Biological activity in hydroethanolic extracts from bark, stem, and leaves of the Stryphnodendron adstringens (Mart.) Coville

Abstract

Stryphnodendron adstringens (Mart.) Coville, commonly known as barbatimão, is native to the Cerrado biome in Brazil and belongs to the botanical family Fabaceae. The objective of this study was to evaluate the biological activity of crude hydroethanolic extracts formulated from the bark, leaves, and stems of S. adstringens. Soluble solids were determined using the incubation drying methodology. Colorimetric methods of complexation with ferric chloride were employed as a qualitative assay to identify the presence of tannins, while phenolics and flavonoids were quantified by the Folin-Ciocalteu method and aluminum chloride complexation, respectively. Antioxidant activity was assessed by the capture of DPPH free radicals. Antibacterial and antifungal analyses in vitro were conducted using the disk diffusion method against Escherichia coli, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Cryptococcus neoformans var. grubii. The MTT assay was used to determine antiparasitic activity against Leishmania amazonensis and to assess cytotoxicity using differentiated THP-1 macrophages. The extracts demonstrated efficacy against yeasts, especially the stem extract against C. albicans (7.62 mm), and against bacteria, with emphasis on the stem and leaf extracts against M. tuberculosis (both 9 mm). All extracts exhibited high antioxidant capacity, particularly the leaf and stem extracts (both over 92%) and low cytotoxicity (Cytotoxic Concentration - CC50 > 300 µg/mL). No extract was effective against L. amazonensis (Inhibitory Concentration - IC50 > 100 µg/mL). In conclusion, S. adstringens is a potential source of compounds with antibacterial properties (particularly against Gram-positive bacteria) and antifungal activity, with low cytotoxicity and high antioxidant activity. This work emphasizes the use of this plant as a source of molecules for the development of drugs against bacterial and fungal infectious diseases, as well as for combating diseases, such as cancer and neurodegenerative disorders, that are linked to cellular and DNA damage due to oxidative stress.