Antifungal activities and mechanisms of trans‐cinnamaldehyde and thymol against food‐spoilage yeast Zygosaccharomyces rouxii

Abstract

Due to hydrophobicity, plant essential oil components transcinnamaldehyde and thymol exert broad-spectrum antimicrobial activities by interfering with the structures and functions of microbial cell membranes, yet their antifungal properties against food-spoilage yeast Zygosaccharomyces rouxii are still unclear. This work aimed to elucidate their antifungal activities and mechanisms against Z. rouxii. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were measured using broth dilution method to evaluate the antifungal activities. Membrane permeability, potential and integrity, intracellular ATP content, and intracellular pH (pH in ) were determined, and membrane damage was observed by scanning electron microscope (SEM) to investigate the antifungal mechanisms. The MICs of transcinnamaldehyde and thymol were 0.3125 and 0.0625 mg/ml, respectively, and the MFCs were 1.25 and 0.125 mg/ml, respectively. Increased membrane permeability, membrane hyperpolarization, decreased membrane integrity, reduced intracellular ATP content, and lowered pH in were found after transcinnamaldehyde or thymol treatment at the MIC and MFC levels, and thymol exhibited more severe influence on cell membrane. SEM observation further confirmed that trans-cinnamaldehyde caused cell membrane shrinkage and invagination, while thymol resulted in perforation in cell membrane. These results suggest that trans-cinnamaldehyde and thymol exert anti-Z. rouxii activities by inducing cell membrane damage and subsequent intracellular homeostasis disruption. Cellular contents leakage and intracellular homeostasis disruption probably proceed more rapidly after thymol inducing perforation in the cell surface, thereby thymol exerting better anti-Z. rouxii activity.

Thymol and trans‐cinnamaldehyde induce apoptosis through a metacaspase‐dependent mitochondrial pathway in food‐spoilage yeast Zygosaccharomyces rouxii

“…Reported studies have shown that thymol and trans ‐cinnamaldehyde could cause microbial cell necrosis mainly by disrupting cellular barriers, interfering with energy metabolism, and affecting the synthesis of nucleic acids and proteins (Kong et al., 2019; Liu et al., 2021). Our previous work confirmed that thymol and trans ‐cinnamaldehyde could result in Z. rouxii necrosis by inducing extensive cell membrane damage (Wang, Peng, et al., 2022). In recent years, many studies have found that natural active substance, including chitosan, quercetin, curcumin, perillaldehyde, silybin, beta‐amyrin, and so forth, could cause fungal cell apoptosis (programmed death) through a metacaspase‐dependent mitochondrial pathway (Kwun & Lee, 2020; Kwun et al., 2021; T. J. Li et al., 2020; Tian et al., 2017).…”

“…Although the authors’ previous work found that the addition of 1.25mg/L of trans ‐cinnamaldehyde or 0.125 mg/ml of thymol had no significant effect on the sensory properties of apple juice, it was determined after adding trans ‐cinnamaldehyde or thymol directly to apple juice concentrate (30 °Brix) and diluting the juice concentrate to 5 °Brix (Wang & Sun, 2020). The direct addition of MIC (0.3125 mg/ml for trans ‐cinnamaldehyde or 0.0625 mg/ml for thymol) or MFC (1.25 mg/ml for trans ‐cinnamaldehyde or 0.125 mg/ml for thymol) of both active compounds will probably affect the sensory characteristics of food, resulting in their limited applications in the food industry (Ahmad et al., 2021; Friedman, 2017; Wang, Peng, et al., 2022). In order to improve their application feasibility, trans ‐cinnamaldehyde liposomes and thymol‐β cyclodextrin inclusion complexes have been successfully developed by the author's group, and it is preliminarily found that the encapsulation technology could effectively mask the odor of both active compounds while maintaining the high anti‐ Z. rouxii activities (unpublished work).…”

Cinnamaldehyde causes developmental neurotoxicity in zebrafishviathe oxidative stress pathway that is rescued by astaxanthin

“…31 At the same time, cinnamon has good hydrophobicity, easily passing through biofilms and inhibiting the growth of bacteria to effectively prevent food contamination. [32][33][34][35] Cinnamaldehyde, as the main component of cinnamon, is also a medicinal material used in health care. At present, the role of cinnamaldehyde in the treatment of diabetes through lowering blood glucose and blood lipids and improving insulin sensitivity is the most studied.…”

Use of Pineapple Waste as Fuel in Microbial Fuel Cell for the Generation of Bioelectricity

“…The observed values of degrees Brix (°Brix) are shown in Figure 2 c, which remained constant until the third day (6° Brix) and then gradually decreased until the twenty-fourth day, when they decreased to zero, and they remained constant until the last day. From monitoring, it has been observed in the literature that the °Brix values decrease mainly due to the decomposition of the nutrients of the substrates in the bioelectricity generation process of the MFCs [ 49 , 50 ].…”