Abstract
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.
Highlights
Seaweeds contain various bioactive metabolites which can benefit human health [1] [2]
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 Enterohaemorrhagic Escherichia coli O157 (EHEC O157) (4 isolates))
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
Summary
Seaweeds contain various bioactive metabolites which can benefit human health [1] [2]. They are currently in different phases of clinical trials [3] [4] due to their highly content of terpenes, alkaloids as well as phenolic compounds. Flavonoids are known to contain a broad spectrum of chemicals and biological activities including antioxidant and free radical scavenging properties, antibacterial, antiviral, anticancer, anti-inflammatory, anti-allergic and as potential therapeutic agents against a wide variety of diseases [6] [7] [8]. Several extraction techniques and solvents are used for obtaining antioxidant and antibacterial agents from natural sources. Microwave assisted extraction (MAE), a new extraction method, has been introduced, in order to reduce the economic, environmental and durational costs of the extraction as well as to improve extraction yield [18] [19]
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