Hinokitiol inhibits Aspergillus fumigatus by interfering with the cell membrane and cell wall

Aspergillus fumigatus-Derived Extracellular Vesicles Mitigate Fungal Keratitis by Modulating the Immune Cell Function

Fungal keratitis (FK) is a refractory global disease characterized by a high incidence of blindness and a lack of effective therapeutic options, and Aspergillus fumigatus (A. fumigatus, AF) is one of the most common causative fungi. This study aimed to investigate the role of extracellular vesicles (EVs) from A. fumigatus in the immune cell function and their protective role in A. fumigatus keratitis in order to explore their therapeutic potential. First, we isolated and characterized the EVs (AF-derived EVs). In vitro, we stimulated RAW264.7 cells and polymorphonuclear cells with AF-derived EVs. The expression levels of inflammatory factors increased in both immune cells along with an M1 polarization variation of RAW264.7 cells. After being incubated with AF-derived EVs, both immune cells exhibited an increased conidia-phagocytic index and a decreased conidia survival rate. In vivo, we injected EVs subconjunctivally on mice resulting in a heightened production of secretory immunoglobulin A (sIgA) in tear fluid. By the injection of EVs on mice in advance, a significant reduction in severity of A. fumigatus FK was witnessed by lower clinical scores, inflammatory appearances, and mitigated fungal load. Collectively, these results positioned AF-derived EVs as a promising and innovative immune therapy for combating FK, while also providing a platform for further investigation into developing an optimal formulation for modulating inflammation in the context of FK.

Natural Compounds with Antifungal Properties against Candida albicans and Identification of Hinokitiol as a Promising Antifungal Drug

Candida albicans is an opportunistic yeast that causes most fungal infections. C. albicans has become increasingly resistant to antifungal drugs over the past decade. Our study focused on the identification of pure natural compounds for the development of antifungal medicines. A total of 15 natural compounds from different chemical families (cinnamic derivatives, aromatic phenols, mono- and sesquiterpenols, and unclassified compounds) were screened in this study. Among these groups, hinokitiol (Hi), a natural monoterpenoid extracted from the wood of the cypress family, showed excellent anti-C. albicans activity, with a MIC value of 8.21 µg/mL. Hi was selected from this panel for further investigation to assess its antifungal and anti-inflammatory properties. Hi exhibited significant antifungal activity against clinically isolated fluconazole- or caspofungin-resistant C. albicans strains. It also reduced biofilm formation and hyphal growth. Treatment with Hi protected Caenorhabditis elegans against infection with C. albicans and enhanced the expression of antimicrobial genes in worms infected with C. albicans. Aside from its antifungal activities against C. albicans, Hi challenge attenuated the LPS-induced expression of pro-inflammatory cytokines (IL-6, IL-1β, and CCL-2) in macrophages. Overall, Hi is a natural compound with antifungal and anti-inflammatory properties, making Hi a promising platform with which to fight against fungal infections.

Inhibitory effects of hinokitiol on the development and pathogenicity of Colletotrichum gloeosporioides

Postharvest anthracnose of mango fruit caused by Colletotrichum gloeosporioides is a devastating fungal disease, which causes tremendous quality deterioration and economic losses. Hinokitiol, an environmentally friendly natural compound, is effective in controlling a variety of postharvest fungal diseases. However, there is still a lack of research on the inhibitory effect of hinokitiol on C. gloeosporioides and its possible modes of action. In the present study, the activity of hinokitiol against C. gloeosporioides and its potential mechanisms involved have been investigated. We found that hinokitiol treatment could effectively inhibit the virulence of C. gloeosporioides to harvested mango fruit. After treatment with 8 mg/L hinokitiol, the mycelial growth of C. gloeosporioides was completely inhibited. When the concentration of hinokitiol reached 9 mg/L, the spore germination rate of C. gloeosporioides decreased to 2.43% after 9 h of cultivation. The inhibitory effect is mainly due to the attenuation in cell viability, and impairment in plasma membrane followed by leakage of cytoplasmic contents such as nucleic acids, proteins, and soluble carbohydrates, which ultimately leads to the destruction of cell structure. Furthermore, hinokitiol suppressed the expression of pathogenicity-related genes, leading to reduced infection activity. Collectively, these results suggest that hinokitiol may be an excellent bio-fungicides for the management of mango anthracnose.