Genus Psidium Research Articles

Psidium Exotic and Native Species from Brazil Abolish Depression-like Behavior and Oxidative Stress induced by Corticosterone in Mice.

Depression is a highly prevalent neuropsychiatric disorder worldwide. One currently accepted hypothesis of this pathogenesis is the hypothalamic-pituitary-adrenal axis dysfunction, which involves oxidative stress and brain damage. Therefore, antioxidants, such as phenolic compounds, could be used in depression. In this study, we investigated the antidepressant-like and antioxidant effects of an aqueous extract of the leaves of three species of the genus Psidium, Myrtaceae family, in mice. The exotic Psidium guajava L.and the natives Psidium guineense Sw. and Psidium cattleianum Sabine (10, 1, and 0.1 mg/kg, respectively) and fluoxetine (10 mg/kg) were administered orally (p. o.) once daily for 21 days, with or without corticosterone (20 mg/kg). After behavioral assessments (tail suspension, splash, and open-field tests), the hippocampus, prefrontal cortex, liver, kidneys, and plasma were examined to determine the oxidative stress status. The three extracts and fluoxetine treatment decreased the immobility time and counteracted the oxidative stress induced by corticosterone administration. The phenolic compounds identified as major components of the extracts, quercetin in P. guajava and P. guineense and o-coumaric acid in P. cattleianum, may be involved in the biological activities. Therefore, the aqueous leaf extracts of P. guajava, P. cattleianum, and P. guineense could be potential antidepressants helpful in treating depression and other diseases with elevated nitro-oxidative stress.

Densidade inicial de inóculo, época de avaliação e reprodução de Meloidogyne enterolobii em goiabeira 'Paluma'

ABSTRACT Guava decline is a complex disease caused by the interaction between Meloidogyne enterolobii and Neocosmospora falciformis (Syn.: Fusarium solani). Thus, selecting M. enterolobii-resistant genotypes within the genus Psidium is essential for controlling this disease, and developing a resistant cultivar of Psidium guajava could significantly impact this issue. Thus, the objective of this study was to assess the response of the guava plants of the cultivar Paluma to different densities of M. enterolobii inoculum. Guava seedlings were inoculated with 500, 1,000, 5,000, 10,000, and 20,000 eggs + second-stage juveniles (J2) of M. enterolobii per plant. Root and shoot fresh weights, shoot dry weight, root length, plant height, and stem base diameter were evaluated at 70 and 135 days after inoculation (DAI). Total number of M. enterolobii eggs + J2 in the root system and nematode reproduction factor nematode were assessed. Nematode multiplication in roots was not proportional to increases in initial inoculum density; thus, the best plant responses to nematode multiplication in the evaluated cultivar were found for the lowest tested densities. The reproduction factor decreased as the inoculum density was increased, at both evaluations (70 and 135 DAI).

Temperatura de secagem afeta a quantidade e a qualidade do óleo essencial de espécies de Psidium e contribui com a fitotoxicidade em plantas modelo

ABSTRACT The genus Psidium is recognized for its economic value and the species that produce essential oils with notable biological activities. This study investigated the characteristics of the essential oil from the leaves of Psidium myrtoides and Psidium cattleyanum under different drying temperatures. We aimed to understand how drying temperatures affect the yield and composition of the essential oil, as well as its biological activity. The oils obtained from the leaves of P. myrtoides and P. cattleyanum dried in an oven at 40°C showed the highest yields (0.86% and 1.07%, respectively). β-caryophyllene was the major compound in all essential oils of P. myrtoides and P. cattleyanum, except in the oil extracted from P. myrtoides leaves dried at room temperature, where the major compound was α-bisabolol (14.46%). Different phytotoxic effects were observed using the emulsion of these oils in bioassays with Lactuca sativa and Sorghum bicolor, which were associated with the chemical composition and synergy of the identified compounds. The essential oil emulsion from leaves dried at room temperature of both species showed greater phytotoxic activity in the bioassays. Thus, optimizing drying conditions to maximize yield and synergy of compounds from the essential oils of P. myrtoides and P. cattleyanum is an important step in developing environmentally friendly natural agrochemicals.

Chemical profile and biological potential of essential oil of Psidium bahianum Landrum & Funch (Myrtaceae).

The genus Psidium, belonging to the family Myrtaceae, encompasses several plant species rich in essential oils. Several studies involving different research areas have shown promising results for essential oils, which has attracted interest from diverse sectors, including pharmaceutical, food, and cosmetic industries. Thus, the objective of this study was to evaluate the biological activity of the essential oil extracted from Psidium bahianum leaves (EOPb) collected in an Atlantic Forest remnant in the northern coast of the state of Bahia, Brazil. EOPb was extracted by steam distillation and analyzed through proton nuclear magnetic resonance (1H-NMR). The free radical scavenging activity was assessed using the DPPH methodology (analyzing the scavenging of the stable free radical 1,1-diphenyl-2-picrylhydrazyl). Antimicrobial disk diffusion assays were conducted; toxicity was determined through assays on sheep erythrocytes and Artemia salina. 1H-NMR evaluation showed the presence mainly of monoterpenes and sesquisterpenes. The percentage of antioxidant activity was 18.03±2.53 53 for 125 125 µg mL-1. Antimicrobial assays showed that the essential oil at a concentration of 10 mg mL-1 inhibited the growth of the microorganisms Staphylococcus aureus, Bacillus subtilis, B. cereus, Micrococcus luteus, Escherichia coli, Aspergillus niger, Candida albicans, and C. glabrata. The toxicity results indicated that concentrations of EOPb at 10, 100, 250, and 500 µg mL-1 were not toxic to sheep erythrocytes. The toxicity assay on A. salina showed that the lethal concentration for 50% of individuals (LC50) within 24 and 48 hours were 371.48 and 302 µg mL-1 of EOPb, respectively, which were considered moderately toxic, whereas the LC50 within 72 horas was 33.11 µg mL-1, considered highly toxic. These findings are promising, as the essential oil from P. bahianum leaves showed antimicrobial activity against both Gram-positive and Gram-negative bacteria and fungi. The data obtained for the essential oil toxicity in A. salina could be tested on different tumor cell lines.

Evaluation of 28-day repeated doses oral toxicity of essential oil from Psidium glaziovianum Kiaersk leaves on various biological parameters in Swiss mice

ABSTRACT Only a small number of the many medicinally important species in the genus Psidium L. have had their safety assessed. Psidium glaziovianum, a plant native to Brazil, is reported to exert antinociceptive and anti-inflammatory effects; however, there are no apparent reports of long-term safety following administering of repeated doses. The aim of this study was to examine the effects of 28-day oral of treatment at 250, 500 or 1,000 mg/kg Psidium glaziovianum essential oil (PgEO) on behavioral and physiological parameters in male and female Swiss mice. First, PgEO was chemically characterized by gas chromatography mass spectrometry (GC-MS). The following parameters were examined: motor activity, body temperature, blood glucose, urine, hematology, biochemistry, histology, and oxidative stress. Characterization of PgEO revealed 48 components which were dominated by sesquiterpenes 1,8-cineol (24.29%), α-pinene (19.73%) and β-pinene (17.31%). Data showed that PgEO treatment in mice increased activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) without markedly affecting body weight, hematological or biochemical parameters, as well as water or food consumption. Administration of PgEO in repeated daily dosages over 28 days did not significantly alter exploratory or locomotor activities. Based upon our findings, PgEO administration daily for 28 days, exhibited low toxicity and absence of effects on the nervous system. Data demonstrated that PgEO produced hypoglycemic and antioxidant actions which need to be considered in safety assessment.

Optimized Ultrasound-Assisted Extraction of Psidium laruotteanum Roots: A Concentrated Source of Piceid from the Brazilian Savanna

Psidium laruotteanum is a subshrub Myrtaceae, native to the Brazilian savanna, and distributed in Central and South America. Here, the health beneficial compound piceid (reservatrol-3-β-mono-d-glucoside) is described for the first time in the genus Psidium. The ultrasound-assisted extraction from P. laruotteanum roots was optimized by a response surface methodology. A central composite design was used to assess six extraction variables. Optimal extractions were obtained with 62.5% MeOH in water at 69.1 °C, amplitude of 70%, cycle of 0.5 s−1, pH 5.7 and solvent–solid ratio of 40:1, for 10 min. The method showed excellent recovery (90%–95%) and precision (CV: 0.69% for repeatability and 0.43% for intermediate precision). This species appears as the most concentrated plant source of piceid reported to date (29.15 mg·g−1 in dry roots). Additionally, a very fast extraction (5 min) can afford 96% recovery of piceid from Psidium laruotteanum roots. It could be used as a natural and cheap source of piceid for several applications.

Genomic and epigenomic variation in Psidium species and their outcome under the yield and composition of essential oils

Diploid and polyploid species derived from the euploid series x = 11 occur in the genus Psidium, as well as intraspecific cytotypes. Euploidy in the genus can alter the gene copy number, resulting in several “omics” variations. We revisited the euploidy, reported genomic (nuclear 2C value, GC%, and copy number of secondary metabolism genes) and epigenomic (5-mC%) differences in Psidium, and related them to essential oil yield and composition. Mean 2C values ranged from 0.90 pg (P. guajava) to 7.40 pg (P. gaudichaudianum). 2C value is intraspecifically varied in P. cattleyanum and P. gaudichaudianum, evidencing cytotypes that can be formed from euploid (non-reduced) and/or aneuploid reproductive cells. GC% ranged from 34.33% (P. guineense) to 48.95% (P. myrtoides), and intraspecific variations occurred even for species without 2C value intraspecific variation. Essential oil yield increased in relation to 2C value and to GC%. We showed that P. guajava (diploid) possesses two and P. guineense (tetraploid) four copies of the one specific TPS gene, as well as eight and sixteen copies respectively of the conserved regions that occur in eight TPS genes. We provide a wide “omics'' characterization of Psidium and show the outcome of the genome and epigenome variation in secondary metabolism.

Antidiabetic effects of Psidium x durbanensis Baijnath & Ramcharun ined. (Myrtaceae) leaf extract on streptozotocin-induced diabetes in rats

Ethnopharmacological relevancePsidium guajava L. leaves are used to treat diabetes in South African folkloric medicine and in other parts of the world. Psidium x durbanensis Baijnath & Ramcharun ined. (PD) is a natural sterile hybrid and congener of Psidium guajava that is expected to share the medicinal properties of the genus Psidium and is widely distributed in South Africa.Aim of the study: This study investigates the antioxidant, antidiabetic effects, and mechanisms of action of hydro-methanolic leaf extracts of PD on streptozotocin-induced diabetes in rats. Material and methodsPhytochemical constituents of hydro-methanolic extract of PD were analyzed by gas chromatography-mass spectrometry (GC-MS). Male Wistar rats 250–300 g body weight (BW) were rendered diabetic after a single intraperitoneal injection with streptozotocin, 45 mg/kg BW. The diabetic rats were treated with hydro-methanolic (20:80 v/v) leaf extracts of PD (400 mg/kg/BW) or subcutaneous injections of regular insulin (2.0U/kg/BW, bid) for 56 days. The body weights of the animals were recorded daily. Fasting blood glucose, glucose tolerance tests, and insulin resistance index were measured. The effects of the extracts on total superoxide dismutase, catalase, and reduced glutathione activities, histopathology, and gene expression of insulin receptor substrate 1 and glucose transporter 4 were determined in the liver, pancreas, and gastrocnemius muscles of the rats. ResultsIn the acute toxicity studies, there were no signs of toxicity observed for PD up to 2000 mg/kg BW doses. Diabetic animals showed significant weight loss, elevated and reduced fasting blood glucose and insulin, respectively, impaired glucose tolerance and diminished antioxidant enzymes’ activities compared to controls. Treatment with PD hydro-methanolic leaf extracts improved body weight, glucose tolerance, insulin resistance, and antioxidant enzymes but not plasma insulin in diabetic animals compared to controls, respectively. GC-MS analysis identified organic acids, alcohols, vitamins, terpenoids, and esters in the extracts. Treatment with PD improved glucose uptake by stimulating mRNA expression of GLUT 4 in gastrocnemius muscles of diabetic animals compared to the untreated control and also restored histological aberrations in the pancreas and liver of diabetic rats compared with the untreated control rats. ConclusionCollectively, the present study suggests that treatment with PD leaf extracts significantly ameliorated diabetes symptoms and oxidative stress in rats, and these effects may be linked to the bioactive phytoconstituents present in the plant. This study further suggests that PD improves insulin resistance by increasing glucose uptake in gastrocnemius muscles in an insulin-independent manner.

Genetic Diversity and Population Structure of Psidium Species from Restinga: A Coastal and Disturbed Ecosystem of the Brazilian Atlantic Forest.

The Atlantic Forest is one of the most threatened biomes in the world. Here, we use a common set of microsatellite markers to assess the genetic diversity and population structure of three species from the genus Psidium (P. guajava, P. macahense, and P. guineense), located in a disturbed environment of the Atlantic Forest, the restinga, in Espírito Santo, Brazil. Psidium guajava populations presented the highest number of alleles (95) followed by P. guineense (81) and P. macahense (68). The genetic variability was high (P. guajava = 0.71; P. guineense = 0.74; P. macahense = 0.63), with greater variation within populations (72 to 84%) than among populations (15 to 27%), reflecting elevated values of genetic differentiation (P. guajava, FST: 0.15; P. macahense, ØST: 0.27; P. guineense, ØST: 0.21). The populations were clustered into two main groups and considered moderately structured. This is the first report of genetic studies and evidence of polyploidy to P. macahense. Our results may provide information that can be used in management and conservation strategies, to preserve the diversity of Psidium populations.

Oral administration of essential oil from Psidium glaziovianum Kiaersk leaves alleviates pain and inflammation in mice.

Plants of the genus Psidium have been employed in "in natura" consumption and agroindustry, and owing to the diversity of phytochemicals, the development of new pharmaceutical forms has received remarkable research interest. In this study, the essential oil obtained from Psidium glaziovianum (PgEO) leaves were evaluated antinociceptive and anti-inflammatory activities were evaluated in mouse models. Initially, PgEO was characterized by gas chromatography-mass spectrometry and gas chromatography with flame ionization detection, and the profile was dominated by sesquiterpene compounds. In the evaluation of acute antinociceptive activity (abdominal contortions induced by acetic acid, formalin, tail immersion, and hot plate tests), PgEO promoted a reduction in nociception in the chemical and thermal models. Additionally, the potential underlying mechanism was investigated using pain pathway blockers, and the results revealed a combined action of opioidergic and muscarinic pathways. The anti-inflammatory potential was confirmed by anti-edematogenic action, reduced cell migration, pro-inflammatory cytokine production, and granuloma formation in chronic processes. This study provides evidence that PgEO can be effective for the treatment of pain and acute and chronic inflammation.

Recent Advances in Novel Packaging Technologies for Shelf-Life Extension of Guava Fruits for Retaining Health Benefits for Longer Duration.

Guava (Psidium guajava L.) fruit is also known as the apple of tropics, belongs to the family of genus Psidium, and is widely cultivated in tropical zones of the world. Recently, the importance of guava fruit has increased due to its inherent nutritional content, pleasant aroma, excellent flavor, and delicious taste. It is considered an excellent source of nutrients and phytochemicals. Guava is a climacteric fruit that continues to mature or ripen even after harvest, showing an increase in the rate of respiration and metabolic activities within a short period, leading to rapid senescence or spoilage of fruit. It has limitations in terms of commercialization due to short storage life after harvest and sensitivity to diseases and chilling injury during the storage period. Many postharvest technologies such as edible packaging, modified atmosphere packaging (MAP), composite packaging, controlled atmosphere packaging (CAP), antimicrobial/antifungal packaging, and nano packaging have been used to retard the chilling injury and enhance the keeping quality of guava fruits during the storage period to control respiration rate, reduce weight loss, minimize lipid oxidation, and maintain organoleptic properties. However, these packaging technologies have varied effects on the internal and external quality attributes of guava fruits. This review, therefore, discusses the physiology, mechanism of ripening, oxidation, and ethylene production of guava fruits. The review also discusses the packaging technologies and their effect on the postharvest characteristics of guava fruits during the storage period.

The Taming of Psidium guajava: Natural and Cultural History of a Neotropical Fruit.

Guava (Psidium guajava L., Myrtaceae) is a Neotropical fruit that is widely consumed around the world. However, its evolutionary history and domestication process are unknown. Here we examine available ecological, taxonomic, genetic, archeological, and historical evidence about guava. Guava needs full sunlight, warm temperatures, and well-distributed rainfall throughout the year to grow, but tolerates drought. Zoochory and anthropochory are the main forms of dispersal. Guava’s phylogenetic relationships with other species of the genus Psidium are unclear. A group of six species that share several morphological characteristics are tentatively accepted as the Psidium guajava complex. DNA analyses are limited to the characterization of crop genetic diversity within localities and do not account for possible evolutionary and domestication scenarios. A significant amount of archeological information exists, with a greater number and older records in South America than in Mesoamerica, where there are also numerous historical records. From this information, we propose that: (1) the guava ancestor may have originated during the Middle or Late Miocene, and the savannas and semi-deciduous forests of South America formed during the Late Pleistocene would have been the most appropriate ecosystems for its growth, (2) the megafauna were important dispersers for guava, (3) dispersal by humans during the Holocene expanded guava’s geographic range, including to the southwestern Amazonian lowlands, (4) where its domestication may have started, and (5) with the European conquest of the Neotropics, accompanied by their domestic animals, new contact routes between previously remote guava populations were established. These proposals could direct future research on the evolutionary and domestication process of guava.

Exploiting the chemical composition of essential oils from Psidium cattleianum and Psidium guajava and its antimicrobial and antioxidant properties.

The genus Psidium comprises several native Brazilian plants, such as the araçá and guava trees. They are interesting sources of essential oils (EOs) that can be used as natural preservatives in foods due to their bioactive properties. This work aimed to evaluate and correlate the biological properties of the EOs from araçá and guava leaves with their chemical compounds. The gas chromatography-mass spectrometry (GC/MS) was used to determine the chemical composition of EOs. The antimicrobial activity was tested against 16 foodborne pathogens and the antioxidant capacity was determined by ABTS, DPPH, and FRAP assays. The major compounds identified in the essential oil of araçá (EOA) were β-caryophyllene and β-elemene, representing 38.69% and 7.47%, respectively, whereas β-selinene (13.83%), α-humulene (10.90%), and β-caryophyllene (7.61%) were the major compounds identified in the essential oil of guava (EOG). Both EOs showed activity against Salmonella Enteritidis, with MIC being 1.41µg/ml for the EOA and 1.37µg/ml for the EOG. The EOA was more effective than the EOG against strains of Listeria monocytogenes and Pseudomonas aeruginosa, with the MIC being 1.41µg/ml. The EOA showed 10.43, 12.35, and 3.92µmol TE/ml at 90µg/ml whereas the EOG showed 4.54, 8.94, and 3.43µmol TE/ml at 88µg/ml for ABTS, DPPH, and FRAP, respectively. Thus, the EOs demonstrated an effective action against foodborne pathogens and free radicals, indicative of their potential use as natural preservatives for foods. PRACTICAL APPLICATION: Guava and araçá are native Brazilian plants producers of essential oils, natural compounds with antimicrobial and antioxidant potential. The chemical composition of essential oils is responsible for its beneficial properties. The results demonstrated that the essential oils studied are rich in β-caryophyllene and has excellent activity against malefic microorganisms and free radicals, and can also be used as natural preservatives in foods.

Quantification of bioactive compounds in guava at different ripening stages

Guava (Psidium guajava L.) is one of the most important tropical fruits belonging to the genus Psidium and the Myrtaceae family and claim to have phenolic compounds that have been reported to possess strong antioxidant activity. This study was aimed to evaluate the bioactive constituents in guava cultivars at different ripening stages by HPLC. The five guava cultivars were selected at different ripening stages and the bioactive components were analysed by high-pressure liquid chromatography. The quantification of bioactive compounds revealed that the highest amount of bioactive compounds was found in cultivar Safeda at the unripe stage, while a minimum amount was found in ripe Apple Colour guava cultivar. The six bioactive compounds were quantified in the range of gallic acid (9.46-63.08 mg/100 g), quercetin (0.11-2.51 mg/100 g), myrcetin (0.09-0.034 mg/100 g), ascorbic acid (7.45-75.07 mg/100 g), apegenin (0.01-0.032 mg/100 g) and lycopene (0.34-0.92 mg/100 g). The exploratory evaluation of guava samples was performed through Principal Component Analysis (PCA), the bioactive compounds, lycopene, myricetin, and quercetin are dominant variables on this PC1 (61.52%) (Scores better than 0.7), thereby causing greater variability among these samples. The second principal component (PC2) represents 16.54% of the total variance and the ascorbic acid, gallic acid and apeginin (score better than 0.7), are the dominant variables on this PC.

Psidium L. genus: A review on its chemical characterization, preclinical and clinical studies

The Myrtaceae family is considered one of the largest known botanical families and the genus Psidium is among the most economically interesting. Psidium genus comprises approximately 112 species, and it has been extensively studied, mainly because of Psidium guavaja species. Phytochemical investigations confirmed the presence of phenolics as the main compounds, as well as the essential oils, which were also widely investigated. Pharmacological studies report analgesic, anthelminthic, acaricidal, antihiperglicemic, among other biological activities for different species. The present review covers the relevant literature until 2019 and outlines the current data on chemical composition, preclinical and clinical studies on Psidium species, as well as the main possible mechanisms of action responsible for the described activities. Therefore, it can provide a reference for pharmaceutical research and clinical application of this genus.

DArTseq-derived SNPs for the genus Psidium reveal the high diversity of native species

In this study, we characterized DArTseq-derived SNPs for species of Psidium, an important Neotropical genus within the family Myrtaceae. Nine Psidium species were used for the identification and characterization of an interspecific set of SNPs. The samples chosen represented a wide range of variation regarding agronomic traits and geographical origin. The samples were genotyped using the DarTseq methodology. This approach, associated with annotation analysis, generated a set of conserved, polymorphic, and possibly functional SNPs. Most of the SNPs in coding regions of Psidium were annotated for the gene ontology classes. We observed high interspecific diversity among species and considerable intraspecific genetic diversity in native species (P. cattleyanum, P. myrtoides, P. acidum, and P. oblongatum). Psidium guajava, a cultivated species, shows low diversity and shares genetic similarities with the tetraploid P. guineense. The group of markers selected in this study will contribute to the development of a panel of interspecific SNPs for Psidium. Our investigation will support further studies regarding genetic variability, diversity, phylogeny, cytogenetics, and other relationships among Psidium species, constituting essential information for the creation, conservation, management, and use of genetic resources in breeding programs.

Effect of cryopreservation on pollen viability, fertility and morphology of different Psidium species

Cryopreservation of pollen is a complementary conservation strategy and can be used for conserve the diversity in the genus Psidium. The present study aims to cryopreserve the pollen of Psidium species to overcome asynchronous flowering. The pollen of different Psidium species were germinated in vitro in an optimized medium of germination. In vitro/in vivo pollen viability assessment and SEM analysis were carried out to determine the changes after cryopreservation. The in vitro pollen viability was determined at monthly intervals starting from fresh pollen until six months of cryopreservation. The in vivo fertility tests were carried out by pollination using both fresh and cryopreserved pollen. The cryopreserved pollen showed in vitro germination ranging from 1.78% (in P. molle) to 81.67% (in “H 12–5”) compared to fresh pollen (2.16% in P. molle to 86.08% in P. guineense). In vivo fertility was tested by controlled pollination using six-month-old cryopreserved pollen and it resulted in fruit setting ranged between 3.33% (P. cattleianum var. cattleianum) and 27.66% (P. chinensis) as compared to fresh pollen between 4.0% (P. cattleianum var. cattleianum) and 30.66% (P. chinensis). Seed set and germination was also recorded in all the crosses attempted using cryopreserved pollen. These in vitro and in vivo results indicated that cryopreservation is an effective technique for breeding and conserving the haploid gene pool in cryo genebank. Scanning Electron Microscopic studies of pollen revealed no significant variation in shape and size after cryopreservation when compared to fresh pollen.

<p><strong>Description of <em>Psidium brevipedunculatum</em> (Myrtaceae), and considerations about the high diversity and endemism for the genus <em>Psidium</em> from Bahia, Brazil</strong></p>

Increased sampling in under-collected areas and the digitization of herbarium collections have led to recent findings revealing the high diversity and endemism of the genus Psidium in the state of Bahia. This paper describes a new species of Psidium (Myrtaceae, Myrteae) occurring in the Caatinga biome of Bahia in Northeastern Brazil. It is a shrub or small tree up to 1.5–5 m tall, with of short peduncles (1.5–5 mm long), blades elliptic to obovate, apex with a cuspidate tip, lower leaf surfaces densely tomentose, hairs yellowish brown. The calyx is closed and tears irregularly. An illustration and comments about morphology, distribution and threats are provided.

Avaliação do potencial antioxidante e da atividade antibacteriana do extrato da polpa de Psidium brownianum Mart. ex DC

Espécies do gênero Psidium tem se apresentado eficiente quanto a características de interesses nutricionais, como riqueza em vitaminas e em substâncias antioxidantes. Além disso, atividade antibacteriana, tem sido evidenciada por extratos de espécies do gênero Psidium. Dessa forma, o presente estudo tem a finalidade avaliar o potencial antioxidante e a atividade antibacteriana do extrato da polpa de Psidium brownianum Mart. ex DC.. Os compostos fenólicos totais foram quantificados utilizando o reagente de Folin – Ciocalteau. O potencial antioxidante do extrato de Psidium brownianum Mart. ex DC. foi determinado pelo método fotocolorimétrico in vitro por sequestro do radical livre estável DPPH. Para avaliar a capacidade antibacteriana do extrato, fez uso do método de microdiluição em caldo. Os compostos fenólicos totais encontrados no extrato representam o valor de 1211 mg GAE/100 g da amostra. O extrato de Psidium brownianum Mart. ex DC. apresentou alto potencial antioxidante, provavelmente devido ao seu elevado teor de compostos fenólicos. A espécie também evidenciou atividade inibitória contra todas as cepas bacterianas testadas. À vista disso é possível inferir que a polpa de Psidium brownianum Mart. ex DC., mostra-se uma fonte rica em compostos fenólicos toais e potencial antioxidante, sendo assim sua ingestão se faz importante. Quanto à atividade antibacteriana mais estudos são necessários envolvendo possíveis associações desse extrato com outras substâncias, como forma de potencializar seu uso.

Chemotaxonomic evaluation of different species from the Myrtaceae family by UPLC-qToF/MS-MS coupled to supervised classification based on genus

Since Myrtaceae is considered a complex family concerning the taxonomic classification due to the elevated number of components, difficult morphologic differentiation, and relatively low amount of studies in area, this article describes the potentiality of classification using chemometrics applied to UPLC-qToF/MS-MS dataset for chemotaxonomy investigation of leaves of fifteen species from the genus Psidium, Plinia, Myrciaria, and Eugenia into the Myrtaceae family. The use of a multivariate tool was indispensable to detect marker compounds since an elevated number of information on chromatograms did not provide conclusive data. The results offered an adequate classification among genus and species, principally based on ellagic acid, catechin, epicatechin, isoquercitrin, quercitrin, reynoutrin, madecassic acid, asiatic acid, and morin, used as marker compounds. Therefore, the method was useful and permitted the satisfactory chemotaxonomic distinction among the genus.