1. Jerveratrum-Type Steroidal Alkaloids Inhibit β-1,6-Glucan Biosynthesis in Fungal Cell Walls.
- Author
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Kubo K, Itto-Nakama K, Ohnuki S, Yashiroda Y, Li SC, Kimura H, Kawamura Y, Shimamoto Y, Tominaga KI, Yamanaka D, Adachi Y, Takashima S, Noda Y, Boone C, and Ohya Y
- Subjects
- Alkaloids isolation & purification, Antifungal Agents isolation & purification, Candida drug effects, Candida genetics, Candida metabolism, Cell Wall drug effects, Fungi genetics, Fungi metabolism, Humans, Mycoses microbiology, Plant Extracts isolation & purification, Alkaloids pharmacology, Antifungal Agents pharmacology, Cell Wall metabolism, Fungi drug effects, Plant Extracts pharmacology, Veratrum chemistry, beta-Glucans metabolism
- Abstract
The limited number of available effective agents necessitates the development of new antifungals. We report that jervine, a jerveratrum-type steroidal alkaloid isolated from Veratrum californicum, has antifungal activity. Phenotypic comparisons of cell wall mutants, K1 killer toxin susceptibility testing, and quantification of cell wall components revealed that β-1,6-glucan biosynthesis was significantly inhibited by jervine. Temperature-sensitive mutants defective in essential genes involved in β-1,6-glucan biosynthesis, including BIG1 , KEG1 , KRE5 , KRE9 , and ROT1 , were hypersensitive to jervine. In contrast, point mutations in KRE6 or its paralog SKN1 produced jervine resistance, suggesting that jervine targets Kre6 and Skn1. Jervine exhibited broad-spectrum antifungal activity and was effective against human-pathogenic fungi, including Candida parapsilosis and Candida krusei. It was also effective against phytopathogenic fungi, including Botrytis cinerea and Puccinia recondita. Jervine exerted a synergistic effect with fluconazole. Therefore, jervine, a jerveratrum-type steroidal alkaloid used in pharmaceutical products, represents a new class of antifungals active against mycoses and plant-pathogenic fungi. IMPORTANCE Non-Candida albicans Candida species (NCAC) are on the rise as a cause of mycosis. Many antifungal drugs are less effective against NCAC, limiting the available therapeutic agents. Here, we report that jervine, a jerveratrum-type steroidal alkaloid, is effective against NCAC and phytopathogenic fungi. Jervine acts on Kre6 and Skn1, which are involved in β-1,6-glucan biosynthesis. The skeleton of jerveratrum-type steroidal alkaloids has been well studied, and more recently, their anticancer properties have been investigated. Therefore, jerveratrum-type alkaloids could potentially be applied as treatments for fungal infections and cancer.
- Published
- 2022
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