Análise fitoquímica e avaliação da presença de lectina e da atividade sobre a susceptibilidade e formação de biofilme bacteriano e fúngico do extrato do colmo do bambu (Guadua angustifolia)

Abstract

Medicinal plants are vegetables used to prevent, treat and alleviate diseases, based on their bioactive components and since ancient times, civilizations have explored the healing properties of plants. Brazil has the greatest forest diversity of native bamboo in the Americas and among the identified species is Guadua angustifolia. Extracts and lectins isolated from plants have shown antimicrobial properties to different species of fungi and bacteria and for this reason have been studied by several research groups, which can assume different biological roles. Secondary metabolites are organic compounds produced by plants that perform diverse functions and are widely studied for their properties to combat pathogenic microorganisms. The present study sought to characterize the stem extract of G. angustifolia and analyze its antimicrobial activity. The experimental procedures consisted of: preparation of the crude extract (20% w/v) of G. angustifolia, hemagglutinating activity assay, carbohydrate inhibition test, phytochemical analysis, determination of protein concentration, affinity chromatography, phenol measurement, chromatography High Efficiency Liquid (HPLC) and antimicrobial test. The 50 mM Tris-HCl buffer, pH 8.0 presented the best extraction condition, where the 0-20% fraction demonstrated the highest hemagglutinating activity of 128 HAU/mg. It is considered that the lectin present in the extract has the ability to bind Nacetylglucosamine, D-maltose and fetuin. A total phenol content of 2.07 ± 0.08 µg EAG/g extract was found in 41.6 mg/mL of G. angustisfolia extract. HPLC determination showed the presence of p-coumaric acid, gallic acid, catechin, 2-coumaric acid, coumarin and resveratrol. The tested sample showed action against bacterial strains E. coli, P. aeruginosa and S. Aureus the MIC values were 7.5, 15, 60 μg/mL respectively. Regarding the fungal strains C. neoformans (H99), C. albicans, C. krusei, C. parapsilosis with IMC values of 7.5, 30, 60, 120 μg/mL respectively. The extract inhibited biofilm formation by 40% for C. albicans and 50% for C. neoformans (B3501) at concentrations of 7.5 and 60 μg/mL.