Identification of Antibacterial Sterols from Korean Wild Mushroom Daedaleopsis confragosa via Bioactivity- and LC-MS/MS Profile-Guided Fractionation

Abstract

As part of an ongoing natural product chemical research for the discovery of bioactive secondary metabolites with novel structures, wild fruiting bodies of Daedaleopsis confragosa were collected and subjected to chemical and biological analyses. We subjected the fractions derived from the methanol extract of the fruiting bodies of D. confragosa to bioactivity-guided fractionation because the methanol extract of D. confragosa showed antibacterial activity against Helicobacter pylori strain 51, according to our bioactivity screening. The n-hexane and dichloromethane fractions showed moderate to weak antibacterial activity against H. pylori strain 51, and the active fractions were analyzed for the isolation of antibacterial compounds. Liquid chromatography-tandem mass spectrometry (LC–MS/MS) analysis revealed that the n-hexane fraction contains several compounds which are absent in the other fractions, so the fraction was prioritized for further fractionation. Through chemical analysis of the active n-hexane and dichloromethane fractions, we isolated five ergosterol derivatives (1–5), and their chemical structures were determined to be demethylincisterol A3 (1), (20S,22E,24R)-ergosta-7,22-dien-3β,5α,6β-triol (2), (24S)-ergosta-7-ene-3β,5α,6β-triol (3), 5α,6α-epoxy-(22E,24R)-ergosta-7,22-dien-3β-ol (4), and 5α,6α-epoxy-(24R)-ergosta-7-en-3β-ol (5) by NMR spectroscopic analysis. This is the first report on the presence of ergosterol derivatives (1–5) in D. confragosa. Compound 1 showed the most potent anti-H. pylori activity with 33.9% inhibition, rendering it more potent than quercetin, a positive control. Compound 3 showed inhibitory activity comparable to that of quercetin. Distribution analysis of compound 1 revealed a wide presence of compound 1 in the kingdom Fungi. These findings indicate that demethylincisterol A3 (1) is a natural antibiotic that may be used in the development of novel antibiotics against H. pylori.

An Investigation of Quorum Sensing Inhibitors against Bacillus cereus in The Endophytic Fungus Pithomyces sacchari of the Laurencia sp.

“…Notably, demethylincisterol A 3 exhibits significant anti-tumor and antiinflammatory effects [31,32]. Studies have demonstrated that the rate of inhibition exhibited by demethylincisterol A 3 towards Helicobacter pylori is 11% greater than that of 100 µM quercetin [33]. Despite its recognized therapeutic potential, there has been limited research on its QS inhibitory effect against pathogens.…”

Global Natural Products Social (GNPS)-Based Molecular-Networking-Guided Isolation of Phenolic Compounds from Ginkgo biloba Fruits and the Identification of Estrogenic Phenolic Glycosides

“…In our recent investigations, we harnessed GNPS-guided isolation, leading to the discovery of four new madurastatin derivatives derived from the fungus Actinomadura sp. RB99 [32]. This outcome highlights the power of GNPS as an invaluable tool for discovering new natural compounds from natural sources.…”

Bioactivity Profiling of Daedaleopsis confragosa (Bolton) J. Schröt. 1888: Implications for Its Possible Application in Enhancing Women’s Reproductive Health

“…This species has also garnered attention for its traditional uses, such as ornamental paper making, due to its unique textures and colors, showcasing its versatility beyond its ecological significance [24]. On the other hand, its pharmacological and medical importance has been overlooked aside from a few studies that have shown that this polypore fungus exhibits promising antibacterial, antifungal, and antioxidative activities [25][26][27].…”