LC–SPE–NMR–MS analysis of Strychnos usambarensis fruits from Rwanda

in Phytochemistry Letters (2012), 5(0), 170-173

The novelty of the present work lies in the characterization of akagerine and palicoside in Strychnos usambarensis fruits by a hyphenated analytical method combining high-performance liquid chromatography ... [more ▼]

The novelty of the present work lies in the characterization of akagerine and palicoside in Strychnos usambarensis fruits by a hyphenated analytical method combining high-performance liquid chromatography coupled with solid-phase extraction (SPE), mass spectrometry (HPLC–MS) and NMR spectroscopy. Akagerine was already known in S. usambarensis roots but palicoside is described for the first time in the species. [less ▲]

17-O-Actetyl-10-hydroxycorynantheol, a selective antiplasmodial alkaloid isolated from Strychnos usambarensis leaves

Conference (2011, December 13)

In the course of our investigations on Strychnos usambarensis leaves in order to isolate isostrychnopentamine, the main alkaloid responsible for the antiplasmodial activity of the plant, a new tertiary ... [more ▼]

In the course of our investigations on Strychnos usambarensis leaves in order to isolate isostrychnopentamine, the main alkaloid responsible for the antiplasmodial activity of the plant, a new tertiary indolic alkaloid has been isolated: 17-O-acetyl, 10-hydroxycorynantheol 1. Its structure was determined by means of spectroscopic and spectrometric methods such as UV, IR, CD, NMR and ESI-MS. 17-O-acetyl, 10-hydroxycorynantheol 1 is one of the most active monomeric indole alkaloid known to date showing an in vitro activity against Plasmodium falciparum close to 5 µM and a high selectivity. [less ▲]

17-O-acetyl, 10-hydroxycorynantheol, a selective antiplasmodial alkaloid isolated from Strychnos usambarensis leaves

Conference (2011, May 13)

In the course of our investigations on Strychnos usambarensis leaves in order to isolate isostrychnopentamine, the main alkaloid responsible for the antiplasmodial activity of the plant, a new tertiary ... [more ▼]

In the course of our investigations on Strychnos usambarensis leaves in order to isolate isostrychnopentamine, the main alkaloid responsible for the antiplasmodial activity of the plant, a new tertiary indolic alkaloid has been isolated: 17-O-acetyl, 10-hydroxycorynantheol 1. Its structure was determined by means of spectroscopic and spectrometric methods such as UV, IR, CD, NMR and ESI-MS. 17-O-acetyl, 10-hydroxycorynantheol 1 is one of the most active monomeric indole alkaloid known to date showing an in vitro activity against Plasmodium falciparum close to 5 µM and a high selectivity. [less ▲]

LC-SPE-NMR-MS analysis of Strychnos usambarensis fruits from Rwanda

in Planta Medica (2010, September), 76(12), 1241-1242

Application of experimental design and design for the separation of compounds extracted from the leaves of Strychnos Usambarensis

Poster (2010, September)

Metabolomic investigation of the ethnopharmacological use of Artemisia afra with NMR Spectroscopy and Multivariate Data Analysis.

in Journal of Ethnopharmacology (2010), 128

Ethnopharmacological relevance: Artemisia afra has been used as an infusion to treat malaria throughout the southern parts of Africa, in much the same way as the antimalarial plant Artemisia annua in ... [more ▼]

Ethnopharmacological relevance: Artemisia afra has been used as an infusion to treat malaria throughout the southern parts of Africa, in much the same way as the antimalarial plant Artemisia annua in China. The antiplasmodial activity of purified components from an apolar fraction of A. afra has been shown in the past. No data on the efficacy of the tea infusion prepared from A. afra are however available. OBJECTIVE: To investigate the antiplasmodial activity of various extracts of A. afra including an ethnopharmacological prepared sample. To identify polar metabolites in A. afra and A. annua and by using multivariate data analysis investigate the metabolic differences between these species. Materials and methods: The antiplasmodial activity of A. afra and A. annua extracts were tested for activity against Plasmodiam falciparum 3D7 (chloroquine-sensitive strain) with chloroquine, quinine and artemisinin as positive controls. Hydrophilic metabolites in A. afra and A. annua were identified directly from the crude extracts through 1D- and 2D-NMR spectra. The NMR spectra were also used to differentiate between the two species using principal component analysis (PCA) for quality control purposes. RESULTS: The apolar fractions of both A. afra and A. annua showed activity against P. falciparum while activity was only found in the tea infusion of A. annua. Metabolomic studies using 1D- and 2D-NMR spectroscopy identified 24 semi-polar components in A. afra including three new phenylpropanoids for this species: caffeic acid, chlorogenic acid and 3,5-dicaffeoyl quinic acid. PCA analysis conducted on the samples yielded good separation between the polar extracts of A. afra and A. annua. CONCLUSION: These findings shows that there are no in vitro activity in the tea infusion of A. afra and lists the identified metabolites causing the metabolic differences between A. afra and A. annua for quality control purposes. [less ▲]

Screening of medicinal plants from Reunion Island for antimalarial and cytotoxic activity.

in Journal of Ethnopharmacology (2008), 120(3), 382-6

AIM OF THE STUDY: Nine plants from Reunion Island, selected using ethnopharmacology and chemotaxonomy, were investigated for their potential antimalarial value. MATERIALS AND METHODS: Thirty-eight ... [more ▼]

AIM OF THE STUDY: Nine plants from Reunion Island, selected using ethnopharmacology and chemotaxonomy, were investigated for their potential antimalarial value. MATERIALS AND METHODS: Thirty-eight extracts were prepared by maceration using CH(2)Cl(2) and MeOH, and were tested for in vitro activity against the 3D7 and W2 strain of Plasmodium falciparum. The most active extracts were then tested for in vitro cytotoxicity on human WI-38 fibroblasts to determine the selectivity index. Those extracts were also investigated in vivo against Plasmodium berghei infected mice. RESULTS: Most active of the extracts tested were the dichloromethane leaves extracts of Nuxia verticillata Lam. (Buddlejaceae), Psiadia arguta Voigt. (Asteraceae), Lantana camara L. (Verbenaceae), the methanol extracts from Aphloia theiformis (Vahl) Benn. (Aphloiaceae) bark, and Terminalia bentzoe L. (Combretaceae) leaves displaying in vitro IC(50) values ranging from 5.7 to 14.1mug/ml. Extracts from Psiadia, Aphloia at 200mg/(kgday) and Teminalia at 50mg/(kgday) also exhibited significant (p<0.0005) parasite inhibition in mice: 75.5%, 65.6% and 83.5%, respectively. CONCLUSION: Two plants showed interesting antimalarial activity with good selectivity: Aphloia theiformis and Terminalia bentzoe. Nuxia verticillata still needs to be tested in vivo, with a new batch of plant material. [less ▲]