Evaluation of Antiradical and Antioxidant Activities of Lipopeptides Produced by Bacillus subtilis Strains
Elodie Dussert, Mélissa Tourret, Chloé Dupuis, Alexandre Noblecourt, Josette Behra-Miellet, Christophe Flahaut, Rozenn Ravallec, François Coutte
Abstract
This study investigated the antiradical and antioxidant potential of the three families of lipopeptides (i.e., surfactin, mycosubtilin, and plipastatin/fengycin) produced by Bacillus subtilis strains. The antiradical/antioxidant activities of highly purified lipopeptides were studied in acellular models using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide anion ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:msubsup><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>.</mml:mo><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:math> ), hydrogen peroxide, (H 2 O 2 ) and hydroxyl radical (HO . ). At a lipopeptide concentration of 500 mg.L −1 , the maximum inhibition of DPPH reached 22.88% (obtained for plipastatin). Moreover, the scavenging effects of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:msubsup><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>.</mml:mo><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:math> , H 2 O 2 , and HO . at the highest concentration tested (250 mg.L −1 ) were found to be 6, 21, and 3% for surfactin, 19, 9, and 15% for mycosubtilin, 21, 18, and 59% for plipastatin, 21, 31, and 61% for the mixture of surfactin/plipastatin, and 13, 16, and 15% for the mixture of surfactin/mycosubtilin, respectively. These results showed that plipastatin was the best candidate due to its antioxidant activities.