| Yang LM |
------>authors3_c= ------>paper_class1=1 ------>Impact_Factor=2.417 ------>paper_class3=2 ------>paper_class2=1 ------>vol=68 ------>confirm_bywho=hsu0320 ------>insert_bywho=hsu0320 ------>Jurnal_Rank=16.3 ------>authors4_c= ------>comm_author= ------>patent_EDate=None ------>authors5_c= ------>publish_day=1 ------>paper_class2Letter=None ------>page2=570 ------>medlineContent= ------>unit=G0200 ------>insert_date=20070331 ------>iam=2 ------>update_date=None ------>author=??? ------>change_event=4 ------>ISSN= ------>authors_c= ------>score=500 ------>journal_name=Phytochemistry ------>paper_name=Microbial Metabolism of Steviol and Steviol-16alpha,17-epoxide ------>confirm_date=20071220 ------>tch_id=074001 ------>pmid=17207824 ------>page1=562 ------>fullAbstract=Steviol (2) possesses a blood glucose-lowering property. In order to produce potentially more- or less-active, toxic, or inactive metabolites compared to steviol (2), its microbial metabolism was investigated. Incubation of 2 with the microorganisms Bacillus megaterium ATCC 14581, Mucor recurvatus MR 36, and Aspergillus niger BCRC 32720 yielded one new metabolite, ent-7alpha,11beta,13-trihydroxykaur-16-en-19-oic acid (7), together with four known related biotransformation products, ent-7alpha,13-dihydroxykaur-16-en-19-oic acid (3), ent-13-hydroxykaur-16-en-19-alpha-d-glucopyranosyl ester (4), ent-13,16beta,17-trihydroxykauran-19-oic acid (5), and ent-13-hydroxy-7-ketokaur-16-en-19-oic acid (6). The preliminary testing of antihyperglycemic effects showed that 5 was more potent than the parent compound (2). Thus, the microbial metabolism of steviol-16alpha,17-epoxide (8) with M. recurvatus MR 36 was continued to produce higher amounts of 5 for future study of its action mechanism. Preparative-scale fermentation of 8 yielded 5, ent-11alpha,13,16alpha,17-tetrahydroxykauran-19-oic acid (10), ent-1beta,17-dihydroxy-16-ketobeyeran-19-oic acid (11), and ent-7alpha,17-dihydroxy-16-ketobeyeran-19-oic acid (13), together with three new metabolites: ent-13,16beta-dihydroxykauran-17-acetoxy-19-oic acid (9), ent-11beta,13-dihydroxy-16beta,17-epoxykauran-19-oic acid (12), and ent-11beta,13,16beta,17-tetrahydroxykauran-19-oic acid (14). The structures of the compounds were fully elucidated using 1D and 2D NMR spectroscopic techniques, as well as HRFABMS. In addition, a GRE (glucocorticoid responsive element)-mediated luciferase reporter assay was used to initially screen the compounds 3-5, and 7 as glucocorticoid agonists. Compounds 4, 5 and 7 showed significant effects. ------>tmu_sno=None ------>sno=14783 ------>authors2=Hsu FL ------>authors3=Chang SF ------>authors4=Cheng JT ------>authors5=Hsu JY ------>authors6=Hsu CY, Liu PC, Lin SJ ------>authors6_c= ------>authors=Yang LM ------>delete_flag=0 ------>SCI_JNo=None ------>authors2_c= ------>publish_area=0 ------>updateTitle=Microbial metabolism of steviol and steviol-16alpha,17-epoxide. ------>language=2 ------>check_flag=None ------>submit_date=None ------>country=None ------>no= ------>patent_SDate=None ------>update_bywho=None ------>publish_year=2007 ------>submit_flag=None ------>publish_month=1 |