Isolation and Photoinduced Conversion of 6-<i>epi</i>-Stephacidins from <i>Aspergillus taichungensis</i>
作者:Shengxin Cai、Yepeng Luan、Xianglan Kong、Tianjiao Zhu、Qianqun Gu、Dehai Li
DOI:10.1021/ol400694h
日期:2013.5.3
Three prenylated indole alkaloids with a rare anti bicyclo-[2.2.2]diazaoctane core ring (5-7) were isolated from Aspergillus taichungensis. The structures including absolute configurations were elucidated based on NMR, X-ray, and CD methods. (+)-Versicolamides B and C (8-9) which contain a spiro-center, together with seven analogues (7, 10-15), were isolated as photoinduced conversion products of 6. Biological evaluation indicated that 6 and 7 exhibited significant cytotoxicities with IC50 values in the low micromolar range.
Flavin‐Dependent Monooxygenases NotI and NotI′ Mediate Spiro‐Oxindole Formation in Biosynthesis of the Notoamides
作者:Amy E. Fraley、Hong T. Tran、Samantha P. Kelly、Sean A. Newmister、Ashootosh Tripathi、Hikaru Kato、Sachiko Tsukamoto、Lei Du、Shengying Li、Robert M. Williams、David H. Sherman
DOI:10.1002/cbic.202000004
日期:2020.9
Common ancestor: We have investigated the enantiodivergent biosynthesis of the notoamides in phylogenetically related Aspergillus strains. NotI and NotI′ are responsible for generating the spirocyclic moiety, with preferential conversion of (−)‐stephacidin A, thus indicating evolutionary divergence from an ancestral strain.