In vitro screening for antiplasmodial activity of isoquinoline alkaloids from Brazilian plant species

In the search for new antimalarial agents, nine Brazilian plant species were selected, from the Annonaceae (6), Menispermaceae (2) and Siparunaceae (1) families naturally occurring at the cerrado and Atlantic rainforest regions, in order to investigate their in vitro antiplasmodial activity. The ethanol and the alkaloid extracts were tested against K1, chloroquine-resistant, and Palo Alto, chloroquine-sensitive, strains of Plasmodium falciparum. The majority of the alkaloid extracts were more active than the ethanol ones, with IC(50) ranging 0.3-8.2 microg/mL. The crude Guatteria australis alkaloids were the most active against K1 with an IC(50) = 0.3 microg/mL. The most promising total alkaloid fractions for further bioguided isolation are those with the IC(50) < or = 5 microg/mL: G. australis, Cissampelos ovalifolia and Duguetia lanceolata.     

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 of Central American medicinal plants

The in vitro antiplasmodial activities of 14 plant species traditionally used in Central America for the treatment of malaria or fever were evaluated. Lipophilic extracts of Piper hispidum, Siparuna andina, S. pauciflora, S. tonduziana, and Xylopia cf. frutescens, proved to be active against both a chloroquine-sensitive and a resistant strain of Plasmodium falciparum. IC50 values ranged between 3.0 microg/ml and 21.9 microg/ml; however, moderate cytotoxicity of active extracts was observed. Bioactivity-guided fractionation of Piper hispidum yielded 2',4, 6'-trihydroxy-4'-methoxydihydrochalcone (asebogenin) as an active compound.     

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 Clathria vulpina sponge associated bacteria against Plasmodium falciparum

ObjectiveTo identify the possible antiplasmodial drugs from bacteria associated with marine sponge Clathria vulpina (C. vulpina).MethodsThe C. vulpina samples were collected from Thondi coast and subjected to enumeration and isolation of associated bacteria. Filtered and sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg/mL) from isolated bacterial strains were screened for antiplasmodial activity against Plasmodium falciparum. Potential extracts were also screened for biochemical constituents.ResultsThirty one bacterial strains were isolated from twelve sponge samples collected from Thondi coast and screened for antiplasmodial assay. The count of bacterial strains were maximum in November 2007 (19×10⁴ CFU/g) and the average count was maximum during the monsoon season (110×10³ CFU/g). The antiplasmodial activity of strain THB15 was highly comparable (IC₅₀ = 20.73 μg/mL) with the positive control chloroquine (IC₅₀ = 19.59 μg/mL) and 21 bacterial strains showed IC₅₀ value of more than 100 μg/mL. Statistical analysis reveals that, significant in vitro antiplasmodial activity (P<0.05) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes showed no morphological changes in erythrocytes by the ethyl acetate extract of bacterial strains after 48 h of incubation. The in vitro antiplasmodial activity might be due to the presence of sugars and alkaloids in the ethyl acetate extracts of bacterial strains.ConclusionThe ethyl acetate extract of THB15 possesses lead compounds for the development of antiplasmodial drugs.     

In vitro antiplasmodial activity of marine sponge Stylissa carteri associated bacteria against Plasmodium falciparum

ObjectiveTo identify the possible antiplasmodial drugs from bacteria associated with marine sponge Stylissa carteri (S. carteri).MethodsThe S. carteri samples were collected from Thondi coast and subjected for enumeration and isolation of associated bacteria. Filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μ g/mL) from isolated bacterial strains were screened for antiplasmodial activity against Plasmodium falciparum (P. falciparum) and potential extracts were also screened for biochemical constituents.ResultsTwelve samples of S. carteri were collected and subjected for enumeration and isolation of associated bacteria. The count of bacterial strains were maximum in November 2007 (34 × 10⁴ CFU/g) and the average count was maximum during the monsoon season (203 × 10³ CFU/g). Thirty two morphologically different bacterial strains were isolated from S. carteri and the ethyl acetate bacterial extracts were screened for antiplasmodial activity against P. falciparum. The antiplasmodial activity of a strain THB17 (IC₅₀ 20.56 μ g/mL) extract is highly comparable with the positive control chloroquine (IC₅₀ 19.59 μ g/mL) and 13 bacterial extracts which showed IC₅₀ value of more than 100 μ g/mL. Statistical analysis reveals that, significant in vitro antiplasmodial activity (P<0.05) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes showed no morphological changes in erythrocytes by the ethyl acetate extract of bacterial strains after 48 h of incubation. The in vitro antiplasmodial activity might be due to the presence of reducing sugars and alkaloids in the ethyl acetate extracts of bacterial strains.ConclusionsThe ethyl acetate extract of THB17 possesses lead compounds for the development of antiplasmodial drugs.     

In vitro antiplasmodial effect of ethanolic extracts of traditional medicinal plant Ocimum species against Plasmodium falciparum

ObjectiveTo identify the possible antiplasmodial compounds from leaf, stem, root and flower extracts of Ocimum canum (O. canum), Ocimum sanctum (O. sanctum) and Ocimum basilicum (O. basilicum).MethodsThe O. canum, O. sanctum and O. basilicum were collected from Ramanathapuram District, Tamil Nadu and the extraction was carried out in ethanol. The filter sterilized extracts (100, 50, 25, 12.5, 6.25 and 3.125 μg/mL) of leaf, stem, root and flower extracts of O. canum, O. sanctum and O. basilicum were tested for antiplasmodial activity against Plasmodium falciparum (P. falciparum). The potential extracts were also tested for their phytochemical constituents.ResultsThe leaf extract of O. sanctum showed excellent antiplasmodial activity (IC₅₀ 35.58 μg/mL) followed by leaf extract of O. basilicum (IC₅₀ 43.81 μg/mL). The leaf extract of O. canum, root extracts of O. sanctum and O. basilicum, the stem and flower extracts of all the three tested Ocimum species showed IC₅₀ values between 50 and 100 μg/mL. Statistical analysis reveals that, significant antiplasmodial activity (P <0.01) was observed between the concentrations and time of exposure. The chemical injury to erythrocytes was also carried out and it shows that, there were no morphological changes in erythrocytes by the ethanolic extract of O. canum, O. sanctum and O. basilicum. The in vitro antiplasmodial activity might be due to the presence of alkaloids, glycosides, flavonoids, phenols, saponins, triterpenoids, proteins, resins, steroids and tannins in the ethanolic extracts of tested plants.ConclusionsThe ethanolic leaf extracts of O. sanctum possess lead compounds for the development of antiplasmodial drugs.     

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.     

In vitro antiplasmodial activity of marine sponge Clathria vulpina extract against chloroquine sensitive Plasmodium falciparum

ObjectiveTo explore the antiplasmodial potential of marine sponge Clathria vulpina (C. vulpina) against chloroquine sensitive Plasmodium falciparum (P. falciparum).MethodsThe marine sponge C. vulpina was collected from Thondi coast, authenticated and subjected for extraction by soaking in ethanol:water mixture (3:1 ratio). The percentage of extract was calculated. Filter sterilized extracts (100, 50, 25, 12.5, 6.25, 3.125 μg/mL) were screened for antiplasmodial activity against chloroquine sensitive P. falciparum. The extract was also tested for its hemolytic activity.ResultsThe percentage yield of extract of C. vulpina was found to be 4.8%. The crude extract of C. vulpina showed excellent antiplasmodial activity (IC₅₀=14.75 μg/mL) which was highly comparable to the positive control chloroquine (IC₅₀=7 μg/mL). Statistical analysis reveals that the significant antiplasmodial activity (P<0.05) was observed between the concentrations and the time of exposure. The chemical injury to erythrocytes was also carried out, which showed that there were no morphological changes in erythrocytes by the ethanolic extracts of sponges after 48 h of incubation. The extract showed slight hemolytic activity which almost equal to chloroquine at 100 μg/mL concentration (1.023%).ConclusionsThe marine sponge C. vulpina can be used as a putative antiplasmodial drug after completing successful clinical trials.     

In vitro antiplasmodial and antioxidant activities of bisbenzylisoquinoline alkaloids from Alseodaphne corneri Kosterm

Objective:To study antiplasmodial and antioxidant activities of the isolation of alkaloids from the active dichloromcthanc extract of Alseodaphne corneri.Methods:Phytochemical studies of the crude extract led to the isolation of six alkaloids using recycle high performance liquid chromatography and preparative thin layer chromatography.The antiplasmodial activity of the isolated compounds was evaluated usingthe histidinc-rich protein II assay.The isolated alkaloids were also tested for their antioxidant activity using three different assays:DPPH.ferric reducing ability of plasma and metal chelating assays.Results:Malaria infection caused the formation of free radicals which subsequently led to oxidative stress and apoplosis.The antioxidant properties of the alkaloids under investigation revealed that in addition to the aniiplasmodial activity,the alkaloids could also prevent oxidative stress.(+)-laurotetanine and(+)-norstephasubine exhibited strong antiplamodial activities with IC_(50) values of 0.189 and 0.116 μM.respectively.Conclusions:Interestingly,the two most potent compounds that exhibit aniiplasmodial activity also exhibit good antioxidant activities.The crude dichloromcthanc extract and the isolated compounds exert substantial aniiplasmodial and antioxidative activities which in turn suppress oxidative stress and cause less damage to the host.     

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).     

In vitro bioactivity and phytochemical screening of Suaeda maritima (Dumort): a mangrove associate from Bhitarkanika, India

ObjectiveTo investigate the in vitro antioxidant and antimicrobial activities along with phytochemical screening of organic and aqueous extracts of leaf and stem of Suaeda maritima (Dumort), a mangrove associate from Bhitarkanika of Odisha, India.MethodsAntioxidant activity of the crude extracts was evaluated in terms of total antioxidant capacity, total phenol content, ascorbic acid content, DPPH radical scavenging, metal chelating, nitric oxide scavenging, and reducing power etc. The antimicrobial activity of the plant was determined by agar well diffusion method along with MIC and MBC carried out by microdilution techniques against 10 gram positive and gram negative human pathogenic bacteria. The qualitative and quantative phytochemical screening were carried out by standard biochemical assays.ResultsOut of the seven antioxidant bioassays, both the leaf and stem extracts were found to posses strong antioxidant properties of 70 % to 92 % for phenol, total antioxidant capacity, DPPH free radical scavenging activity and fairly good ascorbic acid content, metal chelating (1.33 %-22.55 %), reducing power (0.01-0.12) and nitric oxide scavenging (0.84 %-66.99 %) activities. Out of the four extracts evaluated for antimicrobial activity, two leaf extracts such as acetone and ethanol showed promising activity against four pathogenic bacteria and one stem methanol extracts against one pathogenic bacteria when compared with amoxcycillin as standard. The MIC and MBC values of the antimicrobial extracts ranged between 2.5 to 5.0 mg/mL. Screening of phytochemicals showed presence of carbohydrates, protein, tannins, alkaloids and flavonoids in comparatively higher amount than other phytochemicals tested.ConclusionsThe present study reveals the presence of potential antioxidants and antimicrobial properties in the plant extract which could be exploited for pharmaceutical application.     

Antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis

ObjectiveTo explore antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis (A. officinalis).MethodsIn the present study the leaf extracts of A. officinalis were examined for its antibacterial potential using five different solvents against some reference strains of human pathogenic bacteria for the crude extract. Maximum activity was observed for ethyl acetate and hence different concentrations like 15 μL, 25 μL, and 50 μL of ethyl extracts was checked for its antibacterial activity. Partial purification of crude extract was carried by column chromatography and fractions were analyzed using gas chromatography-mass spectrometry (GC-MS) to identify compounds.ResultsThe crude ethyl acetate extracts of A. officinalis showed remarkable antibacterial activity with zones of inhibition of 13 mm against Eschericia coli (E. coli) and 11 mm against Staphylococcus aureus (S. aureus). Fraction 13 (ethyl acetate÷methanol= 8÷2) as the most potent one against with the minimal inhibitory concentration of 30 mm against E. coli and 25 mm against S. aureus. The GCMS resultsof active column fraction (F13) revealed that the active principals were a mixture of hydroxy-4 methoxybenzoic acid, diethyl phthalate, oleic acid.ConclusionsThe leaf extracts with proven antibacterial effects can clearly be directed towards cancer treatment as to inhibiting cancer cell growth. The limited number of test organisms owes to a constraint of resource. So, the effect of strong bursts of leaf extracts on human pathogenic bacteria should further be tested on a wide range of test organisms.     

Antimicrobial activity of mangrove plant (Lumnitzera littorea)

ObjectiveTo investigate the antimicrobial activities of n-hexane, ethyl acetate and methanol extracts of the leaves of Lumnitzera littorea (L. littorea) against six human pathogenic microbes.MethodsThe antimicrobial activity was evaluated using disc diffusion and microdilution methods.ResultsThe antimicrobial activities of the crude extracts were increased with increasing the concentration. It is clear that n-hexane extract was the most effective extract. Additionally, Gram positive Bacillus cereus (B. cereus) appear to be the most sensitive strain while Pseudomonas aeruginosa (P. aeruginosa) and the yeast strains (Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans)) appear to be resistance to the tested concentrations since no inhibition zone was observed. The inhibition of microbial growth at concentration as low as 0.04 mg/mL indicated the potent antimicrobial activity of L. littorea extracts.ConclusionsThe obtained results are considered sufficient for further study to isolate the compounds responsible for the activity and suggesting the possibility of finding potent antibacterial agents from L. littorea extracts.     

In vitro antioxidant activities of selected seaweeds from Southeast coast of India

ObjectiveIn vitro antioxidant activities of three selected Indian seaweeds viz., Halimeda tuna (H. tuna), Turbinaria conoides (T. conoides) and Gracilaria foliifera (G. foliifera) were evaluated.MethodsTotal antioxidant activity, total phenolic content, and reducing power of crude methanol and diethyl ether extracts were determined.ResultsTotal phenolic content and total antioxidant activity were higher (1.231±0.173 mg GAE/g, 1.675± 0.361 mg GAE/g) in T. conoides respectively. Reducing power of crude methanol extract increased with concentrations of the extract. The Fourier transform-infra red spectrum analysis revealed the presence of polyphenolic signals. The seaweed extracts displayed moderate antioxidant activity compared to gallic acid standard.ConclusionsThe seaweeds could be considered for curing diseases from oxidative deteriorations.     

In vitro antimicrobial activity of plant extracts of Avicennia alba against some important pathogens

ObjectiveIn this present study antimicrobial activity of aerial parts of Avicennia alba were evaluated against the resistant pathogens belong to aquatic, human and plant origin.MethodsSoxhlet extraction method was used to get the corresponding extracts of hexane, chloroform and methanol. The antimicrobial activities of the organic solvent extracts on the various test microorganisms, including bacteria and fungi investigated using agar well diffusion technique. The length of inhibition zone was measured in millimeters from the edge of the well to the edge of the inhibition zone. Methanol and chloroform extracts exhibited promising antimicrobial activity than hexane extracts.ResultsThe zone of inhibition of chloroform varies from (9 to 17 mm) where as with methanol (11 to 28 mm) at 100 mg/ml concentration. Among all microorganisms studied Erwinia caratovara and Pseudomonas syringae showed the considerable growth inhibition with chloroform and methanolic extracts.ConclusionsA. alba can be used in the treatment of infectious diseases caused by resistant pathogenic microorganisms. Further studies are being carried out in order to separate the individual components that are present in plant extracts of A. alba using column chromatography.     

In vitro angiogenic activity of RNA from leukemic lymphocytes.

RNA was extracted from leukemic lymphocytes by a fluorocarbon method, and primary cultures of human amniotic cells were exposed to the lymphocyte RNA. Angioid tubular and cordon-like structures in branching out and criss-cross patterns with budding ends developed in these cultures within 7 to 12 days of the first exposure. Although there was no opportunity to study preparations from nonleukemic lymphocytes, extracts of normal peripheral blood cells and blood rich in granulocytes had no angiogenic effects. In view of the recent renewal of interest in tumor and tissue angiogenic factor as well as in angiogenic activity by transformed lymphocytes, in addition to the intriguing angioblastic component of Lukes-Rappaport immunoproliferative syndromes, this work may point to the ribonucleic acid nature of the vessel-forming principle. Various cell-differentiating properties of RNA preparations have been repeatedly described, and thus it is not altogether surprising that lymphocyte angiogenic factor may originate in RNA.     

In vitro steroidogenic properties of a new hypertension-producing compound isolated from normal human urine

The steroidogenic properties of a glycoprotein fraction (ASF), isolated from normal human urine, were studied in cat adrenal capsular collagenase-dispersed cells and its effects compared to those of ACTH and Angiotensin II (AII). ACTH, AII and ASF induced dose-related increases in both aldosterone and cortisol production. In order of potency, ACTH = AII greater than ASF in stimulating aldosterone production and ACTH greater than AII greater than ASF in stimulating cortisol production. Increases in cAMP accompanied the steroidogenic response to ACTH but not to AII or ASF. The response to AII, but not to ASF, was inhibited (87% of normal) by equimolar concentrations of [Sar1, Thr8]AII, a specific AII antagonist. These results suggest that ASF is a true aldosterone secretagogue and that it initiates steroidogenesis by mechanisms similar to those of AII. However, the inability to block it effect with a specific antagonist of AII provides evidence for its action on a separate receptor site.