Fatty acid analysis of saw palmetto (Serenoa repens) and pygeum (Prunus africana) in dietary supplements by gas chromatography/mass spectrometry in the selected ion monitoring mode

Abstract

A GC/selected ion monitoring mode-MS (GC/SIM-MS) method was developed to chemically distinguish saw palmetto and pygeum in dietary supplements. A sample set including authenticated plant samples, commercial plant extracts, a National Institute of Standards and Technology standard reference material extract, and commercial dietary supplements purported to contain either saw palmetto, pygeum, or both was investigated. Fatty acid methyl esters (FAMEs) were analyzed by GC/SIM-MS. The ability to selectively monitor each solute allowed accurate quantitation of all detected FAMEs, even those that were not chromatographically resolved. The major fatty acid components that were common to both saw palmetto and pygeum were oleic, linoleic, and palmitic acids. The major component characteristic of pygeum was stearic acid. Lauric and myristic acids were observed predominantly in saw palmetto samples. Principal component analysis was used for interpretation of the analytical results. A distinct cluster was observed for the samples containing pygeum alone. A separate cluster was observed for the samples containing saw palmetto alone or mixed with pygeum. The proposed GC/MS method is useful for chemical fingerprint analysis and QC of dietary supplements claiming to contain pygeum and/or saw palmetto.