Characterization of the Cytotoxic Compounds of Lactarius salmonicolor R. Heim and Leclair by Gas Chromatography-Mass Spectrometry and Chemometrics

Abstract

The cytotoxic activities of apolar extract of Lactarius salmonicolor and its fractions and subfractions were screened against colon (CaCo-2), prostate (LNCaP), lung (H1299), and breast (MCF-7) cancerous cell lines. The main extract of Lactarius salmonicolor that was cytotoxic to CaCo-2 (EC50: 137.1 ± 2.7 µg/mL) and LNCap (EC50: 131.2 ± 2.6 µg/mL) mainly contains fatty acids (99.9%). To characterize the cytotoxic activity, it was fractionated by a silica gel column. Two cytotoxic fractions were re-fractionated to obtain subfractions. The extract, four cytotoxic fractions, and all subfractions were analyzed by gas chromatography-mass spectrometry (GC-MS). The GC-MS data and the cytotoxic activity (EC50) results were classified using principal component analyses (PCA). According to PCA, the cytotoxic fractions containing abundant benzoic acid (0.01%–0.35%), cinnamic acid (0.01%–0.36%), azelaic acid (0.01%–0.92%), 2,4-decadienal (0.01%–0.12%), (Z)-9-palmitoleic acid (0.01%–1.09%), 18-hydroxy 2,4-diene oleic acid (0.01%–26.71%), arachidic acid (0.01%–6.70%), desmosterol (0.01%–12.27%), and steroids (0.01%–9.51%) were clustered. LSP.9-10, which causes another cluster, is caused by 8,11,14- eicosatrienoic acid, 11,14,17-eicosatrienoic acid, 9(Z)-decenoic acid compounds, and saturated fatty acids with 10 and 16 carbons. Hence, these compounds may be responsible for the cytotoxic activity. This study demonstrates that GC-MS and chemometric analysis can identify the components responsible for biological activity in combination with biological activity data.