Bioprospecting of antioxidant, antibacterial and antibiofilm activities against Corynebacterium ulcerans and toxicity of Stryphnodendron coriaceum Benth

Abstract

The objective of the study was to evaluate the antioxidant, antibacterial and antibiofilm activities against Corynebacterium ulcerans and the toxicity of the Crude Hydroalcoholic Extract (CHE) of Stryphnodendron coriaceum Benth (barbatimão). The leaves of S. coriaceum were subjected to maceration with 70% alcohol. The antioxidant activity by the methods of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and redution of the phosphomolybdenum were reported. Antibacterial activity was measured by microdilution (1:2) for Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal (MBC) and inhibition of biofilm formation in five clinical strains and a standard C. ulcerans test. The toxicity study was carried out by testis of hemolysis, allelopathy and Tenebrio molitor. EBH has antioxidant capacity, capturing 50.7% of DPPH at a concentration of 0.37µg/mL and 21.99% of phosphomolibdenum. The MIC observed was 500 µg/mL for all strains, except of strains 809, and the CHE does not have a bactericidal aspect (MBC). The CDC KC 279 standard decreased the biofilm formation with CHE interference, while a 2649 strain increased (statistically significant). The efficient concentration for hemolysing 50% of the red blood cells was 460.6±0.03881µg/mL. In the allelopathic test, as seeds registered low germination and did not decreases the speed of growth of the roots in contact with CHE. The average concentration rate of T. molitor was 60% in the group with the highest concentration, without statistical significance (p=0.752) with the control, these characteristics suggest low toxicity. A plant species under study, has important pharmacological properties, which can lead to therapeutic substances, necessary complementary studies.