Helen Jacobs

PRENYLATED BENZOPHENONE DERIVATIVES FROM CARIBBEAN CLUSIA SPECIES (GUTTIFERAE). PLUKENETIONES B-G AND XEROPHENONE A

Abstract Six new prenylated benzophenone derivatives plukenetiones B-G (2–7) have been isolated from the fruits of the Barbadian plant Clusia plukenetii. These structures were elucidated by the use of 2D NMR spectroscopic methods. The regiochemistry of xerophenone A from Clusia portlandiana has been revised.

Plukenetione A. An unusual adamantyl ketone from Clusia plukenetii (guttiferae)

Abstract The structure of plukenetione A from Clusia plukenetii Urban has been shown by spectroscopic methods to be 1-benzoyl-8,8-dimethyl-3,5-bis(3-methyl-2-butenyl)-6-(2-methylpropenyl)tricyclo[3.3.1.1 3,7 ]decane-2,4,9-trione.

GLABRESCOL. A UNIQUE SQUALENE-DERIVED PENTA-THF DIOL FROM SPATHELIA GLABRESCENS (RUTACEAE)

Abstract The structure of glabrcscol from Spathelia glabrescens Planch has been shown by spcctroscopic methods to be a meso form of 2,23-dihydroxy-2,6,10,15, 19,23-hexamethyl-3,7,11,15,19-penta(oxacyclopentyl)tetracosane.

Application of the Folin-Ciocalteau reagent to the determination of salbutamol in pharmaceutical preparations

A method for the determination of salbutamol in both tablets and syrups is described. It utilizes the reduction of the Folin-Ciocalteau reagent by the phenolic group, monitoring the absorbance of the resulting complex at 760 nm. Results obtained are linear over the range 0-6 mug ml(-1) salbutamol. Coloring material was removed by anionexchange chromatography prior to analysis and there was no interference from sucrose, neutral flavorings or the common preservative sodium benzoate. This method appears suitable as a general assay for salbutamol.

A prenylated benzopyran derivative from peperomia clusiifolia

The structure of a new compound, clusifoliol, isolated from whole plants of Peperomia clusiifolia has been established as 3,4-dihydro-2,7-dimethyl-6-(3-methyl-2-butenyl)-2-(4-methyl-1,3-pentadienyl)-2H-1-benzopyran-5-ol by spectroscopic methods.

Cytochrome P450 1 enzyme inhibition and anticancer potential of chromene amides from Amyris plumieri.

Cytochrome P450 (CYP) enzyme inhibitory properties of six chromenylated amide compounds (CAs) from Amyris plumieri are described. Inhibition of CYP microsomes (CYP1A1, CYP1A2, CYP1B1, CYP2D6, CYP3A4 and CYP2C19) was monitored using a fluorescent assay. Potent inhibition was found against CYP1A1 with IC(50) and K(i) for CA1 (acetamide), being the lowest at 1.547 ± 1.0 μM and 0.37 μM respectively, displaying non-competitive kinetics. The selectivity for CYP1A1 was increased in CA3 (butanamide), which also exhibited cytotoxicity against breast cancer cells, MCF7 with an IC(50) of 47.46 ± 1.62 μM. Structure-activity relationship studies provide insight at a molecular level for CAs with implications in chemoprevention and chemotherapy.

On the structures of plukenetiones B, D, and E and their relationships to other polycyclic polyprenylated acylphloroglucinols

Abstract Three polycyclic polyprenylated benzoylphloroglucinol natural products, plukenetiones B, D, and E, are shown to be diastereomeric to the related compounds, nemorosone II and sampsonione G.

A short synthesis of 5-methoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoic acid methyl ester

Abstract 5-Methoxy-2,2-dimethyl-2H-1-benzopyran-6-propanoic acid methyl ester was prepared in five steps and approximately 20% overall yield from 2,4-dihydroxybenzaldehyde. The two key reactions are the chromenylation between the unchelated hydroxyl group and C-3 of the resbenzaldehyde and the demethoxycarbonylation-alkylation of dimethyl malonate with a quaternary ammonium iodide.

Xerophenones A and B. New isoprenylated derivatives of 11-oxatricyclo[4.3.1.14,10]undecane-7,9-dione from Clusia portlandiana (Guttiferae)

Abstract A tautomeric pair of new isoprenylated benzophenone derivatives incorporating a novel oxatricyclic skeleton has been isolated from Clusia portlandiana Howard & Proctor and the structures and relative configuration established by NMR methods.

Prenylated hydroxybenzoic acid derivatives from Piper murrayanum

The leaves of Piper murrayanum have yielded the (E) and (Z) isomers of 4-hydroxy-3-(3,7-dimethyl-1-oxo)-2,6-octadienylbenzoic acid, together with the known (E)-4-hydroxy-3-(3,7-dimethyl)-2,6-octadienylbenzoic acid and the chalcone, 1-(2-hydroxy-4,6-dimethoxy)phenyl-3-(4-hydroxy)phenyl-2-propen-1-one.