Inhibitory effect of propolis extract on the growth of Listeria monocytogenes and the mutagenicity of 4-nitroquinoline-N-oxide

✍ Scribed by Hsin-Yi Yang; Cheng-Ming Chang; Yue-Wen Chen; Cheng-Chun Chou

• Book ID: 102434549
• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 256 KB
• Volume: 86
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/jsfa.2441

✦ Synopsis

Abstract

Propolis originates from a resinous substance collected by honeybees from the buds and leaves of trees and plants, which is then mixed with pollen as well as enzymes secreted by the bees. In the present study, the susceptibility of Listeria monocytogenes to the ethanol extract of propolis (EEP) as influenced by EEP concentration, incubation temperature, pH, and cell age was investigated. In addition, the antimutagenic action of EEP against 4‐nitroquinoline‐N‐oxide (4‐NQO) was also examined. Results revealed that EEP at a dosage of 7.5 µg mL^−1^ or higher exerted a bactericidal effect on L. monocytogenes. L. monocytogenes was most susceptible to EEP at 37 °C followed by 25 and 4 °C. At acid pH values, cells of the test organism were more sensitive to EEP than at neutral pH, while most resistant at alkaline pH values. Cell age was also found to affect the susceptibility of L. monocytogenes to EEP. Cells in the mid‐exponential phase showed the highest susceptibility, followed by cells in the late‐exponential phase and stationary phase. EEP caused cell leakage of the test organism. A marked increase in the absorbance at 260 nm, UV‐absorbing material in the supernatant of cell suspension, and irregularly shaped materials around the cell surface were noted after cells of L. monocytogenes were exposed to EEP. Furthermore, EEP at a dosage of 7.5–60.0 µg per plate was found to suppress 4‐NQO‐induced mutation by 17.6–88.8%. Copyright © 2006 Society of Chemical Industry