The role of Chitosan (low molecular weight) on elevation of flavonolignans production in Silybum marianum hairy root culture

Aim: The effect of chitosan (low molecular weight) as elicitor was evaluated on silymarin production and biochemical factors in hairy root cultures of Silybum marianum.
Material and Different concentrations of chitosan (0, 5, 10, 20 and 30 mg/50 ml of culture media) was added to hairy root cultures of S. marianum (30 days) and sampling were carried out after 12, 24, 48, 72, 96 and 120 hours. The silymarin level, activity of guaiacol peroxidase and ascorbate peroxidase as well as concentration of H2O2 were determined in the samples.
The results indicated that the highest dry weight was in cultures treated with 10 mg /50 ml culture chitosan after 48 and 96 h. Silymarin production was significantly increased from 0.37 in control to 1.19 mg g-1 dry weight in the treated samples, at which the increased level was 1.4-fold higher than the control. Guaiacol peroxidase was activated by chitosan and reaching a pick after 120 h (21.86 ∆OD g-1FW min-1) which was 2.2 fold higher than the control. The ascorbate peroxidase activity kept increasing until 96 h after elicitation (5.14 ∆ODg-1FW).
The results showed that the silymarin production has been promoted by chitosan (low molecular weight). Increased of enzymes activity occurs as a result of free radical elimination and represents a reaction to chitosan as a stress factor.