Stimulation of shikonin production by combined fungal elicitation and in situ extraction in suspension cultures of Arnebia euchroma

In this paper, the effects of fungal elicitors, which were prepared from Aspergillus niger and Rhizopus oryzae, on shikonin production were studied during suspension cultures of Arnebia euchroma in Erlenmeyer flasks. The rapid induction and increased shikonin production could be obtained by adding the fungal elicitors to the culture medium. A shikonin maximal concentration of 89.75 mg l(-1) was achieved by adding Rhizopus oryzae elicitors on the 6th day in suspension cultures of Arnebia euchroma. This was 2.24 times higher than that of ordinary culture without elicitors; moreover, by combined fungal elicitation and in situ extraction in suspension cultures of Arnebia euchroma, a maximal shikonin concentration of 245.68 mg l(-1) was obtained in a batch culture. The production of shikonin was 6.15-fold higher than that obtained in a control culture. These results indicated that the simultaneous use of in situ extraction and elicitation cell treatment had a synergistic effect on the stimulation of shikonin production. (C) 1999 Elsevier Science Inc.