Metabolomic profiling of saw palmetto products using proton-NMR spectroscopy and multi-variate analysis

Saw palmetto products with an often poorly known and variable chemical composition are used in the treatment of Benign Prostatic Hyperplasia.(1, 2) Here we present a method for the metabolomic analysis of saw palmetto products using NMR spectroscopy and multi-variate analysis in order to determine if there are significant differences in metabolytes of the given products and if marker compounds can be identified. Spectra were obtained on a Bruker 500MHz spectrophotometer. TOPSPIN was used for spectra acquisition and processing. Deuterated methanol and chloroform were selected as solvents. NMR spectra were transferred to AMIX. The spectra were divided into 251 regions and the signal intensity was integrated. Unscrambler was used for PCA analysis. The analysis showed that saw palmetto products can be grouped according to their metabolic profile. Multi-variate analysis showed significant variations between powders, soft extract and tincture products. The largest variation in any product tested was observed for a hexane extract. Oleic acid and caproic acid ethyl ester were identified as potential marker compounds. Additional information regarding TLC analysis and clinical outcomes was supplied by Andy Suter from Bioforce AG, Switzerland. Variations in chemical content were identified using NMR spectroscopy, however, multivariate analysis of the products suggested that there was no significant difference in metabolites between the European extracts tested but differences were observed when compared to non-European products or products that used hexane as the extraction solvent. It is possible to identify marker compounds in saw palmetto using proton-NMR spectroscopy.