Avaliação da atividade antimicrobiana “in vitro e in vivo” e estudo químico biomonitorado de Piper hayneanum C.DC. (Piperaceae) e Zeyheria tuberculosa (Vell.) Bur. (Bignoniaceae)

Abstract

The present work describes a chemical study, monitored by the antimicrobial activity, from the following plant species from Alagoas flora: Zeyheria tuberculosa (Vell.) Bur. (Bignoniaceae), Capparis cynophallophora L. and C. spinosa Jacq (Capparaceae), Swatzia apetala Raddi. (Fabaceae), Piper marginatum Jacq. and P. hayneanum C.DC. (Piperaceae), and Portulaca cf. elation Mart. ex. Rohrb. (Portulacaceae). The antimicrobial evaluation of the extracts, fractions and subfractions was carried out by the Agar diffusion method, and the bioprospection with isolated substances was investigated by the bioautographic assay. The plant species were tested against a panel of microorganisms, including one Gram positive bacteria Staphylococcus aureus (ATCC 25923), one Gram negative Pseudomonas aeruginosa (ATCC 27853), and one fungus Candida albicans (ATCC 10231). The Minimum Inhibitory Concentration (MIC) was determined for the fractions and subfractions that showed inhibitory activity against the tested microorganisms. Only the material extracted from the species Z. tuberculosa and P. hayneanum were able to inhibt S. aureus and C. albicans growth. These microorganisms were sensible to CHCl3 subfractions from Z. tuberculosa stem and P. hayneanum stem and roots, with MIC from 1 to 250 μg/disc. Active subfractions, submitted to a bioassay with the brine shrimp Artemia salina, presented low or no toxicity at all. Pomade made out of subfracionated extracts CHCl3-MeOH (1:1) and CHCl3-AcOEt (1:1) from P. hayneanum showed a good potential for antimicrobial application in in vivo assays for infected wound treatment in rats. The phytochemical investigation from Z. tuberculosa extracts with antimicrobial potential, led to the isolation of four flavonoids (5,6,7,8-Tetramethoxyflavone 5,6,7-Trimethoxyflavone, 4’-Hydroxy-5,6,7,8-Tetramethoxyflavone and 4’ -Hidroxi-5,6,7-tetramethoxyflavone); while in the P. hayneanum species three phytosteroids were isolated (β-Sitosterol, Stigmasterol and β-Sitosterol-Dglucopiranoside). These substances were identified from analysis of RMN spectroscopics uni and bidimensional (HMBC e HSQC), including DEPT. The phytochemical study contributed to extend the chemical taxonomic profile from Zeyheria gender. The isolated substances tested by bioautography method with antimicrobial activity against S. aureus were 5,6,7,8-Tetramethoxyflavone, 5,6,7-Trimethoxyflavone and 4’-Hydroxy-5,6,7,8-tetramethoxyflavone, while against C. albicans were 5,6,7,8- Tetramethoxyflavone, 4’-Hydroxy-5,6,7,8-tetramethoxyflavone and β-Sitosterol-3-O-β-D-glucopiranoside. The results are considered promising, since that the extracts, fractions and isolated compounds showed ability to control the growth of microorganisms responsible for contamination of wounds that affect the integumentary system.