Estudio de la composición química, actividad antioxidante y antimicrobiana del aceite esencial proveniente de las hojas de Dalea coerulea (L.f.) Schinz & Thell

Abstract

The Dalea coerulea (L.f.) Schinz&Thell species is a native medicinal plant of Ecuador whose main use is related to treating diseases of the respiratory system. Its essential oil was extracted from the leaves of the species, its main components were: α-pinene (25,34 %), α-thujene (16,69 %), β-pinene (8,11 %), a several of these molecules are attributed anti-inflammatory, bronchodilator, antimicrobial and insecticidal properties. The spectrophotometric methods ABTS and DPPH were used to determine the antioxidant activity, which was very close to the essential oil of Thymus vulgaris which was used as a natural reference, in parallel the antioxidant activity of the major component of the oil (pinene) was evaluated, which was priceless. The bioautographic evaluation showed that the activity is provided by the sesquiterpenes cubebol and copaene. The Antimicrobial Activity Study gave very strong results in all strains tested. Gram positive Streptococcus pyogenes ATCC 19615 with MIC 317,0 µg/mL and Staphylococcus aureus ATCC 29213 with MIC 317,0 µg/mL; Gram negative bacteria Klebsiella pneumoniae ATCC 10031 with MIC 64,1 μg/mL and Haemophilus influenzae ATTC 10211 with MIC 239,7 μg/mL; and yeasts Candida tropicalis ATCC 13803 with MIC 317,0 μg/mL and Candia albicans ATCC 10231 with MIC 262,7 μg/mL. The results presented validate the ancestral use of the Andean peoples of Ecuador, both in the presence of secondary metabolites, and in the assays of biological activity