Psidium Myrtoides Research Articles

Green extraction of phenolic compounds from the by-product of purple araçá (Psidium myrtoides) with natural deep eutectic solvents assisted by ultrasound: Optimization, comparison, and bioactivity

The recovery of bioactive compounds is a promising approach for obtaining rich extracts from fruit by-products. This study investigated the influence of Natural Deep Eutectic Solvents (NADES) and Ultrasound-Assisted Extraction (UAE) on the phenolic content, antioxidant capacity, and in vitro antidiabetic activity of Psidium myrtoides by-product. Among eight NADES evaluated based on choline chloride, NADES ChCl:Gly (1:2) was selected for its efficiency in extracting total phenolic compounds (TPC) with high antioxidant capacity. The optimized conditions were 61 °C, a solid–liquid ratio of 100 mg 5 mL−1, and a 60-minute extraction time. ChCl:Gly exhibited superior TPC recovery (2.6-fold greater effectiveness) compared to the 60 % hydroethanolic solution. Twenty-six phenolic compounds were identified, including significant levels of catechin (336.48 mg g−1) and isoquercetin (26.09 mg g−1). Phenolic acids, such as p-anisic acid (5.47 mg g−1) and methoxyphenylacetic acid (0.23 mg g−1), were identified for the first time in the purple araçá by-product. The ChCl:Gly extract demonstrated the highest bioactivity, showcasing antioxidant and antidiabetic capacities. This study introduces an innovative and sustainable alternative for recovering phenolic compounds from fruit by-products, offering enhanced recovery efficiency and/or selectivity compared to organic solvents.

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.

Drought, heat, and their combined effect on the photosynthetic performance of Psidium myrtoides O. Berg (Myrtaceae)

Drought, heat, and their combined effect on the photosynthetic performance of Psidium myrtoides O. Berg (Myrtaceae)

Production of Edible Films Based on Pea Starch with Incorporation of Active Compounds Obtained from the Purple Araçá (Psidium myrtoides).

The aim of this study was to incorporate the active compounds present in purple araçá (Psidium myrtoides) in pea starch-based films and to verify the influence of different plasticizers (glycerol, sorbitol, and polyethylene glycol 400) on film properties. Films were produced and characterized in relation to visual appearance, active compounds, antimicrobial activity, and mechanical and barrier properties. Pea starch has a high amylose content and a final viscosity of 5371.5 RVU, which contributes to the elaboration of films even without the addition of plasticizers. Purple araçá and pea starch formed films with good water vapor barrier characteristics (0.398 g·mm/m2·h·KPa) and low solubility (33.30%). Among plasticizers, sorbitol promoted a lower permeability to water vapor. The selected formulations, 0%, 20%, and 30% sorbitol, presented a high concentration of phenolic compounds (1194.55, 1115.47, and 1042.10 mg GAE 100 g−1, respectively) and were able to inhibit the growth of Staphylococcus aureus. Therefore, films contained the active compounds of purple araçá and potential to be used as food packaging.

Application of the Box–Behnken experimental design for the extraction of phenolic compounds from araçá‐roxo ( Psidium myrtoides )

The purpose of this study was to investigate the bioactive compounds of araçá-roxo by applying the Box–Behnken experimental design to evaluate the effect of temperature, time, and ethanol concentration on the extraction of phenolic compounds. The three variables evaluated significantly affected (p < .05) the extraction, and temperature proved to be the most influential variable. The optimum conditions were as follows: extraction temperature of 50°C, extraction time of 30 min, and ethanol concentration of 40%. Under such optimum conditions, the phenolic compounds, flavonoids, and anthocyanins present in the peel, pulp, and seed were determined and, separately, the phenolic and carotenoid compounds present in the extracts were identified and quantified by high-performance liquid chromatography. This study helped confirm the importance of araçá-roxo as a source of bioactive compounds, thereby demonstrating its potential for consumption. Practical applications Ultrasound can be considered an efficient technique for extracting phenolic compounds from the araçá-roxo, mainly at the optimized conditions. It can be seen that within the studied range (different temperature, solvent concentration, and extraction time), the araçá-roxo is rich in phenolic compounds, anthocyanins, flavonoids, and carotenoids, with the highest concentrations found in the extract obtained from the peel. The use of novel or green extraction methods, such as ultrasound, can provide higher efficiency for obtaining valuable compounds from araçá-roxo which may be an interest to the food industry.

Enhanced conditions to obtain a clarified purple araça (Psidium myrtoides) fruit extract

AbstractThis study evaluated the kinetics of extraction for bioactive compounds from purple araça fruit followed by the microfiltration process for extract clarification. The parametric study showed time (up to 60 min) and temperature (313, 333, 353, and 363 K) influences on the extraction of bioactive compounds from purple araça fruit. Extraction kinetics were adjusted to the second order kinetic model (R2 &gt; 0.9871). The best extraction conditions were at 353 K for 45 min. Purple araça fruit extract presented total phenolic and flavonoid contents of 5.29 ± 0.12 mgGAE g−1 and 2.79 ± 0.09 mgRutin g−1, respectively, FRAP value of 21.77 ± 1.10 mgFeSO4 g−1 and DPPH antioxidant capacity of 48.85 ± 2.02%. Concentrations of gallic acid, (−)‐Epicatechin, and (−)‐Epigallocatechin were 132.01 ± 1.22, 127.03 ± 1.45, and 60.45 ± 0.59 μg g−1, respectively. The microfiltration process with an acetate cellulose membrane of 0.22 μm pore size was efficient for clarifying the purple araça fruit extract, with steady state flux of 4.17 × 10−6 m3s−1 m−2 and reductions in total solids from 2.83 ± 0.01 to 1.43 ± 0.02%, without significant reductions in the concentration of bioactive compounds. These results suggest the valorization of purple araça fruit as a promising source of bioactive compounds for cosmeceutical, pharmaceutical and food industries and application of the microfiltration process for clarification purposes.Practical ApplicationsPurple araça (Psidium myrtoides) is a tropical and exotic fruit with considerable concentration of bioactive compounds. The purple araça fruit extract presents higher concentration of bioactive compounds than other fruits from the same Psidium species, such as the guava fruit. Suggested aqueous extraction conditions are temperature and time of 80°C 45 min, respectively. The microfiltration process is then proposed for extract clarification, with substantial reductions in total solid concentration and turbidity, without reducing bioactive compound concentrations. Thus, the microfiltered purple araça fruit presents suitable characteristics to be used as a ready‐to‐drink product or to be submitted for further concentration processes.

Avaliação de corantes para determinação de venação foliar e prospecção fitoquímica de Psidium myrtoides (araçá-roxo)

A espécie Psidium myrtoides encontrada no domínio Cerrado no Brasil apresenta escassos dados na literatura sobre o padrão de venação foliar e sobre sua prospecção fitoquímica preliminar. O trabalho visou avaliar diferentes corantes para determinação do padrão de venação e da prospecção fitoquímica do extrato hidroetanólico foliar. Foram coletadas 10 folhas sadias em 5 exemplares de P. myrtoides, para o experimento de identificação utilizando os seguintes corantes: azul de toluidina, fucsina, safranina e violeta de genciana. Para o segundo experimento, folhas sadias foram coletadas em duas sazonalidades, período (seco e chuvoso). Extratos foliares hidroetanólicos 70% (v/v) foram produzidos e analisados para: ácidos orgânicos, açúcares redutores e não redutores, alcaloides, flavonoides, saponinas espumídicas e hemolíticas, cumarinas, glicosídeos cardíacos, fenólicos, taninos, polissacarídeos, derivados de benzoquinonas, depsídeos e depsidonas, antraquinonas e duplas olefínicas. O uso dos corantes atípicos apresentaram excelentes resultados para distinção das estruturas morfológicas de venação, sendo boas opções para o estudo taxonômico. A análise fitoquímica apresentou resultados importantes para a maioria das classes químicas avaliadas, exceto para os compostos polissacarídeos, derivados de benzoquinonas e antraquinonas que apresentaram resultados negativos. Este estudo apresentou resultados inéditos que comporá os dados científicos sobre a sistemática vegetal para a correta classificação de P. myrtoides a partir da análise de venação foliar. Os corantes empregados na diferenciação de estruturas de venação poderão ser utilizados para outros estudos com esta e como novas opções para determinação de outros padrões de venação em variadas famílias botânicas. Quanto aos resultados de prospecção fitoquímica, os extratos devem ser avaliados quanto a cada composto fitoquímico e sua concentração, observando ser uma espécie vegetal rica em diversificados compostos fitoquímicos importante para a indústria farmacêutica, agrícola, de biotecnologia e alimentícia.

Hydrodynamic performance of 3D printed turbulence promoters in cross-flow ultrafiltrations of Psidium myrtoides extract

Membrane separations for fruit juice processing have been largely investigated, but membrane fouling is still a limitation to be overcome. Here, the use of turbulence promoters to increase the permeate flux of purple araça fruit (Psidium myrtoides) extract through flat polymeric membranes was investigated. The turbulence promoters were produced using 3D printing technology with two different cylindrical pin diameters (2.5 and 3.5 cm). Results show that the ultrafiltration membrane was efficient to concentrate the bioactive compounds of purple araça fruit extract. Retentions of total polyphenol and flavonoid compounds were 95 % and 90 %, respectively. The use of turbulence promoters increased the permeate flux by up to 78 %. According to computational fluid dynamics (CFD), the turbulence promoters with diameters of 2.5 and 3.5 mm increased the flow velocity on the membrane surface in 38.4 % and 30.7 %, respectively, and increases in turbulence intensity were of 69.0 % and 43.2 %, respectively. In addition, the turbulence promoters with diameters of 2.5 and 3.5 mm increased the wall shear stress from 1.57 to 3.12 and 3.07 Pa, respectively. Thus, the turbulence promoters had positive effects on hydrodynamics during ultrafiltration of purple araça fruit extract.

Seasonality influence on the chemical composition and antifungal activity of Psidium myrtoides O. Berg

The present study aimed to investigate the influence of seasonality from different collection periods on the chemical composition and antifungal activity of the Psidium myrtoides O. Berg essential oil (OEFPm). The OEFPm chemical composition was evaluated through gas chromatography coupled to mass spectrometry (GC/MS). The oil's antifungal activity against species from the Candida genus, in isolation and in combination with Fluconazole at a subinhibitory concentration (MFC/16), was evaluated using the broth microdilution method, while its effect on Candida albicans pleomorphism was evaluated by microculture. The results showed the compound 1–8 cineol was the major component in all the samples. The OEFPm showed significant MFC ranging from 1,024 to ≥ 16,384 μg/mL for the C. albicans, C. krusei and C. tropicalis strains with IC50 values ranging from 103.3 to 3564.5 μg/mL. The essential oils affected morphological transition at all tested concentrations in the C. albicans morphological alteration assays. The results from this study show the collection period affected the chemical composition and the antimicrobial activity of the essential oil. A significant variation was documented for most chemical components and the biological activity of the seasonally collected samples, in addition to variations in morphological transition inhibition, an important virulence factor for the genus.

Chemical composition and in vitro antibacterial and antiproliferative activities of the essential oil from the leaves of Psidium myrtoides O. Berg (Myrtaceae)

In this study, the chemical composition and antibacterial and antiproliferative potential of the essential oil obtained from fresh leaves of Psidium myrtoides (PM-EO) against oral pathogens and human tumour cell lines were investigated for the first time. GC-FID and GC-MS analyses showed that trans-β-caryophyllene (30.9%), α-humulene (15.9%), α-copaene (7.8%), caryophyllene oxide (7.3%) and α-bisabolol (5.3%) are the major constituents of PM-EO. The antibacterial activity of PM-EO against a panel of oral pathogens was investigated in terms of their minimal inhibitory concentrations (MIC) using the broth microdilution method. PM-EO displayed moderate activity against Streptococcus mitis (MIC = 100 μg/mL), S. sanguinis (MIC = 100 μg/mL), S. sobrinus (MIC = 250 μg/mL), and S. salivarius (MIC = 250 μg/mL), and strong activity against S. mutans (MIC = 62.5 μg/mL). The antiproliferative activity in normal (GM07492A, lung fibroblasts) and tumour cell lines (MCF-7, HeLa, and M059 J) was performed using the XTT assay. PM-EO showed 50% inhibition of normal cell growth at 359.8 ± 6.3 μg/mL. Antiproliferative activity was observed against human tumour cell lines, with IC50 values significantly lower than that obtained for the normal cell line, demonstrating IC50 values for MCF-7 cells (254.5 ± 1.6 μg/mL), HeLa cells (324.2 ± 41.4 μg/mL) and M059 J cells (289.3 ± 10.9 μg/mL). Therefore, the cytotoxicity of PM-EO had little influence on the antibacterial effect, since it showed antibacterial activity at lower concentrations. Our results suggest that PM-EO is a promising source of new antibacterial and antitumour agents.

Cytological cycles and fates in Psidium myrtoides are altered towards new cell metabolism and functionalities by the galling activity of Nothotrioza myrtoidis.

The morphogenesis of galls occurs by the redifferentiation of cells that assume new functions in the modified host plant organs. The redifferentiated cells in the galls of Nothotrioza myrtoidis on Psidium myrtoides have low complexity metabolism and are photosynthesis-deficient. These galls were studied in search for evidences of the establishment of new cell cycles and fates and cytological gradients that corroborate their metabolic profile. Young and mature leaves of P. myrtoides and leaf galls induced by N. myrtoidis at different developmental stages were collected along 24 months and analyzed under light and transmission electron microscopy. The leaves of P. myrtoides are long-lasting and did not senesce within the analyzed period, while the galls have a shorter cycle, and senesce within 1 year. A homogenous parenchyma is established by a "standby-redifferentiation" of the chlorophyllous tissues, and sclerenchyma cells redifferentiate from parenchyma cells in the outer cortex of the mature galls. The lack of organelles, the underdeveloped lamellation of chloroplasts, and the occurrence of few plastoglobules are related to the photosynthetic deficiency of the galls. No cytological gradients were observed, but the organelle-rich cells of the vascular and perivascular parenchymas are similar to those of the nutritive tissues of galls induced by other insect taxa. These cells nearest to the feeding sites of N. myrtoidis present higher metabolism and well-developed apparatus for the prevention of oxidative stress. The features herein described corroborate the low metabolic profile of the galls as the cell cycles and fates of P. myrtoides are manipulated for completely new functionalities.

Developmental anatomy and immunocytochemistry reveal the neo-ontogenesis of the leaf tissues of Psidium myrtoides (Myrtaceae) towards the globoid galls of Nothotrioza myrtoidis (Triozidae).

The temporal balance between hyperplasia and hypertrophy, and the new functions of different cell lineages led to cell transformations in a centrifugal gradient that determines the gall globoid shape. Plant galls develop by the redifferentiation of new cell types originated from those of the host plants, with new functional and structural designs related to the composition of cell walls and cell contents. Variations in cell wall composition have just started to be explored with the perspective of gall development, and are herein related to the histochemical gradients previously detected on Psidium myrtoides galls. Young and mature leaves of P. myrtoides and galls of Nothotrioza myrtoidis at different developmental stages were analysed using anatomical, cytometrical and immunocytochemical approaches. The gall parenchyma presents transformations in the size and shape of the cells in distinct tissue layers, and variations of pectin and protein domains in cell walls. The temporal balance between tissue hyperplasia and cell hypertrophy, and the new functions of different cell lineages led to cell transformations in a centrifugal gradient, which determines the globoid shape of the gall. The distribution of cell wall epitopes affected cell wall flexibility and rigidity, towards gall maturation. By senescence, it provided functional stability for the outer cortical parenchyma. The detection of the demethylesterified homogalacturonans (HGAs) denoted the activity of the pectin methylesterases (PMEs) during the senescent phase, and was a novel time-based detection linked to the increased rigidity of the cell walls, and to the gall opening. Current investigation firstly reports the influence of immunocytochemistry of plant cell walls over the development of leaf tissues, determining their neo-ontogenesis towards a new phenotype, i.e., the globoid gall morphotype.

Unique histochemical gradients in a photosynthesis-deficient plant gall

Galls usually present low chlorophyll content, and their metabolism may vary depending on the taxa of the inducer and on the complexity of the gall structure. Primary and secondary plant metabolites allocated in gall tissues are evidenced with histochemical tests and may indicate the physiological status of such tissues. The histochemical and biochemical profiles of the galls induced by Nothotrioza myrtoidis Burck. (Hemiptera: Psylloidea) on Psidium myrtoides (Myrtaceae) were compared to those reported for some other Neotropical galls. The extralaminar galls of N. myrtoidis have low chlorophyll and nitrogen contents, but they accumulate more polysaccharides than the non-galled leaves. The histochemical gradient of reducing sugars is guaranteed by the activity of acid phosphatase, and ensures the nourishment of the gall inducer, while the gradients of phenolics and proanthocyanidins are both related to protection of the gall inducer and modulation of plant cell growth. The accumulation of reactive oxygen species seems to play a major role on the determination of the extent of tissue alterations during gall morphogenesis. The lack of morphological continuum and physiological continuum between the extralaminar galls of N. myrtoidis and the leaves of P. myrtoides, together with the low impacting feeding activity of the sucking insect, determine the establishment of a photosynthesis-deficient structure with unique features among Neotropical galls.

Biology and systematics of gall-inducing triozids (Hemiptera: Psylloidea) associated with Psidium spp. (Myrtaceae).

Psidium myrtoides (Myrtaceae) shelters the gall inducer Nothotrioza myrtoidis gen. et sp. n. (Hemiptera: Psylloidea) which is described and illustrated here. Nothotrioza belongs to the family Triozidae and is probably most closely related to Neolithus, a monotypic Neotropical genus associated with Sapiun (Euphorbiaceae). Three species are recognized within Nothotrioza: the type species N. myrtoidis sp. n. associated with Psidium myrtoides, N. cattleiani sp. n. (misidentified by Butignol & Pedrosa-Macedo as Neotrioza tavaresi) with Psidium cattleianum, and N. tavaresi (Crawford) comb. n. (from Neotrioza) with an unidentified species of Malpighiaceae, respectively. A lectotype is designated here for Neotrioza tavaresi. Also, the diversity of insect galls associated with P. myrtoides and the biology of N. myrtoidis were examined. N. myrtoidis presents five instars and an annual life cycle synchronised with the phenology of P. myrtoides. Gall size was proportional to the insect developmental stages, and rates of parasitism and mortality were 15.7 % and 29.8 %, respectively. The red colour is an important macroscopic diagnostic feature of the gall that could be associated with parasite-free condition of the galling insect. The biological features presented by the system Psidium myrtoides--Nothotrioza myrtoidis are in accordance with other systems involving sucking galling insects, however, it is exceptional by its univoltine life cycle associated with a perennial plant in the Neotropics. The galls induced by the three known Nothotrioza spp. are morphologically similar, i.e. closed, globoid and unilocular, as well as the opening mechanism for releasing the adults.

Feeding habit of the Brazilian tapir, Tapirus terrestris (Perissodactyla: Tapiridae) in a vegetation transition zone in south-eastern Brazil

Tapirs are considered generalist herbivores and the differences in the proportions of dietary items are often attributed to differences in the habitats where individuals live. This study characterized the feeding habit of Tapirus terrestris (Linnaeus, 1758) in a nature reserve in south-eastern Brazil, located in a region considered a transition zone between the Cerrado (Brazilian savanna) and the Atlantic Forest biomes. Fecal samples from T. terrestris individuals were collected monthly at six sampling areas that encompassed a total of 242.22 ha. There were 147 fresh samples found (77 during the dry season and 70 during the wet season). The diet of the tapirs in this reserve was characterized by the prevalent browsing on leaves and stems. There was a low frequency of fruit seeds in the diet of the tapirs during both the wet and dry seasons. However, in the dry season a higher percentage of samples containing seeds was observed. Fruits of Rubiaceae, Solanaceae, and Annonaceae were most consumed during the dry season. Most of the fruit seeds found presented small mean diameter (3.7-8.4 mm) and most of the fruits were capsules and dry fruits. The characteristics of the fruits consumed by the tapirs indicate that they forage in the lower forest stratum and upon species from Cerrado. Additionally, Psidium myrtoides O. Berg. clusters found in the study site suggest that the tapirs may be acting as dispersal agents of this species.