Production of kavapyrones by Kava (Piper methysticum) tissue cultures

Kava (Piper methysticum) is extensively used for the generation of a ceremonial intoxicating beverage in South Pacific Island cultures and for the production of a sedating phytomedicine worldwide. Callus cultures were successfully initiated from shoot explants of Kava cvs. Makea and Awke and from leaf explants of cv. Awke. Bacterial and fungal contamination were decreased by multiple steps of tissue sterilization and the inclusion of a biocide in the medium. The production of kavapyrones by the Kava callus cultures was measured relative to the levels of these chemicals generated by intact plant tissues. The results showed that total kavapyrone production in callus cultures was less than 1% of that observed for root tissue from which the phytomedicine and intoxicating beverage is typically produced. Although callus cultures were initiated from stem and leaf explant materials, the corresponding callus cultures yielded a relative pattern of kavapyrone production similar to that of root extracts, with kavain and methysticin present as the predominate kavapyrones. This differed from stem tissues and the reported values for leaf tissues, where dihydrokavain and dihydromethsticin represent the predominant kavapyrones.