Abstract
The anti-microbial properties of acetone extracts from Hibiscus sabdariffa calyces, fractions isolated by silica gel chromatography and hibiscus acid purified from some of these fractions and additionally identified by nuclear magnetic resonance spectroscopy, mid-infrared spectroscopy and X-ray diffraction, were studied against both multidrug-resistant Salmonella strains and pathogenic Escherichia coli bacteria. Gel diffusion was used to determine the anti-microbial effects. The mode of action of hibiscus acid was determined by crystal violet assay. Hibiscus acid and 17 of the 25 chromatographic fractions obtained, displayed an anti-microbial effect against all bacterial strains tested. Hibiscus acid showed a greater anti-microbial effect than the acetone extract against most of the bacteria strains, while chromatographic fractions IX–XIV exerted the greatest anti-microbial effect against all bacteria. The minimum inhibitory concentration of the acetone extract was 7 mg/mL, and the minimum bactericidal concentration was 10 mg/mL, while the corresponding values for hibiscus acid were 4–7 and 7 mg/mL, respectively. The results of the crystal violet assay indicate that hibiscus acid alters membrane permeability. Hibiscus acid is a potential alternative to control multidrug-resistant bacteria. Due to its ready availability and easy extraction from H. sabdariffa, hibiscus acid is potentially useful in the food industries.
Highlights
Salmonella is one of the leading causes of foodborne diseases, and its infection is spread worldwide
The dry extract had anti-microbial activity against the eight multidrug-resistant Salmonella and pathogenic E. coli strains, while the radial inhibition zone on the culture medium varied from 9.8 to 12.6 mm. These results agree with those previously reported on the anti-microbial effect of extracts obtained from H. sabdariffa calyces [18]
The present work showed that hibiscus acid is one of the compounds responsible for the anti-microbial effect of H. sabdariffa calyces
Summary
Salmonella is one of the leading causes of foodborne diseases, and its infection (salmonellosis) is spread worldwide. Salmonellosis has become a public health burden, representing significant costs in many countries. A range of fresh fruit and vegetables, especially those eaten raw (lettuce, sprouts, melon and tomatoes), are implicated in Salmonella infection [1]. S. enterica subspecies enterica is composed of more than 1500 serotypes with some of great importance, such as S. Enterica is responsible for more than 99% of human salmonellosis and it is widely studied [2] S. enterica subsp. enterica is responsible for more than 99% of human salmonellosis and it is widely studied [2]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
