BIOTRANSFORMATION OF 4(20),11-TAXADIENES BY CELL SUSPENSION CULTURES OF PLATYCODON GRANDIFLORUM.

Platycodon grandiflorum cell suspension cultures were employed to biotransform the taxane diterpenoids 2α,5α, 10β,14β-tetraacetoxy-4(20),11-taxadiene (1) and 9α-hydroxy-2α,5α,10β,14β-tetraacetoxy-4(20),11-taxadiene (2). One product, 10b-hydroxy-2α,5α,14β-triacetoxy-4(20),11-taxadiene (3) was obtained from 1 and two products, 9α,10β-dihydroxy-2α,5α,14β-triacetoxy-4(20),11-taxadiene (4) and 10β-hydroxy-2α,5α,9α,14β-tetraacetoxy-4( 20),11-taxadiene (5) were obtained from 2 incubated with Platycodon cultured cells respectively, among which 5 is characterized as a new taxoid compound. The effects of the addition stage for 1 and 2 on the biotransformation were investigated and the results revealed that: (1) the optimal addition stage for 1 was in the early logarithmic phase (6th day) of the cell growth period, in which 78% of 1 was converted and the yield for 3 reached 75%; (2) the optimal addition stage for 2 was on the mid-logarithmic phase (12th day) of the cell growth period, in which 25.3% of 2 was converted and the yields for 4 and 5 reached 18.9 and 14.5%, respectively. [ABSTRACT FROM AUTHOR]