Adventitious roots of Hypericum perforatum are potential material for inhibiting foodborne bacteria.

Plant adventitious root (AR) culture is an alternative route to obtain plant raw material. Hypericum perforatum L. is a precious medicinal herb and its ARs have been mass produced in bioreactors. To utilization of the cultured H. perforatum ARs in the production of food products, this study explored the effect of crude extract (CE) of ARs and its five fractions (i.e., petroleum ether, dichloromethane, ethyl acetate, n-butyl alcohol, and water) from stepwise extraction with different solvents on antibacterial activity against four foodborne pathogenic bacterial species (i.e., Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Salmonella choleraesuis); and antibacterial mechanisms of petroleum ether fraction were investigated in terms of cell permeability and respiration. The results showed that CE and five fractions all had antibacterial effects on the tested four bacterial species, and the lowest minimal inhibitory concentration against B. cereus and S. aureus was found in the fraction of petroleum ether (PE-F). PE-F increased the leakage of alkaline phosphatase, electrolyte, nucleic acid, and protein of B. cereus and S. aureus, indicating that bacterial cell permeability was increased. Meanwhile, PE-F inhibited respiration of B. cereus and S. aureus, and the superposition rate of the combination group of PE-F and iodoacetic acid (IA) was lowest, demonstrating that PE-F might be involved in regulation of IA-represented respiratory pathway, namely, tricarboxylic acid cycle. This study suggested that H. perforatum ARs have potential application value and could be used in the food industry. Key message: 1. Adventitious roots of Hypericum perforatum possessed antibacterial activity. 2. The highest antibacterial activity was in fraction of petroleum ether. 3. Fraction of petroleum ether affected cell permeability and respiration. [ABSTRACT FROM AUTHOR]