A new fatty acid ester from an edible mushroom Rhizopogon luteolus

Abstract

Phytochemical investigation of the Rhizopogon luteolus Fr. led to the isolation of one new fatty acid ester, 3-hydroxy-2,4-dimethylheptacosyl acetate (1) together with two known compounds tetracosanoic acid (2) and ergosterol (3). 1D and 2D NMR, and MS techniques were used for structural elucidation. Phenolic and fatty acid compositions were identified using HPLC-DAD and GC-MSD, respectively. Fumaric acid was the major phenolic acid, whereas linoleic, stearic and oleic acids were the most abundant fatty acids. Antioxidant and anticholinesterase activities of the extracts and compounds (1-3) were tested spectrophotometrically. Among the extracts, hexane extract showed the highest activity in all tests, particularly in β-carotene-linoleic acid assay (IC50: 16.65 ± 1.12 μg/mL). Furthermore, compound 3 exhibited higher antioxidant and anticholinesterase activities. The study indicates that R. luteolus can be used in food, cosmetic and pharmaceutical industries.

Keywords: Rhizopogon luteolus; anticholinesterase activity; antioxidant activity; ergosterol; fatty acid; phenolic compounds.