In vitro antiplasmodial activity and cytotoxicity of extracts and fractions of Vitex madiensis, medicinal plant of Gabon

Vitex madiensis Oliv. (Lamiaceae) is traditionally used to treat malaria symptoms in Haut‐Ogooué, Gabon. Leaves and stem barks extracts were obtained using dichloromethane (CH₂Cl₂), ethyl acetate (EtOAc) and methanol (MeOH) as extraction solvents and fractionated on silica gel column. The in vitro antiplasmodial activity of CH₂Cl₂, EtOAc and MeOH extracts and fractions was evaluated against the chloroquine‐resistant FCB strain and field isolates of Plasmodium falciparum using the DELI test. The cytotoxicity of the extracts was tested on MRC‐5 and THP1 cells using the tetrazolium salt MTT colorimetric assay, and the selectivity index (SI) of each extract was calculated. CH₂Cl₂ extract, the EA1 fraction from EtOAc extract of stem barks and cyclohexane (L_cycl), dichloromethane (L_DM) and butanol (L_but) fractions from MeOH/H₂O extract of leaves exhibited the highest in vitro antiplasmodial activity on FCB strain and field isolates (IC₅₀ from 0.53 to 4.87 μg/ml) with high selectivity index (of 20.15–1800). These data support the use of V. madiensis in malaria treatment along with continued investigations within traditional medicines in the search of new antimalarial agents. The EA1, C₆H₁₂ and CH₂Cl₂ fractions could be selected for future investigation or/and for the treatment of malaria symptoms after standardization.     

In vitro antiplasmodial activity of crude extracts from Togolese medicinal plants

ObjectiveTo investigate the antimalarial effect of a few plants in Togo folk medicine.MethodsAfter ethnobotanical survey, Opilia celtidifolia, Pavetta corymbosa (P. corymbosa) and Tamarindus indica (T. indica) were selected for screening. In vitro antimalarial tests were performed on crude extracts against fresh clinical isolates of Plasmodium falciparum using the semi microtest.ResultsDifferent IC₅₀ values of the extracts ranged from 2.042 to 100.000 μg/mL. According to the results, the methanol extract of aerial part of P. corymbosa followed by aqueous extract of fruit of T. indica were the most active (IC₅₀ of 2.042 and 4.786 μg/mL, respectively). Qualitative test revealed the presence of alkaloids in the leaves of P. corymbosa that may be responsible for the activity of the plant.ConclusionsOur study provides scientific evidence for usage of plant in the folk medicine, and further studies are needed for identification and purification of the active principles.     

In vitro antiplasmodial activity and cytotoxicity of newly synthesized N-alkyl and N-benzyl-1,10-phenanthroline derivatives

A previous study showed that the 1,10-phenanthroline skeleton was active in vitro against chloroquine-resistant and sensitive strains of Plasmodium falciparum. Based on this skeleton, 8 derivatives of N-alkyl and N-benzyl-1,10-phenanthrolines have been synthesized. This study was conducted to evaluate the in vitro antiplasmodial activity and cytotoxicity of these compounds. The in vitro antiplasmodial activity was tested on two strains of P. falciparum, FCR-3 chloroquine-resistant and D10 chloroquine-sensitive strains, while their cytotoxicity was tested on the Vero cell line. The parasite and cell growth were estimated by hypoxantine-[2,8-3H] uptake after 24- and 72-hour incubation with each compound tested. The control parasite or cell free from any compounds was referred to as having 100% growth. For this radioactive method, the IC50 value showing concentration inhibiting 50% of the parasite growth was determined by probit analysis. The results showed that the highest antiplasmodial activity was observed with (1)-N-benzyl-1,10-phenanthrolinium iodide with the IC50 0.18-0.45 microM, and the IC50 of the compound on Vero cells ranged from 2,582.30 to 7,057.71 microM. The cytotoxic/ antiplasmodial ratio indicates that this compound has high selectivity (10,993 +/- 330.79-38,965 +/- 6,888.27).     

Isolation,fractionation and evaluation of the antiplasmodial properties of Phyllanthus niruri resident in its chloroform fraction

ObjectiveTo investigate the antiplasmodial activity of Phyllanthus niruri (P. niruri) methanol extract (ME) and its fractions in mice.MethodsP. niruri methanol extract and its chloroform, ethanol and aqueous portions were tested against chloroquine-sensitive Plasmodium berghei berghei in early, established and repository models of infection using Knight and Peter's 4-day suppressive model, Ryley and Peters curative model and Peters prophylactic model respectively.ResultsChemosuppression of parasitaemia (37.65%–50.53 %) was elicited by 100–400 mg/kg (b.w.) of ME. At doses of 100 mg/kg b.w., the chloroform fraction (F1) significantly (P<0.01) suppressed parasitaemia by 85.29%, while ethanol and aqueous fractions (F2 and F3, respectively) elicited 67.06% and 51.18% chemosuppression. The most active fraction, F1 was selected for further antiplasmodial screening. In established infection, ME reduced parasitaemia (15.81%–62.96%) while F1 significantly (P<0.01) reduced parasitaemia (44.36%–90.48%), with effects comparable to that of chloroquine (96.48%). The prophylactic antiplasmodial activity of ME (92.50% suppression) was also significant (P<0.01) and was more effective than pyrimethamine (85.00%). Additionally, cell membrane integrity of non-parasitized erythrocytes incubated with 125–500 mg/mL F1 was maintained.ConclusionsThese findings indicate the antiplasmodial efficacy of P. niruri methanol extract, and the localization of this effect in its chloroform fraction.     

In vitro antiplasmodial activity of ethanolic extracts of South Indian medicinal plants against Plasmodium falciparum

ObjectiveTo explore the antiplasmodial potential ofCatharanthus roseus L (C. roseus), Coccinea grandis (C. grandis), Thevetia peruviana (T. peruviana), Prosopis juliflora (P. juliflora), Acacia nilotica (A. nilotica), Azadirachta indica (A. indica) (Abr. Juss) and Morinda pubescens (M. pubescens).MethodsThe C. roseus L, C. grandis, T. peruviana, P. juliflora, A. nilotica, A. indica (Abr. Juss) and M. pubescens were collected from Ramanathapuram District, Tamil Nadu, India and the extraction was carried out in ethanol. The filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg/mL) were tested for antiplasmodial activity against Plasmodium falciparum. The phytochemical constituents in the potential extracts were also detected.ResultsOf the selected plants species, the bark extract of A. indica (Abr. Juss) showed excellent antiplasmodial activity (IC₅₀ 29.77 μg/mL) followed by leaf extract of A. indica (Abr. Juss) (IC₅₀47.20 μg/mL) and leaf extract of C. roseus L (IC₅₀49.63 μg/mL). The leaf, bark and flower extracts of P. juliflora showed IC₅₀values of more than 100 μg/mL. Statistical analysis reveals significant antiplasmodial activity (P<0.01) between the concentrations and time of exposure. Additionally, no chemical injury was found in the erythrocytes incubated with the ethanolic extract of all the tested plants. The in vitro antiplasmodial activity might be due to the presence of alkaloids, glycosides, carbohydrates, flavonoids, phenols, saponins, triterpenoids, proteins and tannins in the ethanolic extracts of the tested plants.ConclusionsThe ethanolic bark extracts of A. indica (Abr. Juss) possess lead compounds for the development of antiplasmodial drugs.     

Effects of an extract from Phyllanthus niruri on hepatitis B and woodchuck hepatitis viruses: in vitro and in vivo studies.

An aqueous extract of the plant Phyllanthus niruri inhibits endogenous DNA polymerase of hepatitis B virus and binds to the surface antigen of hepatitis B virus in vitro. The extract also inhibits woodchuck hepatitis virus (WHV) DNA polymerase and binds to the surface antigen of WHV in vitro. The extract, nontoxic to mice, was tested for antiviral activity in woodchucks (Marmota monax). In a trial using six long-term WHV-carrier woodchucks, five treated animals showed a faster decrease in woodchuck hepatitis virus surface antigen titer compared to one untreated control. In animals recently infected with WHV, the extract was effective when administered i.p. in three out of four animals in reducing and within 3-6 weeks eliminating both the surface antigen titer and DNA polymerase activity in serum. The treatment was discontinued after 10 weeks, and the treated animals have remained free of detectable markers of WHV for more than 45 weeks. In contrast, three untreated controls remained positive for both markers for WHV. One of the controls died after 8 weeks; the other two controls have remained positive for WHV markers for more than 45 weeks. In a third trial with long-term carriers, test animals treated subcutaneously with the extract for 12 weeks did not respond; but on switching the mode of administration to i.p., two out of the five animals showed a significant decrease in woodchuck hepatitis virus surface antigen titer compared to controls.     

In vitro screening of traditionally used medicinal plants in China against enteroviruses

AIM: To search for new antiviral agents from traditional Chinese medicine, specifically anti-enterovirosuses agents. METHODS: The aqueous extracts (AE) of more than 100 traditionally used medicinal plants in China were evaluated for their in vitro anti-Coxsackie virus B3 activities with a MTT-based colorimetric assay. RESULTS: The test for AE of 16 plants exhibited anti-Coxsackie virus B3 activities at different magnitudes of potency. They can inhibit three steps (inactivation, adsorption and replication) during the infection. Among the 16 plants, Sargentodoxa cuneata (Oliv.) Rehd. et Wils., Sophora tonkinensis Gapnep., Paeonia veitchii Lynch, Spatholobus suberectus Dunn. and Cyrtomium fortunei J. sm. also have activity against other enterovirus, including Coxsackie virus B5, Polio virus I, Echo virus 9 and Echo virus 29. Cell cytotoxic assay demonstrated that all tested AE had CC50 values higher than their EC50 values. CONCLUSION: The sixteen traditionally used medicinal plants in China possessed antiviral activity, and some of them merit further investigations.     

In vivo and in vitro studies of chloroquine-resistant malaria in Thailand.

Fourteen patients infected with falciparum malaria admitted to the Hospital for Tropical Diseases in Bangkok, Faculty of Tropical Medicine, Mahidol University, were studied. In vivo and in vitro methods were used to compare the effects of chloroquine on Plasmodium falciparum. The results showed that RI in vivo corresponded to samples containing chloroquine base 2.5-3.5 millimicromoles per ml of blood in vitro and RII in vivo corresponded to samples with chloroquine base of 4.0 millimicromoles per ml of blood.     

In vitro antitrypanosomal activity of African plants used in traditional medicine in Uganda to treat sleeping sickness

In Uganda, as in many other African countries, herbal treatment of various diseases is still common. In the present study, 9 plant species collected from Tanzania and Uganda and used by traditional healers in southern-eastern Uganda for the treatment of human African trypanosomiasis (sleeping sickness) were extracted and screened for their in vitro activity against Trypanosoma brucei rhodesiense, one of the two causative agents of sleeping sickness. Eight lipophilic extracts of 5 plants revealed very promising antitrypanosomal activity with IC₅₀ values below 1 µg/ml; among them were extracts prepared from Albizia gummifera (2), Ehretia amoena (1), Entada abyssinica (2), Securinega virosa (1) and Vernonia subuligera (2). Activity with IC₅₀ values between 1 and to µg/ml was determined for 15 further extracts. Cytotoxicity of active extracts, tested on a human fibroblast cell line (WI-38), was found to be high, and therefore selectivity indices resulted in less favourable ranges than those for the few commercially available drugs. Nevertheless, the results confirm the potential of ethnobotanically selected plants as remedies against sleeping sickness and call for phytochemical studies.     

In vitro antimalarial activity of extracts of three plants used in the traditional medicine of India.

In an attempt to search for new antimalarial drugs, we studied plants used by traditional healers of southwest India to treat malaria. Aqueous and organic solvent extracts obtained from specific parts of the plants Swertia chirata, Carica papaya, and Citrus sinensis were tested on malaria strain Plasmodium falciparum FCK 2 in vitro. The temperatures of extraction were the same as that used by the traditional healers in their plant preparations. Visual evaluation of the antimalarial activity of the plant extracts on thin blood smears was followed by quantification of the activity by use of [35S]-methionine incorporation into parasite proteins to determine the value that inhibits 50% (IC50). Among the 3 plants tested, 2 had significant inhibitory effect on P. falciparum in vitro.     

The antiplasmodial effect of the extracts and formulated capsules of Phyllanthus amarus on Plasmodium yoelii infection in mice

ObjectiveTo investigate the antiplasmodial activity of the extracts of Phyllanthus amarus (P. amarus) on Plasmodium yoelii (P. yoelii) (a resistant malaria parasite strain used in animal studies) infection in mice.MethodsThe aqueous and ethanol extracts of the whole plant of Phyllanthus amarus was administered to Swiss albino mice at doses of 200 mg/kg/day, 400 mg/kg/day, 800 mg/kg/day and 1600 mg/kg/day and the prophylactic and chemotherapeutic effect of the extracts against P. yoelii infection in mice was investigated and compared with those of standard antimalaria drugs used in the treatment of malaria parasite infection. Acute toxicity test was carried out in mice to determine the safety of the plant extract when administered orally.ResultsThe results showed that the extracts demonstrated a dose—dependent prophylactic and chemotherapeutic activity with the aqueous extracts showing slightly higher effect than the ethanol extract. The antiplasmodial effects of the extracts were comparable to the standard prophylactic and chemotherapeutic drugs used in chloroquine resistant Plasmodium infection although the activity depended on the dose of the extract administered. The extracts showed prophylactic effect by significantly delaying the onset of infection with the suppression of 79% at a dose of 1600 mg/kg/day.ConclusionsThe results obtained indicate that the extracts of the whole plant of P. amarus possess repository and chemotherapeutic effects against resistant strains of P. yoelii in Swiss albino mice. The findings justify the use of the extract of P. amarus in traditional medicine practice, for the treatment of malaria infections.     

Antimicrobial activity of Sapindus mukorossi and Rheum emodi extracts against H pylori： In vitro and in vivo studies

INTRODUCTION H pylori has infected more than half the population of the world. Most people are unaware that they are infected because they remain asymptomatic throughout life and survive without any harmful infection-related clinical sequelae. However, so…     

Natural killer cell activity in hepatocellular carcinoma. In vitro and in vivo responses to interferon

We have measured natural killer (NK) cell activity in patients with hepatocellular carcinoma (HCC) and have examined the effects of in vitro and in vivo administration of alpha-interferon (IFN) on NK cell activity. The NK cell cytotoxicity of HCC patients was significantly lower than that of patients with cirrhosis or healthy controls. Reduced NK cell cytotoxicity in HCC did not correlate significantly with either the serum alpha-foetoprotein concentration or the patient WHO performance grade. NK cell cytotoxicity in all groups could be increased by prior incubation of effector cells with IFN, but this was significant only in HCC patients, in whom 10 IU/ml of IFN increased NK cell cytotoxicity from 37 +/- 10% to 53 +/- 8% (effector to target ratio, 50:1, mean +/- SEM; p less than 0.05). Further increases in IFN concentration failed to increase NK cell activity further. NK cell cytotoxicity was measured immediately before and 24 h after 2.5 x 10(6) IU/m2 of IFN was given subcutaneously to four HCC patients. NK cell cytotoxicity rose from 27 +/- 9% to 61 +/- 5% (effector to target ratio, 50:1, mean +/- SEM; p = 0.05).     

In vitro antibody-mediated macrophage activity on Breinlia macropi microfilariae. I. Adherence and cytotoxicity

Intense adherence accompanied by cytotoxicity, which initially occurred at 4 h of interaction was observed when the microfilariae of Breinlia macropi were introduced to cultures of quokka peritoneal macrophages previously sensitized in 20% immune serum. No significant difference in the adherence or cytotoxic effects was observed among macrophages from normal, microfilaraemic and amicrofilaraemic quokkas. However, the serum component mediating these effects was found only in microfilaraemic and seropositive amicrofilaraemic quokkas. This mediator was heat-labile and its mediation of the adherence and cytotoxic effects was independent of complement. Because of its apparent dissociation from IgG and its heat lability, the possibility that the mediator resides in the previously-described reaginic antibody of the quokkas was discussed.     

In vitro and in vivo anticancer activity of Indigofera cassioides Rottl. Ex. DC

ObjectiveTo evaluate the antitumor, cytotoxic and antioxidant activities of methanolic leaf extract of Indigofera cassioides (MEIC) against transplantable tumors and human cancer cell lines.MethodsMEIC was investigated for its short term cytotoxicity on EAC and DLA cells by trypan blue dye exclusion method and in vitro cytotoxicity on HeLa, HEp-2, HEpG-2, MCF-7, HT-29, Vero and NIH 3T3 cells by MTT assay. In vivo antitumor activity was studied on EAC and DLA tumor bearing mice. Activity was assessed by monitoring the mean survival time, effect on hematological parameters, antioxidant enzyme levels and solid tumor volume.ResultsMEIC exhibit potent in vitro cytotoxicity against all the tested cancer cell lines, but it was found to be safe on normal cells. The extract significantly (P < 0.001) increase the mean survival time and also have a protective effect on the hemopoietic system at the tested dose levels (200 and 400 mg/kg). The extract prevented lipid peroxidation and restored the antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase and glutathione-s-transferase in the liver of tumor control animals. It also significantly (P < 0.01) reduce the solid tumor volume.ConclusionsThe results strongly support that MEIC shows potent antitumor and cytotoxic effects against EAC, DLA and human cancer cell lines. The extract prevents lipid peroxidation and promotes the enzymatic antioxidant defense system in tumor bearing animals which might be due to activities like scavenging of free radicals by the phytochemicals in MEIC.     

Immediate hypersensitivity to tuberculin. In vivo and in vitro studies.

Immediate responses of hypersensitivity to skin testing with purified derivative of tuberculin (PPD) were observed in 2.3 percent of 3,248 patients seen in an allergy clinic, and the relationship to delayed responses was questioned. Immediate cutaneous reactions to testing with PPD appeared in all age groups and occurred in nonatopic patients but were more common in atopic patients (p less than 0.005). Delayed cutaneous reactions to testing with PPD occurred in only three out of 76 patients with immediate reactivity. Antihistaminic suppression of immediate reactivity was not followed by evidence of delayed cutaneous reactivity. In vitro tests of lymphocytic stimulation revealed indices of stimulation with PPD to be similar both in patients with immediate and delayed cutaneous reactivity. Failure to manifest delayed cutaneous reactivity following immediate cutaneous reactions alone may be explained by antigen-antibody binding and phagocytosis, by suppressor T-lymphocytes, or by impaired release or lack of response to T-lymphocytic mediators. Adverse reactions to administration of BCG vaccine in patients with immediate cutaneous reactivity might be anticipated.     

In vitro and in vivo anticandidal activity of human immunodeficiency virus protease inhibitors.

Highly active antiretroviral therapy that includes human immunodeficiency virus (HIV) aspartyl protease inhibitors (PIs) causes a decline in the incidence of some opportunistic infections in AIDS, and this decline is currently attributed to the restoration of specific immunity. The effect of two PIs (indinavir and ritonavir) on the enzymatic activity of a secretory aspartyl protease (Sap) of Candida albicans (a major agent of mucosal disease in HIV-infected subjects) and on growth and experimental pathogenicity of this fungus was evaluated. Both PIs strongly (>/=90%) and dose dependently (0.1-10 microM) inhibited Sap activity and production. They also significantly reduced Candida growth in a nitrogen-limited, Sap expression-dependent growth medium and exerted a therapeutic effect in an experimental model of vaginal candidiasis, with an efficacy comparable to that of fluconazole. Thus, besides the expected immunorestoration, patients receiving PI therapy may benefit from a direct anticandidal activity of these drugs.     

In vivo and in vitro cytotoxicity of R-etodolac with dexamethasone in glucocorticoid-resistant multiple myeloma cells

Glucocorticoids have been widely used in the treatment of multiple myeloma (MM) both as single agents and in combination with other drugs. However, primary or acquired glucocorticoid resistance occurs in most cases. It was recently reported that R-etodolac induced in vitro cytotoxicity in MM cell lines and in primary MM cells, as well as synergistically enhanced dexamethasone (Dex)-induced apoptosis in Dex-sensitive MM.1S cells. This study examined the in vitro and in vivo effects of combination treatment with R-etodolac and Dex on Dex-resistant OPM1 cells. Treatment with R-etodolac and Dex was found to enhance cytotoxicity, inhibit nuclear factor kappaB activity via upregulation of IkappaBalpha, as well as enhance Dex-induced caspase activation and poly (ADP)-ribose polymerase cleavage in OPM1 cells. R-etodolac also enhanced Dex cytotoxicity in patient MM cells that were resistant to glucocorticoids. The in vivo anti-tumour effect of this combination on MM cells was evaluated by using severe combined immunodeficient mice engrafted with OPM1. Treatment with R-etodolac or Dex alone did not induce a significant reduction of tumour volume; in contrast, combination treatment with R-etodolac and Dex induced significant synergistic inhibition of tumour growth. These data indicate that R-etodolac overcomes resistance to Dex in glucocorticoid-resistant MM cells, providing the framework for clinical trials of R-etodolac combined with Dex, to improve patient outcome in MM.     

In vitro antimalarial activity and cytotoxicity of some selected cuban medicinal plants

Terrestrial plants have been demonstrated to be sources of antimalarial compounds. In Cuba, little is known about antimalarial potentials of plant species used as medicinals. For that reason, we evaluated the antimalarial activity of 14 plant species used in Cuba as antimalarial, antipyretic and/or antiparasitic. Hydroalcoholic extracts were prepared and tested in vitro for the antimalarial activity against Plasmodium falciparum Ghana strain and over human cell line MRC-5 to determine cytotoxicity. Parasite multiplication was determined microscopically by the direct count of Giemsa stained parasites. A colorimetric assay was used to quantify cytotoxicity. Nine extracts showed IC50 values lower than 100 μg/mL against P. falciparum, four extracts were classified as marginally active (SI < 4), one as partially active (Parthenium hysterophorus) exhibiting SI equal to 6.2 and two extracts as active (Bambusa vulgaris and Punica granatum), showing SI > 10. B. vulgaris showed the most potent and specific antiplasmodial action (IC50 = 4.7 μg/mL, SI = 28.9). Phytochemical characterization of active extracts confirmed the presence of triterpenoids in B. vulgaris and polar compounds with phenol free groups and fluorescent metabolites in both extracts as major phytocompounds, by thin layer chromatography. In conclusion, antimalarial use of B. vulgaris and P. hysterophorus was validated. B. vulgaris and P. granatum extracts were selected for follow-up because of their strong antimalarial activity.