Atividade antifúngica, caracterização fitoquímica e perfil térmico da Anadenanthera colubrina (Vell.) Brenan

Abstract

There is a great demand for new antifungals of different structural classes, acting selectively on new cellular targets with fewer side effects, accordingly medicinal plants are excellent sources for obtaining a wide variety of drugs. This study aimed to investigate the antifungal activity of the plant extract Anadenanthera colubrina (Vell.) Brenan and fitoquimicamente characterize it and set its thermal profile. Shells Anadenanthera colubrina (Vell.) Brenan were collected in the semiarid Paraiba (7º22 '25 "S, 35 ° 59' 32" W), the extract obtained by maceration, using a rotary evaporator and freeze region. For the Determination of Minimum Inhibitory Concentration technique microdilution broth and microorganisms Candida albicans (ATCC 18804), Candida krusei (ATCC 34135), Candida guillermondii (ATCC 6260), Candida parapsilosis (ATCC 22019), Candida tropicalis (ATCC 13803) and clinical strains was used recently isolated from Candida albicans (LM 11, LM 70, LM 410). The Determination of Minimum Fungicidal Concentration was performed by subculture on Sabouraud dextrose agar plates. The action on the cell wall of Candida albicans was investigated by determining the MIC of plant extract in the presence of sorbitol (0.8M), using the microdilution technique. Through scanning electron microscopy, we evaluated the cellular morphology of Candida albicans treated with the MIC of plant extract, the MIC of nystatin suspension (100,000 UI) and free treatment. The combined effect of the two substances (nystatin and vegetable extract Anadenanthera colubrina) studied was determined from the microdilution technique - checkerboard for derivation of Fractional Inhibitory Concentration Index (FIC Index) and by the method of counting viable cells (kinetics growth). In the latter, the following different concentrations of the extract and nystatin products association (CIM; CIM/4; CIM/8) were analyzed. Nonparametric tests Fridman and the Kruskal Wallis test (p <0.05) were performed. In phytochemical screening, we determined the content of total polyphenols, total flavonoids and condensed tannins by spectrophotometry. The thermal profile was traced with the determination of termograviméricas curves (TG) and differential scanning calorimetry (DSC). The toxicity was assessed by quantitation of erythrocyte lysis suffering with different concentrations of plant extract (0.25, 0.5, 1, 2, 4 mg / ml). It was observed that the A.colubrina have fungistatic potential against all tested strains pattern, and fungicidal against recent clinical isolates of Candida albicans. An increase of 1 mg/ml to 8mg/ml of MIC in the presence of sorbitol suggests that this statement acts by modifying the fungal cell wall. The SEM images show the reduction in the amount of yeast cells after treatment with the plant extract and changes in the fungal cell wall. The FIC index was calculated at 0.375, indicating synergism between the nystatin and the plant extract. Kinetics was observed maintaining the synergism between the products tested over time (p <0.05). 53.18% of total polyphenols were determined, 8.73% from 0.28% condensed tannins and flavonoids. The TG curve A.colubrina extract showed the presence of three stages of thermal decomposition, the more significant weight loss was observed between the extract temperatures and 229,17ºC 657,39ºC with loss of 37.44%. The DSC curves of the extract showed that the thermal processes occur at temperatures between 52,37 °C to 195,5°C. In toxicity testing, none of the tested concentrations became effective cytotoxic concentration 50% (EC50). It is concluded that the plant extract from the bark of Anadenanthera colubrina (Vell.) Brenan is a promising resource in getting a new drug for treatment of oral candidiasis.