Editorial 21

25-Dihydrosaframycin A(AR1) and 21-decyano-25-dihydrosaframycin A(AR3) were produced by the microbial conversion of saframycin A(SA). Efficient conversion of SA to AR, and AR3 was observed with Rhodococcus amidophifus IFM 144. Though the antimicrobial activity of AR, was one tenth that of SA, the in vitro antitumor activity of AR1 was found to be equivalent to that of SA. In contrast, AR, was b...