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Deuterium‐labelled brassinosteroids, namely [26,28‐2H6]castasterone, 8 , and [26,28‐2H6]brassinolide, 9 , were synthesized starting from 6,6‐ ethylenedioxy‐20‐formyl‐2α,3α‐isopropylidenedioxy‐5α‐pregnane, 1 , and 3‐[2H3]methyl‐but‐1‐yne‐[4,4,4‐2H3], 11 . Upon alkylating cleavage of the epoxide 6 with trimethylaluminium‐n‐butyllithium an unusual migration of a neighbouring [2H3]methyl group takes place to afford deuteriation at positions 26 and 28.

Recent cell culture experiments indicated that extracts of Vitex agnus-castus (VAC) may contain yet unidentified phytoestrogens. Estrogenic actions are mediated via estrogen receptors (ER). To investigate whether VAC compounds bind to the currently known isoforms ERα or ERß, ligand binding assays (LBA) were performed. Subtype specific ER-LBA revealed a binding of VAC to ERß only. To isolate the ERß-selective compounds, the extract was fractionated by bio-guidance. The flavonoid apigenin was isolated and identified as the most active ERß-selective phytoestrogen in VAC. Other isolated compounds were vitexin and penduletin. These data demonstrate that the phytoestrogens in VAC are ERß-selective.

From the ethyl acetate extract of the tuberous roots of Ophiopogon japonicus (Liliaceae) eight known and five new homoisoflavonoidal compounds were isolated. The new compounds are 5,7-dihydroxy-8-methoxy-6-methyl-3-(2′-hydroxy-4′-methoxybenzyl)chroman-4-one (1), 7-hydroxy-5,8-dimethoxy-6-methyl-3-(2′-hydroxy-4′-methoxybenzyl)chroman-4-one (2), 5,7-dihydroxy-6,8-dimethyl-3-(4′-hydroxy-3′-methoxybenzyl)chroman-4-one (3), 2,5,7-trihydroxy-6,8-dimethyl-3-(3′,4′-methylenedioxybenzyl)chroman-4-one (4) and 2,5,7-trihydroxy-6,8-dimethyl-3-(4′-methoxybenzyl)chroman-4-one (5). Their structures have been elucidated by mass and NMR spectroscopy. Compounds 4 and 5 are the first isolated homoisoflavonoids with a hemiacetal function at position 2.Five new and eight known homoisoflavonoids were isolated from the tuberous roots of the medicinal plant Ophiopogon japonicus (Liliaceae) and identified by spectroscopic data.

The aminocoumarin antibiotic coumermycin A1 produced by Streptomyces rishiriensis DSM 40489 contains two amide bonds. The biosynthetic gene cluster of coumermycin contains a putative amide synthetase gene, couL , encoding a protein of 529 amino acids. CouL was overexpressed as hexahistidine fusion protein in Escherichia coli and purified by metal affinity chromatography, resulting in a nearly homogenous protein. CouL catalysed the formation of both amide bonds of coumermycin A1, i.e. between the central 3‐methylpyrrole‐2,4‐dicarboxylic acid and two aminocoumarin moieties. Gel exclusion chromatography showed that the enzyme is active as a monomer. The activity was strictly dependent on the presence of ATP and Mn2+ or Mg2+. The apparent K m values were determined as 26 µm for the 3‐methylpyrrole‐2,4‐dicarboxylic acid and 44 µm for the aminocoumarin moiety, respectively. Several analogues of the pyrrole dicarboxylic acid were accepted as substrates. In contrast, pyridine carboxylic acids were not accepted. 3‐Dimethylallyl‐4‐hydroxybenzoic acid, the acyl component in novobiocin biosynthesis, was well accepted, despite its structural difference from the genuine acyl substrate of CouL.