Cytotoxic and antiplasmodial xanthones from Pentadesma butyracea.

Four new xanthones, butyraxanthones A-D (1-4), were isolated from the stem bark of Pentadesma butyracea, together with six known xanthones (5-10) and a triterpenoid (lupeol). The structures of 1-4 were established by spectroscopic methods. Compounds 1-10 were tested in vitro for antiplasmodial activity against a Plasmodium falciparum chloroquine-resistant strain and for cytotoxicity against a human breast cancer cell line (MCF-7).

Effects of the aqueous and hexane extracts of Mondia whitei on the sexual behaviour and some fertility parameters of sexually inexperienced male rats.

The effects of Mondia whitei Hook (Skeels) were studied on the sexual behaviour and some fertility parameters of sexually inexperienced male rats. Animals were orally administered 100 mg/kg and 500 mg/kg of body weight (b.w) of either the aqueous or the hexane extracts of Mondia whitei whilst the control group received 10 mL/kg b.

Effects of Basella alba and Hibiscus macranthus extracts on testosterone production of adult rat and bull Leydig cells.

Aim: To determine the androgenic effects of Basella alba and Hibiscus macranthus extracts in the rat and the bull, and to develop a novel in vitro test system using Leydig cells from bull testes.

Methods: The effect of methanol extracts from both plants on testosterone production in isolated Leydig cells from the rat and the bull was analyzed using 125I-radioimmunoassay (125I-RIA). Rat Leydig cells were obtained by common methods, whereas a novel technique was used to purify Leydig cells from bull testes.

Prolyl endopeptidase and thrombin inhibitory diterpenoids from the bark of Xylopia aethiopica.

The inhibitory effects of seven diterpenes, belonging to three different structural classes and isolated from the bark of Xylopia aethiopica, were investigated against the enzymes prolyl endopeptidase (PEP) and alpha-thrombin. Five compounds exhibited inhibitory activity against them.

Xanthones and other constituents of Allanblackia monticola (Guttiferae).

A xanthone derivative, 3,6,7-trihydroxy-1-methoxyxanthone has been isolated from the stem bark of Allanblackia monticola together with other known compounds, 2,6-dihydroxy-1-methoxyxanthone, allanxanthone A, epicathechin and oleanolic acid acetate. The structure of the new compound was elucidated by spectroscopic methods.

A prenylated xanthone with antimicrobial activity from the seeds of Symphonia globulifera.

A prenylated xanthone has been isolated from the seeds of Symphonia globulifera together with the known compounds sitosterol and oleanolic acid. The structure of the new compound was elucidated by spectroscopic methods.