J Asian Nat Prod Res. 2003 Mar; 5(1): 5-10.

Biotransformation of 4(20),11-taxadienes by cell suspension cultures of Platycodon grandiflorum.

Dai JG, Guo HZ, Ye M, Zhu WH, Zhang DY, Hu Q, Han J, Zheng JH, Guo DA.

The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China.

Platycodon grandiflorum cell suspension cultures were employed to biotransform the taxane diterpenoids 2alpha,5alpha,10beta,14beta-tetraacetoxy-4(20),11-taxadiene (1) and 9alpha-hydroxy-2alpha,5alpha,10beta,14beta-tetraacetoxy-4(20),11-taxadiene (2). One product, 10beta-hydroxy-2alpha,5alpha,14beta-triacetoxy-4(20),11-taxadiene (3) was obtained from 1 and two products, 9alpha,10beta-dihydroxy-2alpha,5alpha,14beta-triacetoxy-4(20),11-taxadiene (4) and 10beta-hydroxy-2alpha,5alpha,9alpha,14beta-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.