Induction of naphthoquinone formation in Impatiens balsamina cell suspension cultures

Pharkphoom Panichayupakaranant, Asst. Prof., D. of Pharmacognosy and Pharmaceutical Botany, F. of Pharmaceutical Sci., PSU.
Pramote Pannueng, D. of Pharmacognosy and Pharmaceutical Botany, F. of Pharmaceutical Sci., PSU.

Presented : The 4th NRCT-JSPS Joint Seminar in Pharmaceutical Sciences, "Drug Development through Biopharmaceutical Sciences, November 24-26, 1998, Hat Yai, Songkhla
Key words : naphthoquinone formation, Impatiens balsamina, cell suspension cultures

Cell suspension cultures of Impatiens balsamina have been established in order to study their ability to biosynthesize secondary metabolites. It has been reported that I. balsamina cell cultures were capable of producing coumarin derivatives, scopoletin and isofraxidin, some of which was re-leased into the culture medium. The cell cultures, however, could not produce any naphthoquinone such as lawsone and 2-methoxy-1,4-naphthoquinone which were accumulated in the intact plants. To induce the naphthoquinone formation in I. balsamina cell cultures, the parent plant with high yielding of 2-methoxy-1,4-naphthoquinone was selected and used for an initiation of the suspension cultures in B5 medium suplemented with 0.1 mgl^-1 2,4-D and 1.0 mgl^-1 kinetin. Based on this strategy, the ceil cultures with a red colour were obtained. These cell cultures were capable of producing two naphthoquinones, lawsone and an unknown compound which was more polar than lawsone. 2-me-thoxy-1,4-naphthoquinone, however, was not detected in the cell cultures.

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