Antibacterial activity of fractions obtained from stem bark of Geoffroea decorticans tincture

PASTORIZA, A.C.; SOBERÓN, J. R.; SGARIGLIA, M.A.

Tafi Viejo, Tucumán, Argentina

Congreso; XXXVI ANNUAL SCIENTIFIC MEETING; 2019

TUCUMAN BIOLOGY ASSOCIATION

Geoffroea decorticans, popularly known as "chañar", traditionally as an anti-inflammatory, to treat infected wounds and dysentery. The chañar bark is an external tissue known for its medicinal properties, but its bioactive components have not yet been reported. To evaluate the antibacterial activity of polyphenolic (PG) and triterpenic (TG) enriched fractions obtained from Geoffroea decorticans bark (CC) on the Escherichia coli and Staphylococcus aureus. CC grounded powder was washed with an n-hexane and extracted with methanol. The extract was dried and fractionated by acetone precipitation to remove TG from PG. Antibacterial activity was tested on E. coli (ATCC25922) and S. aureus (ATCC 29213) (105 CFU/mL) by dot-blot bioautography and disk diffusion assay. The samples were assayed at 250?750 μg of EM and Ciprofloxacin was used as a form of control. The plates were incubated at 37°C for 24 h. The bioactive fractions were analyzed by GC-MS. PG (250 μg) was active against both strains. The inhibitory halo obtained against S. aureus was significantly higher than for E. coli (p > 0.05). TG did not show activity against the assayed strains. The GC-MS experiments performed for PG showed the presence of Dihydroquercetin, 3,4'-Dimethoxy-5,7,3'-trihydroxyflavone, and protocatechuic acid. The CC exhibited antibacterial activityagainst Gram-positive and Gram-negative strains, which support ethnomedicinal use. This activity could be attributed to its phenolic compounds constituents.