The absolute configurations of halogenated chamigrene derivatives from the marine alga, laurencia glandulifera kützing

The absolute configurations of halogenated chamigrene derivatives, isolated from L. glandulifera Kützing, 10-bromo-3,4-epoxy-α-chamigrene (1), glanduliferol (2), 10-bromo-α-chamigren-4-one (3), 4,10-dibromo-3-chloro-α-chamigrene (4) and 10-bromo-α-chamigrene (5), have been determined by X-ray diffraction analysis of 1 and subsequently, by relating 2, 3, 4 and 5 to 1 with the chemical methods. In addition, the absolute configuration of (?)-α-chamigrene (6), yielded on the process of the above chemical transformation, has been elucidated.     

The structure of spirolaurenone,a halogenated sesquiterpenoid from the red alga laurencia glandulifera kützing

The structure of spirolaurenone (1), a halogenated metabolite isolated from the red alga Laurencia glandulifera Kützing, was determined on the basis of the chemical and spectroscopic evidence. The absolute configuration of spirolaurenone (1) was established as shown in formula 1 by the chemical correlation with glanduliferol (18), a halo-chamigrene derivative isolated from the same alga.     

The structure of laurobtusol, a new rearranged sesquiterpenoid from the mediterranean red alga laurencia obtusa

An alcohol with a new tricyclic humulane skeleton, laurobtusol was isolated from the Mediterranean Red Alga Laurencia obtusa. The structure was established mainly by 2 D NMR methods and the relative configuration was assigned by a quantitative computer simulation of the lanthanide induced shifts in the ¹H NMR spectrum and Molecular Mechanics calculation (MM2).     

New Xanthones from Polygala crotalarioides

Introduction Xanthonesaresecondarymetabolitescommonly occurringinafewhigherplantfamilies,fungiandli chen.Theirhightaxonomicvalueinsuchfamiliesand theirpharmacologicalproperties,includinginvitrocy totoxicity,invivoantitumouractivity,antifungal,anti bacteri…     

Enzymatic synthesis of bioactive compounds by Rhus laccase from Chinese Rhus vernicifera

A simple one step synthesis of pinoresinol and its derivatives-active components of Du-Zhong (Eucommia ulmoides)-from coniferyl alcohol and p-courmaryl alcohol with higher yields was achieved by Rhus laccases (RL) catalysis in water miscible organic solvents. Biomacromolecules dehydrogenative polymers (DHP) were only synthesized by fungal laccases, not by RL. The structures and the reaction mechanism were discussed to promote the understanding of the function of laccases in the process of lignin biosynthesis. Supported by the Research Project Grant A by Institute of Science & Technology, Meiji University, and the National Natural Science Foundation of China (Grant No. 30170757).     

New lignan glycosides from Glehnia littoralis

From the roots ethanol extract of Glehnia littoralis, two new lignan glycosides, named glehlinoside E （1） and F （2）, were obtained. Their structures were determined to be （-）-secoisolariciresinol 4-O-β-D-（6-O-feruloyl） glucopyranoside （1） and （-）- secoisolariciresinol 4-O-f-β-D-（6-O-caffeloyl） glucopyranoside （2） by analysis of their spectral data, respectively.     

Two new compounds from the stem of Vernonia cumingiana

Two new compounds vemonioside S and vemoniether S were isolated from the stem of Vernonia cumingiana, and their structures were elucidated on the basis of spectroscopic evidences.     

Phenolic compounds from the aqueous extract of Acacia catechu

From the aqueous extract of Acacia catechu,two new phenolic compounds(3R,4R)-3-(3,4-dihydroxyphenyl)-4-hydroxycy-clohexanone (1) and(4R)-5-(1-(3,4-dihydrophenyl)-3-oxobutyl)-dihydrofuran-2(3H)-one(2) were obtained.Their structures were determined on the basis of spectroscopic analysis.Free-radical scavenging activities of them were evaluated.