Trypanocidal and leishmanicidal activity of six limonoids.

Six limonoids [kotschyienone A and B (1, 2), 7-deacetylgedunin (3), 7-deacetyl-7-oxogedunin (4), andirobin (5) and methyl angolensate (6)] were investigated for their trypanocidal and leishmanicidal activities using bloodstream forms of Trypanosoma brucei and promastigotes of Leishmania major. Whereas all compounds showed anti-trypanosomal activity, only compounds 1-4 displayed anti-leishmanial activity. The 50% growth inhibition (GI) values for the trypanocidal and leishmanicidal activity of the compounds ranged between 2.

Bioactive Seco-Lanostane-Type Triterpenoids from the Roots of Leplaea mayombensis.

Fractionation of the ethyl acetate-soluble extract of the roots of Leplaea mayombensis afforded two new 3,4-seco-lanostane-type triterpenoids, leplaeric acids A and B (1, 2), the new lanostane-type triterpenoid leplaeric acid C (3), and six known natural products (5-10). Derivatization of the main constituent, 1, afforded the dimethyl ester 4, the monoamide 11, and diamide 12 for SAR studies. The structures of these compounds were established through spectroscopic methods, and a single-crystal X-ray diffraction analysis was used to confirm the relative configuration of compound 1.

Kostchyienones A and B, new antiplasmodial and cytotoxicity of limonoids from the roots of Pseudocedrela kotschyi (Schweinf.) Harms.

Two new limonoids, kostchyienones A (1) and B (2), along with 12 known compounds 3-14 were isolated from the roots of Pseudocedrela kostchyi. Compound (7) was isolated for the first time from a natural source. Their structures were elucidated on the basis of spectroscopic evidence.

A mechanistic study on the Hooker oxidation: synthesis of novel indane carboxylic acid derivatives from lapachol.

The Hooker oxidation is one of the most intriguing transformations wherein lapachol (1) is readily converted to norlapachol (2) in very good yield. This one-pot reaction involves a very intricate mechanism in which the alkyl side chain of lapachol is shortened by one carbon unit. Previous studies have unequivocally established the involvement of an indane carboxylic acid derivative 3, as a key intermediate (Hooker intermediate), and its simultaneous conversion to norlapachol (2) via the oxidative cleavage of vicinol diol and subsequent intramolecular aldol reaction of the resulting keto acid.

Anticancer activities of six selected natural compounds of some Cameroonian medicinal plants.

Background: Natural products are well recognized as sources of drugs in several human ailments. In the present work, we carried out a preliminary screening of six natural compounds, xanthone V(1) (1); 2-acetylfuro-1,4-naphthoquinone (2); physcion (3); bisvismiaquinone (4); vismiaquinone (5); 1,8-dihydroxy-3-geranyloxy-6-methylanthraquinone (6) against MiaPaCa-2 pancreatic and CCRF-CEM leukemia cells and their multidrug-resistant subline, CEM/ADR5000. Compounds 1 and 2 were then tested in several other cancer cells and their possible mode of action were investigated.