Complement-Inhibiting Constituents of Bridelia ferruginea Stem Bark.

A bioassay-guided fractionation of an 80% acetone extract from BRIDELIA FERRUGINEA stem bark showing a dose-dependent inhibitory effect towards both the classical and the alternative pathways of the complement system resulted in the isolation of a biflavanol (gallocatechin-(4'- O-7)-epigallocatechin) ( 1), 3,5-dicaffeoylquinic acid ( 2), 1,3,4,5-tetracaffeoylquinic acid ( 3), and a series of 3-methoxyflavone derivatives, including quercetin 3-methyl ether ( 4), quercetin 3,7,3',4'-tetramethyl ether ( 5), myricetin 3',4',5'-trimethyl ether ( 6; new compound) named ferrugin, myricetin 3,3',4',5'-tetramethyl ether ( 7), myricetin ( 8), and quercetin 3- O-glucoside ( 9) as the active constituents. Especially the biflavanol 1 and the caffeoyl esters of quinic acid 2 and 3 showed a strong inhibitory effect (IC (50) < 10 microM) on the classical pathway, compared to rosmarinic acid. Also on the alternative pathway, the biflavanol 1, the quinic acid derivatives 2 and 3, and some of the 3-methoxyflavones 5, 7 and 8 were more active than rosmarinic acid.

Radical scavenging and xanthine oxidase inhibitory activity of phenolic compounds from Bridelia ferruginea stem bark.

Bridelia ferruginea Benth. (Euphorbiaceae) is a subtropical medicinal plant widely used in traditional African medicine against various diseases, including rheumatic pains. Seven of its constituents (3-O-methylquercetin (1), 3,7,3',4'-tetra-O-methylquercetin (rutisin, 2), myricetin (3), 3',4',5'-tri-O-methylmyricetin (ferrugin, 4), 3,3',4',5'-tetra-O-methylmyricetin (5), quercetin 3-O-glucoside (6), and a biflavanol gallocatechin-[4'-O-7]-epigallocatechin (7)) have been evaluated in-vitro in the xanthine-xanthine oxidase enzymatic system for inhibition of xanthine oxidase and radical scavenging activity.

Complement-modulating properties of a kaempferol 7-O-rhamnosylsophoroside from the leaves of Morinda morindoides.

A kaempferol 7-O-rhamnosylsophoroside isolated from the leaves of Morinda morindoides showed dose-dependent complement-modulating properties towards both the classical (inhibiting effect) and alternative (activating effect) pathways of the complement system. Its structure was elucidated by chemical and spectroscopic methods as kaempferol 7-O-[alpha-L-rhamnopyranosyl-(1-->6)]-[beta-D-glucopyranosyl-(1-->2)]-be ta-D-glucopyranoside, a new natural product which was named morindaoside.

Structure and chemotherapeutical activity of a polyisoprenylated benzophenone from the stem bark of Garcinia huillensis.

The stem bark of Garcinia huillensis grown in Zaïre and used in central-African traditional medicine has been subjected to a bioassay-guided fractionation. The chemotherapeutically active petroleum ether extract afforded fatty acids, aliphatic alcohols, triterpenes and a polyisoprenylated benzophenone, which was identified as garcinol, also named camboginol. This compound has been shown to exhibit chemotherapeutical activity gram-positive and gram-negative cocci, mycobacteria and fungi.

Stereochemical considerations in relation to the pharmacological activity of Pterotaberna alkaloids.

Five 2-acylindole alkaloids, isolated from the leaves of Pterotaberna inconspicua, were pharmacologically investigated. The major alkaloids methuenine and 16-epimethuenine showed some interesting pharmacological features, whereas the minor alkaloids including 6-oxomethuenine and methuenine N-oxide were almost devoid of these pharmacological properties. Methuenine, being the most potent, was characterized as a non competitive antagonist against acetylcholine (pD'2=5.