Background: In the last few decades, the development of multidrug-resistant (MDR) microbes has accelerated alarmingly and resulted in significant health issues. Morbidity and mortality have increased along with the prevalence of infections caused by MDR bacteria, making the need to solve these problems an urgent and unmet challenge. Therefore, the current investigation aimed to evaluate the activity of linseed extract against Methicillin-resistant Staphylococcus aureus (MRSA) as an isolate from diabetic foot infection. In addition, antioxidant and anti-inflammatory biological activities of linseed extract were evaluated. Result: HPLC analysis indicated the presence of 1932.20 µg/mL, 284.31 µg/mL, 155.10 µg/mL, and 120.86 µg/mL of chlorogenic acid, methyl gallate, gallic acid, and ellagic acid, respectively, in the linseed extract. Rutin, caffeic acid, coumaric acid, and vanillin were also detected in the extract of linseed. Linseed extract inhibited MRSA (35.67 mm inhibition zone) compared to the inhibition zone (29.33 mm) caused by ciprofloxacin. Standards of chlorogenic acid, ellagic acid, methyl gallate, rutin, gallic acid, caffeic acid, catechin, and coumaric acid compounds reflected different inhibition zones against MRSA when tested individually, but less than the inhibitory action of crude extract. A lower MIC value, of 15.41 µg/mL, was observed using linseed extract than the MIC 31.17 µg/mL of the ciprofloxacin. The MBC/MIC index indicated the bactericidal properties of linseed extract. The inhibition % of MRSA biofilm was 83.98, 90.80, and 95.58%, using 25%, 50%, and 75%, respectively, of the MBC of linseed extract. A promising antioxidant activity of linseed extract was recorded, with an IC50 value of 20.8 µg/mL. Anti-diabetic activity of linseed extract, expressed by glucosidase inhibition, showed an IC50 of 177.75 µg/mL. Anti-hemolysis activity of linseed extract was documented at 90.1, 91.5, and 93.7% at 600, 800, and 1000 µg/mL, respectively. Anti-hemolysis activity of the chemical drug indomethacin, on the other hand, was measured at 94.6, 96.2, and 98.6% at 600, 800, and 1000 µg/mL, respectively. The interaction of the main detected compound in linseed extract (chlorogenic acid) with the crystal structure of the 4G6D protein of S. aureus was investigated via the molecular docking (MD) mode to determine the greatest binding approach that interacted most energetically with the binding locations. MD showed that chlorogenic acid was an appropriate inhibitor for S. aureus via inhibition of its 4HI0 protein. The MD interaction resulted in a low energy score (−6.26841 Kcal/mol) with specified residues (PRO 38, LEU 3, LYS 195, and LYS 2), indicating its essential role in the repression of S. aureus growth. Conclusion: Altogether, these findings clearly revealed the great potential of the in vitro biological activity of linseed extract as a safe source for combatting multidrug-resistant S. aureus. In addition, linseed extract provides health-promoting antioxidant, anti-diabetic, and anti-inflammatory phytoconstituents. Clinical reports are required to authenticate the role of linseed extract in the treatment of a variety of ailments and prevent the development of complications associated with diabetes mellitus, particularly type 2.
