Atividade antimicrobiana de espécies ocorrentes na Serra do Cipó e estudo fitoquímico de Xyris pterygoblephara Kunth

Abstract

Serra do Cipó is part of a Brazilian bioma qualified as a hotspot for conservation priority, an area featuring exceptional concentrations of endemic species and experiencing exceptional loss of habitat. The in vitro antimicrobial activity of seven Xyris spp. (X. cipoensis L. B. Sm. & Downs, X. longiscapa Alb. Nilss., X. peregrina Malme, X. pilosa Kunth, X. platystachia Alb. Nilss., X. pterygoblephara Kunth. and X. tortula Mart.) along with Trempleya lanifora (D. Don) Cogn., species collected in thishabitat, was evaluated against 5 microorganism strains, by the microdilution assay. All assayed extracts were active. The ethanol extract from X. pteygoblephara aerial parts was selected for phytochemical study. Its fractionation by silica gel column chromatography and partition between immiscible solvents, following purification by semi preparative NP-HPLC and Sephadex LH20 column chromatography, resulted inthe isolation of three compounds. The structures were assigned by spectroscopic data (1D and 2D NMR, IR, MS and UV) as moronic acid, quercetin and the new compound (3R,4R)-()-6- ethoxy-3,4-dihydro-4-acethoxy-5-n-pentil-1H-2-benzopyran-1-one (1). The absolute configuration of 1 was defined using circular dichroism spectroscopy and by comparison with data previously reported for other dihydroisocoumarins. Assay of 1 (100 g/disc) by the agar diffusion method against isolates of the dermatophytous fungi Epidermophyton floccossum, Tricophyton mentagrophytes and Tricophyton rubrum revealed similar activity to the positive control amphotericin B (32 g/disc). Some Xyris plants, popularly named semprevivas (everlasting plants), are traditionally used to treat eczemas and dermatitis. Therefore, the obtained data might corroborate the ethomedical use of Xyris spp. to treat dermatitis.