Phenolic content, antibacterial and antioxidant activities of herbal infusions

Abstract

Natural products derived from plants are considered the oldest medicine in the world. Teas are an accessible source of antioxidant compounds, especially polyphenols that impart flavor, aroma and pharmacological properties. Considering the context of using natural products for health maintenance, the present study aimed to analyze the content of total phenolic compounds, antibacterial and antioxidant activities of infusions using Morus nigra, Casearia sylvestris, Hibiscus sabdariff and Moringa oleifera commercialized in Muzambinho/MG. The infusions were prepared by adding 100 mL of distilled water at approximately 100ºC over 1 g of herb at room temperature for 10 minutes. The analysis of total phenolic compounds was performed using Folin-Ciocalteau. For the analysis of antioxidant activity, the free radical DPPH was used and the results were expressed as a percentage of scavenging activity. For the analysis of antibacterial activity, the microdilution in broth assay was performed in order to find the minimum inhibitory concentrations. It was possible to conclude that the infusion with the highest levels of phenolic compounds were C. sylvestris and M. oleifera, while those that showed a greater antioxidant activity were M. oleifera and M. nigra. As for antibacterial activity, all infusions were able to inhibit E. coli, especially the infusion of C. sylvestris, which was also able to inhibit S. aureus. Although all of the herbs showed antioxidant and antibacterial activities, and also phenolic compounds, C. sylvestis was the herb that stood out in this work because of its phenolic composition and antibacterial activity. In sum, it is concluded that future work is needed to elucidate the exact chemical composition of the infusions and other biological activities.