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Perillaldehyde (PAE), a natural monoterpenoid agent extracted from Perilla frutescence, PAE has been reported to present various physiological capabilities, such as anti-inflammation, anti-oxidative and anti-fungal. In this study, we show that PAE exhibits strong antifungal activity against Candida albicans (C. albicans). C. albicans, a fungal pathogen with high incidence of antifungal resistance in clinical settings, is the major cause of oropharyngeal candidiasis (OPC). OPC is characterized by inflammatory immunological responses to fungal infections. Our in vitro results show PAE inhibited several virulence attributes of C. albicans including biofilm formation, yeast-to-hyphal transition and secreted aspartic proteinases (SAPs) gene expression. Using an experimental murine model of OPC, we found that PAE inhibited NLRP3 inflammasome assembly, reduced the excessive accumulation of ROS and prevented the p65 transfer in nuclear; processes all leading to reduced inflammation burden in the host. Together, this supports use PAE as a promising new agent to improve OPC., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Candida albicans invasion is one of the most serious fungal infections in clinical history. In recent years, because of the widespread use of immunosuppressive drugs, chemotherapy drugs, glucocorticoids, and broad-spectrum antibiotics, serious drug resistance has been reported; therefore, a new type of antifungal drug needs to be developed. In this study, we found that Nerol (NEL) had strong antimicrobial activity and 0.77 μL/mL NEL was the minimum inhibitory concentration (MIC) effective against C. albicans. We determined the change of the growth curve of NEL for C. albicans, to identify the trend of NEL activity against C. albicans. Through the determination of the ergosterol content and glucose-induced extracellular fluid acidification of NEL on C. albicans, we found that NEL inhibits the growth of C. albicans by destroying cell membranes. This finding was also supported by the expression of SAP (secreted aspartyl proteinase) involved in cell membrane synthesis. Finally, demonstrations of phenotype investigation, colony-forming unit (CFU) counts, and PAS (periodic acid-Schiff) staining were conducted to prove that NEL had the ability to treated mouse oral C. albicans infection and vaginal C. albicans infection. This research may help us to investigate new antimicrobial agents for treating C. albicans infections. KEY POINTS: • NEL can inhibit the growth of C. albicans. • NEL destroys the cell membrane formation and permeability of C. albicans. • NEL can treat vulvovaginal candidiasis and oropharyngeal candidiasis in mice. • NEL could be used as a possible antifungal agent.

The invasion of Candida albicans is one of the most common fungal infections seen in clinical practice, and serious drug resistance has been reported in recent years. Therefore, new anti-C. albicans drugs must be introduced. In this research, it was demonstrated that cinnamaldehyde (CA) shows strong antimicrobial activity, with 0.26 mg/mL CA being the minimum inhibitory concentration to manage C. albicans. Extraordinarily, we detected that CA accumulated the intracellular reactive oxygen species (ROS) and enhanced the calcium concentration in the cytoplasm and mitochondria through flow cytometry. In addition, we observed that C. albicans cells released Cytochrome c from the mitochondria to the cytoplasm, depolarized the mitochondrial membrane potential, and activated the metacaspase when exposed to 0.065, 0.13, 0.26, and 0.52 mg/mL CA. Furthermore, to confirm that CA introduces the C. albicans apoptosis, we discovered that when the phosphatidylserine was exposed, DNA damage and chromatin condensation occurred, which were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and 4',6-diamidino-2-phenylindole (DAPI) staining. Finally, demonstrations of phenotype investigation, colony-forming unit (CFU) counts, and periodic acid-Schiff (PAS) staining were conducted to prove that CA possessed the ability to treat oropharyngeal candidiasis (OPC) and vulvovaginal candidiasis (VVC). From the above, our research indicates that CA is a promising antifungal candidate when applied to C. albicans infections.

New anti-Candida albicans drugs are needed due to the emergence of resistant cases in recent years. Perillaldehyde (PAE) is a natural monoterpenoid compound derived from Perilla frutescens. The minimum inhibitory concentration of PAE against C. albicans was 0.4 μL/mL. We aimed to elucidate the antifungal mode of action of PAE against C. albicans. The antifungal activity of PAE against C. albicans was found to correlate with an elevation in intracellular Ca 2+ and accumulation of ROS. Several downstream apoptosis events such as the disruption of mitochondrial membrane potential, phosphatidylserine externalization, cytochrome c release, and metacaspase activation were observed in PAE-treated cells. DNA damage and nuclear fragmentation assays also revealed apoptosis of C. albicans cells. In summary, by means of fluorescent microscopy, flow cytometer analysis, and Western blot, our data uncovered that PAE exerts its antifungal activity through Ca 2+ and oxidative stress-mediated apoptosis mechanisms. This study deciphered the mode of action of PAE, which will be useful in the design of improved antifungal therapies.

Vulvovaginal candidiasis is a common fungal infection afflicting women which is primarily caused by the yeast Candida albicans (C. albicans). It is imperative to introduce new drug classes to counter this threat due to the continuous emergence of drug-resistant cases in recent years. The purpose of this study was to clarify the in vivo antifungal activity of perillaldehyde (PAE) against C. albicans and to prove that PAE is a promising candidate for the control of vaginal candidiasis. An animal model of vaginitis was developed to demonstrate the therapeutic and preventive effects of PAE on vaginal candidiasis, and these were evaluated through fungal and histopathological examinations. In clarifying the mechanism of PAE, standard hematological test results indicated that white blood cells (WBC) were elevated abnormally in mice infected with C. albicans , whereas when the mice were treated with various concentrations of PAE, the number of WBC in the blood was reduced. Flow cytometry was used to detect the populations of neutrophils, macrophages and CD4 T cells in the vaginal tissue of the mice. PAE was found to reduce these immune cells, which all play a key role in the inflammatory response, and the related interleukin and pro-inflammatory cytokines, including IL-17, IL-22 and TNF-α. These were detected using ELISA. Finally, we detected the expression levels of E-cadherin in the PAE treatment mouse group and discovered that it had recovered to its normal levels, but in the infection mouse group, the E-cadherin expression was clearly suppressed by the presence of C. albicans. Our data demonstrated that PAE targets these cytokines and possesses the ability to fight the fungal infection while also reducing the levels of the inflammatory factors identified. Our results demonstrated that PAE has a significant preventative and therapeutic effect on vaginal candidiasis and is a potential candidate for the treatment of vaginal Candida infections. [ABSTRACT FROM AUTHOR]

Vulvovaginal candidiasis (VVC) is one of the most frequent diseases induced by Candida albicans (C. albicans) during pregnancy, which results in enormous pain to women and their partners in daily life. Perillaldehyde (PAE), a natural monoterpenoid, has significant anti-microbial, anti-inflammatory and anti-oxidation effects. Reactive oxygen species (ROS) are key factors for the host to resist the invasion of fungi. However, excess ROS can cause additional damage independent of the pathogen itself, and the mechanism of ROS in VVC has not been investigated. In this murine study, we revealed that C. albicans infection increased the expression of NADPH oxidase 2 (NOX2) and the content of malonaldehyde (MDA). C. albicans inhibited the activity of antioxidant enzymes in the vagina, including superoxide dismutase (SOD), Catalase (CAT), glutathione peroxidase (GSH-PX) and heme oxygenase (HO-1), which were returned to normal levels after treatment with PAE. Furthermore, PAE inhibited the activities of Keap1 and promoted Nrf2 transfer from cytoplasm to nucleus, which were mediated by excessive accumulation of ROS in the VVC mice. In this study, we also indicated that PAE inhibited the apoptosis of vagina cells via Caspase 9- Caspase 7-PARP pathway and prevented the release of IL-1ꞵ in VVC mice. In summary, this study revealed that the treatment of VVC in mice with PAE might be mediated by inhibition of ROS, and established the therapeutic potential of PAE as an antifungal agent for the treatment of VVC. [ABSTRACT FROM AUTHOR]