Millaurine A, a new guanidine alkaloid from seeds of Millettia laurentii.

A new guanidine alkaloid, millaurine A (1), was isolated from the methanol extract of the seeds of Millettia laurentii. The structure of the new compound was elucidated on the basis of spectral analysis.

Estrogenic effects of the ethyl-acetate extract of the stem bark of Erythrina lysistemon Hutch (Fabaceae).

The stem bark of Erythrina lysistemon, one of the traditionally used "women remedies", has been assessed for its estrogenic activity. The ethyl-acetate extract of the stem bark of E. lysistemon showed estrogenic activities in vitro either in a yeast-based estrogen receptor assay or on the estrogen-dependent stimulation of alkaline phosphatase activity in the human endometrial carcinoma cell line Ishikawa. The estrogenic activity was investigated in vivo in young ovariectomized Wistar female rats after a 7-day treatment. The estrogenicity was evaluated through the proliferative status of target sex organs such as uterus and vagina. The results obtained showed that oral administration of 200 mg/kg BW/d of E. lysistemon extract in comparison to untreated ovariectomized rats significantly increased the vaginal epithelial height by 47.23% (from 8.71+/-0.47 to 12.34+/-1.31 microm); and induced a weak increase of uterine epithelial height by 6.76% (from 5.42+/-0.52 to 5.84+/-0.91 microm). Both were not as pronounced as those elicited in the positive control of 100 microg/kg BW/d of ethinylestradiol given orally. Overall our results suggest that the extract of E. lysistemon contains secondary metabolites endowed with estrogenic activity.

Evaluation of Antimicrobial Activity of the Stem Bark of Cylicodiscus Gabunensis (Mimosaceae)

Ethyl acetate(EA) extract of the stem bark of Cylicodiscus gabunensis (CG) was analysed phytochemically and evaluated for its antimicrobial activity against 17 pathogenic species isolated from patient: Escherichia coli; Klebsiella pneumoniae; Shigella dysenteriae; Shigella flexneri; Morganella morganii; Proteus vulgaris; Proteus mirabilis; Salmonella typhi; Citrobacter freundii; Enterobacter cloacae; Enterobacter agglomerans; Staphylococcus aureus; Streptococcus feacalis; Pseudomonas aeruginosa; Bacillus cereus T; Candida albicans and Candida glabrata. Flavonoids; saponins; tannins; polyphenols; coumarins; triterpenes and/or sterols and reducing sugars were detected in the (EA) extract of CG. The best MIC and MBC values for the microorganisms sensitive to the extract were 0.00078 and 0.00315 mg/ml respectively. The greater and remarkable antimicrobial activity of the (EA) extract of CG was recorded with Staphylococcus aureus; Proteus vulgaris and Bacillus cereus T. These results provide a rationalization for the traditional use of this plant for the treatment of infections diseases

Triterpenoids from Drypetes chevalieri Beille (euphorbiaceae).

The CH2Cl2/CH3OH (1/1) extract of the dried stem of Drypetes chevalieri Beille afforded two new triterpenoïds named drypechevalin A (11-oxo-beta-amyrin-3beta-ylcaffeate) and drypechevalin B (3,7-dioxo-D:A-friedooleanan-24-al) along with five known compounds: lupeol, lupeone, erythrodiol, putranjivadione, friedelin. Their structures were established on the basis of spectroscopic analysis and chemical evidence.

Secondary metabolites from Senecio burtonii (Compositae).

A cacalolide derivative named 4alpha-[2'-hydroxymethylacryloxy]-1beta-hydroxy-14-(5-->6) abeo eremophilan-12,8-olide and a shikimic acid derivative named (3'E)-(1alpha)-3-hydroxymethyl-4beta,5alpha-dimethoxycyclohex-2-enyloctadec-3'-enoate along with three known compounds, octacosan-1-ol, 3beta-hydroxyolean-12-en-28-oic acid and 3beta-acetoxyolean-12-en-28-oic acid were isolated from Senecio burtonii. Their structures and relative configurations were established on the basis of spectroscopic analysis.

Sesquiterpene lactones from Crepis cameroonica (Asteraceae).

In addition to one known compound, 3beta,8alpha-dihydroxyguaian-4(15),10(14),11(13)-trien-6,12 olide (8-desacylcynaropicrin) (3), two new sesquiterpene lactones have been isolated from the aerial parts of Crepis cameroonica. By means of spectroscopic analysis, the structures and relative configurations of the new compounds were established as 3beta,9beta-dihydroxyguaian-4(15),10(14),11(13)-trien-6,12 olide (1) and 8alpha-hydroxy-4alpha(13),11beta(15)-tetrahydrozaluzanin C (2). The in vitro antimicrobial spectrum of pure compounds and crude extracts are also reported.

Evaluation of antimicrobial activity of the stem bark of Cylicodiscus gabunensis (Mimosaceae).

Ethyl acetate (EA) extract of the stem bark of Cylicodiscus gabunensis (CG) was analysed phytochemically and evaluated for its antimicrobial activity against 17 pathogenic species isolated from patient: Escherichia coli, Klebsiella pneumoniae, Shigella dysenteriae, Shigella flexneri, Morganella morganii, Proteus vulgaris, Proteus mirabilis, Salmonella typhi, Citrobacter freundii, Enterobacter cloacae, Enterobacter agglomerans, Staphylococcus aureus, Streptococcus feacalis, Pseudomonas aeruginosa, Bacillus cereus T, Candida albicans and Candida glabrata. Flavonoids, saponins, tannins, polyphenols, coumarins, triterpenes and/or sterols and reducing sugars were detected in the (EA) extract of CG. The best MIC and MBC values for the microorganisms sensitive to the extract were 0.00078 and 0.00315 mg/ml respectively. The greater and remarkable antimicrobial activity of the (EA) extract of CG was recorded with Staphylococcus aureus, Proteus vulgaris and Bacillus cereus T. These results provide a rationalization for the traditional use of this plant for the treatment of infectious diseases.

Cytotoxic and antimicrobial coumarins from Mammea africana.

Six coumarin derivatives [three 4-phenylcoumarins (Mammea A/AA, Mammea A/BA and MAB 3), two 4-n-propylcoumarins (Mammea B/BB and Mammea B/BA) and one 4-n-pentylcoumarin (Mammea C/OB)], 1,5-dihydroxyxanthone and 1-methoxy-5-hydroxyxanthone have been isolated from the stem bark of Mammea africana Sabine collected in Cameroon. Although known, the structures of the coumarin derivatives were confirmed by spectral analysis, including two-dimensional nuclear magnetic resonance. All the coumarin compounds showed noteworthy cytotoxicity against the human 9-KB cell line. Both of the 4-n-propylcoumarins were also found to exhibit significant activity against Staphylococcus aureus.

In-vivo antimalarial activity of some oxygenated xanthones.

A series of oxygenated xanthones was prepared so that the antimalarial activity of each compound could be evaluated in vivo, using 4-day suppressive assays against Plasmodium berghei ANKA in BALB/c mice. When given in a dose of 20 mg/kg.day for 4 days, most of the compounds produced significant chemosuppression of parasitaemia. The most active compound was 1,3,6,8-tetrahydroxyxanthone, which reduced the percentage of erythrocytes infected by 70.5%, followed by norlichexanthone (44.3%) and its isomer, 1,3,8-trihydroxy-6-methylxanthone (37.0%). Whereas di-C-allyl-dihydroxyxanthone showed lower but still notable activity (33.4%), 1,3-dihydroxyxanthone was much less active (15.1%). This appears to be the first demonstration of the antimalarial activity of some hydroxyxanthones in vivo.

Pentacyclic triterpenoid and saponins from Gambeya boukokoensis.

Chemical studies of the EtOAc extract of Gambeya boukokoensis Aubr. et Pellegr. stem bark led to the isolation of eight compounds. Three of them were elucidated as new compounds and designated as: gamboukokoensein A, 1alpha,2alpha,3beta,19alpha,23-pentahydroxyurs-12-en-28-oic acid; gamboukokoenside A, 2beta,3beta,6beta,28-tetrahydroxyolean-12-en-23-oic acid 23-O-alpha-L-arabinopyranosyl ester and gamboukokoenside B, 6beta,28-dihydroxy-3-oxoolean-12-en-23-oic acid 23-O-alpha-L-arabinopyranosyl ester. The other five compounds were known and identified as myrianthic acid, protobassic acid, oleanolic acid, erythrodiol and chondrillasterol. Their structures were elucidated on the basis of one and two dimensional NMR spectroscopic techniques, FABMS, ESMS and chemical evidence.

Scaphopetalone and scaphopetalumate, a lignan and a triterpene ester from Scaphopetalum thonneri.

From the methanol extract of the stem bark of Scaphopetalum thonneri, two new compounds, including one lignan, named scaphopetalone, one new ester of ferulic acid, named scaphopetalumate were isolated together with three known compounds including: two coumarins (scopoletin and scopolin), and one pentacyclic triterpene (oleanolic acid). The structure of the new compounds were elucidated by means of spectroscopic analyses.

Antimicrobial activity of Bridelia ferruginea leaves extracts.

Methanol, ethyl acetate, and hexane extracts of Bridelia ferruginea leaves exhibited significant activity against Pseudomonas frutescens, Bacillus subtilis, Echerichia coli, Staphylococcus aureus and Streptococcus faecalis.

Chalconoid and stilbenoid glycosides from Guibourtia tessmanii.

Phytochemical studies on the stem bark of Guibourtia tessmanii yielded a dihydrochalcone glucoside, 2',4-dihydroxy-4'-methoxy-6'-O-beta-glucopyranoside dihydrochalcone and a new stilbene glycoside, 3,5-dimethoxy-4'-O-(beta-rhamnopyranosyl-(1-->6)-beta- glucopyranoside) stilbene besides the known pterostilbene. Their structures were established on the basis of one and two dimensional NMR spectroscopic techniques, FABMS and chemical evidence.

Cytotoxic isoflavones from Erythrina indica.

Bioassay-directed fractionation of the CH(2)Cl(2)-MeOH (1:1) extract of the stem bark of Erythrina indica, has resulted in the isolation of two new isoflavone derivatives named indicanines D and E together with 11 known compounds including: six isoflavones (genistein, wighteone, alpinumisoflavone, dimethylalpinumisoflavone, 8-prenyl erythrinin C, and erysenegalensein E), one cinnamate (erythrinassinate B), two pentacyclic triterpenes (oleanolic acid and erythrodiol), and two phytosterols (stigmasterol and its 3-O-beta-D-glucopyranoside). The structures of the new compounds were elucidated by means of spectroscopic analysis. The in vitro cytocidal activity against KB cells of some of the isolated compounds is also reported.

Asebotin, a dihydrochalcone glucoside from Guibourtia tessmannii.

Asebotin (1), a dihydrochalcone glucoside, was isolated from the stem bark of Guibourtia tessmanni and characterised by means of spectroscopic analysis including 1H-, 13C, MS and 1D Noe difference experiment.

Diterpenoid and limonoids from the stem of Pterorhachis zenkeri.

One new diterpenoid, methyl 3alpha-hydroxy-7-oxo-dehydroabietate (1), two new limonoids, 3alpha-deacetyl-amoorastatin (2) and 9beta-amoorastatin (3), and the known limonoid amoorastatin (4) were isolated from the stem of Pterorhachis zenkeri.

Further isoflavonoid metabolites from Millettia griffoniana (Bail).

Three new isoflavonoids, griffonianone A (1), B (2) and C (4) were isolated from the root bark of Millettia griffoniana, along with the known maximaisoflavone G (5) and 7-hydroxy-6-methoxy-3',4'-methylenedioxyisoflavone (6). Their structures were assigned on the basis of spectroscopic data and chemical transformations.

Sesquiterpene lactone and friedelane derivative from drypetes molunduana.

A new sesquiterpene lactone, drypemolundein A and a new friedelane derivative, drypemolundein B, along with seven known compounds have been isolated from the whole stems of Drypetes molunduana Pax and Hoffm. Their structures were established on the basis of one- and two-dimensional NMR, homo- and hetero-nuclear spectroscopic evidence.

2-Oxo-2H-Pyrimido[2,1-b]benzothiazoles inhibit brain benzodiazepine receptor binding in vitro.

2-Oxo-2H-pyrimido[2,1-b]benzothiazole derivatives were found to inhibit the in vitro binding of (3)H-Ro 15-1788 ((3)H-flumazenil) to rat cortical benzodiazepine receptors with IC(50) values in the range of 0.7-13 micromol/l. The most potent compound, 2-oxo-4-phenyl-2H-pyrimido[2,1-b]- benzothiazole showed a similar potency to inhibit (3)H-Ro 15-1788 binding to membrane preparations of rat brain cortex, cerebellum and hippocampus as well as to various subunit combinations of recombinant human gamma-aminobutyric acid(A)/benzodiazepine receptors. Scatchard plot analysis showed that 2-oxo-4-phenyl-2H-pyrimido[2,1-b]benzothiazole is a competitive inhibitor of (3)H-Ro 15-1788 binding to rat brain cortical membrane preparations.

Indicanine A, a new 3-phenylcoumarin from root bark of Erythrina indica.

A new 3-phenylcoumarin, indicanine A (1), has been isolated from the root bark of the African medicinal plant Erythrina indica, together with three known compounds, robustic acid (2), daidzein, and 8-prenyldaidzein. The structure of the new compound was characterized, as 4-hydroxy-5-methoxy-3-(4'-methoxyphenyl)-2" -(1-methylethenyl)dihydrofurano[4",5":6,7]coumarin by means of extensive spectroscopic analyses. The compounds were found to be devoid of in vitro antibacterial activity.