Análise fitoquímica e avaliação da atividade antimicrobiana de plantas medicinais de ocorrência no Cerrado

Abstract

Infectious diseases have been a major cause of morbidity and mortality worldwide. Despite the discovery and development of antibiotics, the treatment of these diseases today has not always been successful due to the emergence of antimicrobial resistance. Thus, this study aimed to evaluate the antioxidant activity, the content of phenolic compounds, total flavonoids and the antimicrobial action of six extract of medicinal plants of Cerrado, Boldo (Peumus boldus), Goiaba (Psidium guajava), Assa-Peixe (Vernonia polysphaera) , Avocado (Persea americana), Balm (Jatropha multifida) and Eucalyptus (Eucalyptus citriodora). The content of total phenolics was determined by the Folin-Ciocalteu method and the total flavonoid dosage was performed by the Aluminum Chloride method. Antioxidant activity was assessed using DPPH methods, ABTS, and Phosphomolybdenum complexation. The extract of Guava showed the highest yield of phenolic compounds (532.56 mg EAG g-1), total flavonoids (406.01 mg EQ g-1), antioxidant activity by DPPH (93.1%) and reduction of the complex Phosphomolybdenum (1613.3 mg EBHT g-1), demonstrating that this species contains antioxidant components that can sequester free radicals under in vitro conditions. The diffusion disc method was used to determine the antimicrobial activity on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Aspergillus fumigatus. In the agar diffusion tests, all the extracts, except Assa-Peixe, revealed promising for the development of phytochemicals inhibiting the growth of S. aureus, with halos ranging from 13-20 mm. In the micro dilution tests, all extracts were active on S. aureus, with concentrations varying from 3.12 - 12.5 mg / mL, a significant result, considering that S. aureus is one of the main causes of hospital infections. Therefore, the extracts investigated are promising and their antibacterial e antioxidant actions should be thoroughly studied.