Antibacterial, Antioxidant, and Anticholinesterase Activities of Plant Seed Extracts from Brazilian Semiarid Region

<jats:p>The antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from Brazilian semiarid region were investigated. The extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. Six extracts presented activity against the Gram (−) organism<jats:italic>Salmonella choleraesuis</jats:italic>and the Gram (+) organisms<jats:italic>Staphylococcus aureus</jats:italic>and<jats:italic>Bacillus subtilis</jats:italic>. The MIC values ranged from 4.96 to 37.32 mg/mL. The<jats:italic>Triplaris gardneriana</jats:italic>extract presented activity against the three species, with MIC values 18.8, 13.76, and 11.15 mg/mL, respectively. Five extracts presented antioxidant activity, with EC<jats:sub>50</jats:sub>values ranging from 69.73 <jats:italic>μ</jats:italic>g/mL (<jats:italic>T. gardneriana</jats:italic>) to 487.51 <jats:italic>μ</jats:italic>g/mL (<jats:italic>Licania rigida</jats:italic>). For the anticholinesterase activity, eleven extracts were capable of inhibiting the enzyme activity. From those,<jats:italic>T. gardneriana</jats:italic>,<jats:italic>Parkia platycephala</jats:italic>and<jats:italic>Connarus detersus</jats:italic>presented the best activities, with inhibition values of 76.7, 71.5, and 91.9%, respectively. The extracts that presented antimicrobial activity were tested for hemolytic assay against human A, B, and O blood types and rabbit blood. From those, only the<jats:italic>Myracrodruon urundeuva</jats:italic>extract presented activity (about 20% of hemolysis at the lowest tested concentration, 1.9 µg/mL). Infrared spectroscopy of six representative extracts attested the presence of tannins, polyphenols, and flavonoids, which was confirmed by a qualitative phytochemical assay.</jats:p>