Salpianthus macrodontus Extracts, a Novel Source of Phenolic Compounds with Antibacterial Activity against...

Area of Science:

• Phytochemistry
• Aquatic Animal Health
• Microbiology

Background:

• Pacific white shrimp aquaculture faces significant losses due to bacterial pathogens like Vibrio and Photobacterium species.
• Antibiotic resistance and environmental concerns necessitate the exploration of alternative antibacterial agents.

Purpose of the Study:

• To evaluate the in vitro antibacterial activity of Salpianthus macrodontus and Azadirachta indica extracts against key shrimp pathogens.
• To identify compounds responsible for inhibition and assess their impact on bacterial virulence factors such as motility and biofilm formation.

Main Methods:

• Ultrasound-assisted extraction of S. macrodontus and A. indica using methanol, acetone, and hexane.
• Determination of Minimum Inhibitory Concentration (MIC) against Vibrio parahaemolyticus, V. harveyi, Photobacterium damselae, and P. leiognathi.
• Analysis of polyphenol profiles and assessment of bacterial swimming, swarming motility, and biofilm formation.

Main Results:

• Acetone extract of S. macrodontus leaf and methanol extract of S. macrodontus flower exhibited significant inhibitory activity (MICs ranging from 25-50 mg/mL).
• Both effective extracts reduced bacterial motility and biofilm formation.
• Key phenolic compounds like naringin, vanillic acid, rosmarinic acid, hesperidin, kaempferol pentosyl-rutinoside, and rhamnetin were identified.

Conclusions:

• Salpianthus macrodontus and Azadirachta indica extracts possess strong antibacterial properties against important shrimp pathogens.
• These plant-derived compounds can modulate bacterial virulence, suggesting their potential as natural alternatives in aquaculture disease control.