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.

Keywords:

• Cytotoxic activity
• edible mushrooms
• fatty acids
• gas chromatography-mass spectrometry (GC-MS)
• Lactarius salmonicolor
• principal component analysis (PCA)
• steroids

Author contributions

Dilaycan Çam: methodology, conceptualization, investigation, formal analysis, fractionation of bioactive extract, GC-MS analyses, elucidation of compounds, writing drafts; Cansel Çakır: methodology, formal analysis for extraction; Ayşe Hale Karaman: methodology, formal analysis, investigation for cytotoxic activity; Amine Hafis Abdelsalam: methodology, formal analysis, investigation for cytotoxic activity; Yusuf Sıcak: methodology, investigation, elucidation of compounds, data curation of GC-MS results; Ilgaz Akata: collection and identification of mushroom material, resources; Sevki Arslan: methodology, formal analysis, investigation for cytotoxic activity, writing draft for cytotoxic activity results; Mehmet Öztürk: supervision, project administration, methodology, elucidation of compounds, data curation of GC-MS results, chemometric analyses, writing an original draft, writing—review and editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data will be made available upon request.

Additional information

Funding

This study is part of D.Ç.’s Master’s thesis and was supported by The Scientific and Technological Research Council of Turkey by project number TUBITAK 1001-121Z551 (Turkiye Bilimsel ve Teknolojik Arastirma Kurumu).