INDUCTION OF ROSMARINIC ACID BIOSYNTHESIS IN LITHOSPERMUM-ERYTHRORHIZON CELL-SUSPENSION CULTURES BY YEAST EXTRACT

A transient increase in rosmarinic acid (RA) content in cultured cells of Lithospermum erythrorhizon was observed after addition of yeast extract (YE) to the suspension cultures, reaching a maximum at 24 hr. The highest increase of the RA content (2.5-fold) was obtained when 6-day-old cells in the exponential growth phase were with YE. Preceding the induced RA accumulation, phenylalanine ammonia-lyase (PAL) activity increased rapidly, whereas tyrosine aminotransferase (TAT) activity was largely unaffected by the treatment. The incorporation of both C-14-phenylalanine and C-14-tyrosine into RA was enhanced in the YE-treated cells, consistent with increased synthesis of the ester.