Qualitative phytochemical evaluation and antibacterial activity of the hydroalcoholic extract of Hibiscus acetossela leaves Welw

Amid the diversity of the flora, the species of the genus Hibiscus, belonging to the family Malvaceae, stand out for the great variety of natural compounds, such as polyphenols, saponins and flavonoids. In addition, these species stand out for their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa microorganisms1. The species Hibiscus acetosella Welw, known as purple vinegar, purple okra and / or currant, is used in folk medicine against fever, bronchitis, anemia, gastritis and allergy, and is considered anti-hemorrhagic4. In this sense, this study aimed to evaluate the qualitative phytochemical assays and antibacterial activity of the hydroalcoholic extract (70% water and 30% ethanol P.A.) of Hibiscus acetosella Welw leaves against Staphylococcus aureus, Salmonella sp and Escherichia coli.The phytochemical study of the hydroalcoholic leaf extract was performed for saponins, organic acid, polysaccharides, phenols and tannins, proteins and amino acids, flavonoids, catechins, steroids, triterpenoids and alkaloids, using an appropriate methodology2. All tests were performed in triplicate. Antibacterial activity analyzes were tested on three strains of bacteria: Pseudomonas aeruginosa, Salmonella sp and Escherichia coli, performed by the diffusion method using a paper disk, with some adaptations3. The phytochemical results of H. acetosella Welw leaf extract indicated the presence of foam saponins, steroids and triterpenoids. The results obtained for the phytochemical assays presented two special metabolic classes: foamed saponins, which have great property of producing persistent and abundant foam. The literature mentions that Hibiscus has steroid and triterpenoid in its chemical composition that can be found in moderate amounts for both stem and leaves5. Antibacterial activity results for hydroalcoholic extract of H. acetosella Welw leaves showed that E. coli presented showed higher sensitivity, followed by S. aureus and Salmonella sp. The average diameter of the diluted Hibiscus sp inhibition halos obtained with the E. coli paper disk agar diffusion test was 6 mm, 7 mm and 6 mm at 10-1 CFU / mL, 10-2 dilutions. CFU / mL and 10-3 CFU / mL, respectively. At the same dilutions, the inhibition of S. aureus halos was 4 mm, 6 mm and 6 mm, and the inhibition of Salmonella sp halos was 4 mm, 4 mm and 5 mm. However, E. coli and S. aureus is one of the most widely used strains for the analysis of antibacterial activity in plant extracts. It is noteworthy that there are no studies related to the hydroalcoholic extract of the flowers Hibiscus acetosella Welw against Salmonella sp, which showed little inhibitory action. Therefore, it is important to perform inhibitory action with other plant extracts using the strain Salmonella sp.