PubMed Health⌕ Search

Biomedical subjects

S Apers

Publications and source records attributed to S Apers.

At least 19 recordsLinked to original sources
PubMed2006

Cytotoxicity and in vitro susceptibility of Entamoeba histolytica to Morinda morindoides leaf extracts and its isolated constituents.

An aqueous decotion (dried extract), an 80% MeOH extract from Morinda morindoides leaves, and 10 flavonoids and 4 iridoids isolated from the 80% MeOH extract were evaluated in vitro for their potential antiamoebic activity and their cytotoxic effect against MT-4 cells. Results indicated that the aqueous decoction and the 80% MeOH extract exhibited an interesting antiamoebic activity with IC(50) values of 3.1 +/- 1.7 and 1.7 +/- 0.6 microg/ml, respectively. Apigenin-7-O-glucoside and luteolin-7-O-glucoside exhibited a moderate antiamoebic activity with IC(50) values of 22.3 +/- 3.2 and 37.4 +/- 2.7 microg/ml, respectively. Kaempferol (IC(50) = 10.3 +/- 2.3 microg/ml), apigenin (IC(50) = 12.7 +/- 4.3 microg/ml), and luteolin (IC(50) = 17.8 +/- 4.3 microg/ml) showed a more pronounced activity than their corresponding glycosides. All tested iridoids displayed a very good activity with IC(50) values less than 10 microg/ml. The most active iridoids were epoxygaertneroside (IC(50) = 1.3 +/- 0.4 microg/ml) and methoxygaertneroside (IC(50) = 2.3. +/- 0.7), followed by gaertneroside and gaertneric acid with IC(50) values of 4.3 +/- 1.8 and 7.1 +/- 1.4 microg/ml, respectively. Except quercetin and quercetin-7,4'-dimethylether which have shown a cytotoxic effect with IC(50) ranging from 14 to 22 microg/ml. No correlation could be deduced between the observed antiamoebic and cytotoxic activity of these tested samples. A structure-activity relationship for isolated compounds is discussed. These findings support the medicinal report for the traditional use of Morinda morindoides leaves for the treatment of amoebiasis.

Amebicides↗
PubMed2005

Biologically active bisbenzylisoquinoline alkaloids from the root bark of Epinetrum villosum.

Methanol and water extracts of the root of Epinetrum villosum (Exell) Troupin (Menispermaceae) were found to exhibit antimicrobial and antiplasmodial activities. Investigation of the active methanol fraction led to the isolation of four bisbenzylisoquinoline alkaloids, i.e., cycleanine, cycleanine N-oxide, isochondodendrine and cocsoline. Structures were established by spectroscopic methods. Cocsoline displayed antibacterial and antifungal activities (MIC values of 1000-15.62 and 31.25 microg/ml, respectively). Isochondodendrine was found to have the most potent antiplasmodial activity (IC50 = 0.10 microg/ml), whereas the IC50 on HCT-116 human colon carcinoma cells was 17.5 microg/ml (selectivity index 175). Cycleanine acted against HIV-2 (EC50=1.83 microg/ml) but was at least 10-fold less active against HIV-1. Cycleanine N-oxide showed no activity towards all tested microorganisms.

Alkaloids↗
PubMed2005

Antimalarial activities and toxicities of three plants used as traditional remedies for malaria in the Democratic Republic of Congo: Croton mubango , Nauclea pobeguinii and Pyrenacantha staudtii.

The antimalarial activities of crude extracts and 17 fractions from the partition of 80%-methanolic extracts of three plants (the stem bark of Croton mubango, the stem bark of Nauclea pobeguinii and the leaves of Pyrenacantha staudtii) used as antimalarial remedies in the Democratic Republic of Congo were studied both in vitro (against Plasmodium falciparum) and in mice infected with Pl. berghei berghei. The toxic effects of dried aqueous extracts of the plants were also investigated, in uninfected mice. The most active crude extracts in vitro, with median inhibitory concentrations (IC(50)) of <1 microg/ml, were found to be the methanolic and dichloromethane extracts of C. mubango, and the dichloromethane extracts of N. pobeguinii and Py. staudtii. The aqueous extract with the most antimalarial activity in vitro was that of C. mubango (IC(50) = 3.2 microg/ml), followed by that of N. probeguinii (IC(50) = 5.3 microg/ml) and then that of Py. staudii (IC(50) = 15.2 microg/ml). Results from the in-vivo tests of antimalarial activity showed that, at a daily oral dose of 200 mg/kg, all the dichloromethane extracts, the petroleum-ether, chloroformic, ethyl-acetate and residual water-soluble fractions from C. mubango, and the chloroformic, ethyl-acetate and n-butanolic fractions from Py. staudtii produced >80% chemosuppression of the parasitaemias by day 4. The aqueous extracts of C. mubango and N. probeguinii produced a slightly lower but still significant inhibition of parasitaemia (60%-80%) whereas that of Py. staudtii only suppressed the day-4 parasitaemias by 37%. The dried aqueous extract of the stem bark of C. mubango showed some signs of toxicity in mice, with median lethal doses (LD(50)) of 350 mg/kg in the female mice and 900 mg/kg in the male. The extract significantly increased the serum concentrations of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) in mice of both sexes, but had no effect on the blood levels of creatinine or urea. No significant toxic effect was observed for the dried aqueous extracts of N. pobeguinii and Py. staudtii (LD(50) >5 g/kg). Neither of these extracts affected the serum concentrations of GPT or the blood concentrations of creatinine and urea, although the N. pobeguinii extract did increase the serum concentration of GOT.

Animals↗
PubMed2004

Evaluation of bioactive saponins and triterpenoidal aglycons for their binding properties on human endothelin ETA and angiotensin AT1 receptors.

Different types of triterpenes including saponins and aglycons were evaluated for their ability to inhibit [3H] BQ-123 and [3H] angiotensin II binding to the human endothelin 1 ETA and angiotensin II AT1 receptors, respectively. Selectivity for only one of the two receptors was exhibited by asiatic acid and its saponins (ETA) and oleanolic acid (AT1). To a lesser extent betulinic acid, beta-amyrin and friedelin also showed selectivity for the ETA receptor. To address the question whether the effect of saponins on cell membranes might interfere with the normal binding of specific radioligands to their receptors, the activity of saponins with different haemolytic properties were compared. Highly haemolytic saponins such as alpha-hederin and beta-escine showed partial (60%) inhibition of radioligand-binding to the ETA receptor and complete inhibition (100%) to the AT1 receptor. Moreover, the haemolytically inactive kryptoescine, at the same concentration, caused complete inhibiton of radioligand-binding to both receptors, indicating that inhibition of receptor binding was not related to the membrane-interacting properties of saponins.

Animals↗
PubMed2004

In vitro antiplasmodial activity of extracts and fractions from seven medicinal plants used in the Democratic Republic of Congo.

The in vitro antiplasmodial activity of seven EtOH extracts and twenty fractions from the partition of the initial ethanolic extracts from seven African medicinal plants used in the Democratic Republic of Congo (DR Congo) for the treatment of malaria was evaluated. The most active EtOH extracts (IC50 < 3 microg/ml) were those from Cassia occidentalis leaves, Euphorbia hirta whole plant, Garcinia kola stem bark and Phyllanthus niruri whole plant. Their respective petroleum ether soluble fractions also exhibited an antiplasmodial activity with IC50 < 3 microg/ml. EtOH extracts from Vernonia amygdalina leaves (5 < IC50 < 10 microg/ml), Tetracera poggei leaves (10 < IC50 < 50 microg/ml) and Morinda morindoides leaves (50 < IC50 < 100 microg/ml) were less active, but their petroleum ether fractions exhibited a pronounced antiplasmodial activity (IC50 < 3 microg/ml). The same observation could also be made for the petroleum ether fraction from Cassia occidentalis, Euphorbia hirta, Garcinia kola and Phyllanthus niruri. Isoamyl alcohol fractions from Euphorbia hirta, Phyllanthus niruri and Vernonia amygdalina showed IC50) values less than 3 microg/ml, and from Cassia occidentalis, Garcinia kola, Morinda morindoides and Tetracera poggei between 10 and 50 microg/ml. The observed antiplasmodial activity may be related to the presence of terpenes, steroids, coumarins, flavonoids, phenolic acids, lignans, xanthones and anthraquinones.

Animals↗
PubMed2004

In vitro antiplasmodial activity of callus culture extracts and fractions from fresh apical stems of Phyllanthus niruri L. (Euphorbiaceae): part 2.

The ethanolic extracts from fresh apical stems of Phyllanthus niruri L. (Euphorbiaceae) cultured on Murashige and Skoog (MS) medium supplemented with IBA/BAP/Coco nucifera L. milk for 1, 2, 4 and 6 months were phytochemically and biologically investigated and compared with intact plant part and whole plant extracts. Results from the in vitro antiplasmodial testing indicated that the EtOH extract of a 1-month-old callus culture (IC(50) = 16.3 +/- 2.5 microg/ml) exhibited a higher activity than the ethanolic extracts of the fresh apical stem (IC(50) = 18.2 +/- 2.4 microg/ml) and callus cultures of 2-, 4- and 6-months-old (25 microg/ml < IC(50) < 40 microg/ml). These activities were however lower than that displayed by the ethanolic extract of the whole plant (IC(50) < 3 microg/ml). The EtOH extract of 1-month-old callus culture (the most active) was fractionated with solvents of different polarities. Its CH(2)Cl(2) fraction rich in terpenic constituents (IC(50) = 9.2 +/- 3.4 microg/ml) exhibited a higher antiplasmodial activity than its isoamylic alcohol fraction obtained at pH 2-3 (IC(50) = 25.6 +/- 2.3 microg/ml) rich in flavonoids. The activity of these two fractions was lower than that displayed by the same fractions from the whole plant (2 microg/ml < IC(50) < 3 microg/ml). Alkaloidic fractions from the whole plant and 1-month-old callus culture of fresh apical stem were considered as inactive (IC(50) > 100 microg/ml).

Animals↗
PubMed2004

Proanthocyanidins in health care: current and new trends.

Polyphenolic compounds are widely distributed in higher plants and are an integral part of the human diet. Recent interest in these substances has been stimulated by their potential health benefits, which are believed to arise mainly from their antioxidant activity. In the past years, the antioxidant activity of flavonoids has been studied in detail. An important but often overlooked group of polyphenols is that of the proanthocyanidins. Therefore, the present review is focused mainly on the antioxidant activity of proanthocyanidins and its relevancy in vivo. The three most important mechanisms of their antioxidant action will be discussed, i.e. free radical scavenging activity, chelation of transition metals, and inhibition of enzymes. In addition, the protective role of proanthocyanidins against lipid peroxidation and peroxynitrite, as well as their antimicrobial properties will be discussed. To study the in vivo relevancy of the proanthocyanidin activities, the knowledge of their pharmacokinetic parameters is crucial. Although bioavailability and metabolism data on polyphenols in general and proanthocyanidins in particular are still largely unavailable, the first reports indicate that at least monomers and smaller oligomeric procyanidins are absorbed. There is also considerable scientific and public interest in the important role that antioxidants may play in health care, e.g. by acting as cancer chemopreventive and anti-inflammatory agents and by reducing risk of cardiovascular mortality. Each of these aspects will be discussed, with special attention to the role of proanthocyanidins on apoptosis, gene expression and transcription factors, such as NF-kappa B.

Animals↗
PubMed2002

Further evaluation of Rwandan medicinal plant extracts for their antimicrobial and antiviral activities.

A total of 45 Rwandan plant extracts, belonging to 37 different plant species out of 21 families, were investigated for their antibacterial, antifungal, and antiviral properties. The plants were selected on the base of their ethnomedicinal use against infections and autoimmune diseases. From all the plant extracts tested, only Clematis hirsuta (leaves) showed a pronounced antifungal activity against Candida albicans and the dermatophytes Trichophyton rubrum, Epidermophyton floccosum, and Microsporum canis. Seven plant extracts showed a high antiviral activity against the DNA-virus Herpes simplex type 1, while five and three plant extracts were highly active against the RNA-viruses Coxsackie and Polio, respectively. Only Macaranga kilimandscharica (leaves) showed an interesting anti-measles activity, whereas Eriosema montanum (leaves) and Entada abyssinica (leaves) were highly active against Semliki forest virus. Some plant extracts showed an antibacterial activity against Gram-positive bacteria and Mycobacterium fortuitum, but none of them were active against the Gram-negative bacteria tested.

Anti-Bacterial Agents↗
PubMed2002

Correlation between chemical composition and antibacterial activity of essential oils of some aromatic medicinal plants growing in the Democratic Republic of Congo.

The chemical composition of essential oils from 15 aromatic medicinal plant species growing in the Democratic Republic of Congo have been studied. More than 15 constituents in an amount higher than 0.1% were identified in each essential oil. 1,8-cineole, alpha and beta-pinene, p-cymene, myrcene, gamma-terpinene, alpha-terpineol and limonene were prevalent constituents in almost more than 10 selected plant species. Results from the antibacterial testing by the diffusion method indicate that all essential oils (5 microl per disc) inhibited the growth of selected bacteria at different extents. The most active antibacterial essential oils were those of the leaves of Eucalyptus camadulensis and Eucalyptus terticornis (12-30 mm zone diameter of inhibition). They showed particularly a most potent inhibition of Pseudomonas aeruginosa growth (15-16 mm), followed by Eucalyptus robusta (12 mm). Essential oils from the leaves of Eucalyptus alba, Eucalyptus citriodora, Eucalyptus deglupta, Eucalyptus globulus, Eucalyptus saligna, Eucalyptus robusta, Aframomum stipulatum, Cymbopogon citratus, Ocimum americanum and that of the seeds of Monodora myristica showed also a good antibacterial activity (10-18 mm). Eucalyptus propinqua, Eucalyptus urophylla and Ocimum gratissimum essential oils were the less active samples against the selected bacteria. No correlation between the amount of major constituents such as 1,8-cineol, alpha-pinene, p-cymene, cryptone or thymol and the antibacterial activity was observed.

Anti-Bacterial Agents↗
PubMed2002

Antiviral activity of Rwandan medicinal plants against human immunodeficiency virus type-1 (HIV-1).

Selected plants used in Rwandan traditional medicine for the treatment of infections and/or rheumatoid diseases were investigated for antiviral activity in vitro against human immunodeficiency virus type-1 (HIV-1). Of the 38 tested 80% ethanolic extracts, belonging to plants of 21 different families only the extracts from the leaves of Aspilia pluriseta (Asteraceae) and Rumex bequaertii (Polygonaceae) had interesting selectivity indices (SI = ratio of the 50% cytotoxic concentration to the 50% effective antiviral concentration) higher than 1. Further fractionation of the initially antivirally inactive ethanolic extract of Tithonia diversifolia, however, led to an aqueous fraction with a high anti-HIV-1 activity (SI > 461), indicating that the cytotoxicity of some plant components may mask the antiviral properties of the active plant substances in total plant extracts.

Anti-HIV Agents↗
PubMed2002

Complement modulating activity of Rwandan medicinal plants.

Forty-two ethanolic extracts of thirty-six Rwandan medicinal plants were investigated for their influence on complement-mediated hemolysis. The plants were selected on the base of their ethnomedicinal use in infections and autoimmune diseases. Eight plant extracts showed an inhibitory activity against the classical pathway of the complement system and ten plant extracts against the alternative pathway. Three plant extracts exhibited an interesting activity against both pathways, i.e. Aspilia pluriseta, Coleus kilimandschari, and Macaranga kilimandscharica (leaves and stem). Further study indicated that the complement inhibitory activity was not caused by chelation of bivalent cations or by direct action on the target erythrocytes.

Complement Activation↗
PubMed2001

Chemical and biological investigations on Zizyphus spina-christi L.

Different extracts and fractions of the leaves, fruits and seeds of Zizyphus spina-christi L. grown in Egypt were investigated in vitro for their antiviral, antifungal and antibacterial activities. The flavonoids quercetin, hyperoside, rutin and quercetin-3-O-[beta-xylosyl-(1-2)-alpha-rhamnoside] 4'-O-alpha- rhamnoside) were isolated.

Anti-Bacterial Agents↗
PubMed2001

Antiviral, haemolytic and molluscicidal activities of triterpenoid saponins from Maesa lanceolata: establishment of structure-activity relationships.

Ten saponins isolated from the leaves of Maesa lanceolata were tested for their antiviral, haemolytic and molluscicidal activities. The influence of the substitution pattern of these acylated triterpenoid saponins on their biological activities was investigated and structure-activity relationships were established. Maesasaponin VI(2) (3 beta-O-[[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-galactopyranosyl-(1 --> 3)]-[beta-D-galactopyranosyl-(1 --> 2)]-beta-D-glucopyranuronyl]-21 beta,22 alpha-diangeloyloxy-13 beta,28-epoxyolean-16 alpha,28 alpha-diol), the most potent molluscicidal compound (LC(50) 0.5 ppm), also showed virucidal and haemolytic activity. In general, 21,22-diacylation appeared to be associated with a virucidal (reduction factor of the viral titer > or = 10(3) at 50 microg/ml) and haemolytic activity (HC(50) < or = 1 microg/ml).

Animals↗
PubMed2001

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. Results indicated that compounds 1, 3, 4 and 6 exhibited, at different levels, xanthine oxidase inhibiting and superoxide scavenging activity at micromolar concentrations, whereas compound 7 showed scavenging activity only. Compounds 2 and 5 were inactive in both cases. Study of the structure-activity relationship demonstrated that for flavonoids the xanthine oxidase inhibitory activity was reduced by methylation of the hydroxyl functionality at C-3 and in rings A and B. These results may partly explain and support the use of B. ferruginea stem bark for the treatment of rheumatic pains in traditional medicine.

Arthritis, Rheumatoid↗
PubMed2001

In-vivo antimalarial activity of Cassia occidentalis, Morinda morindoides and Phyllanthus niruri.

The ethanolic, dichloromethane and lyophilized aqueous extracts of Cassia occidentalis root bark, Morinda morindoides leaves and whole plants of Phyllanthus niruri were evaluated for their antimalarial actvity in vivo, in 4-day, suppressive assays against Plasmodium berghei ANKA in mice. No toxic effect or mortality was observed in mice treated, orally, with any of the extracts as a single dose, of 500 mg/kg body weight, or as the same dose given twice weekly for 4 weeks (to give a total dose of 4 g/kg). No significant lesions were observed, by eye or during histopathological examinations, in the hearts, lungs, spleens, kidneys, livers, large intestines or brains of any mouse. At doses of 200 mg/kg, all the ethanolic and dichloromethane extracts produced significant chemosuppressions of parasitaemia (of > 60% for C. occidentalis root bark and Ph. niruri whole plant, and of 30% for M. morindoides leaves) when administered orally. The most active ethanolic extract, that of Ph. niruri, reduced parasitaemia by 73%. The dichloromethane extracts of M. morindoides and Ph. niruri produced similar reductions (74% and 72% chemosuppression, respectively), whereas that of C. occidentalis was slightly less active (60% chemosuppression). Each lyophilized aqueous extract was less active than the corresponding ethanolic extract.

Administration, Oral↗
PubMed2000

Antiamoebic and spasmolytic activities of extracts from some antidiarrhoeal traditional preparations used in Kinshasa, Congo.

Three major extracts from some traditional preparations, based on medicinal plants, used as antidiarrhoeal agents were investigated for their putative antiamoebic and spasmolytic activities in vitro. Results indicated that both biological activities are concentrated in the polyphenolic fraction, and not in the saponin or alkaloid containing fractions. The most active polyphenolic extracts were those from Euphorbia hirta whole plant, leaves of Alchornea cordifolia, Crossopteryx febrifuga, Nauclea latifolia, Psidium guajava, Tithonia diversifolia, stem bark of Harungana madagascariensis, Mangifera indica, Maprounea africana and Psidium guajava, inhibiting Entamoeba histolytica growth with MAC < 10 micrograms/ml. The same extracts, at a concentration of 80 micrograms/ml in an organ bath, also exhibited more than 70% inhibition of acetylcholine and/or KCl solution-induced contractions on isolated guinea-pig ileum.

Amebicides↗