Absolute Configuration Of Metabolite Research Articles

A new [7.7]paracyclophane from Vietnamese marine snail Planaxis sulcatus (Born, 1780)

A new [7.7]paracyclophane (1), together with eight known compounds (2–9), were isolated from a MeOH extract of the sea snail Planaxis sulcatus (Born, 1780). Their structures were elucidated by HR-ESI-MS and NMR techniques as well as comparison with those reported in literatures. The absolute configuration of metabolite 1 was determined using ECD spectroscopy. Among nine compounds, 1 exhibited significant cytotoxicity toward all eight cancer cells tested with IC50 values between 1.81 and 3.80 µg/mL.

Cadinane-Type Sesquiterpenoids from Heterotheca inuloides: Absolute Configuration and Anti-inflammatory Activity.

Eight cadinane-type sesquiterpenoids (1-8) together with some triterpenoids, flavonoids, and sterols were isolated from the aerial parts of Heterotheca inuloides. The structures of the new compounds (1-4) were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis. The structures of the new (1-3) and the known (5-7) sesquiterpenoids were confirmed by X-ray crystallography. The absolute configurations of metabolites 2-5 were determined by comparing their experimental and calculated electronic circular dichroism spectra and confirmed via refinement of the Flack parameter using anomalous X-ray scattering from the oxygen atoms and chemical correlation methods. The sesquiterpenoids were evaluated for their anti-inflammatory potential by applying the TPA-induced mouse ear edema model. The results revealed that some of these metabolites exhibit moderate anti-inflammatory activity. At a dose of 228 μg/ear compound 1 showed 43.14 ± 8.09% inhibition on ear edema, indicating an IC50 > 228 μg/ear.

Isolation and structure elucidation of three new dolastanes from the brown alga Dilophus spiralis.

Three new dolastane diterpenes (1–3) and five previously reported perhydroazulenes were isolated from the organic extracts of the brown alga Dilophus spiralis. The structure elucidation and the assignment of the relative configurations of the isolated natural products were based on extensive analyses of their spectroscopic data, whereas the absolute configuration of metabolite 2 was determined through its chemical conversion to a previously isolated compound of known configuration.

Biphenyl dioxygenase-catalysed cis-dihydroxylation of tricyclic azaarenes: chemoenzymatic synthesis of arene oxide metabolites and furoquinoline alkaloids

Biotransformation of acridine, dictamnine and 4-chlorofuro[2,3-b]quinolone, using whole cells of Sphingomonas yanoikuyae B8/36, yielded five enantiopure cyclic cis-dihydrodiols, from biphenyl dioxygenase-catalysed dihydroxylation of the carbocyclic rings. cis-Dihydroxylation of the furan ring in dictamnine and 4-chlorofuro[2,3-b]quinoline, followed by ring opening and reduction, yielded two exocyclic diols. The structures and absolute configurations of metabolites have been determined by spectroscopy and stereochemical correlation methods. Enantiopure arene oxide metabolites of acridine and dictamnine have been synthesised, from the corresponding cis-dihydrodiols. The achiral furoquinoline alkaloids robustine, γ-fagarine, haplopine, isohaplopine-3,3′-dimethylallylether and pteleine have been obtained, from either cis-dihydrodiol, catechol or arene oxide metabolites of dictamnine.

Cytotoxic Halogenated Metabolites from the Brazilian Red Alga Laurencia catarinensis

Seven new (1-7) and seven previously reported (8-14) halogenated metabolites were isolated from the organic extract of the Brazilian red alga Laurencia catarinensis. The structure elucidation and the assignment of the relative configurations of the new natural products were based on detailed NMR and MS spectroscopic analyses, whereas the structure of metabolite 6 was confirmed by single-crystal X-ray diffraction analysis. The absolute configuration of metabolite 1 was determined using the modified Mosher's method. The in vitro cytotoxicity of compounds 1-14 was evaluated against HT29, MCF7, and A431 cell lines.

Processing of Cyclopropylarenes by Toluene Dioxygenase: Isolation and Absolute Configuration of Metabolites.

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Processing of cyclopropylarenes by toluene dioxygenase: isolation and absolute configuration of metabolites

Several arenes possessing a cyclopropyl substituent were subjected to enzymatic oxidation with toluene dioxygenase. The absolute configuration of metabolites was established by chemical means.

Enzymatic oxidation of thioanisoles: isolation and absolute configuration of metabolites

Oxidation of p-bromothioanisole with toluene dioxygenase provides the corresponding diene diol 2 in good yield. Electrochemical reduction of 2 gives access to diene diol 3, which is not accessible by direct bio-oxidation of thioanisole. Absolute configuration and enantiomeric purity are reported for the new metabolites.