High-Resolution Screening Combined with HPLC-HRMS-SPE-NMR for Identification of Fungal Plasma Membrane H⁺‑ATPase Inhibitors from Plants

Abstract

Crude extracts of 33 plant species were assessed for fungal plasma membrane (PM) H⁺-ATPase inhibition. This led to identification of 18 extracts showing more than 95% inhibition at a concentration of 7.5 mg/mL and/or a concentration-dependent activity profile. These extracts were selected for semi-high-resolution fungal PM H⁺-ATPase inhibition screening, and, on the basis of these results, Haplocoelum foliolosum (Hiern) Bullock and Sauvagesia erecta L. were selected for investigation by high-resolution fungal PM H⁺-ATPase inhibition screening. Structural analysis performed by high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-HRMS-SPE-NMR) led to identification of chebulagic acid (<b>1</b>) and tellimagrandin II (<b>2</b>) from H. foliolosum. Preparative-scale isolation of the two metabolites allowed determination of IC₅₀ values for PM H⁺-ATPase, and growth inhibition of Saccharomyces cerevisiae and Candida albicans. Chebulagic acid and tellimagrandin II are both potent inhibitors of the PM H⁺-ATPase with inhibitory effect on the growth of S. cerevisiae