Elicitor-enhanced Silymarin production in hairy root cultures of Silybum marianum L. Gaertn

Abstract

Silymarin is an antihepatotoxic polyphenolic substance isolated from the milke thistle (Silybum marianum) plant [1]. Hairy roots cultures of S. marianum produce silymarin. In an attempt to increase productivity, the effect of yeast extract was tested. The hairy roots induced by inoculation of leaf explants with A. rhizogenes (AR15834). One month old hairy roots were dissected from the explants and growth in the Erlenmeyer flask containing 50ml MS liquid medium [2]. PCR analysis using rolb gene and GUS assay were used for identification of transformed hairy roots [3]. The presences of flavonolignans in the hairy roots were determined by high-performance liquid chromatography (HPLC). There were five isolated components; taxifolin, silychristin, silydianin, silybin and isosilybin and the major flavonolignan was silybin that has not been reported in previous published work. For increasing the growth rate of hairy roots, effects of NAA, IBA and IAA (0.1, 0.5 and 1mg/L) were tested. The best media was achieved by 0.5mg/L NAA. Elicitation was carried out with yeast extract (0, 0.5, 1, 2.5 and 5mg/L) and different exposure times (24, 48 and 72h). The highest silymarin content (0.476mg/g DW) was obtained by 2.5mg/mL yeast extract, after 72h. This study indicates that elicitor treatment promotes silymarin production in hairy root culture of S. marianum.