Fatty acids, essential oil and phenolics composition of Silybum marianum seeds and their antioxidant activities

Abstract

The presentstudydescribes the biochemical evaluation of Silybum marianum seed. The analysis of essential oil composition of Silybum marianum seed by Gas Chromatography-Mass Spectrometry GC-MS showed the presence of14 volatile components with the predominance of γ-cadinene (49.8%) and α-pinene (24.5%). Whereas, the analysis of fatty acids composition, showed the predominance of linoleic (50.5%) and oleic (30.2%) acids. Silybum marainum presented also an important polyphenol contents with 29mgGAE/g DW, a good antiradical activity (CI(50)=39μg/ml) but a lower reducing power ability. Flavonoid and condensed tannin contents were about 3.39mg EC/g DW and 1.8mg EC/gDW, respectively. The main phenolic compounds identified by RP-HPLC, were silybin A (12.2%), silybin B (17.67%), isosilybin A (21.9%), isosilybin B (12.8%), silychristin (7.9%) andsilydianin (7.5%).