Essential oil analysis and anticancer activity of leaf essential oil of Croton flavens L. from Guadeloupe

The leaf essential oil of Croton flavens L., a native plant from the Caribbean area used in traditional medicine, was extracted by hydrodistillation. The composition of the volatile fraction of this essential oil was determined by GC and GC-MS analyses. We have identified 47 compounds, of which viridiflorene (12.22%), germacrone (5.27%), (E)-gamma-bisabolene (5.25%) and beta-caryophyllene (4.95%) are the main components. The anticancer activity of this extract was tested on human lung carcinoma cell line A-549 and human colon adenocarcinoma cell line DLD-1. Croton flavens leaf essential oil was found to be very active against both tumor cell lines, with a GI(50) of 27 +/- 4 microg/ml for A-549 and 28 +/- 3 microg/ml for DLD-1. Three compounds identified in the leaf essential oil, alpha-cadinol (3.97%), beta-elemene (1.53%) and alpha-humulene (1.06%) are cytotoxic against tumor cell lines.     

Evaluation of the anti-inflammatory and anti-proliferation tumoral cells activities of Antrodia camphorata, Cordyceps sinensis, and Cinnamomum osmophloeum bark extracts

The extracts of chloroform (1) and methanol (2) from Antrodia camphorata (AC), and chloroform (3) and n-butanol (4) fractions of methanol extract from Cordyceps sinensis (CS), and hexane (5), ethyl acetate (6), and methanol (7) from Cinnamomum osmophloeum bark (CO) were evaluated for their anti-inflammatory as well as tumor-cell growth inhibitory activities in vitro. All the tested extracts dose dependently inhibited the enhanced production of inflammatory mediators such as nitric oxide (NO) through reducing inducible NO synthase expression, and cytokines (tumor necrosis factor (TNF)-alpha and interleukin (IL)-12 in LPS/IFN-gamma activated murine peritoneal macrophages. In addition, extracts 1 from AC, and 5 and 6 from CO significantly arrest the mitogen-stimulated spleen cells in G0/G1 stage. On the other hand, all these extracts were also evaluated for their tumor-cell proliferation activities in different type of cancer cell lines such as Jurkat, HepG2, PC 3, Colon 205, and MCF 7 as well as normal PBMCs. Compared to untreated controls, the extracts 1, 2, and 4-7 were most active and inhibited Jurkat cells with IC50 value of 22, 40, 18, 4, 5, and 45 microg/ml, respectively. In addition, the extracts 5, 6, and 7 from CO showed potent growth inhibition of HepG2 and PC 3 with IC50 values of 35, 80, 55 microg/ml; and 42, 125, and 50 microg/ml, respectively. Similarly, the extracts 1 and 5 inhibited the growth of Colon 205 and MCF 7 cells with IC50 values of 65, 33; and 95 and 30 microg/ml, respectively. Interestingly, none of the tested extract has shown cytotoxicity towards normal PBMCs up to the concentration range studies (0-150 microg/ml). Taken together, these data suggest that the anti-inflammatory and anti-cancer properties of AC, CS, and CO might result from the growth inhibition of NO, TNF-alpha and IL-12, and tumor cells proliferation, respectively.     

Isolation and identification of cytotoxic compounds from the wood of Pinus resinosa

Methanol extracts of wood from Pinus resinosa were found to be selectively cytotoxic against human lung carcinoma cells, A549 (IC50 41 +/- 6 microg/mL), human colorectal adenocarcinoma cells, DLD-1 (IC50 47 +/- 4 microg/mL) in comparison with healthy cells, WS1 (IC50 130 +/- 11 microg/mL). Five known compounds were isolated and identified by 1H, 13C NMRspectroscopy and HR-ESI-MS mass spectrometry as, pinosylvin monomethyl ether (1), pinosylvin (2), pinosylvin dimethyl ether (3), pinobanksin (4) and (-)-norachelogenin (5). Compound 4 was isolated for the first time in P. resinosa. The cytotoxicity of compounds 1-5 was evaluated against A549, DLD-1 and WS1. Compound 1 exhibited the strongest cytotoxicity against both tumor cell lines and the healthy cell line with an IC50 of 25 +/- 4 microm for A549, 20 +/- 1 microm for DLD-1 and 34 +/- 3 microm for WS1.     

The in vitro biological activity of selected South African Commiphora species

Ten South African Commiphora (Burseraceae) species were investigated to validate their use in traditional healing rites. The leaf and stem extracts of each species were analysed for the anti-oxidant (ABTS and DPPH assays), antimicrobial (MIC and death kinetic assays), anti-inflammatory (5-LOX assay), anticancer (SRB assay) properties, as well as the cytotoxic effects (tetrazolium-based assay). The best anti-oxidant activity (ABTS assay) was observed for the stem extracts of Commiphora tenuipetiolata IC(50)=5.10 microg/ml), Commiphora neglecta (IC(50)=7.28 microg/ml) and Commiphora mollis (IC(50)=8.82 microg/ml). Extracts generally exhibited poor anti-oxidant activity in the DPPH assay, with the exception of Commiphora schimperi (stem), Commiphora neglecta (stem), Commiphora tenuipetiolata (stem and leaf), and Commiphora edulis (stem), with IC(50) values ranging between 7.31 and 10.81 microg/ml. The stem extracts exhibited moderate to good 5-LOX inhibitory activity with Commiphora pyracanthoides (stem) displaying the greatest inhibitory effect (IC(50)=27.86+/-4.45 microg/ml). For the antimicrobial (MIC) assay, a greater selectivity was exhibited by the extracts against the Gram-positive bacteria (0.01-8.00 mg/ml) and the yeasts (0.25-8.00 mg/ml) than against the Gram-negative bacteria (1.00-8.00 mg/ml). Using death kinetic studies (time-kill studies), the rate at which Commiphora marlothii (stem) kills Staphylococcus aureus over a 24h period was determined. Mostly, a concentration-dependent antibacterial activity was observed beginning after ca. 30 min. All concentrations exhibited antibacterial activity, with complete bactericidal effect achieved by the 24(th) hour. The most active Commiphora species against the HT-29 cells (SRB anticancer assay) were Commiphora glandulosa (leaf and stem) and Commiphora marlothii (leaf). The MCF-7 cells (SRB anticancer assay) exhibited the highest sensitivity to indigenous Commiphora species, with Commiphora edulis (leaf and stem), Commiphora glandulosa (leaf and stem), Commiphora marlothii (leaf), Commiphora pyracanthoides (leaf and stem), Commiphora schimperi (stem), and Commiphora viminea (stem) all possessing a percentage inhibition greater than 80% at 100 microg/ml. Commiphora glandulosa (leaf and stem) and Commiphora pyracanthoides (leaf and stem) were the two most active species against the SF-268 cells (SRB anticancer assay), with IC(50) values ranging between 68.55+/-2.01 and 71.45+/-1.24 microg/ml. The majority of the Commiphora extracts were largely non-cytotoxic against Graham human kidney epithelial cells when investigated in the MTT assay.     

Antiparasitic activity of some New Caledonian medicinal plants

Twenty-nine extracts of 18 medicinal plants used in New Caledonia by traditional healers to treat inflammation, fever and in cicatrizing remedies were evaluated in vitro against several parasites (Leishmania donovani, Trypanosoma brucei brucei, Trichomonas vaginalis and Caenorhabditis elegans). Among the selected plants, Scaevola balansae and Premna serratifolia L. were the most active against Leishmania donovani with IC(50) values between 5 and 10microg/ml. The almond and aril extracts from Myristica fatua had an IC(50) value of 0.5-5microg/ml against Trypanosoma brucei brucei. Only Scaevola balansae extract presented a weak activity against Trichomonas vaginalis. The almond extract from Myristica fatua presented significant activity against Caenorhabditis elegans (IC(50) value of 6.6+/-1.2microg/ml).     

In vitro anti-inflammatory and anti-oxidative effects of Cinnamomum camphora extracts

Cinnamomum camphora Sieb (Lauraceae) has long been prescribed in traditional medicine for the treatment of inflammation-related diseases such as rheumatism, sprains, bronchitis and muscle pains. In this study, therefore, we aimed to investigate the inhibitory effects of Cinnamomum camphora on various inflammatory phenomena to explore its potential anti-inflammatory mechanisms under non-cytotoxic (less than 100 microg/ml) conditions. The total crude extract (100 microg/ml) prepared with 80% methanol (MeOH extract) and its fractions (100 microg/ml) obtained by solvent partition with hexane and ethyl acetate (EtOAc) significantly blocked the production of interleukin (IL)-1 beta, IL-6 and the tumor necrosis factor (TNF)-alpha from RAW264.7 cells stimulated by lipopolysaccharide (LPS) up to 20-70%. The hexane and EtOAc extracts (100 microg/ml) also inhibited nitric oxide (NO) production in LPS/interferon (IFN)-gamma-activated macrophages by 65%. The MeOH extract (100 microg/ml) as well as two fractions (100 microg/ml) prepared by solvent partition with n-butanol (BuOH) and EtOAc strongly suppressed the prostaglandin E(2) (PGE(2)) production in LPS/IFN-gamma-activated macrophages up to 70%. It is interesting to note that hexane, BuOH and EtOAc extracts (100 microg/ml) also inhibited the functional activation of beta1-integrins (CD29) assessed by U937 homotypic aggregation up to 70-80%. Furthermore, EtOAc and BuOH extracts displayed strong anti-oxidative activity with IC(50) values of 14 and 15 microM, respectively, when tested by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine oxide (XO) assays. Taken together, these data suggest that the anti-inflammatory actions of Cinnamomum camphora may be due to the modulation of cytokine, NO and PGE(2) production and oxidative stress, and of the subfractions tested, the EtOAc extract may be further studied to isolate the active anti-inflammatory principles.     

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).     

Nitric oxide inhibitory substances from the rhizomes of Dioscorea membranacea

Thai medicinal plants locally known as Hua-Khao-Yen were examined for their inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cell lines. Among the plant species studied, an ethanolic extract of Dioscorea membranacea exhibited the most potent inhibitory activity, with an IC(50) value of 23.6 microg/ml. From this extract, eight compounds [two naphthofuranoxepins (1, 2), one phenanthraquinone (3), three steroids (4-6) and two steroidal saponins (7, 8)] were isolated and further investigated for their inhibitory properties of NO production. It was found that diosgenin-3-O-alpha-L-rhamnosyl (1-->2)-beta-D-glucopyranoside (7) possessed the highest activity (IC(50)=3.5 microM), followed by dioscoreanone (3, IC(50)=9.8 microM) and dioscorealide B (2, IC(50)=24.9 microM). Regarding structural requirements of diosgenin derivatives for NO production inhibitory activity, compound 7 which has a rhamnoglucosyl moiety at C-3 exhibited much higher activity than compounds that have either a diglucosyl substitution (8) or its aglycone (9); whereas, hydroxyl substitution at position 8 of naphthofuranoxepin derivatives conferred higher activity than the methoxyl group. It is concluded that diosgenin-3-O-alpha-L-rhamnosyl (1-->2)-beta-D-glucopyranoside (7), dioscoreanone (3) and dioscorealide B (2) are active principles for NO inhibitory activity of Dioscorea membranacea. Compounds 1-3 were also tested for the inhibitory effect on LPS-induced TNF-alpha release in RAW 264.7 cells. The result revealed that 3 possessed potent activity against TNF-alpha release with an IC(50) value of 17.6 microM, whereas, 1 and 2 exhibited mild activity. The present study may support the use of Dioscorea membranacea by Thai traditional doctors for treatment of the inflammatory diseases.     

Supercritical carbon dioxide extract exhibits enhanced antioxidant and anti-inflammatory activities of Physalis peruviana

Physalis peruviana L. (PP) is a medicinal herb widely used in folk medicine. In this study, supercritical carbon dioxide (SFE-CO2) method was employed to obtain three different PP extracts, namely SCEPP-0, SCEPP-4 and SCEPP-5. The total flavonoid and phenol concentrations, as well as antioxidant and anti-inflammatory activities of these extracts were analyzed and compared with aqueous and ethanolic PP extracts. Among all the extracts tested, SCEPP-5 demonstrated the highest total flavonoid (234.63+/-9.61 mg/g) and phenol (90.80+/-2.21 mg/g) contents. At concentrations 0.1-30 microg/ml, SCEPP-5 also demonstrated the strongest superoxide anion scavenging activity and xanthine oxidase inhibitory effect. At 30 microg/ml, SCEPP-5 significantly prevented lipopolysaccharide (LPS; 1 microg/ml)-induced cell cytotoxicity in murine macrophage (Raw 264.7) cells. At 10-50 microg/ml, it also significantly inhibited LPS-induced NO release and PGE2 formation in a dose-dependent pattern. SCEPP-5 at 30 microg/ml remarkably blocked the LPS induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Taken together, these results suggest that SCEPP-5, an extract of SFE-CO2, displayed the strongest antioxidant and anti-inflammatory activities as compared to other extracts. Its protection against LPS-induced inflammation could be through the inhibition of iNOS and COX-2 expression.     

Spasmolytic action of Lepechinia caulescens is through calcium channel blockade and NO release

The present study was undertaken to elucidate the mode of action of methanol extract from aerial parts of L. caulescens (TC-MELc) as spasmolytic agent on in vitro rat ileum test, and investigate the possible antibacterial activity of different extracts from the plant. TC-MELc induced a concentration-dependent (0.001 to 100microg/mL) antispasmodic effect on spontaneous contractions. TC-MELc also (IC50 11.2microg/mL) induced a marked depression on cumulative concentration-response curve for carbachol (Emax=2.3+/-0.3g vs. 0.66+/-0.1g) and serotonin (Emax=1.1+/-0.3g vs. -0.01+/-0.09g). Besides, extract decreased and displaced to the right KCl and CaCl2 concentration-response curves. Moreover, TC-MELc (11.2microg/mL) provoked a total relaxation when ileum strips were contracted with carbachol (1microM) in calcium-free Krebs solution. Pre-treatment with l-NAME (10microM) produced a significant change of the relaxant response and activity was markedly inhibited. Additionally, hexanic (HELc), dichloromethanic (DELc) and methanolic (MELc) extracts from aerial parts were studied to determine their antibacterial activity. DELc showed antibacterial activity on all bacterial strains assayed (相似文献   

Effects of compounds from Kaempferia parviflora on nitric oxide, prostaglandin E2 and tumor necrosis factor-alpha productions in RAW264.7 macrophage cells

Kaempferia parviflora Wall. ex Baker, is one of the plants in the Zingiberaceae family, locally known in Thai as kra-chai-dam. The rhizome of this plant has been used for treatment of gout, apthous ulcer and abscesses. Since K. parviflora rhizomes have long been used for treatment of inflammation and possessed marked nitric oxide (NO) inhibitory activity (IC(50)=7.8microg/ml), we thus investigated the inhibitory activity of compounds isolated from this plant against lipopolysaccharide (LPS)-induced NO release in RAW264.7 cells. From bioassay-guided fractionation of K. parviflora, seven methoxyflavones were isolated from the hexane fraction and were tested for their anti-inflammatory effects. Among the isolated compounds, compound 5 (5-hydroxy-3,7,3',4'-tetramethoxyflavone) exhibited the highest activity against NO release with an IC(50) value of 16.1microM, followed by 4 (IC(50)=24.5microM) and 3 (IC(50)=30.6microM). Compound 5 was also tested on LPS-induced prostaglandin E(2) (PGE(2)) and tumor necrosis factor-alpha (TNF-alpha) releases from RAW264.7 cells. It was revealed that 5 showed appreciable inhibitory effect on PGE(2) release (IC(50)=16.3microM), but inactive on TNF-alpha (IC(50)>100microM). These findings may support the use in Thai traditional medicine of K. parviflora for treatment of inflammatory-related diseases through the inhibition of NO and PGE(2) releases but partly due to that of TNF-alpha.     

Suppressive effect of inducible nitric oxide synthase (iNOS) expression by the methanol extract of Actinodaphne lancifolia

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has played a crucial role in various pathophysiological processes including inflammation and carcinogenesis. Therefore, the inhibitors of NO synthesis or iNOS gene expression have been considered as potential anti-inflammatory and cancer chemopreventive agents. In our continuous search for iNOS inhibitors from natural products we have evaluated indigenous Korean plant extracts using an assay for inhibition of nitric oxide formation on lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells. As a result, the methanolic stem extract of Actinodaphne lancifolia showed an inhibitory activity of NO production in a dose-dependent manner (IC50 = 2.5 microg/ml). Additional study demonstrated that the extract of Actinodaphne lancifolia significantly suppressed the iNOS protein and gene expression in a dose-dependent manner. These results suggest that Actinodaphne lancifolia could be a potential candidate for developing an iNOS inhibitor from natural products. Further elucidation of active principles for development of new cancer chemopreventive and/or anti-inflammatory agents could be warranted.     

Calcium antagonistic activity of Bacopa monniera on vascular and intestinal smooth muscles of rabbit and guinea-pig.

The present study demonstrates the calcium antagonistic activity in ethanol extract of Bacopa monniera. The plant extract inhibited the spontaneous movements of both guinea-pig ileum (IC50 = 24+/-4 microg/ml) and rabbit jejunum (IC50 = 136+/-9 microg/ml). A marked reduction in acetylcholine- and histamine-induced responses (0.0001-10 microM) in the ileum was evident in the presence of extract (260 microg/ml). The acetylcholine (1 microM)-induced contraction in the ileum was also inhibited by the extract (100-700 microg/ml) in a concentration dependent way (IC50 = 285+/-56 microg/ml). All these results indicate a direct action of the extract on smooth muscles. Calcium chloride-induced responses in the rabbit blood vessels and jejunum were attenuated in the presence of plant extract (10-700 microg/ml) implying a direct interference of plant extract with influx of calcium ions in the cells. However, the lack of modification of either noradrenaline- or caffeine-induced contractions in the presence of extract suggests that extract has no detectable effect on mobilization of intracellular calcium. These results indicate that spasmolytic effect of the B. monniera extract in smooth muscles is predominantly due to inhibition of calcium influx via both voltage and receptor operated calcium channels of the cell membrane.     

Composition and cytotoxic activity of the leaf essential oil of Comptonia peregrina (L.) Coulter

Comptonia peregrina (L.) Coulter, a native plant from Canada used in traditional medicine against cancer, was extracted by hydrodistillation. Two fractions were collected, one over 0-30 min and one over 30-60 min, to assess the influence of time of hydrodistillation on the composition of essential oil. The chemical composition of these two extracts was determined by GC and GC-MS analyses. Fifty five components were identified: beta-caryophyllene (23.69% and 15.16%) and alpha-humulene (9.67% and 7.43%) were the major components in the 0-30 min and 30-60 min fractions, respectively, while beta-myrcene was detected in a higher amount in the 0-30 min fraction (12.58%) than in the 30-60 min fraction (0.15%). The cytotoxic activities of these fractions were assessed against human lung carcinoma cell line A-549 and human colon adenocarcinoma cell line DLD-1. Only the 30-60 min fraction was found to be active against both tumor cell lines, with GI(50) values of 66 +/- 12 microg/mL for A-549 and of 46 +/- 7 microg/mL for DLD-1. Two sesquiterpenes present in the oil, alpha-humulene and (E)-nerolidol, have been found to be cytotoxic against both tumor cell lines.     

In vitro antitrypanosomal activity of ethnopharmacologically selected Beninese plants

The in vitro antitrypanosomal activity of methylene chloride, methanol and aqueous extracts of the leaves and twigs of five plant species traditionally used in Benin for the treatment of sleeping sickness were evaluated on Trypanosoma brucei brucei and their selectivity was analysed on Leishmania mexicana mexicana and J774 macrophage-like murine cells. The results showed that the four most active extracts had MIC values < or =19 microg/ml (Hymenocardia acida twig and leaf, Strychnos spinosa leaf, Trichilia emetica leaf methylene chloride extracts). All these extracts had a lower activity on L. m. mexicana and J774 cells. Determination of the IC50 values of the methylene chloride leaf extracts on two strains of trypanosomes (T. b. brucei and T. b. rhodesiense) and two mammalian cell lines (L6 and J774 cells) showed that all extracts possessed some antitrypanosomal activity with IC50's ranging from 1.5 to 39 microg/ml. All were also toxic to the mammalian cells, but usually with higher IC50's. The only exception was the S. spinosa methylene chloride leaf extract which had no toxicity on J774 cells. Although tannins have been identified in most of the species studied, they could not be detected in the most active extracts, just as alkaloids. The presence of flavonoids and quinones may at least in part explain the observed activities of some of the active extracts.     

In vitro antiplasmodial activity of Brazilian Cerrado plants used as traditional remedies

Twenty-seven species of native Brazilian Cerrado plants commonly used by traditional healers to treat malaria and other diseases were collected and 204 hexanic and ethanolic extracts were obtained by maceration. The antiplasmodial activity of the extracts was tested in vitro against a chloroquine resistant strain (FcB1) of Plasmodium falciparum, and cytotoxicity against the cell lines L-6 of rats and MRC-5 of human was evaluated. Thirty-two extracts showed significant inhibition rates of Plasmodium falciparum growth and of these six showed cytotoxicity against the cell lines. The strongest antiplasmodial activity was found for the hexanic extracts of Xylopia aromatica root wood (IC(50)=4.7 microg/ml), Xylopia emarginata root bark (IC(50)=4.9 microg/ml), Casearia sylvestris var. lingua leaves, stem wood and stem bark, and root wood and root bark (IC(50) values from 0.9 to 2.3 microg/ml), and Cupania vernalis leaves (IC(50)=0.9 microg/ml); and for the ethanolic extract of Aspidosperma macrocarpon root bark (IC(50)=4.9 microg/ml). However, the best selectivity towards Plasmodium falciparum was observed for the hexanic root bark extract of Matayba guianensis (IC(50) on Plasmodium falciparum=6.1 microg/ml, SI=16.4 for MRC-5) and the ethanolic root bark extract of Aspidosperma macrocarpon (IC(50) on Plasmodium falciparum=4.9 micro/ml, SI=16.2 for MRC-5).     

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.     

Studies of the anticancer potential of plants used in Bangladeshi folk medicine

The present study evaluated the anticancer potential of 11 plants used in Bangladeshi folk medicine. The extracts were tested for cytotoxicity using the brine shrimp lethality assay, sea urchin eggs assay, hemolysis assay and MTT assay using tumor cell lines. The extract of Oroxylum indicum showed the highest toxicity on all tumor cell lines tested, with an IC(50) of 19.6 microg/ml for CEM, 14.2 microg/ml for HL-60, 17.2 microg/ml for B-16 and 32.5 microg/ml for HCT-8. On the sea urchin eggs, it inhibited the progression of cell cycle since the frist cleavage (IC(50)=13.5 microg/ml). The extract of Aegle marmelos exhibited toxicity on all used assays, but in a lower potency than Oroxylum indicum. In conclusion, among all tested extracts, only the extracts of Oroxylum indicum, Moringa oleifera and Aegles marmelos could be considered as potential sources of anticancer compounds. Further studies are necessary for chemical characterization of the active principles and more extensive biological evaluations.     

In vitro 12(S)-HETE inhibitory activities of naphthoquinones isolated from the root bark of Euclea racemosa ssp. schimperi

Platelet 12-lipoxygenase is believed to play a role in cancer and other pathological conditions, such as psoriasis, atherosclerosis and arthritis. The inhibition of 12-LOX is a potential therapeutic approach in the treatment of tumor metastasis. The extracts of Euclea racemosa Murr. ssp. schimperi (A. DC.) F. White (Ebenaceae) obtained by maceration and naphthoquinones isolated from the dichloromethane extract have been investigated for their 12(S)-HETE inhibitory activity using human platelets. At 100 microg/ml, the dichloromethane extract inhibited the formation of 12(S)-HETE by 88.7% and compounds 7-methyljuglone (2), isodiospyrin (3), neodiospyrin (4) and mamegakinone (5), isolated from this extract, exhibited significant activities with IC(50) values ranging from 4 to 58 microg/ml (22.2-155.7 microM). Of these the most abundant compound, 7-methyljuglone displayed a potent inhibitory activity with an IC(50) value of 4.18 microg/ml (22.2 microM), which was comparable to the positive control baicalein with an IC(50) value of 5 microg/ml (18.5 microM). In contrast, 4(S)-shinanolone (1), the reduced form of compound 2, did not show any significant inhibitory activity even at a concentration of 60 microg/ml.