Alpha-hederin potentiates 5-FU antitumor activity in human colon adenocarcinoma cells.

The aim of this study was to investigate the ability of alpha-hederin to improve the efficacy of widely prescribed 5-fluorouracil (5-FU) in a human colon adenocarcinoma model. Drug combinations of alpha-hederin and 5-FU using both fixed-concentration and combination index methods were performed in vitro in HT-29 cells. The results showed that alpha-hederin at sub-IC(50) cytotoxic concentrations enhanced 5-FU cytotoxicity about 3.3-fold (p < 0.001). Simultaneous combination of alpha-hederin and 5-FU at their IC(50) ratio showed either a synergistic effect at a moderate cytotoxic range (25% of cell growth inhibition) or an antagonistic effect at a high level of growth inhibition. The data indicate therefore that it is possible to optimize colorectal cancer cell sensitivity to 5-FU with alpha-hederin.

Alternative and complementary antileishmanial treatments: assessment of the antileishmanial activity of 27 Lebanese plants, including 11 endemic species.

Aqueous, methanolic, and dichloromethane extracts from 27 Lebanese plants were investigated for their in vitro immunomodulatory and antileishmanial activities as compared to their toxicity against human cells. Extracts from yellow chamomile (Anthemis tinctoria), white larkspur (Consolida rigida), Syrian broom (Cytisus syriacus), coast spurge (Euphorbia paralias), shield fibigia (Fibigia clypeata), Auchers golden-drop (Onosma aucheriana), shell-flower sage (Salvia multicaulis), snowy woundwort (Stachys nivea), Palestine woundwort (Stachys palaestina), and polium-leaved speedwell (Veronica polifolia) exhibited interesting antileishmanial activities on the intracellular amastigote form of the parasite, while several extracts from A. tinctoria, F. clypeata, and O. aucheriana were shown to induce nitrous oxide (NO) production by human macrophages. Further experiments should be performed in order to purify and characterize the chemical compounds responsible for these activities.

Monoterpene glycosides isolated from Fadogia agrestis.

Six monoterpene glycosides were isolated from Fadogia agrestis. Their structures were elucidated using a combination of mass spectroscopy, 1D- and 2D-homo- and hetero-NMR spectroscopy and chemical analysis, and established as being derivatives of 2,6-dimethyl-2(E),6(Z)-octadiene-1,8-diol containing from two to four units of rhamnopyranose and, three of them, one or two additional units of glucopyranose. In three of the compounds an acyl group of 8-hydroxy-2,6-dimethyl-2(E),6(Z)-octadienoyl was found esterifying the O-2 position of one of the units of rhamnopyranose.

Reversal of P-glycoprotein-mediated drug efflux by eudesmin from Haplophyllum perforatum and cytotoxicity pattern versus diphyllin, podophyllotoxin and etoposide.

The present study focuses on eudesmin (bicyclic lignan, 0.15 % of dry leaves) and diphyllin (arylnaphthalene lignan, 0.1 % of dry roots), both isolated from H. perforatum Kar. et Kir, a Rutaceae species endemic to Uzbekistan. We first compared their specificity for cancer cells with those of etoposide and podophyllotoxin by screening their cytotoxicity on 3 healthy cell-lines and 7 sensitive or resistant human solid cancer lines. We then tested their capacity to reverse P-glycoprotein-mediated multidrug resistance (MDR) by assaying dye and drug uptake in MDR1-transfected Madin-Darby canine kidney (MDCK-MDR1) and doxorubicine-resistant human breast carcinoma cells (MCF7/Dox). Eudesmin displays IC (50) values > 100 microM on all tested lines. Our data provide the first demonstration that this non-toxic lignan reverses Pgp-mediated drug efflux and supports the hypothesis that it may inhibit resistance mediated by MDR1 and MRP proteins. Even if its reversal activity is insufficient for clinical application, its capacity to accumulate [(3)H]-vinblastine in MDCK/MDR1 and MCF7/Dox cells suggests that eudesmin may positively affect the bioavailability and, thereby, the therapeutic potency of anticancer drugs in Pgp-overexpressing cells. Diphyllin exhibits IC (50) values ranging from 10 (- 6) to 10 (- 4) M. It is markedly less toxic than podophyllotoxin (IC (50) : 13 - 61 nM), but exhibits tumoricidal effects close to those of etoposide. Unfortunatly, it is 65-fold more toxic than etoposide on human primary fibroblasts. Consequently, it has no value as an anticancer drug. Its value as raw material for the hemisynthesis of anticancer drugs is discussed.

In vitro antimicrobial activity of plants used in Cambodian traditional medicine.

The purpose of the present study was to screen 27 plant species used in the traditional medicine of Cambodia for in vitro antibacterial and antifungal activities. Thirty-three methanolic extracts were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium smegmatis and Candida albicans. Screened by disk diffusion assay, the extracts showed antimicrobial activity especially on Gram-positive bacteria. None of the crude methanolic extracts showed activity against P. aeruginosa. Twenty-five selected extracts were evaluated using a micro-dilution test. Harrisonia perforata (roots) and Hymenodictyon excelsum (bark) exhibited a bactericidal effect against S. aureus at a concentration of 500 microg/ml. Azadirachta indica (bark), Harrisonia perforata (roots and stem) and Shorea obtusa (roots) exhibited a bactericidal effect against M. smegmatis at 250 microg/ml.

Antimalarial activity of alkaloids isolated from Stephania rotunda.

Stephania rotunda (Menispermaceae) is used in traditional medicine for the treatment of fever. Four major alkaloids: dehydroroemerine, tetrahydropalmatine, xylopinine, cepharanthine as well as aqueous extract (SA), dichloromethane extracts (SD1 and SD2) from this plant were tested against Plasmodium falciparum W2 in vitro. Dehydroroemerine, cepharanthine and SD1 were the most active against W2 with IC(50) of 0.36, 0.61microM and 0.7microg/mL, respectively. Their IC(50) on human monocytic THP1 cells were 10.8, 10.3microM and >250microg/mL, respectively. Cepharanthine, SD1 and SA were selected for in vivo antimalarial test against Plasmodium berghei in mice. The results of SD1 and SA at dose of 150mg/kg showed a decrease of 89 and 74% of parasitaemia by intra-peritoneal injection and 62.5 and 46.5% of parasitaemia by oral administration, respectively. The result of cepharanthine at dose of 10mg/kg showed a decrease of 47% of parasitaemia by intra-peritoneal injection and 50% of parasitaemia by oral administration. Drug interaction of chloroquine and major alkaloids indicates that cepharanthine-chloroquine and tetrahydropalmatine-xylopinine associations are synergistic. These results are in agreement with the use of this plant in the treatment of malaria. This is the first report on in vivo antimalarial investigation for Stephania rotunda.

Antileishmanial activity of quinovic acid glycosides and cadambine acid isolated from Nauclea diderrichii.

Nine quinovic acid glycosides and the alkaloid cadambine acid isolated from N. diderrichii, an evergreen endemic plant of West and Central Africa, were assessed for their in vitro antileishmanial activity against Leishmania infantum. Four quinovic acid glycosides and cadambine acid revealed a strong antileishmanial activity (IC (50) = 1 microM) highly specific for the intracellular amastigote form of the parasite. Quinovic acid glycosides were shown to inhibit parasite internalisation by interfering with promastigotes while cadambine acid exerted immunomodulatory activity by inducing NO production in human macrophages. The association of cadambine acid with amphotericin B demonstrated an interesting synergism, suggesting that cadambine acid could be used as a complement of such conventional therapy.

HPLC quantification of alkaloids from Haplophyllum extracts and comparison with their cytotoxic properties.

An efficient system for the analysis of total alkaloids extracted from the aerial parts from different species of genus Haplophyllum (Rutaceae) by HPLC on a reversed-phase column is described. The HPLC method described was validated for its specificity, linearity and precision using external standards (haplopine, skimmianine and haplamine). The chromatographic conditions allowed the separation of alkaloids and the quantification of haplopine, skimmianine and haplamine in different samples of species of Haplophyllum collected in Uzbekistan. The alkaloidal contents of samples were compared with their in vitro cytotoxic properties against two cancer cell lines (HeLa and HCT-116). The cytotoxicity of extracts was correlated with the concentration of haplopine, skimmianine or haplamine in aerial parts of species of Haplophyllum.

Screening of selected indigenous plants of Cambodia for antiplasmodial activity.

The in vitro antiplasmodial activity of 117 aqueous, methanol and dichloromethane extracts derived from different parts of 28 indigenous wild plant species was studied. These plants are commonly used in Cambodian traditional medicine. The plant extracts were tested for in vitro activity against a chloroquine resistant Plasmodium falciparum strain (W2). Nine extracts were moderately active with IC(50) values ranging between 5 and 10 microg/ml, 17 extracts were active with IC(50) values ranging between 1 and 5 microg/ml. These 26 extracts derived from eight plants belong to six families. The most active extracts were dichloromethane and came from Stephania rotunda and Brucea javanica with IC(50) values of 1 microg/ml and a selectivity index > or = 25. It is interesting to note that some aqueous extracts were as active as dichloromethane extracts especially aqueous extracts of Stephania rotunda, Brucea javanica, Phyllanthus urinaria and Eurycoma longifolia with IC(50) values of < or = 4 microg/ml. These results are in agreement with statements of healers on traditional uses of these plants for the treatment of malaria and/or fever. In this study, we report the antiplasmodial potential activity of eight plant species from Cambodia. Among them four are tested for the first time.

Phytochemical and pharmacological study of roots and leaves of Guiera senegalensis J.F. Gmel (Combretaceae).

The chemical composition of total alkaloids from leaves and roots of Guiera senegalensis was investigated. Three beta-carboline alkaloids were purified: in addition to harman and tetrahydroharman, known in roots and leaves, harmalan (dihydroharman) was isolated for the first time from roots of Guiera senegalensis. Guieranone A, a naphthyl butenone, was also purified from leaves and roots. The in vitro antiplasmodial activity and the cytotoxicity of extracts and pure compounds were evaluated. Each total alkaloid extract and beta-carboline alkaloids presented an interesting antiplasmodial activity associated with a low cytotoxicity. Harmalan was less active than harman and tetrahydroharman. Guieranone A showed a strong antiplasmodial activity associated with a high cytotoxicity toward human monocytes. Its cytotoxicity was performed against two cancer cell lines and normal skin fibroblasts in order to study its anticancer potential: guieranone A presented a strong cytotoxicity against each cell strains. Finally, we evaluated the potent synergistic antimalarial interaction between Guiera senegalensis and two plants commonly associated in traditional remedies: Mitragyna inermis and Pavetta crassipes. Three associations evaluated were additive. A synergistic effect was shown between total alkaloids extracted from leaves of Guiera senegalensis and those of Mitragyna inermis. This result justified the traditional use of the plants in combination to treat malaria.

Lignans and secoiridoids from the root bark of Chionanthus virginicus L.: isolation, identification and HPLC analysis.

Five lignans, phillyrin (1), pinoresinol-beta-D-glucoside (2), pinoresinol di-beta-D-glucoside (3), phillyrin-2-O-beta-D-glucoside (6), phillyrin-6-O-beta-D-glucoside (7), and three secoiridoids, oleuropein (4), ligustroside (5) and angustifolioside B (8), have been isolated from the root bark of Chionanthus virginicus L. (Oleaceae), a raw material used in the commercial preparation of homeopathy tinctures. Compound 6 is a new lignan, and compounds 2, 3, 4, 5, 7 and 8 are described for the first time in the title plant. The structures of these compounds were elucidated by spectroscopic methods (NMR and HPLC-MS). An isocratic HPLC method for the rapid characterisation and quantification of the major constituents, 1 and 4, of the root bark is described and validated.

HPLC quantification of uncarine D and the anti-plasmodial activity of alkaloids from leaves of Mitragyna inermis (Willd.) O. Kuntze.

An efficient system for the analysis of the total alkaloids extracted from leaves of Mitragyna inermis (Willd.) O. Kuntze (Rubiaceae) by HPLC using a reversed-phase column is described. The chromatographic conditions allowed the separation of indole and oxindole alkaloids in leaf extracts, and the quantification of uncarine D in samples collected in Burkina Faso and Mali. The HPLC method described was validated for its specificity, linearity and precision using an internal standard (naphthalene). The concentrations of uncarine D in various extracts were compared with their in vitro anti-plasmodial activity. The anti-proliferative activity on chloroquine-resistant strain (W2) of Plasmodium falciparum was not correlated with the concentration of uncarine D in leaves.

Triterpenoid saponins from leaves of Hedera pastuchowii.

Five new triterpenoid saponins, pastuchoside A (1), B (3), C (5), D (7) and E (9), were isolated from the leaves of Hedera pastuchowii. They have oleanolic acid or hederagenin as aglycone. The structures were established by NMR spectroscopy including gs (gradient selected)-COSY, gs-HSQC, gs-HSQC-TOCSY and gs-HMBC experiments, and mass spectrometry (ESI-HR-MS). Heptaoside saponins, compounds 1 and 3, are described for the first time in the genus Hedera.

In vitro activity of hederacolchisid A1 compared with other saponins from Hedera colchica against proliferation of human carcinoma and melanoma cells.

Hederacolchisid A1, a new oleanolic acid monodesmoside, isolated from Hedera colchica K. Koch, an ivy species endemic in Georgia, was evaluated in vitro for antiproliferative activity on cancer cells versus normal cells in comparison to cisplatin. Investigations were made on six human cell lines (colon adenocarcinoma DLD-1, ovarian teratocarcinoma PA 1, lung carcinoma A 549, breast adenocarcinoma MCF7, prostatic adenocarcinoma PC 3 and malignant melanoma M4 Beu) versus normal human fibroblasts, by assaying both cellular metabolic activity (RTT test) and DNA content in living cells (test with Hoechst 33,342) after 48 h continuous contact. Results demonstrated the strong cytotoxicity of hederacolchisid A 1 on all cancer cells (IC50 from 4.5 to 12 microM). The antiproliferative effects on malignant melanoma M4 Beu (IC50 ca 4.5 microM) versus normal cells (IC50 ca 7.5 microM) suggests that, despite a lack of specificity for cancer cells, hederacolchisid A1 has potential anti-tumor applications. Comparison of the cytotoxicity of hederacolchisid A 1 with that of five other saponins from H. colchica, offers some new information about structure-activity relationships. It was observed that i) for a same sugar sequence, monodesmosides with oleanolic acid as aglycone exhibit higher cytotoxicity than those containing hederagenin, ii) the sugar sequence O-alpha-L-rhamnopyranosyl (1 --> 2)-alpha-L-arabinopyranoside at C3 induces strong cytotoxicity and might be identified as a basic sequence for anti-tumor activity of oleanolic acid monodesmosides. iii) a complementary glucopyranosyl moiety branched at C1 of arabinose increases the cytotoxicity against malignant melanoma M4 Beu, prostatic adenocarcinoma PC 3 and normal fibroblasts in a different manner for each type of monodesmoside. A slight increase whose amplitude was quite similar on cancers and normal cells, was observed with oleanolic acid monodesmoside. This increase was much higher with hederagenin monodesmoside and markedly elevated in normal cells than in cancer cells.

In vitro anti-tumor promoting and anti-parasitic activities of the quassinoids from Eurycoma longifolia, a medicinal plant in Southeast Asia.

Some quassinoids (1-6) isolated previously as plant growth inhibitors from the leaves of Eurycoma longifolia Jack. (Simaroubaceae) were subjected to in vitro tests on anti-tumor promoting, antischistosomal and plasmodicidal activities. The most active compound for inhibition of tumor promoter-induced Epstein-Barr virus activation (anti-tumor promotion) was 14,15beta-dihydroxyklaineanone (5, IC(50) = 5 microM). Longilactone (1) gave significant antischistosomal effect at a concentration of 200 microg/ml. 11-Dehydroklaineanone (3) and 15beta-O-acetyl-14-hydroxyklaineanone (6) showed potent plasmodicidal activity (IC(50) = 2 microg/ml). Thus it was suggested that E. longifolia possesses high medicinal values due to the occurrence of a variety of quassinoids.