Phytochemical characterization by HPLC and evaluation of antibacterial and aminoglycoside resistance-modifying activity of chloroform fractions of Cordia verbenacea DC leaf extracts

Introduction“Erva-baleeira,” Cordia verbenacea DC. (Boraginaceae), is one of the species of plants currently exploited for the purpose of producing a phytotherapeutic product, which is extracted from the leaves.MethodsExtracts of C. verbenacea were prepared from fresh leaves, and chloroform fractions were obtained from the different extracts for evaluation. Phytochemical screening was performed and the phytochemicals were quantified by HPLC-DAD. The microdilution assay was used to determine antibiotic and aminoglycoside-modifying activities (2.4–2500 μg/mL), and the results were analyzed using two-way ANOVA and Bonferroni post-test.ResultsPhytochemical screening and HPLC analysis of the fractions were in agreement with the literature, which describes the presence of several tannins and flavonoids in C. verbenacea leaves. The fractions showed moderate antibacterial activity when considering clinical relevance with a MIC of 128 μg/mL against a resistant strain of Staphylococcus aureus and 512 μg/mL against a resistant strain of Pseudomonas aeruginosa. However, when they were combined with antibiotics, synergism was observed, significantly lowering the MIC of the antibiotics by 12.5 (P < 0.001).ConclusionsOur results indicated that the fractions of C. verbenacea, when combined with an antibiotic, demonstrated significant synergistic activity. Due the extensive use and sale of products derived from C. verbenacea may exert pressure on the populations of this species. The development of management plans for rational and sustainable use of the species and more studies with emphasis on the use of such fractions in the treatment of other diseases are necessary.