Antibacterial activity of extracts from the flowers of the double-feathered cosmea (Cosmos bipinnatus Cav.) in relation to some clin-ical isolates

Abstract

The article is devoted to study the antibacterial activity of alcoholic and aqueous extracts from the flowers of two varieties of double-feathered cosmea (Cosmos bipinnatus Cav.) – ‘Rosea’ and ‘Dazzler’ in relation to clinical strains of S. aureus II, S. pneumonia UEV-1, E. coli 89, K. rpeimopiae SES 11/02. The conducted studies have shown that the studied extracts, both with respect to gram-positive and gram-negative strains, exhibit bacteriostatic activity. High bacteriostatic activity of extracts No. 5, 11, 12 was detected with respect to S. aureus at a concentration of 0.08 mcg/ml. Extract No. 6 showed antimicrobial action only at high concentrations of 0.96-0.8 mcg/ml. The activity against S. pneumoniae was shown by extract No. 6 in the concentration range of 0.96-0.32 mcg/ml, it was inferior in antibacterial effect to the comparison drug in high dosages. High bacteriostatic activity was detected in extract No. 12, with respect to E. coli, where the degree of growth suppression relative to the control was 70%, which corresponded to the minimum studied concentration (0.02 mcg/ml). The comparison drug was inferior in action to extract No. 12 and demonstrated a comparable effect at a concentration of 128 mcg/ml. In relation to K. pneumoniae, extract No. 12 showed the best result at the lowest concentration of 0.02 mcg/ml, it showed a growth suppression percentage of 60%, which is comparable to the comparison drug ceftriaxone at a concentration of 32 mcg/ml. The leader was an aqueous extract No. 12 obtained from the flowers of the double-feathered cosmea of the Dazzler variety, which showed bacteriostatic activity against gram-positive and gram-negative test cultures. The most intense effect of the studied extracts was shown in relation to gram-negative flora.