Percorrer por autor "Brito, Sara Samanta da Silva"
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- Croton argyrophyllus Kunth and Croton heliotropiifolius Kunth: phytochemical characterization and bioactive propertiesPublication . Brito, Sara Samanta da Silva; Silva, Franceli; Malheiro, Ricardo; Baptista, Paula; Pereira, J.A.Croton heliotropiifolius Kunth and Croton argyrophyllus Kunth are endemic plant species from northeastern Brazil widely used in folk medicine and scarcely studied. In this context, the essential oils (EO's) and methanolic extracts (leaves and stalk) of both species were chemically characterized, and their antioxidant and antimicrobial activities were assessed. The chemical characterization of the EO's identified sixty components,being the major ones in C. argyrophyllus bicyclogermacrene (14.0%), β-pinene (8.9%) and spathulenol (8.7%), and in C. heliotropiifolius limonene (16.9%), α-pinene (13.3%) and caryophyllene (12.1%). Essential oils and methanolic extracts from leaves of C. argyrophyllus possess greater antioxidant potential, which could be related to the high levels of total phenols and flavonols. The antimicrobial activity of C. argyrophyllus essential oil proven to be more efficient than chloramphenicol (30 μg mL−1), with a minimum inhibitory concentration (MIC) of 25 μL mL−1 against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and 10 μL mL−1 against B. cereus. Leaf extracts presented high activity against yeasts (MIC = 50 mg mL−1) being C. heliotropiifolius effective against Candida albicans and C. parapsilosis, while C. argyrophyllus was effective against C. glabrata. Overall results showed that these plant species are potential sources of phytochemicals with interest in the fields of both pharmacology (e.g., antimicrobial) and human health (e.g., antioxidant). Furthermore, in the socio-economic aspect, these results can improve and disseminate the cultivation of these species, inducing improvements in the rural populations.
- The temporal and spatial variation of arthropod associations inhabiting non-crop vegetation in a sisal crop, agave sisalana in the caatinga biomePublication . Brito, Sara Samanta da Silva; Villa, Maria; Benhadi-Marín, Jacinto; Silva, Franceli; Pereira, J.A.Sisal, Agave sisalana Perrine, is cultivated for fiber production, with Brazil being its leading producer. Nowadays, given the increasing interest in organic products, the market for sisal could become an economical alternative for rural areas with low economic inputs. However, sisal is threatened by different pests and diseases. Conservation biological control could contribute to the limitation of these plant enemies, but this agroecosystem is poorly known. In this context, we aimed: (i) to identify the diversity of plants and arthropods and their potential relations, (ii) to study the spatial patterns of arthropods and plants in function of the proximity to the margin of the field, and (iii) to determine the minimum sampling effort needed to record the occurring biodiversity in a sisal crop. Arthropods were sampled using pit-fall traps located close to the border and in the inner plant of the sisal crop from June to September. Simultaneously, plant species and their abundance in quadrats next to each pitfall were recorded. Diversity indexes were calculated to describe the biodiversity, a redundancy analysis was performed to analyze relations among arthropods and plants and the spatial distribution was evaluated using the non-parametric Wilcoxon rank-sum test. The redundancy analysis and the Wilcoxon test revealed a temporal and spatial distribution of arthropods and plants during the period of study. Results indicated (i) similar temporal diversity patterns from June to July for both plants and arthropods, with a maximum in July, whereas in September the biodiversity increased for arthropods and decreased for plants; (ii) the importance of particular plant species for Collembola; and (iii) that arthropods seem to colonize the sisal crop from the fields beyond the crop during the rainy season. These results provide new information about arthropods and plant biodiversity from an agroecosystem in a semi-arid region and raise further queries about the management of sisal crops.