Antiplasmodial activity of silver nanoparticles: A novel green synthesis approach

Objective:To synthesize silver nanoparticles using silver nitrate by a green technique which involves different compositions of aqueous leaf extracts of Azadirachta indica(neem)and Ocimum sanctum(tulsi).Methods:Their shape and size were determined using transmission electron microscopy and UV-visible spectroscopy.Their antiplasmodial activity was studied using the malarial parasite strain(Plasmodium falciparum,3D7).The parasite strain(3D7)was collected and revived in vitro using Trager and Jensen method in RPMI 1640 medium for 7-8cycles.Half maximal effective concentration values were calculated by nonlinear regression analysis.Results:Transmission electron microscopy results confirmed the formation of silver nanoparticles with size ranging from 4.74-39.32 nm and their size differs by varying the concentrations from 20%to 100%of neem extract in neem and tulsi extracts.It was observed that samples B and C showed half maximum effective concentration of about 0.3μM.Conclusions:It can be easily established that the aqueous leaf extracts of neem and tulsi in combination can be a good source for synthesis of silver nanoparticles with small size possessing appreciable antiplasmodial activity.

Antiplasmodial activity of traditional polyherbal remedy from Odisha, India:Their potential for prophylactic use

Objective:To evaluate the potential prophylactic activity of traditional polyherbal remedy against malaria.Methods:A traditional polyherbal remedy against malaria from Odisha,India was evaluated for its potential prophylactic activity using in vitro hepatic cell lines assay and the murine malaria system Plasmodium yoelii yoelii/Anopheles stephensi.Results:The polyherbal extract inhibited the Plasmodium yoelii hepatic stages in vitro(IC500.74 mg/m L),a therapeutic index of 9.54.In mice treated with the aqueous extract(2 000 mg/kg/day),peak parasitaemia values were 81%lower in the experimental2.35%±0.14%as compared to controls 12.62%±0.52%(P<0.001),suggesting significant prophylactic activity.Conclusions:The observations provide a proof of concept for a traditional malaria prophylactic remedy used by tribal populations in India.

In vitro antiplasmodial activity of methanolic extracts from seaweeds of South West Coast of India

Objective:To identify the in vitro antiplasmodial activity of seaweed plants against Plasmodium falciparum strains.Methods:A total of eight seaweeds were collecled from Kanvakumari district,Tainilnadu,India.The in vitro antiplasmodial activity was performed in 96 well plates against Plasmodium falciparum,and preliminary phytochemcial analysis were performed for the extracts.Results:Of the selected plants Enteromorpha intestinalis(2.61%) showed maximum percentage of extraction.The minimum concentration of inhibitory(IC_(50)) value was observed with Chaetomorpha antennina[(26.37±4.14)μg/ml.]further,the positive controls such as chloroquine and artemether showed antiplasmodial activities(IC_(50)) with(19.10±5.93) and(6.03±0.21)μg/mL concentrations,respectively.The preliminary phytochemical analysis of the seaweed extracts showed a variety of phytochemical constituents such as carboxylic acids,phenols,protein, resins,steroids and sugars.Conclusions:The antiplasmodial activity of the seaweed extract might due to the presence of sugars and phenolic compounds.From the present findings,it is concluded that,the seaweed extract of Chaetomorpha antennina can be further used as a putative antiplasmodial drugs in near future.

Antiplasmodial Activity and Phytochemical Analysis of Phyllanthus niruri L. （Phyllanthaceae） and Morinda lucida Benth （Rubiaceae） Extracts

The antiplasmodial activity and phytochemical analysis of P. niruri and All. lucida leaves and stem parts have been evaluated in different solvent （aqueous, ethanolic and dichloromethane）. Phytochemical analysis has been done using 5-methoxyflavone 10-4 M andα-gluconolactone 10-4 M in methanol 80% （pH 2） solvent to the HPLC （high performance liquid chromatography） and the TLC （thin layer chromatography）. RPMI 1640 （Rose Park Memorial Institute medium 1640） has been used for plasmodium strain culture and the antiplasmodial activity has been evaluated under microscopy with infected blood colored by Giemsa-stained thick. IC50 （The inhibitory concentration of extract would be killed 50% of parasites） was estimated. The results show that extracts of P. niruri exhibit more antiplasmodial activities （IC50：3.98 μg/50 μL for aqueous extract, between 9.5-19 μg/50 p.L for ethanolic extract and 5.3 Itg/50 laL for dichloromethane extract） than those of M. lucida （IC50：5.39 to 10.78 μg/50 μL, 12.265 μg/50 μL and 24.53 μg/50 μL） successively for queous, ethanolic and dichloromethane extracts. For the same antiplasmodial activity, the amount of extract of M. lucida is still higher than that of P. niruri. These results are explained by the composition of phenolic compounds that are found in P. niruri. This plant has therefore presented more spectra in the chromatogram （20 peaks for hydrolyzed extract and 27 peaks for unhydrolyzed extracts） comparing that ofM. lucida hydrolyzed or unhydrolyzed extracts with 13 and 14 peaks. TLC revealed compounds such as flavonols, flavan-3-ols. Nevertheless, quinine used as positive control presented the same antiplasmodial activity for the low doses for the drugs and our extracts presented weak antiplasmodial activity comparing previous works. The studies could continue for the isolation of active principle that of P. niruri.

AN ORIGINAL DIAGNOSTIC SYSTEM FOR MALARIA TO SCREEN THE ANTIPLASMODIAL ACTIVITY OF AFRICAN HERBAL MEDICINES

Malaria,caused by protozoa of the genus Plasmodium,causes some 198 million of confirmed cases and about584,000 of deaths per year.Its management needs both accurate diagnostic and treatments availability.The current diagnostic techniques(rapid diagnostic tests and microscopy)appear either too expensive,lowly sensitive or difficult to implement.The hemozoin('malaria pigment')

LC-MS Phytochemical Profiles of Phenolic Compounds and Antimicrobial, Antioxidant, and Antiplasmodial Activities of Ethanol Extracts of Pycnostachys erici-rosenii R.E.Fr and Leucas martinicensis (Jack.) R.Br (Lamiaceae)

This study has been conducted to analyze the chemical composition and antimicrobial, antioxidant and antiplasmodial properties of ethanol extracts of Pycnostachys erici-rosenii R.E.Fr and Leucas martinicensis (Jack.) R.Br that are not yet well known. The HPLC-DAD-MS-ESI+ method was used to investigate the chemical profile, the disc diffusion and microdilution method for the antimicrobial activities, the DPPH and FRAP assays for antioxidant property and SYBR Green I-based growth inhibition assay on Pf 3D7 (CQ-sensitive) strain for antiplasmodial properties. The results indicated significant amounts of hydroxybenzoic acid, flavonol and hydroxycinnamic acid in the two species. The total polyphenols analysis gave 209.0 ± 16.1 mg GAE/100g DW for P. erici-rosenii and 175.3 ± 1.6 mg GAE/100g DW for L. martinicensis while for total flavonoids analysis 33.4 ± 1.8 mg TE/100g DW was found for P. erici-rosenii and 39.6 ± 0.6 mg TE/100g DW for L. martinicensis. Moreover, antimicrobial tests revealed 0.125 mg/mL on E. faecalis ATCC25922 for ethanol extracts P. erici-rosenii and L. martinicensis. The antioxidant assays revealed IC50 56.17 μg/mL and 78.43 μg/mL for DPPH assay, and 112.03 μM TE/100mL and 90.46 μM TE/100mL) for FRAP assay for ethanol extracts of P. erici-rosenii and L. martinicensis respectively. Finally, for Antiplasmodial activity, IC50 was 4.07 μg/mL for P. erici-rosenii and 12.29 μg/mL for L. martinicensis. Therefore, the antimicrobial, the antioxidant, and the antiplasmodial results suggest that the ethanolic extracts of the aerial parts of P. erici-rosenii and L. martinicensis contain compounds with antimicrobial, antioxidant, and antiplasmodial properties, which can be searched in new drug discovery for treatment of infectious diseases.

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

Objective:To 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).Methods:The O.canum,O.sanctum and O.basilicum were collected from Ramanalhapuram District,Tamil Nadu and the extraction was carried out in ethanol.The filter sterilized extracts(100,30,23,12.5,6.23 and 3.125μg/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.Results:The leaf extract of O.sanctum showed excellent antiplasmodial activity(IC_(50) 3538μg/mL) followed by leaf extract of O.basilicum(IC_(50) 4341μg/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 IC_(50) values between 50 and 100μg/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.Conclusions:The ethanolic leaf extracts of O.sanctum possess lead compounds for the development of antiplasmodial drugs.

In vitro antiplasmodial effect of ethanolic extracts of coastal medicinal plants along Palk Strait against Plasmodium falciparum

Objective:To identify the possible anliplasmodial compounds from Achyranlhes aspera(A. aspera).Acalypha indica(A.indica),Jatropha glandulifera(J.glanduUfera)and Phyllanlhus amarus(P.amarus).Methods:The A.aspera,A.indica,J.glandulifera and P.ainarus were collected along Palk Strait and the extraction was carried out in ethanol.The filter sterilized extracts(100,50,25,12.5,6.25 and 3.125μg/mL) of leaf,stem,root and flower extracts of A aspera,A. indica,J.glandulifera and P.amarus were tested for anliplasmodial activity against Plasnuxlium falciparum.The potential extracts were also tested for their phytochemical constituents.Results: Of the selected plants species parts,the stem extract of A.indica showed excellent antiplasmodial activity(IC_(50)=43.81μg/mL) followed by stem extract of J.glandulifera(IC_(50)= 49.14μg/mL).The stem extract of A.aspera,leaf and root extracts of A.indka,leaf,root and seed extracts of J. glanduUfera and leaf and stem extracts of P.amarus showed IC_(50),values between 50 and 100 μg/ mL.Statistical analysis revealed that,significant antiplasmodial activity(P<0.0l) was observed between the concentrations and time of exposure.The chemical injury to erythrocytes was also carried out and it showed that there were no morphological changes in erythrocytes by the elhanolic extract of all the tested plant extracts.The in vitro antiplasmodial activity might be due to the presence of alkaloids,glycosides,flavonoids.phenols,saponins,triterpenoids,proteins, and lannins in the elhanolic extracts of tested plants.Conclusions:The elhanolic stem extracts of P.amarus and J.glandulifera possess lead compounds for the development of antiplasmodial drugs.

Antioxidant and Antiplasmodial Activities of Extracts from <i>Gardenia erubescens</i>Stapf et Hutch. and <i>Fadogia agrestis</i>Schweinf. ex Hiern. (Rubiaceae)

Two medicinal plants, Gardenia erubescens and Fadogia agrestis were selected to evaluate their biological activities. Their total phenolic and flavonoid contents were assessed using folin-ciocalteu and aluminum chloride regents’ methods. The antioxidant activity was estimated using DPPH (1,1-diphényl-2-picrylhydrazyl), ABTS (2,2’-azinobis-[3-ethylenzothiazoline-6-sulfonic acid]) and FRAP (ferric reducing antioxidant power). The antiplasmodial activity of the extracts was determined in vivo on 42 NMRI mice. The results indicate that all the extracts from both two plants contain some polyphenols. The ethanolic extract of the leaves of Gardenia erubescens showed the best antioxidant activity by the method of DPPH. The aqueous extracts of the leaves of Gardenia erubescens and the whole plant of Fadogia agrestis have a reducing power similar to control (quercetin). All the extracts have a low capacity to scavenge the ABTS radical cation compared to the controls (trolox and quercetin). Concerning the antiplasmodial activity, all the extracts presented moderate antiplamodial activities. This result could justify the traditional uses of Gardenia erubescens and Fadogia agrestis to treat of malaria in Burkina Faso.

Structure modification,antialgal,antiplasmodial,and toxic evaluations of a series of new marine-derived 14-membered resorcylic acid lactone derivatives

Marine natural products play critical roles in the chemical defense of many marine organisms and are essential,reputable sources of successful drug leads.Sixty-seven 14-membered resorcylic acid lactone derivatives 3–27 and 30–71 of the natural product zeaenol(1)isolated from the marine-derived fungus Cochliobolus lunatus were semisynthesized by chlorination,acylation,esterification,and acetalization in one to three steps.The structures of these new derivatives were established by HRESIMS and NMR techniques.All the compounds(1–71)were evaluated for their antialgal and antiplasmodial activities.Among them,14 compounds displayed antifouling activities against adhesion of the fouling diatoms.In particular,9 and 34 exhibited strong and selective inhibitory effects against the diatoms Navicula laevissima and Navicula exigua(EC50=6.67 and 8.55μmol/L),respectively,which were similar in efficacy to those of the positive control SeaNine 211(EC50=2.90 and 9.74μmol/L).More importantly,38,39,and 69–71 showed potent antiplasmodial activities against Plasmodium falciparum with IC50 values ranging from 3.54 to 9.72μmol/L.Very interestingly,the five antiplasmodial derivatives displayed non-toxicity in the cytotoxicity assays and the zebrafish embryos model,thus,representing potential promising antiplasmodial drug agents.The preliminary structure–activity relationships indicated that biphenyl substituent at C-2,acetonide at positions C-5′and C-6′,and tri-or tetra-substituted of acyl groups increased the antiplasmodial activity.Therefore,combining evaluation of chemical ecology with pharmacological models will be implemented as a systematic strategy,not only for environmentally friendly antifoulants but also for structurally novel drugs.