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Biomedical subjects

B Weniger

Publications and source records attributed to B Weniger.

At least 19 recordsLinked to original sources
PubMed2006

In vitro antiprotozoal activities and cytotoxicity of some selected Cameroonian medicinal plants.

Eight extracts from seven selected Cameroonian medicinal plants, traditionally used to treat malaria and other protozoal diseases, were tested in vitro for their antiprotozoal activities against Plasmodium falciparum K1 chloroquine-resistant strain, Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei rhodesiense, protozoa responsible for malaria, visceral leishmaniasis, Chagas disease and African trypanosomiasis, respectively. The most active extract against Plasmodium falciparum K1 strain and Trypanosoma brucei rhodesiense was the methanolic extract of Albizia zygia (Fabaceae) stem bark with IC(50) values of 1.0 microg/ml and 0.2 microg/ml, respectively. Five extracts showed IC(50) values below 5mug/ml against Leishmania donovani, with the methanolic seed extract of Harungana madagascarensis showing the highest activity, but only the methanolic extract of Albizia zygia showed activity against Trypanosoma cruzi. Cytotoxicity and selectivity indexes were estimated for the most active extracts. The best ratio of cytotoxicity to antiplasmodial activity (SI(a)=14) was established for the methanolic leaf extract of Symphonia globulifera (Clusiaceae), while the methanolic stem bark extract of Albizia zygia showed the best ratio of cytotoxicity to antitrypanosomal activity (SI(b)=22.5).

Albizzia↗
PubMed2005

Comparative antiplasmodial, leishmanicidal and antitrypanosomal activities of several biflavonoids.

The antiplasmodial, leishmanicidal and antitrypanosomal activities of eight natural biflavonoids were estimated in vitro on a chloroquine-resistant strain of Plasmodium falciparum, axenically grown Leishmania donovani amastigotes and Trypanosoma cruzi trypomastigotes and Trypanosoma brucei rhodesiense bloodstream forms. Lanaroflavone showed the highest antiplasmodial activity (IC(50) = 0.48 microM), isoginkgetin was the most active leishmanicidal compound (IC(50) = 1.9 microM), whereas ginkgetin (IC(50) = 11 microM) and isoginkgetin (IC(50) = 13 microM) showed the best antitrypanosomal activity in our assays. The cytotoxicity and the selectivity indices for the most active compounds were also estimated. Lanaroflavone exhibited a high selectivity index value (SI = 159), indicating selective antiplasmodial activity.

Animals↗
PubMed2004

A bioactive biflavonoid from Campnosperma panamense.

Lanaroflavone (1), a biflavonoid isolated from the methanol extract of the aerial part of Campnosperma panamense by bioguided fractionation, has been assessed for in vitro antiprotozoal activity. Lanaroflavone showed both antimalarial and leishmanicidal activities, but was inactive against Chagas disease vector, Trypanosoma cruzi.

Anacardiaceae↗
PubMed2001

Saponins from Strasburgeria robusta.

The isolation of three saponins, 24-hydroxytormentic acid ester glucoside (1), niga-ichigoside F1 (2) and niga-ichigoside F2 (3), from the stem bark of Strasburgeria robusta, an endemic plant from New Caledonia, is reported.

Humans↗
PubMed2001

Antiprotozoal activities of Colombian plants.

In our search for therapeutical alternatives for antiprotozoal chemotherapy, we collected a selection of 44 plants from western Colombia upon ethnopharmacological and chemotaxonomic considerations. Polar and apolar extracts of these species were examined for antimalarial activity using in vitro tests with two clones of Plasmodium falciparum. Leishmanicidal and trypanocidal activity were determined in vitro using promastigote and amastigote forms of several strains of Leishmania sp. and epimastigotes of Trypanosoma cruzi. Among the selected plants, the 15 following species showed good or very good antiprotozoal activity in vitro: Aspidosperma megalocarpon, Campnosperma panamense, Conobea scoparioides, Guarea polymera, Guarea guidonia, Guatteria amplifolia, Huberodendron patinoi, Hygrophila guianensis, Jacaranda caucana, Marila laxiflora, Otoba novogranatensis, Otoba parviflora, Protium amplium, Swinglea glutinosa and Tabernaemontana obliqua. Cytotoxicity was assessed in U-937 cells and the ratio of cytotoxicity to antiprotozoal activity was determined for the active extracts. Ten extracts from eight species showed selectivity indexes > or = 10. Among the extracts that showed leishmanicidal activity, the methylene chloride extract of leaves from C. scoparioides showed a selectivity index in the same range that the one of the Glucantime control. Several of the active leishmanicidal plants are traditionally used against leishmaniasis by the population of the concerned area.

Animals↗
PubMed2001

Bioactive acridone alkaloids from Swinglea glutinosa.

A new prenylated acridone alkaloid, 1,3,5-trihydroxy-2,8-bis(3-methylbut-2-enyl)-10-methyl-9-acridone (1), was isolated from the stembark of Swinglea glutinosa, along with three known acridone alkaloids, 5-hydroxynoracronycine (2), 1,3,5-trihydroxy-4-methoxy-2-(3-methylbut-2-enyl)-10-methyl-9-acridone (3), and 1,3,5-trihydroxy-4-methoxy-10-methylacridone (4). The isolated alkaloids were assessed in vitro against chloroquine-sensitive and -resistant Plasmodium falciparum strains and for cytotoxicity using HeLa cells.

Acridines↗
PubMed2001

Triterpenoid saponins from Isertia pittieri.

Two new 27-nor-triterpenoid saponins, pyrocincholic acid 3 beta-O-beta-D-quinovopyranosyl-28-[beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl] ester (1) and pyrocincholic acid 3 beta-O-beta-D-quinovopyranosyl(1-->6)-beta-D-glucopyranosyl-28-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl] ester (2) were isolated from the stem bark of Isertia pittieri, together with two known bidesmosidic quinovic acid glycosides. The structures of 1 and 2 were determined on the basis of spectroscopic studies.

Chromatography, High Pressure Liquid↗
PubMed1996

Structure elucidation of three triterpene glycosides from the trunk of Argania spinosa.

The structures of three novel saponins from Argania spinosa, named arganines G, H, and J, have been elucidated by MS and NMR techniques as 3-O-beta-D-apiofuranosyl- (1-->4)-beta-D-glucopyranosyl-28-O-beta-D-glucopyranosylbayogenin (1), 3-O-beta-D-apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-28-O-alpha- L- arabinopyranosylbayogenin (2), and 3-O-beta-D-apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-28-O- [beta-D-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L - rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]bayogenin (3), respectively.

Carbohydrate Sequence↗
PubMed1995

Triterpenoid saponins from the root of Sideroxylon foetidissimum.

Two novel triterpenoid saponins named sideroxyloside B and sideroxyloside C were isolated from the root of Sideroxylon foetidissimum. On the basis of spectroscopic and chemical methods, their structures were established as 3-O-beta-D-glucopyranosyl-28-O([beta-D-apiofuranosyl-(1-->3)-beta- D- xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)] [beta-D-apiofuranosyl(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alph a-L- arabinopyranosyl) protobassic acid and 28-O([beta-D-xylopyranosyl-(1-->4)- alpha-L-rhamnopyranosyl-(1-->4)] [beta-D-apiofuranosyl-(1-->3)]-alpha-L- rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl) protobassic acid, respectively.

Carbohydrate Conformation↗
PubMed1995

Triterpenoid saponins from Mimosa pigra.

Two novel triterpene glycosides have been isolated from Mimosa pigra. The aglycone of these two compounds was identified as machaerinic acid by 1H- and 13C-nmr spectroscopy and by comparison with an authentic sample. This aglycone is substituted at position C-3 by an identical oligosaccharide chain in these glycosides, and at position C-21 by either a Z/E-methoxycinnamic [1] unit or an E-cinnamic acid [2] unit.

Carbohydrate Sequence↗
PubMed1995

Cytotoxic activity of Amaryllidaceae alkaloids.

25 Amaryllidaceae alkaloids belonging to different skeletal types were evaluated for their cytotoxic activity against one murine non-tumoral cell line (LMTK) and two human tumoral cell lines (Molt4 and HepG2) according to established protocols. Significant differences of activity related with the type of skeleton of the tested alkaloids could be observed. Pretazettine (22) was among the most active compound among the 25 tested alkaloids on the Molt4 lymphoid cells, but was inactive against HepG2 hepatoma. On the other hand, lycorenine (11) was found to be the most cytotoxic compound against HepG2 hepatoma, even though it appears to be active against Molt4 cells. Almost all of the tested alkaloids showed cytotoxic activity against fibroblastic LMTK cells. Only mesembrenone (25) showed some specificity against Molt4 cells in comparison to LMTK cells.

Alkaloids↗
PubMed1994

Triterpenoid saponins from the root of Sideroxylon cubense.

Two triterpenoid saponins were isolated from the root of Sideroxylon cubense and their structures were established as 3-O-beta-D-glucopyranosyl-28-O-[alpha-L-rhamnopyranosyl(1-->3)- beta-D-xylopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->2) beta-D-xylopyranosyl] protobassic acid and 3-O-beta-D-glucopyranosyl protobassic acid. The first, designed as sideroxyloside A, is a new natural product.

Carbohydrate Sequence↗
PubMed1994

Mabiosides C-E: triterpenoid saponins from the bark of Colubrina elliptica.

Three novel saponins, mabiosides C-E, were isolated from the bark of Colubrina elliptica together with the known mabioside B and [alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->3)-alpha-L- arabinopyranosyl]-(1-->3)-jujubogenin. All the structures were established by spectroscopic methods.

Carbohydrate Sequence↗
PubMed1993

Pharmacognosy of Mimosa tenuiflora (Willd.) Poiret.

A chemical investigation of the bark of Mimosa tenuiflora (Willd.) Poiret, performed in our laboratory, allowed the isolation and identification of three new triterpenoid saponins (mimonosides A, B and C), three steroid saponins (3-O-beta-D-glucopyranosyl campesterol, 3-O-beta-D-glucopyranosyl stigmasterol and 3-O-beta-D-glucopyranosyl beta-sitosterol) together with lupeol, campesterol, stigmasterol and beta-sitosterol. The three new triterpenoid saponins were subjected to in vitro biological tests (immunomodulation and proliferation) using different animal and human cells in culture. The results of these tests contribute to explain the traditional use of this plant material.

Animals↗
PubMed1992

Two new alkaloids from Xestospongia sp., a New Caledonian sponge.

Five alkaloids have been isolated from a New Caledonian sponge Xestospongia sp. These include three known xestospongin derivatives, the new demethylxestospongin B (1) and a tetrahydrocarboline derivative 5. The structures of the new compounds 1 and 5 have been established by nmr studies and comparison with previously described products.

Alkaloids↗
PubMed1991

Interest and limitation of a global ethnopharmacological survey.

Since 1983 an ethnopharmacological research called the TRAMIL Programme (Applied Research on the Traditional Popular Medicine in the Caribbean Basin) has been underway in several countries of the West Indies and Central America. The programme, which started in Haiti and in the Dominican Republic, has now extended to Colombia, Costa Rica, Dominica, Guatemala, Honduras and Venezuela. The most important goal of the programme is to evaluate the traditional use of medicinal herbs in order to help unprivileged populations from this geographical area. The study is approached from the point of view of solutions to everyday health problems, rather than as a simple catalogue of plant or traditional remedy usage. An appropriate methodology is employed, including inventory and botanical determination, bibliographical research, study of the unknown species through analytical, toxicological and/or pharmacological methods and transmission of controlled information which ensures the value of natural medication to the public. The TRAMIL Programme leads to protection of cultural heritage and integration of effective and secure traditional remedies in primary health care.

Central America↗