RESUMO Um transecto de 320 km foi explorado na Serra do Tumucumaque, ao longo da fronteira entre o sul da Guiana Francesa e o Brasil por meio da amostragem de todas as árvores e lianas com DAP ≥ 10 cm em sete parcelas de 25 x 25 m instaladas perto de sete marcos fronteiriços. Isolamos DNA de tecido cambial e sequenciamos dois códigos de barra de DNA (rbcLa e matK) para auxiliar na identificação das espécies. Também coletamos espécimes de herbário férteis de outras espécies (árvores/arbustos/ervas) dentro e fora das parcelas. Os códigos de barra de DNA selecionados foram úteis em nível de família, mas não conseguiram identificar espécimes em nível de espécie. Com base na identificação de DNA barcoding, as famílias mais abundantes nas parcelas foram Burseraceae, Fabaceae, Meliaceae, Moraceae, Myristicaceae e Sapotaceae. Um terço das imagens de plantas amostradas postadas no website iNaturalist foram identificadas em nível de espécie. Novas abordagens, incluindo o sequenciamento da região ITS e regiões de DNA plastidial de rápida evolução, ainda precisam ser testadas quanto à sua utilidade na identificação de espécimes até níveis taxonômicos mais baixos em inventários florísticos na região amazônica.

ABSTRACT We explored a 320-km transect in the Tumucumaque mountain range along the border between southern French Guiana and Brazil, sampling all trees and lianas with DBH ≥ 10 cm in seven 25 x 25-m plots installed near seven boundary milestones. We isolated DNA from cambium tissue and sequenced two DNA barcodes (rbcLa and matK) to aid in species identification. We also collected fertile herbarium specimens from other species (trees/shrubs/herbs) inside and outside the plots. The selected DNA barcodes were useful at the family level but failed to identify specimens at the species level. Based on DNA barcoding identification, the most abundant families in the plots were Burseraceae, Fabaceae, Meliaceae, Moraceae, Myristicaceae and Sapotaceae. One third of the images of sampled plants posted on the iNaturalist website were identified by the community to species level. New approaches, including the sequencing of the ITS region and fast evolving DNA plastid regions, remain to be tested for their utility in the identification of specimens at lower taxonomic levels in floristic inventories in the Amazon region.

This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 µg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis.