Evaluation of the Antioxidant, Antimicrobial, and Anti-Biofilm Effects of the Stem Bark, Leaf, and Seed Extracts from Hymenaea courbaril and Characterization by UPLC-ESI-QTOF-MS/MS Analysis

Currently, biofilm-forming bacteria are difficult to treat by conventional antibiotic therapy and are, thus, becoming a clinical and epidemiological problem worldwide. Medicinal plants have been identified as novel alternative treatments due to their therapeutic and antimicrobial effects. In this context, the present study aimed to determine the total phenolic content, antioxidant capacity, and antimicrobial and anti-biofilm potential of nine extracts of Hymenaea courbaril (Fabaceae), popularly known as Jatobá. Furthermore, extracts that exhibited biofilm inhibitory activity against S. aureus (ATCC 25923) were selected for UPLC-HRMS/MS chemical analysis. Our results showed a high total phenolic content, mainly in the stem bark extract, and that the plant is rich in compounds with antioxidant activity. In the anti-biofilm analysis, leaf extracts stood out in comparison with chloramphenicol, with inhibition percentages of 78.29% and 78.85%, respectively. Through chemical analysis by UPLC-HRMS/MS, chrysoeriol-7-O-neohesperidoside, isorhamnetin-3-O-glucoside, and 3,7-di-O-methylquercetin were annotated for the first time in the leaves of H. courbaril. Therefore, these results showed the potential use of H. courbaril as an antioxidant and point to its use in antimicrobial therapy with an anti-biofilm effect.

Phytochemical Analysis and Evaluation of Antimicrobial Activity of Peumus boldus, Psidium guajava, Vernonia polysphaera, Persea Americana, Eucalyptus citriodora Leaf Extracts and Jatropha multifida Raw Sap

BACKGROUND

Currently, the treatment of infectious diseases has not always been successful due to the emergence of microbial resistance worldwide.

OBJECTIVES

This study aimed to evaluate the antioxidant activity, content of total phenolic compounds and flavonoids, antifungal potential and antibacterial action of six medicinal plants found in the Cerrado, leaf extracts of Boldo (Peumus boldus), Goiaba (Psidium guajava), Assa-Peixe (Vernonia polysphaera), Abacate (Persea americana), Eucalipto (Eucalyptus citriodora) and raw sap of Bálsamo (Jatropha multifida).

METHODS

The antioxidant activity was also determined through the DPPH, ABTS and phosphomolybdenum assays. In addition, the total phenolic content and flavonoid dosage were analyzed using the Folin- Ciocalteu method and the aluminum chloride test, respectively.

RESULTS

All extracts, except from Assa-Peixe, showed promising values against Staphylococcus aureus, with halos varying from 13-20 mm. Analysis of the minimum inhibitory concentration (MIC) values of the six medicinal plants revealed inhibitory activity of S. aureus, with concentrations varying from 3.12-12.5 mg/mL, which is a significant result considering that S. aureus is one of the main causes of hospital infections.

CONCLUSION

In the analysis of the phytochemical profile, Goiaba contained the best yield of phenolic compounds and total flavonoids, as well as higher antioxidant activity by DPPH and phosphomolybdenum, demonstrating that this species contains antioxidant components that can sequester free radicals under in vitro conditions. Therefore, the crude extracts investigated are promising and their antibacterial and antioxidant actions should be thoroughly studied.

New insights into tomato microRNAs

Cultivated tomato, Solanum lycopersicum, is one of the most common fruits in the global food industry. Together with the wild tomato Solanum pennellii, it is widely used for developing better cultivars. MicroRNAs affect mRNA regulation, inhibiting its translation and/or promoting its degradation. Important proteins involved in these processes are ARGONAUTE and DICER. This study aimed to identify and characterize the genes involved in the miRNA processing pathway, miRNA molecules and target genes in both species. We validated the presence of pathway genes and miRNA in different NGS libraries and 6 miRNA families using quantitative RT-PCR. We identified 71 putative proteins in S. lycopersicum and 108 in S. pennellii likely involved in small RNAs processing. Of these, 29 and 32 participate in miRNA processing pathways, respectively. We identified 343 mature miRNAs, 226 pre-miRNAs in 87 families, including 192 miRNAs, which were not previously identified, belonging to 38 new families in S. lycopersicum. In S. pennellii, we found 388 mature miRNAs and 234 pre-miRNAs contained in 85 families. All miRNAs found in S. pennellii were unpublished, being identified for the first time in our study. Furthermore, we identified 2471 and 3462 different miRNA target in S. lycopersicum and S. pennellii, respectively.

Effect of edible coatings with essential oils on the quality of red raspberries over shelf-life

BACKGROUND

The objective of the present work was to develop strategies for increasing the shelf-life of red raspberries (Rubus idaeus L.), by preventing microorganism growth.

RESULTS

Fruits coated with alginate plus lemon essential oil (0.2%) or orange essential oil (0.1%) after 15 days of storage had less red skin than the remaining samples. The less red color verified in these samples was also coincident with the lower concentration of anthocyanins at the end of the experiment as well as the lower capacity for scavenging ABTS free radicals or quenching singlet oxygen. Cyanidin and pelargonidin glucosides were found in raspberries fruits. The edible coatings supplemented with the essential oil of orange either at 0.1% or 0.2% were very efficient for controlling yeast and mold growth after 15 days of storage. To control the development of aerobic mesophilic bacteria the use of essential oil of lemon 0.2% and essential oil of orange 0.1% were the most efficient.

CONCLUSION

The application of the film improved post-harvest quality of raspberry, since the addition of essential oils of citrus films promoted to the inhibitory effect of fungi and bacteria growth after 15 days of storage, without changing quality parameters. © 2016 Society of Chemical Industry.

Biological activity of the essential oils from Cinnamodendron dinisii and Siparuna guianensis

This study had analyzed the antibacterial, antifungal and trypanocidal activity of the essential oils from Cinnamodendron dinisii Schwacke (Canellaceae) and Siparuna guianensis Aublet (Siparunaceae). The essential oils were obtained from fresh leaves by hydrodistillation, using a modified Clevenger apparatus. Chemical analysis by gas-liquid chromatography coupled to mass spectrometry (GC-MS) showed that these essential oils are rich in monoterpene and sesquiterpene hydrocarbons. Activity against the pathogenic bacteria Escherichia coli , Listeria monocytogenes , Pseudomonas aeruginosa , Salmonella choleraesuis and Staphylococcus aureus was evaluated with the agar cavity diffusion method, while activity on the filamentous fungi Aspergillus flavus , Aspergillus niger , Aspergillus carbonarius and Penicillium commune was evaluated by the disk diffusion technique. Trypanocidal activity was tested against Trypanosoma cruzi epimastigotes, using the Tetrazolium salt (MTT) colorimetric assay. Both essential oils exhibited low inhibitory effect towards bacteria, showing high MIC values (125-500 μg mL (-1) ), with Gram positive bacteria being more susceptible. Better inhibitory effect was obtained for the evaluated fungi, with lower MIC values (7.81-250 μg mL (-1) ), being A. flavus the most susceptible species. Both essential oils presented low trypanocidal activity, with IC 50 /24 h values of 209.30 μg mL (-1) for S. guianensis and 282.93 μg mL (-1) for C. dinisii . Thus, the high values observed for the MIC of evaluated bacteria and for IC 50 /24 h of T. cruzi , suggest that the essential oils have a low inhibitory activity against these microorganisms. In addition, the low MIC values observed for the tested fungi species indicate good inhibitory activity on these microorganisms's growth.