Caracterização química e atividades biológicas de Bryophyllum pinnatum (Lam.) Oken

Abstract

Bryophyllum pinnatum (Lam.) Oken (Crassulaceae), known as "folha-da-fortuna" (leaves-of-fortune), has been widely used in traditional medicine, mainly for the treatment of inflammation, infection, wound, ulcer and gastritis. The aim of the present study was to identify and quantify bioactive constituents, as well as evaluating the antioxidant, antibacterial and topical anti-inflammatory activities of B. pinnatum leaves. Dried and pulverized plant material was subjected to maceration with ethanol followed by partition to obtain the hexanic, dichloromethanic, in ethyl acetate and butanolic fractions. Constituents of the ethanol extract and fractions were identified by high performance liquid chromatography coupled to ultraviolet detector and gas chromatography coupled to mass spectrometry. The total phenols and flavonoids contents were determined by spectrophotometry and the antioxidant activity was evaluated using DPPH, reducing power, β-carotene/linoleic acid co-oxidation system and bioautography assays. The antibacterial activity was investigated by diffusion and microdilution methods. The topical anti-inflammatory activity was evaluated through ear oedema models induced by croton oil, arachidonic acid, phenol, capsaicin, ethyl phenyl propiolate and histological analysis. The results were demonstrated as mean ± standard error. Analysis of variance followed by Tukey or Student-Newman-Keuls test was used to measure the degree of significance of p < 0.05. Quercetin, rutin, kaempferol, apigenin 7-O-β-D-glucoside and luteolin 7-O-β-D-glucoside were identified by HPLC-UV DAD, while -amyrin by GC-MS. The total phenolic content ranged from 3.45 to 25.34 g/100 g, while flavonoids were 0.66 to 23.31 g/100 g. Using the DPPH assay, the values of EC50 ranged from 9.44 ± 0.01 to 57.29 ± 0.11 g/mL and the reducing power assay produced EC50 of 234,22 ± 0,61 and ± 1235.17 ± 1.39. The values of inhibition of lipid peroxidation were between 39,4 and 58,3% and the bioautography assay detected substances with antioxidant activity. The ethanol extract and fractions inhibited the growing of bacteria tested producing bactericidal and bacteriostatic activities. Concentrations of 0.5 and 1.0 mg/ear of the ethanol extract reduced the ear oedema induced by croton oil in 54.85 and 57.11%, while the ear oedema induced by arachidonic acid was inhibited by 41.67, 53.82 and 67.01% at concentrations of 0.1, 0.5 and 1.0 mg/ear, respectively. The phenol-induced oedema was inhibited by 79.73, 33.14 and 33.71% in 0.1, 0.5 and 1.0 mg/ear, respectively. After treatment, 0.1 (43.22%), 0.5 (72.53%) and 1.0 mg/ear (35.16%) of the ethanol extract reduced the ear oedema induced by capsaicin. The phenyl-ethyl propriolato-induced oedema at concentrations of 0.1 (75.00%) 0.5 (69.77%) and 1.0 mg/ear (43.60%) was inhibited. Results from chronic ear oedema test and histological analysis confirmed the effect of the ethanol extract on inhibition of oedema induced by croton oil. The results indicated that B. pinnatum possesses antioxidant, antibacterial and topical anti-inflammatory effects justifying the popular use and highlighting the species as a potential target for the discovery of new therapeutic agents.