Antimicrobial, Cytotoxic and Antioxidant Activities and Determination of the Total Tannin Content of Bark Extracts Endopleura uchi

Abstract

Endopleura uchi is a typical Amazonian tree and its bark is popularly employed in the preparation of teas against myomas, arthritis, influenza, diarrhea and cancer. In this study, the antioxidant activity, cytotoxicity and antimicrobial activity of five different extracts of the bark, selected by their total tannin content, were assessed. The potential antioxidant activity of the extracts was determined by 2.2-diphenyl-1-picrylhydrazyl radical scavenging assay and the values found were very similar among the extracts and to the standards antioxidants used in the tests. Cytotoxicity analysis in mammalian cells indicated that all the tested extracts exhibited IC 50 values higher than the highest concentration used, showing that they do not present a risk when consumed under these conditions. Extract tested against five bacterial strains and one yeast strain did not show satisfactory growth inhibitory activity, and even the extracts that showed some antimicrobial activity were not OPEN ACCESS Int. J. Mol. Sci. 2011, 12 2758 effective at any dilution to determine the minimum inhibitory concentration. The results may serve as a reference for subsequent works, since such reference values described in the literature for the bark of E. uchi.

Tannins extraction: A key point for their valorization and cleaner production

“…Regarding ratio solid-liquid, it is showed that the decrease of this parameter provides higher 16 extraction yields, since higher amounts of solvent are employed (Politi et al, 2011). Nevertheless, 17 at low solid-liquid ratios, the differences between the extraction efficiencies are normally 18 minimized and therefore this parameter is generally optimized at certain value.…”

Assessment of the antibacterial, cytotoxic and antioxidant activities of Morus nigra L. (Moraceae)

“…Several alternatives have been suggested to solve this problem, such as the search for new antimicrobials in plant species. Some plants synthetize substances with antimicrobial properties such as terpenoids, phenolics (especially flavonoids) and nitrogen compounds (Politi et al, 2011). The results from the evaluation of the antibacterial activity for extracts of M. nigra are shown in Table 1, and are expressed as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).…”

Endopleura uchi (Huber) Cuatrec, a medicinal plant with potential anti-inflammatory activity: A review of its phytochemistry and biological activities

“…However, in nitric oxide and superoxide radicals scavenging, the hydroethanolic extract was more effective (IC 50 = 12 mg/mL) than infusion (IC 50 = 33 mg/mL) (Silva and Teixeira, 2015). Politi et al (2011), using barks from E. uchi collected in São Paulo (Brazil), reported that its concentration of tannins ranged from 9.65 to 32.85% depending on the extraction method, decoction, infusion, maceration, percolation, and turbo-extraction. The aqueous solutions from these extracts (5 to 20% w/v) had antioxidant activities values in DPPH assay ranging from 79 to 90%; despite being statistically lower, these values were close of those from control compounds such as gallic acid (97%), rutin (96.83%), and vitamin C (98.14%) at 250 µg/mL (in methanol).…”

“…Natural compounds with anti-inflammatory activity add value to herbal products containing them, making these products commercially attractive. The use of natural products with useful pharmacological activities has attracted attention in Brazil, where was created the National List of Medicinal Plants of Interest to the Health Unic System (RENISUS) in 2009, evidencing the importance of medicinal plants in therapeutics (Marmitt, 2015).Concerning the plant safety assessments, cytotoxic assays using bark extracts in fibroblast cells showed no toxicity, with 100% of cell survival and IC 50 higher than 0.2 mg/mL (Politi et al, 2011). However, the type-II arabinogalactan, isolated from E. uchi bark had a cytotoxic effect on HeLa cells, reducing cell viability in 20% over 48 and 72 h in all concentrations tested (5 to 500 µg/mL); at 100 µg/mL, this molecule inhibited HeLa cells proliferation in 25% (Bento et al, 2014).…”