia uniflora L. silver and gold nanoparticle synthesis, characterization, and evaluation of the photoreduction process in antimicrobial activities

Eugenia uniflora linnaeus, known as Brazilian cherry, is widely distributed in Brazil, Argentina, Uruguay, and Paraguay. E. uniflora L. extracts contain phenolic compounds, such as flavonoids, tannins, triterpenes, and sesquiterpenes. The antimicrobial action of essential oils has been attributed to their compositions of bioactive compounds, such as sesquiterpenes. In this paper, the fruit extract of E. uniflora was used to synthesize silver and gold nanoparticles. The nanoparticles were characterized by UV–Vis, transmission electron microscopy, elemental analysis, FTIR, and Zeta potential measurement. The silver and gold nanoparticles prepared with fruit extracts presented sizes of ~32 nm and 11 nm (diameter), respectively, and Zeta potentials of −22 mV and −14 mV. The antimicrobial tests were performed with Gram-negative and Gram-positive bacteria and Candida albicans. The growth inhibition of EuAgNPs prepared with and without photoreduction showed the important functional groups in the antimicrobial activity.

Bioactive Compounds of Fruit Parts of Three Eugenia uniflora Biotypes in Four Ripening Stages.

Variability of secondary metabolites in edible (peel and pulp) and inedible (seeds) parts of three pitanga varieties, red, red-orange and purple, was investigated during the maturation process. Hydrolysable tannins, anthocyanins, and flavonoids were quantified by HPLC/DAD and carotenoids by absorbance. Peel/pulp showed greater complexity of constituents (carotenoids, anthocyanins, flavonoids, and hydrolysable tannins), while only tannins were identified in seeds, but in quantities of 10 to 100 times greater. The red-orange variety showed the highest levels of phenolic compounds in seeds and peel/pulp, except anthocyanins. The analysis of the principal response curves showed that the pitanga biotype has greater influence on metabolite variation than ripening stages. During peel/pulp maturation, a reduction in the levels of flavonoids and tannins contrasted with an increase in carotenoids and cyanidin-3-O-glucoside in all varieties, whereas in the seeds oenothein B, the major tannin, increased up to 1.32 g/100 g fresh weight. Such marked differences between fruit parts demonstrate that the seeds in stages E3 and E4 are a source of hydrolysable tannins, compounds known for their antitumor activity, while peel/pulp of all varieties in the ripe stage provide natural antioxidants, such as carotenoids and flavonoids. Lastly, the purple biotype can be a rich source of the cyanidin-3-O-glucoside pigment a potent bioactive compound.

LC-MS/MS screening and identification of bioactive compounds in leaves, pulp and seed from Eugenia calycina Cambess.

The Eugenia calycina Cambess, also known as pitanga-do-cerrado, is an unexplored Brazilian fruit used by native people for the treatment of diabetes. The aim of this study was to identify the phenolic compounds from the leaves, pulp and seed of Eugenia calycina by using LC-MS-based targeted and untargeted analysis. The LC-MS-based targeted quantitative analysis showed a high phenolic content in all plant parts in which the ellagic acid was the main phenolic compound with values of 8244.53 µg/g dw (leaves), 5054.43 µg/g dw (pulp) and 715.42 µg/g dw (seed). The leaves, pulp and seed showed a high total phenolic content of 20371.96, 7139.70 and 2204.75 µg/g dw, respectively. In addition, the LC-MS-based targeted analysis showed ellagic acid, myricitrin and epicatechin gallate as the main phenolic compounds in the Eugenia calycina. The LC-MS-based untargeted analysis showed the phytochemical profile of the leaves, pulp and seed in which 153 phytochemicals from different chemical classes were annotated, including organic acids, phenolic acids, flavonoids, and other compounds. The Eugenia calycina has high potential as a plant-based food due to its phytochemical profile and high phenolic content.

Determination of acetylcholinesterase and α-glucosidase inhibition by electrophoretically-mediated microanalysis and phenolic profile by HPLC-ESI-MS/MS of fruit juices from Brazilian Myrtaceae Plinia cauliflora (Mart.) Kausel and Eugenia uniflora L.

Alzheimer's disease and diabetes mellitus are contemporary diseases of great concern. Phenolic compounds are linked to several health benefits and could lead to novel strategies to combat these ailments. The objective of this study was to evaluate by electrophoretically-mediated microanalysis the potential inhibitory activity of the fruit juices from Plinia cauliflora ("jaboticaba") and Eugenia uniflora ("pitanga") toward acetylcholinesterase (AChE) and α-glucosidase, target enzymes in strategies for the treatment of these diseases. The phenolic profiles of the samples were also investigated. Jaboticaba and pitanga juices inhibited 85.90 ± 1.73 and 52.67 ± 1.24% of AChE activity at 5 mg mL-1, and 57.91 ± 2.60 and 69.47 ± 2.89% of α-glucosidase activity at 1 mg mL-1, respectively. Total phenolic content of the juices were 303.54 ± 28.28 and 367.00 ± 11.42 mgGA L-1, respectively. The observed inhibitory activity can be explained, at least in part, by the presence of the phenolic compounds.

Characterization and expression analysis of P5CS (Δ1-pyrroline-5-carboxylate synthase) gene in two distinct populations of the Atlantic Forest native species Eugenia uniflora L.

Eugenia uniflora is an Atlantic Forest native species, occurring in contrasting edaphoclimatic environments. The identification of genes involved in response to abiotic factors is very relevant to help in understanding the processes of local adaptation. 1-Pyrroline-5-carboxylate synthetase (P5CS) is one interesting gene to study in this species since it encodes a key enzyme of proline biosynthesis, which is an osmoprotectant during abiotic stress. Applying in silico analysis, we identified one P5CS gene sequence of E. uniflora (EuniP5CS). Phylogenetic analysis, as well as, gene and protein structure investigation, revealed that EuniP5CS is a member of P5CS gene family. Plants of E. uniflora from two distinct environments (restinga and riparian forest) presented differences in the proline accumulation and P5CS expression levels under growth-controlled conditions. Both proline accumulation and gene expression level of EuniP5CS were higher in the genotypes from riparian forest than those from restinga. When these plants were submitted to drought stress, EuniP5CS gene was up-regulated in the plants from restinga, but not in those from riparian forest. These results demonstrated that EuniP5CS is involved in proline biosynthesis in this species and suggest that P5CS gene may be an interesting candidate gene in future studies to understand the processes of local adaptation in E. uniflora.

Cytotoxic and antioxidative potentials of ethanolic extract of Eugenia uniflora L. (Myrtaceae) leaves on human blood cells.

Eugenia uniflora is used in the Brazilian folk medicine to treat intestinal disorders and hypertension. However, scanty information exist on its potential toxicity to human, and little is known on its antioxidant activity in biological system. Hence, we investigated for the first time the potential toxic effects of ethanolic extract (EtOH) of E. uniflora (EEEU) in human leukocytes and erythrocytes, as well as its influence on membrane erythrocytes osmotic fragility. In addition, EEEU was chemically characterized and its antioxidant capacity was evaluated. We found that EEEU (1-480µg/mL) caused neither cytotoxicity nor DNA damage evaluated by Trypan blue and Comet assay, respectively. EEEU (1-480µg/mL) did not have any effect on membrane erythrocytes fragility. In addition, EEEU inhibited Fe2+-induced lipid peroxidation in rat brain and liver homogenates, and scavenged the DPPH radical. EEEU presented some polyphenolic compounds with high content such as quercetin, quercitrin, isoquercitrin, luteolin and ellagic acid, which may be at least in part responsible for its beneficial effects. Our results suggest that consumption of EEEU at relatively higher concentrations may not result in toxicity. However, further in vitro and in vivo studies should be conducted to ascertain its safety.

Quorum Quenching and Microbial Control through Phenolic Extract of Eugenia Uniflora Fruits.

We describe the characterization of the centesimal composition, mineral and phenolic content of Eugenia uniflora fruit and the determination of the antioxidant, antimicrobial and quorum quenching activities of the pulp phenolic extract. Centesimal composition was determined according to standard methods; trace elements were measured by total reflection X-ray fluorescence spectroscopy. The phenolic compounds were extracted by solid-phase chromatography and quantified by spectrophotometry. Antioxidant activity was determined by using 3 different methods. Antimicrobial activity was evaluated against a panel of foodborne microorganisms and antiquorum sensing activity in Chromobacterium violaceum was performed by measuring inhibition of quorum sensing dependent violacein production. The centesimal composition (per 100 g of pulp) was as follows: protein 3.68 ± 0.21 g, lipids 0.02 ± 0.03 g, carbohydrates 10.31 g and fiber 2.06 g. Trace elements (mg/g of pulp) were determined as: K 0.90, Ca 3.36, Fe 0.60, Zn 0.17, Cl 0.56, Cr 0.06, Ni 0.04, and Cu 0.07. The pulp is a source of phenolic compounds and presents antioxidant activity similar to other berries. The fruit phenolic extract inhibited all tested bacteria. We also found that the fruit phenolic extract at low subinhibitory concentrations inhibited up to 96% of violacein production in C. violaceum, likely due to the fruit's phenolic content. This study shows the contribution of E. uniflora phenolic compounds to the antioxidant, antimicrobial and the newly discovered quorum quenching activity, all of which could be used by the food and pharmaceutical industries to develop new functional products.

Seasonal variation in the phenol content of Eugenia uniflora L. leaves / Variação sazonal nos teores de fenóis de folhas de Eugenia uniflora L

Hydrolysable tannins, total phenols and flavonoids in Eugenia uniflora leaves were monthly analysed for one year. The results were correlated with climate conditions (rainfall, humidity, cloudiness and mean temperature) through chemometric methods. Principal component analysis revealed high levels of hydrolysable tannins in the rainy season, whereas flavonoids were mainly produced in the dry season. These facts suggest that climatic changes may be one of the factors affecting phenol levels in Eugenia uniflora.

Taninos hidrolisáveis, fenóis totais e flavonóides presentes em folhas de Eugenia uniflora foram quantificados mensalmente durante um ano. Os resultados foram correlacionados com as condições climáticas (pluviosidade, umidade, nebulosidade e temperatura média) através de métodos quimiométricos. Análise de componentes principais revelou a ocorrência de altos teores de taninos hidrolisáveis durante a estação de chuvas, enquanto os flavonóides foram produzidos principalmente na estação seca. Estes fatos sugerem que mudanças climáticas podem ser um dos fatores que afetam os níveis de fenóis em Eugenia uniflora.