Elicitor effect of chitosan and pectin on the biosynthesis of anthraquinones, phenolics and flavonoids in adventitious root suspension cultures of Morinda citrifolia (L.)

摘要

In this study, the effect of chitosan and pectin on the accumulation of anthraquinones (AQ), phenolics and flavonoids was investigated by adventitious root suspension cultures of Morinda citrifolia in shake flasks. Adventitious root cultures elicitor treated with various combinations of chitosan and pectin or chitosan alone resulted in enhanced biosynthesis of secondary metabolite but inhibited root growth. The strong inhibition of root growth might be due to the lethal effect of elicitor as evidenced by 36-79% cell death was measured. The optimum concentration of elicitor for enhancing metabolite biosynthesis was found at the concentration of 0.2 mg ml-1 chitosan, in which 103.16, 48.57 and 75.32 mg g-1 dry weight (DW) of AQ, phenolics and flavonoids, respectively were achieved. To elucidate the optimum contact period and reduction of inhibitory effect of chitosan on root growth, a two-stage culture system was adopted. The optimum contact period of root to elicitor was observed when adventitious culture was elicitor treated with 0.2 mg ml-1 chitosan on day 28 and harvest after 2 days of elicitation. Although, root growth slightly decreased by this treatment, the yield of AQ, phenolics and flavonoids was enhanced by 45%, 8% and 12%, respectively compared to without elicitor treated culture.