Dieudonné Njamen

Learn More
Hyphenated techniques and especially ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) are nowadays widely employed in natural products research. However, the complex nature of plant extracts complicates considerably the analysis and the identification of their constituents. Nevertheless, new MS analyzers with increased resolving(More)
The MeOH stem bark extract of Erythrophleum suaveolens dissolved in water and shaken up with ethylacetate (EtOAc) and fractionated on a polyamide column with methanol as eluent produced five principal fractions. These fractions were designated as fraction A (74.8 mg yield and rich in alkaloids), fraction B (36.6 mg), fraction C (7.8 mg yield, monomeric(More)
Two prenylated flavanones isolated from Erythrina sigmoidea Hua (sigmoidin A and sigmoidin B) were studied for their ability to inhibit the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and arachidonic acid metabolism. In addition, the compounds were studied in two experimental models of inflammation induced in mouse ears by 12-(More)
A new sesquiterpene lactone, drypemolundein A and a new friedelane derivative, drypemolundein B, along with seven known compounds have been isolated from the whole stems of Drypetes molunduana Pax and Hoffm. Their structures were established on the basis of one- and two-dimensional NMR, homo- and hetero-nuclear spectroscopic evidence.
Phytochemical study on an EtOAc-soluble extract of the root bark of Erythrina mildbraedii resulted in the isolation of six prenylated flavonoids 1-6. Based on physicochemical and spectroscopic analyses, their structures were determined to be new natural products licoflavanone-4'-O-methyl ether (1), 2',7-dihydroxy-4'-methoxy-5'-(3-methylbut-2-enyl)isoflavone(More)
The prenylisoflavone warangalone has been isolated from the bark of Erythrina addisoniae. This compound, previously recognized as a powerful inhibitor of protein kinase A, showed marked effectiveness as an anti-inflammatory on the phospholipase A(2)-induced paw edema and on the 12-O-tetradecanoylphorbol 13-acetate-induced ear edema in mice, after systemic(More)
Erythrina poeppigiana is a medicinal plant which is widely used in Asia, Latin America, and Africa in traditional remedies for gynecological complications and maladies. In continuation of studies for the discovery of novel phytoestrogens, four erythroidine alkaloids, namely α-erythroidine, β-erythroidine, and their oxo-derivatives 8-oxo-α-erythroidine and(More)
Approximately 80 % of the population in Africa use traditional medicinal plants to improve their state of health. The reason of such a wide use of medicinal plants has been mainly attributed to their accessibility and affordability. Expectation of little if any side effects, of a "natural" and therefore safe treatment regimen, as well as traditional beliefs(More)
In most developing countries, 70-80% of the population still resort to traditional medicine for their primary health care. This medicine utilises medicinal plants which are traditionally taken as concoction and infusion. The root and stem bark of Millettia griffoniana (Leguminosae), has been reported to contain isoflavonoids, alkaloids, and diterpenoids.(More)
A new isoflavone, griffonianone D (1), and the previously known compounds durmillone and odorantin were isolated from a chloroform extract of the root bark of Millettia griffoniana. The structure of 1 was established as (7E)-(6",7"-dihydroxy-3",7"-dimethyloct-2"-enyl)oxy-4'-methoxyisoflavone on the basis of its spectral data. The chloroform extract of the(More)