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8-Benzyloxymethyl-3,4,5-tribenzoyloxy-9-oxa-1-azabicyclo-[4.2.1]nonane was prepared as the single diastereoisomer from an intramolecular 1,3-dipolar cycloaddition of [omega]-unsaturated nitrones. The analogous 8-methoxycarbonyl-9-oxa-1-azabicyclo-[4.2.1]nonane was afforded from methyl D-galactopyranoside and methyl glyoxylate as 3:1 mixture of diastereoisomers.

Research explores the synthesis of cyclodextrin derivatives containing the same substituent for the hydroxyl groups at the 2-, 3-, and 6-position. Data discuss the electrophilic reaction mediating the production of the monoalkylated cyclodextrin derivatives.

A novel approach for the unambiguous identification of regioisomers in selectively altered beta-cyclodextrins was presented. The utility of the method was demonstrated in three regioisomers in which the same group (4-methylamino-3-nitrobenzyl) is linked to the 2-, 3- or 6-position. The procedure uses two sets of experiments, namely, a selective long-range INEPT experiment and a two-dimensional heteronuclear multiple bond correlation experiment. It is applicable to modified cyclodextrins in which the substituent is attached through a -CH- or -CH(sub 2)- group.

Techniques for the modification of cyclodextrins, particularly those in which the number and the exact locations of modifications are known and pure compounds with unambiguous structures are derived, are reviewed. Methods involved in primary face modification include monosubstitution at the 6-position of cyclodextrins, disubstitution at the 6-position of cyclodextrins and trisubsitution at the 6-position of cyclodextrins. Techniques involving secondary face modification include monosubstitution at the 2-position of cyclodextrins and disubstitution at the 2-position of cyclodextrins.

Two-dimensional nuclear magnetic resonance spectrometry, restrained simulated annealing and molecular dynamics calculations were used to study the structure and dynamics of the peptidoglycan monomer obtained from Brevibacterium divaricatum. It was found that both the interglycosidic and glycopeptide linkages exist in a single, well-defined conformation and that no conformational changes occur during its simulations with molecular dynamics.

Abstract Background Bryophyllum pinnatum (Lank.) Oken (Crassulaceae) is a perennial succulent herb widely used in traditional medicine to treat many ailments. Its wide range of uses in folk medicine justifies its being called "life plant" or "resurrection plant", prompting researchers' interest. We describe here the isolation and structure elucidation of antimicrobial and/or antioxidant components from the EtOAc extract of B. pinnatum. Results The methanol extract displayed both antimicrobial activities with minimum inhibitory concentration (MIC) values ranging from 32 to 512 μg/ml and antioxidant property with an IC50 value of 52.48 μg/ml. Its partition enhanced the antimicrobial activity in EtOAc extract (MIC = 16-128 μg/ml) and reduced it in hexane extract (MIC = 256-1024 μg/ml). In addition, this process reduced the antioxidant activity in EtOAc and hexane extracts with IC50 values of 78.11 and 90.04 μg/ml respectively. Fractionation of EtOAc extract gave seven kaempferol rhamnosides, including; kaempferitrin (1), kaempferol 3-O-α-L-(2-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (2), kaempferol 3-O-α-L-(3-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (3), kaempferol 3-O-α-L-(4-acetyl)rhamnopyranoside-7-O-α-L-rhamnopyranoside (4), kaempferol 3-O-α-D- glucopyranoside-7-O-α-L-rhamnopyranoside (5), afzelin (6) and α-rhamnoisorobin (7). All these compounds, except 6 were isolated from this plant for the first time. Compound 7 was the most active, with MIC values ranging from 1 to 2 μg/ml and its antioxidant activity (IC50 = 0.71 μg/ml) was higher than that of the reference drug (IC50 = 0.96 μg/ml). Conclusion These findings demonstrate that Bryophyllum pinnatum and some of its isolated compounds have interesting antimicrobial and antioxidant properties, and therefore confirming the traditional use of B. pinnatum in the treatment of infectious and free radical damages.

Phytochemical investigation of the whole plant of Filago vulgaris Lam. (Asteraceae) resulted in the isolation and characterization of seven compounds, including a rare methoxylated flavonol (araneol), tetrahydrofurofuranolignans (pinoresinol and syringaresinol), p-hydroxybenzaldehyde, vanillin, vanillic acid and scopoletin. The structures of the compounds were determined by NMR and mass spectroscopy. All compounds were first obtained from this species and reported for the genus Filago. Our results demonstrate that highly methoxylated flavonols lacking substituents on ring B and lignans can be regarded as taxonomic markers for the tribe Inuleae. The lipophilic extract of F. vulgaris was found to have antiproliferative activity against HeLa cells (62.1±0.9% inhibition at 30 µg/ml), and araneol was highly effective against this tumour cell line (IC50 8.36 M). [ABSTRACT FROM AUTHOR]