ABSTRACT The impacts caused on Chaco plant communities by the removal of woody species, together with the effects on the composition and functional structure of herbaceous plants, are still unknown. Therefore, this study aimed to assess the effects of anthropization on herb-subshrub communities in preserved and disturbed Chaco areas. Specifically, we examined differences and similarities in species diversity, composition and proportion of life forms in eight areas of Brazilian Chaco. Samples were taken from herb-subshrub communities using 800 1x1m² plots located in disturbed and preserved areas. Among 130 recorded species, 46 were exclusive to disturbed areas. The composition of species differed between preserved and disturbed areas (PERMANOVA; p = 0.001). PCoA ordination analysis showed greater aggregation of the plots in disturbed areas than in preserved areas. In preserved areas, an analysis of indicator species showed Hemicryptophytes species as the most representative life form. In disturbed areas, the proportion of life forms among indicator species was Hemicryptophytes, followed by Therophytes and Chamaephytes. Our study shows evidence that alterations in species composition, structure, and diversity, as well as sets of indicator species, occur in herb-subshrub communities. The removal of trees and bushes leads to a new configuration of this component in Chaco environments.

Abstract We evaluated the antimicrobial activity of Aspilia latissima - an abundant plant from the Brazilian Pantanal region - against Candida albicans, Candida parapsilosis, Candida krusei, Candida tropicalis, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus. The crude extracts and fractions showed activity in all tested microorganisms. The chloroform fraction of the leaves and roots showed the most antimicrobial activity against S. aureus, with an MIC of 500 μg/mL. This fraction was submitted to bioautographic assays to characterize the activity of the compounds. Two bands from the leaves (L-A and L-B) and three bands from the roots (R-C, R-D and R-E) were bioactive. Within the root-derived bands, the terpene derivatives stigmasterol, kaurenoic acid and kaura-9(11), 16-dien-18-oic acid were identified. Antibiotic activity of A. latissima is reported for the first time.

Este trabalho avaliou a atividade acaricida in vitro de extratos de 21 espécies de plantas do Pantanal de Mato Grosso do Sul. Na etapa I, foi realizado um teste de imersão larval utilizando três concentrações de extrato (5%, 20% e 40%). Na etapa II, utilizou-se apenas as plantas que apresentaram eficácia superior a 95%, na concentração de 40% na etapa I e que apresentasse quantidade suficiente para o teste de imersão de adulto. Aeschynomene denticulata, Angelonia hirta, Aspilia latissima, Caperonia castaneifolia, Centratherum punctatum, Crotalaria micans, Diodia kuntzei, Echinodorus paniculatus, Hyptis mutabilis, Lantana canescens, Melanthera latifolia, Ocotea diospyrifolia, Richardia grandiflora, Sebastiana hispida, Tocoyena formosa, Zanthoxylum rigidum e Sesbania virgata (extrato do fruto) apresentaram atividade acaricida sobre larvas de Rhipicephalus (Boophilus) microplus superior a 95% na concentração de 40% (w/v), enquanto Hippocratea volubilis e Randia armata apresentaram eficácia moderada e Croton glandulosus e Senna obtusifolia não apresentaram efeito acaricida. Os extratos brutos de M. latifolia, A. hirta, R. grandiflora e A. latissima foram avaliados sobre adultos e A. hirta apresentou eficácia próxima de 90%. Dezoito extratos apresentaram eficácia de até 95%, contra larvas, na concentração de 40%, sete extratos foram eficazes a 20% e apenas um (Sebastiana hispida) foi eficaz na concentração de 5%.

This research evaluated the in vitro acaricidal activity of extracts from 21 plant species from the Pantanal of Mato Grosso do Sul. During stage I, a larval immersion test was performed using three extract concentrations (5%, 20%, and 40%). During stage II, we used only plants that showed over 95% efficiency at the 40% concentration in stage I in an amount sufficient for the adult immersion test. Aeschynomene denticulata, Angelonia hirta, Aspilia latissima, Caperonia castaneifolia, Centratherum punctatum, Crotalaria micans, Diodia kuntzei, Echinodorus paniculatus, Hyptis mutabilis, Lantana canescens, Melanthera latifolia, Ocotea diospyrifolia, Richardia grandiflora, Sebastiana hispida, Tocoyena formosa, Zanthoxylum rigidum, and Sesbania virgata (fruit extract) showed acaricidal activity against the larval stage of Rhipicephalus (Boophilus) microplus higher than 95% at a 40% (w/v) concentration, while Hippocratea volubilis and Randia armata showed moderate efficacy and Croton glandulosus and Senna obtusifolia had no effect. The M. latifolia, A. hirta, R. grandiflora, and A. latissima raw extracts were evaluated for their activity against adults, and only A. hirta showed an efficacy close to 90%. Eighteen extracts had an efficacy of up to 95% against larvae at a 40% concentration, seven extracts were effective at 20%, and only one (Sebastiana hispida) was effective at a 5% concentration.