Engineering of acyl ligase domain in non-ribosomal peptide synthetases to change fatty acid moieties of lipopeptides.

Cyclic lipopeptides (CLPs) produced by the genus Bacillus are amphiphiles composed of hydrophilic amino acid and hydrophobic fatty acid moieties and are biosynthesised by non-ribosomal peptide synthetases (NRPSs). CLPs are produced as a mixture of homologues with different fatty acid moieties, whose length affects CLP activity. Iturin family lipopeptides are a family of CLPs comprising cyclic heptapeptides and β-amino fatty acids and have antimicrobial activity.

HPLC analysis of ammonium glycyrrhizate listed in the European, United States, and Japanese Pharmacopoeias under reported and modified conditions: revision of the peak assignment for 18α-glycyrrhizin in the European and United States Pharmacopoeias.

We examined ammonium glycyrrhizate listed in the monographs of the European Pharmacopoeia (EP) and United States Pharmacopoeia (USP) as well as in the reagents and solutions used in the general test of the Japanese Pharmacopoeia by performing HPLC on their sample standards or reference reagents under reported and modified conditions. Comparative experiments involving five authentic samples, namely, 18β-glycyrrhizin (1), 18α-glycyrrhizin (2), licorice-saponin G2 (3), licorice-saponin H2 (4), and galacturonic acid-replaced glycyrrhizin (the 4″-epimer of 18β-glycyrrhizin) (5), led us to propose the revision of the peak assignment of 18α-glycyrrhizin (2) and postscript a possible co-existence of galacturonic acid-replaced glycyrrhizin (5) as a hidden component in the EP and USP. We also proposed that the α-configuration used in the nomenclature of the glycosidic bond between aglycone and the sugar units of ammonium glycyrrhizate and impurities in the EP and USP should be revised to the β-configuration.

Is 18α-Glycyrrhizin a real natural product? Improved preparation of 18α-Glycyrrhizin from 18β-Glycyrrhizin as a positive standard for HPLC analysis of licorice extracts.

18α-Glycyrrhizin is an epimer of 18β-glycyrrhizin, a major component of licorice (Glycyrrhiza sp.), which is widely used as a traditional medicine. Whether 18α-glycyrrhizin is a real natural product has been debated in the long history of glycyrrhizin chemistry because 18β-glycyrrhizin is epimerizable to a more thermodynamically stable 18α-glycyrrhizin under aqueous alkali conditions.

Kaempferol from the leaves of Apocynum venetum possesses anxiolytic activities in the elevated plus maze test in mice.

The present work evaluated the anxiolytic activity of an aqueous extract of Apocynum venetum L. (Apocynaceae) and bioguided its fractionation using the elevated plus maze (EPM) in mice as a model of anxiety. A single treatment of AV extract markedly increased the percentage time spent on the open arms of the EPM in two distinct concentration ranges of 22.

Constituents from leaves of Apocynum venetum L.

An analysis using HPLC-MS revealed that an extract from dried leaves of Apocynum venetum L. contained more than 15 kinds of phenolic constituents. Two malonated flavonol glycosides were further isolated, and their structures were determined to be quercetin 3-O-(6''-O-malonyl)-beta-D-glucoside (1) and quercetin 3-O-(6''-O-malonyl)-beta-D-galactoside (2) by NMR spectroscopic analysis.

Bisindole alkaloids from myxomycetes Arcyria denudata and Arcyria obvelata.

A new bisindole sulfate (1) and arcyroxocin B (2) were isolated from wild fruiting bodies of Arcyria denudate, along with three known bisindoles (4-6). Dihydroarcyriacyanin A (3) was obtained from wild fruiting bodies of Arcyria obvelata, along with a known bisindole (7). The structures of these compounds were elucidated on the basis of spectroscopic data, and this is the first report of full characterizations of arcyroxocin B (2) and dihydroarcyriacyanin A (3).

New bisindole alkaloids isolated from Myxomycetes Arcyria cinerea and Lycogala epidendrum.

Two new bisindole alkaloids, named cinereapyrrole A (1) and B (2), were isolated from wild fruit bodies of Arcyria cinerea and three new bisindole alkaloids (3-5) were isolated from wild fruit bodies of Lycogala epidendrum. Seven known bisindoles (6-12) were concomitantly obtained from them. The structures of the new compounds were elucidated by spectral data.