Author(s)

Rabia Alghazeer^1*, Abdalla Elmansori², Moammar Sidati³, Ftaim Gammoudi⁴, Salah Azwai⁴, Hesham Naas⁵, Aboubaker Garbaj⁵, Ibrahim Eldaghayes⁴

¹Department of Chemistry, Faculty of Sciences, University of Tripoli, Tripoli, Libya.
²Department of Botany, Faculty of Sciences, University of Tripoli, Tripoli, Libya.
³Marin Biology Research Center, Tajura-East of Tripoli, Tripoli, Libya.
⁴Department of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Tripoli, Tripoli, Libya.
⁵Department of Food Hygiene and Control, Faculty of Veterinary Medicine, University of Tripoli, Tripoli, Libya.

This study aimed to evaluate the antibacterial activity of flavonoids extracted from two Libyan brown algae namely Cystoseira compressa and Padina pavonica using microwave-assisted extraction method against pathogenic bacteria isolated from meat, meat products, milk and dairy products (Staphylococcus aureus subsp. aureus (5 isolates), Bacillus cereus (3 isolates), Bacillus pumilus (1 isolate), Salmonella enterica subsp. enteric (4 isolates) and Enterohaemor-rhagic Escherichia coli O157 (EHEC O157) (4 isolates)). All of these isolates were muti-drug resistant with high MAR index. The results showed that C. compressa extract exhibited better and stronger antibacterial activities against the seventeen tested isolates with inhibition zones diameter ranged from 14 - 22 mm compared to P. pavonica extract which showed positive effect against 9 isolates with low inhibition zone ranged from 11 - 16.5 mm. Flavonoids extracted from C. compressa also displayed the best spectrum of bactericidal effect with a ratio MBC/MIC ≤ 4 obtained on all susceptible tested bacterial strains. Flavonoids and proanthocyanidins significantly contributed to the antibacterial properties. The mode of action of these active extracts is under investigation.

Brown Algae, Flavonoids, Multi-Drug Resistant Bacteria, Antibacterial Activity

Alghazeer, R. , Elmansori, A. , Sidati, M. , Gammoudi, F. , Azwai, S. , Naas, H. , Garbaj, A. and Eldaghayes, I. (2017) In Vitro Antibacterial Activity of Flavonoid Extracts of Two Selected Libyan Algae against Multi-Drug Resistant Bacteria Isolated from Food Products. Journal of Biosciences and Medicines, 5, 26-48. doi: 10.4236/jbm.2017.51003.