Title: Biotransformation of 6-Deoxotyphasterol in a Liverwort, Marchantia polymorpha
Abstract:A series of our researches revealed that a Bryophyte, Marchantia polymorpha, contained steroidal plant hormones, collectively named brassinosteroids (BRs), such as 6-deoxocastasterone (7), castasteron...A series of our researches revealed that a Bryophyte, Marchantia polymorpha, contained steroidal plant hormones, collectively named brassinosteroids (BRs), such as 6-deoxocastasterone (7), castasterone (8) and brassinolide (9),1,2 and potent biosynthetic precursors of the BRs, campesterol (1) and campestanol (2).3 Together with demonstrating the presence of a biosynthetic sequence, 7 -8 -9, the result strongly suggested that a biosynthetic pathway from 1 to 9 via 2, 7 and 8, so called the C6-oxidation pathway found in higher plants,4-8 is operative to produce BRs in the lower plants (Fig. 1).9Nevertheless, biosynthetic intermediates between 2 and 7 in the C6-oxidation pathway have not been identified from the lower plant, so that the precise pathway to synthesize 7 from 2 in M. polymorpha still remains to be elucidated.This prompted us to investigate in vivo and in vitro conversion(s) of [26, 28-2瓦]-and [2H°]-6-deoxotyphasterol ( 6), a potent biosynthetic precursor of 7, in cultured cells of M. polymorpha in this study,10,11 which gives information on biosynthetic processes for A-ring hydroxyl ation to produce the BRs identified from the lower plant.First, [2H6]-6 was fed to the media of suspension cultured cells of M. polymorpha to investigate in vivo conversion of 6 in the lower plant.After incubation for 7 days, the cells were harvested and extracted with 80% methanol followed by chloroform.The extract was reduced to aqueous phase, combined with the media, and purified by column chromatoRead More