Phytochemical analysis, toxicity and evaluation of antioxidant and antimicrobial activities of leaves of Dipteryx alata Vogel.

In this study, our objective was to conduct a comprehensive phytochemical analysis, determine toxicity levels, and assess the antioxidant and antimicrobial properties of extracts derived from the leaves of Dipteryx alata Vogel, a native species of the Brazilian cerrado flora. Three distinct extracts were prepared utilizing assisted ultrasound and the Soxhlet apparatus, namely, Ultrasound Crude Extract (UCE), Soxhlet Crude Extract (SCE), and the Soxhlet Ethanol Extract (SEE). The phytochemical analysis revealed the presence of flavonoids, tannins, phytosterols, and saponins in all extracts. Additionally, alkaloids were specifically identified in the SCE and SEE extracts. In the analysis using LC-DAD, the compounds gallic acid, rutin, quercetin, luteolin and kampefrol were determined in higher concentrations in the SCE, followed by the SEE and UCE, respectively. The GC-MS analysis revealed the presence of campesterol, stigmasterol and ß-sitosterol in all extracts, with UCE and SCE showing a higher concentration of ß-sitosterol. SCE showed the highest concentration of all identified compounds. In the analysis of antioxidant activity by DPPH• and ABTS•+, SEE showed greater efficiency (IC50 = 2.98 ± 2.92 and 6.57 ± 0.89 µg/mL, respectively). In the toxicity test with Allium cepa, all extracts stimulated root growth at 50 g/mL; UCE and SEE stimulated root growth at 250 g/mL; and SEE inhibited root growth at 750 g/mL. In the Artemia salina toxicity, all extracts were non-toxic. Antibacterial activity was identified in the microorganisms S. aureus and S. mutans; however, the extracts did not show antifungal action against the strain of C. albicans. The extracts of D. alata have therapeutic potential for applicability in dentistry.

Integrated control of Penicillium digitatum by the predacious yeast Saccharomycopsis crataegensis and sodium bicarbonate on oranges.

Our investigation of integrated biological control (IBC) started with an assay testing activity of the predacious yeast Saccharomycopsis crataegensis UFMG-DC19.2 against Penicillium digitatum LCP 4354, a very aggressive fungus that causes postharvest decay in oranges. Under unfavourable environmental conditions, the yeast showed a high potential for control (39.9% disease severity reduction) of this fungus. This result was decisive for the next step, in which S. crataegensis was tested in association with sodium bicarbonate salt, a generally regarded as safe (GRAS) substance. The yeast was able to survive at different concentrations of the salt (1%, 2% and 5%), and continued to grow for a week at the wound site, remaining viable at high population for 14 days on the fruit surface. The yeast alone reduced the severity of decay by 41.7% and sodium bicarbonate alone reduced severity of decay by 19.8%, whereas the application of both led to a delay in the development of symptoms from 2 to 10 days. Ingredients of the formulations were not aggressive to fruits since no lesions were produced in control experiments.

Reduction of aflatoxin B1 in stored peanuts (Arachis hypogaea L.) using Saccharomyces cerevisiae.

Aflatoxin B(1) is a toxigenic and carcinogenic compound produced by Aspergillus flavus and Aspergillus parasiticus. To inhibit aflatoxin contamination of peanuts, seeds of two peanut breeds, IAC Caiapó and IAC Runner 886, were inoculated with A. parasiticus (1.0 × 10(6) spores per ml) and the yeast Saccharomyces cerevisiae (3.2 × 10(7) cells per ml) and incubated at 25°C for 7 and 15 days. Two experiments were conducted for each incubation period separately. The treatments were completely randomized, with three replications per treatment. Treatments included the two cultivars and three types of inoculation (pathogen alone, yeast and pathogen, and yeast 3 h before pathogen). Aflatoxin B(1) was quantified with a densitometer at 366 nm after thin layer chromatography. Aflatoxin B(1) contamination in peanuts was reduced after the addition of S. cerevisiae. The concentration of aflatoxin B(1) decreased by 74.4 and 55.9% after 7 and 15 days, respectively. The greatest aflatoxin reduction was observed when S. cerevisiae was inoculated 3 h before the pathogen in IAC Caiapó seeds and incubated for 7 days at 25°C. The use of S. cerevisiae is a promising strategy for biological control of aflatoxin contamination in peanuts.

Determinação do perfil fitoquímico de extrato com atividade antioxidante da espécie medicinal Cordia verbenacea DC. por HPLC-DAD / Phytochemical profile determination from extracts with antioxidant activity of the medicinal species of Cordia verbenacea DC. by HPLC-DAD

O presente trabalho teve por objetivo investigar a atividade antioxidante dos extratos das folhas de Cordia verbenacea obtido por maceração em etanol e partição em solventes orgânicos. O infuso das folhas também foi investigado. O teor de fenóis totais foi avaliado pelo método de Folin-Ciocalteau e o de flavonoides totais pela formação de complexo com cloreto de alumínio. O extrato etanólico, as subfrações e o infuso foram testados em diversas concentrações para determinar a atividade sequestradora de DPPH expressa em termos de sua CE50. A melhor atividade antioxidante encontrada foi para o extrato em acetato de etila, EA, CE50 15,0 ± 0,5 µg.mL-1. Os ensaios espectrofotométricos revelaram altas concentrações de fenóis e de flavonoides no extrato EA. A análise por HPLC-DAD foi realizada para se obter o perfil de UV-Vis dos picos cromatográficos do extrato EA. As características espectrais foram relacionadas a compostos fenólicos e flavonoídicos.

The objective of the present study was to investigate the antioxidant activity of extracts from Cordia verbenacea leaves obtained by maceration in ethanol and partitioned with organic solvents. The infusion of leaves was also investigated. The total phenolic and total flavonoid content was evaluated by the Folin-Ciocalteau method and by the aluminum chloride complex method, respectively. The ethanol extract, the subfractions and the infusion were assayed at various concentrations to determine the DPPH scavenging activity expressed in terms of CE50. The best antioxidant activity was found on the ethyl acetate extract, EA, CE50 15.0 ± 0.5 µg.mL-1. The spectrophotometric assays revealed high phenol and flavonoid concentrations on the EA extract. The HPLC-DAD analysis was performed to reveal the UV-Vis profile of the chromatographic peaks of the EA extract. The UV spectral characteristics were related to phenol and polyphenol compounds.

In vitro and in vivo determination of antioxidant activity and mode of action of isoquercitrin and Hyptis fasciculata.

Reactive oxygen species (ROS) are thought to underline the process of ageing and the pathogenicity of various diseases, such as neurodegenerative disorders and cancer. The use of traditional medicine is widespread and plants still present a large source of natural antioxidants that might serve as leads for the development of novel drugs. In this paper, the alcoholic extract from leaves of Hyptis fasciculata, a Brazilian medicinal plant, and isoquercitrin, a flavonoid identified in this species, showed to be active as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavengers. The extract of Hyptis fasciculata and isoquercitrin were also able to increase tolerance of the eukaryotic microorganism Saccharomyces cerevisiae to both hydrogen peroxide and menadione, a source of superoxide. Cellular protection was correlated with a decrease in oxidative stress markers, such as levels of ROS, protein carbonylation and lipid peroxidation, confirming the antioxidant potential of Hyptis fasciculata and isoquercitrin.

Integrated control of penicillium digitatum by the predacious yeast Saccharomycopsis crataegensis and sodium bicarbonate on oranges

Our investigation of integrated biological control (IBC) started with an assay testing activity of the predacious yeast Saccharomycopsis crataegensis UFMG-DC19.2 against Penicillium digitatum LCP 4354, a very aggressive fungus that causes postharvest decay in oranges. Under unfavourable environmental conditions, the yeast showed a high potential for control (39.9 percent disease severity reduction) of this fungus. This result was decisive for the next step, in which S. crataegensis was tested in association with sodium bicarbonate salt, a generally regarded as safe (GRAS) substance. The yeast was able to survive at different concentrations of the salt (1 percent, 2 percent and 5 percent), and continued to grow for a week at the wound site, remaining viable at high population for 14 days on the fruit surface. The yeast alone reduced the severity of decay by 41.7 percent and sodium bicarbonate alone reduced severity of decay by 19.8 percent, whereas the application of both led to a delay in the development of symptoms from 2 to 10 days. Ingredients of the formulations were not aggressive to fruits since no lesions were produced in control experiments.

Evaluation of antioxidant activity of Brazilian plants.

In this work, 22 alcoholic extracts, obtained from 14 species of plants belonging to four families, used for different food and medicinal purposes in Brazil, were evaluated for their capacity to inhibit the reduction of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and to protect Saccharomyces cerevisiae cells, an eukaryotic cell model, against the lethal oxidative stress caused by tert-butylhydroperoxide (TBH). Five extracts, two from Lamiaceae family (ethanol and butanol extracts from aerial parts of Hyptis fasciculata) and three from Palmae family (Copernicia cerifera leaves and mesocarp of fruits and the endocarp/mesocarp of fruits from Orbignya speciosa) were able to increase the tolerance of S. cerevisiae to TBH and showed to be active as DPPH radical scavengers, thus indicating that these plant extracts could be considered as potential sources of antioxidants. With the exception of ethanol extract of H. fasciculata, the remainder four extracts exhibited a DPPH radical scavenging activity higher than that obtained from Ginkgo biloba, a reference plant with well documented antioxidant activity. Interestingly, the ethanol extract of G. biloba were not effective for yeast cell protection, reinforcing the antioxidant potential of these extracts.