Assessing the effects of water quality on leaf morphoanatomy, ultrastructure and photosynthetic pigment content of Salvinia auriculata Aubl. (Salviniaceae).

The objective of this study is to evaluate the effects of physical-chemical and biological variables of the water of the Capibaribe River (state of Pernambuco, Brazil) on leaf anatomy, including ultrastructure and photosynthetic pigment of Salvinia auriculata. Specimens of S. auriculata collected in the Gurjaú River, an area with a low pollution degree, were acclimatized in Hoagland's solution and then subjected to three water samples of the Capibaribe River with different levels of pollution. Twenty-one physical-chemical and biological variables were analyzed according to the Standard Methods for the Examination of Water and Wastewater. The results showed that the samples of the Capibaribe River presented nine parameters that did not comply with the current Brazilian legislation. After 15 days of bioassay, S. auriculata presented variations in mesophyll and cuticle thickness, changes in trichome morphology and accumulation of phenolic compounds. No significant differences were observed for photosynthetic pigment content and leaf length of S. auriculata. Multivariate analyses (PCA and Cluster) showed that the point in the Capibaribe River with the highest number of variables that do not comply with the current legislation was responsible for major structural and chemical changes observed in S. auriculata.

Myrmecochores can target high-quality disperser ants: variation in elaiosome traits and ant preferences for myrmecochorous Euphorbiaceae in Brazilian Caatinga.

Recent evidence suggests that the traditional view of myrmecochory as a highly diffuse interaction between diaspores and a wide range of ant species attracted to their elaiosomes may not be correct. The effectiveness of dispersal varies markedly among ant species, and combined with differential attractiveness of diaspores due to elaiosome size and composition, this raises the potential for myrmecochorous plants to target ant species that offer the highest quality dispersal services. We ask the question: Do particular physical and chemical traits of elaiosomes result in disproportionate removal of Euphorbiaceae diaspores by high-quality disperser ants in Caatinga vegetation of north-eastern Brazil? We offered seeds of five euphorb species that varied in morphological and chemical traits of elaiosomes to seed-dispersing ants. High-quality seed-disperser ants (species of Dinoponera, Ectatomma and Camponotus) were identified as those that rapidly collected and transported diaspores to their nests, often over substantial distances, whereas low-quality disperser ants (primarily species of Pheidole and Solenopsis) typically fed on elaiosomes in situ, and only ever transported diaspores very short distances. Low-quality disperser ants were equally attracted to the elaiosomes of all study species. However, high-quality dispersers showed a strong preference for diaspores with the highest elaiosome mass (and especially proportional mass). As far as we are aware, this is the first study to identify a mechanism of diaspore selection by high-quality ant dispersers based on elaiosome traits under field conditions. Our findings suggest that myrmecochorous plants can preferentially target high-quality seed-disperser ants through the evolution of particular elaiosome traits.

Chemical composition and antimicrobial activity of Cordiera myrciifolia leaves against pathogenic bacteria and fungi: Drug potentiation ability and inhibition of virulence.

Cordiera myrciifolia is an abundant species in Northeast Brazil that presents metabolites of biological/therapeutic interest. From this perspective, the present study aimed to investigate the chemical constituents and evaluate the in vitro antimicrobial activity of hexane (HECM) and ethanolic (EECM) extracts of C. myrciifolia leaves. The extracts were analyzed by chromatographic techniques (GC and UPLC) coupled with mass spectrometry. The antimicrobial activity of the extracts and the extracts combined with conventional drugs was evaluated by microdilution. The in vitro effect of the treatments on Candida's morphological transition was verified through cultivation in humid chambers. In HECM, 11 constituents including fatty acids, and triterpenes, including phytosterols, alkanes, tocols, and primary alcohols were identified. Triterpenes represented >40% of the identified constituents, with Lupeol being the most representative. In EECM, 13 constituents were identified, of which eight belonged to the class of flavonoids. High antibacterial activity of HECM was detected against Escherichia coli and Staphylococcus aureus, with Minimum Inhibitory Concentrations of 8 and 16 µg/mL, respectively. The combined activity was more effective when combined with Norfloxacin and Imipenem. In anti-Candida activity, the IC50 of the extracts ranged from 36.6 to 129.1 µg/mL. There was potentiating effect when associated with Fluconazole. Both extracts inhibited the filamentous growth of C. tropicalis at a concentration of 512 µg/mL. C. myrciifolia extracts prove to be candidates for the development of new therapeutic formulations to treat bacterial and fungal infections.

Organic extracts from Indigofera suffruticosa leaves have antimicrobial and synergic actions with erythromycin against Staphylococcus aureus.

A characteristic feature of Staphylococcus aureus is its ability to acquire resistance to antimicrobial agents. There is a need, therefore, for new approaches to combat this pathogen; for example, employing a combination of plant-derived products and antibiotics to overcome bacterial resistance. Indigofera suffruticosa is a plant popularly used to treat infections and has verified antimicrobial action. Here, we investigate the antimicrobial activity of different extracts from I. suffruticosa against S. aureus and their synergistic effects with erythromycin. Leaves of I. suffruticosa were extracted sequentially using diethyl ether, chloroform and acetone and the antimicrobial activity of each extract then tested against nine clinical isolates of S. aureus. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by microdilution tests, while the fractional inhibitory concentration (FIC) was assessed by checkerboard assay. All organic solvent extracts showed antimicrobial activity against S. aureus strains. The acetone extract was the most potent inhibitor of S. aureus (MIC and MBC of 0.78 and 3.12 mg/mL), followed by the chloroform extract (MIC and MBC of 3.12 and 6.25 mg/mL). Furthermore, acetone or chloroform extracts of I. suffruticosa enhanced the activity of erythromycin against S. aureus (FIC ≤ 0.5). We conclude that organic extracts from leaves of I. suffruticosa, alone or combined with erythromycin, are promising natural products for the development of new anti-S. aureus formulations.