LC-MS/MS-Based Phenolic Profiling of Flaxseed (Linum usitatissimum L.) and Safflower (Carthamus tinctorius L.) Seed Extracts and Their Antibacterial Activity Against Selected Fish Pathogenic Bacteria
Year: 2026
Type: article
Abstract: The growing demand for sustainable disease-control strategies in aquaculture has increased interest in plant-derived compounds with potential antibacterial activity against fish pathogens. This study investigated the LC-MS/MS-based phenolic profile and in vitro antibacterial activity of aqueous methanolic flaxseed (Linum usitatissimum L.) and safflower (Carthamus tinctorius L.) seed extracts against selected fish pathogenic bacteria. The extracts were obtained using 40% methanol, concentrated, and prepared as aqueous stock solutions. The stock concentrations were 0.148 g mL-1 for flaxseed and 0.101 g mL-1 for safflower. The phenolic profiles of the final aqueous stock solutions were then determined by LC-MS/MS and expressed as µg L-1 (ppb). LC-MS/MS analysis showed that the flaxseed extract was mainly characterized by a tannic acid-rich profile, together with trans-ferulic acid, caffeic acid, gallic acid, quercetin, rutin trihydrate, cinnamic acid, and 2,5-dihydroxybenzoic acid. In contrast, the safflower seed extract contained trans-ferulic acid, cinnamic acid, 2,5-dihydroxybenzoic acid, ellagic acid, caffeic acid, and quercetin as the detected phenolic constituents. Antibacterial activity was tested by the broth microdilution method against Aeromonas hydrophila, Aeromonas salmonicida, Pseudomonas putida, Yersinia ruckeri, and Vibrio anguillarum. The strongest antibacterial activity was observed for flaxseed extract against A. hydrophila and A. salmonicida, with MIC values of 25 and 50 µg mL-1, respectively. Safflower seed extract showed its highest inhibitory activity against A. salmonicida, with an MIC value of 50 µg mL-1, while higher MIC values were recorded against A. hydrophila, Y. ruckeri, and V. anguillarum. No inhibitory activity was detected against P. putida for either extract within the tested concentration range. These results indicate that aqueous methanolic flaxseed and safflower seed extracts, particularly flaxseed, have species-dependent antibacterial activity against fish pathogens. Although these findings suggest that the tested extracts may be considered as preliminary natural antibacterial candidates for aquaculture-related research, further studies are needed to evaluate their safety, stability, and in vivo applicability.
Source: Acta Natura et Scientia
Institution: Kastamonu University
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7165882011