Evaluation of Antiplasmodial Effect of Methanol Leaf Extract and Fractions of Eucalyptus camadulensis (Denhn) in Albino Wistar Mice

Nigeria is one of the malaria-endemic countries, where the treatment of malaria has relied heavily on natural and traditional medicines. This study was designed to investigate and ascertain the preference of Eucalyptus camaldulensis in treating malaria using three standard models among local herbalists. Extraction was carried out on the leaves of Eucalyptus camadulensis using methanol. The methanol crude extract and other solvent fractions obtained were used for analysis. An acute toxicity test (LD50) was carried out using Lorke’s Method. The extract and its fractions were screened for phytochemical constituents using standard procedures. Different doses of the methanol crude extract (250 mg/kg, 500 mg/kg, and 1000 mg/kg) and other solvent fractions (250 mg/kg, 500 mg/kg) were assessed for their antiplasmodial property using the Suppressive, Curative, and Prophylactic models on different days. One hundred and eighty grams (18% w/w) of the extract were recovered from 1000 g of powdered leaves. The weight of fractions and their yields calculated from 50 g crude extract are n-hexane fraction (3.45 g, 6.9%), ethylacetate fraction (11.65 g, 23.3%), and butanol (7.84 g, 15.68%). The result of the acute toxicity test showed that the lethal dose of the plant was above 5000 mg/kg. For the crude extract, the 1000 mg/kg dose had the highest percentage of parasitemia suppression of 97.3%, 95.30%, and 75.97% in the curative, suppressive, and prophylactic models, respectively. The fractions exhibited a significant chemosuppressive effect when compared with the negative control, with the butanol fraction (500 mg/kg) showing a higher percentage suppression. The findings in this study justify the use of this plant in traditional medicine for the management of malaria fever and tally with its folkloric use. However, more research is needed to establish the functions of the constituents in relation to antiplasmodial activity.

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.

Synthesis of silver nanoparticles using leaves of Catharanthus roseus Linn.G.Don and their antiplasmodial activities

Objective:To develop a novel approach for the green synthesis of silver nanoparticles using aqueous leaves extracts of Catharanthus roseus(C.roseus) Linn.G.Don which has been proven aclive against malaria parasite Plasmodium falciparum(P.falciparum).Methods:Characterizations were determined by using ultraviolet-visible(UV-Vis) spectrophotometry,scanning electron microscopy(SEM).energy dispersive X-ray and X-ray diffraction.Results:SLM showed the formation of silver nanoparticles with an average size of 35-55 nm.X-ray diffraction analysts showed that the particles were crystalline in nature with face centred cubic structure of the hulk silver with the broad peaks at 32.4.46.4 and 28.0.Conclusions:It can be concluded that the leaves of C.roseus can he good source for synthesis of silver nanoparticle which shows aiitiplasmodial activity against P.falciparum.The important outcome of the study will he the development of value added products from medicinal plants C.roseus lor hionicdical and nanotechnology based industries.

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 activity of Spiro benzofuran compound from mangrove plant of Southern India

Objective:To find out the in vitro antipalsmodial activities of mangrove leaf extracts.Methods: In vitro antiplasmodial assay was carried out with 13 different mangrove plants.Column chromatography was performed with the most potent Agecerious corniculatum（A.corniculatum） by using various solvent extractions.GC-MS was also preformed with the most potent ethanolic fraction of the A.corniculatum extract.Results:Of the 13 mangroves plants, A.corniculatum showed maximum percentage of parasitemia suppression（94.98±1.16）%.Column chromatography was performed with A.corniculatum with different solvents and the methanolic extract showed maximum percentage（99.73±1.63）%of parasitemia inhibition at 150μg/mL concentration with the IC50 value of（29.28±3.23）μg/mL concentration.The results of the GC-MS analysis observed that,the most potent methanolic extract showed maximum retention time（30.687 RT） and the chemical class was identified as Spiro[benzofuran-2（3 H）,1’-（3 cyclohexane）-2’,3- dione,7-chloro-4’,6]which was responsible for the antiplasmodial activity.Conclusions:It is concluded from the present study that,the chemical constituents of A.corniculatum collected from Pichavaram mangrove forest can be used as a putative antiplasmodial drugs in future.

3D-QSAR Studies on a Series of Indoleamide Derivatives as Antiplasmodial Drugs

In this study, three-dimensional quantitative structure-activity relationship（3D-QSAR） was studied for the antiplasmodial activity of a series of novel indoleamide derivatives by comparative molecular field analysis（CoMFA） and comparative molecular similarity indices analysis（Co MSIA）. 3D-QSAR model was established by a training set of 20 compounds and was externally validated by a test set of 4 compounds. The best prediction（Q2 = 0.593 and 0.527, R2 = 0.990 and 0.953, r（pred）2 = 0.967 and 0.962 for CoMFA and CoMSIA） was obtained according to CoMFA and CoMSIA. Those parameters indicated the model was reliable and predictable. We designed several molecules with high activities according to the contour maps produced by the CoMFA and CoMSIA models.

Antiplasmodial and antiulcer activities of Melanthera scadens

Objective:To evaluate the antimalarial and antiulcerogenic activities ofleaf exlracl and fractions of Melanthera scandens(M.scandens).Methods:The crude leaf extract(37-111 mg/kg)and fractions(chloroform,ethylacetale and methanol;78 mg/kg)of M.scadens were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei infections in mice and for antiulcer activity against experimentally-induced ulcers.The antimalarial activity during early and established infections as well as prophylactic was investigated.Artesunate(5 mg/kg)and pyrimethamine(1.2 mg/kg)were used as positive controls.Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice.Antiulcer activity of the crude extract was also evaluated against indomethacin,ethanol and histamine induced ulcers.Results:The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine-sensitive Plasmodium berghei infection in prophylactic,suppressive and curative models in mice.These reductions were statistically significant(P<0.00l),They also improved the mean survival time(MST)from 9.28 to 17.73 days as compared with the control(P<0.0l-0.001).The activities of extract/fractions were incomparable to that of the standard drugs ie.artesunate and pyrimethamine.On experimentally-induced ulcers,the extract inhibited indomethacin,ethanol and histamine induced ulcers.These inhibitions were statistically significant(P<0.001)and in a dose-dependent fashion.Conclusions:The antiplasmodial and antiulcerogenic effects of this plant may in part be mediated through the chemical constituents of the plant.

Antiplasmodial and analgesic activities of Clausena anisata

Objective:Antiplasmodial and analgesic activities of the leaf extract and fractions of Clausena anisata(C.anisata) were evaluated for antimalarial and analgesic activities.Methods:The crude leaf extract(39-117mg/kg) and fractions(chloroform and acqeous;78mg/kg) of C. anisata were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei(P.berghei) infections in mice using suppressive,prophylactic and curative models and analgesic activity against acetic acid,formalin and heat-induced pains.Artesunate,5 mg/kg and pyrimethamine,1.2mg/kg were used as positive controls.Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice.Results:The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine-sensitive P.berghei in prophylactic,suppressive and curative models in mice.These reductions were statistically significant(P【0.001).They also improved the mean survival time(MST) from 17 to 21 days relative to control(P【0.01-0.001).On chemically and thermally-induced pains,the extract inhibited acetic acid and formalin-induced inflammation as well as hot plate-induced pain in mice.These inhibitions were statistically significant(P【0.001) and in a dose-dependent fashion. Conclusions:The antiplasmodial and analgesic effects of this plant may in part be mediated through its chemical constituents and it can be concluded that the C.anisata possess significant antimalarial and analgesic properties.

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 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.

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

Objective:To 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 stuthes) infection in mice.Methods:The 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 1 600 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. Results:The 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 1 600 mg/kg/day.Conclusions:The 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.

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.

Further antiplasmodial effects of the aqueous extract of cymbopogon citratus stapf (lemon grass) against plasmodium berghei in Swiss albino mice

Lemon grass(Cymbopogon citratus Stapf) is a popular alternative to western medicines for a number of conditions, including fevers,muscle soreness and superficial infections in Nigeria.In addition to its already reported suppressive effects against P.berghei infection,this study sought to determine its repository and blood schizonticidal activities in established P.berghei infection using Swiss albino mice as models.Mice weighing on average, between 15 and 25g were given 103mg/kg,155mg/kg and 310mg/kg/day of the crude aqueous extract of cymbopogon citratus stapf,in the 4-day test,24-hour Rane test and 72-hour Rane test.The effects of these doses of the extract were then compared with chloroquine(5mg/kg/day) and sulphadoxine/pyrimethamine (3mg/kg/day).We report an average percentage suppressive repository activity of 65.8%for the extract at a dose of 310mg/kg and a blood schizonticidal activity that increased from 68.33%in the 24-hour Rane test to 92%in the 72-hour Rane test for the same dose of extract.The crude aqueous extract of C.citratus stapf thus has significant repository and blood schizonticidal activities against established P.berghei infection in Swiss albino mice compare to that of pyrimethamine and sulphadoxine/pyrimethamine respectively.

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.

Ethnobotanical database based screening and identification of potential plant species with antiplasmodial activity against chloroquine-sensitive(3D7) strain of Plasmodium falciparum

Objective: To evaluate the antiplasmodial activity of aqueous-methanolic plant extracts of nine plant species selected, based on ethnobotanical data. Methods: Based on ethnobotanical database, the selected plants were tested for their antiplasmodial activity against chloroquinesensitive(3 D7) strain of Plasmodium falciparum. Qualitative tests and high performance thin layer chromatography analysis were carried out to explore the phytocomponents present in the plant extracts. 1,1-diphenyl-2-picrylhydrazyl antioxidant activity was also determined to check the antioxidant activity of the plant extracts. Results: Moringa oleifera(IC_(50): 3.906 μg/mL),Acalypha indica(IC_(50): 3.906 μg/mL), Hyptis suaveolens(IC_(50): 3.906 μg/mL), Mangifera indica(IC_(50): 4.150 μg/mL) and Averrhoa bilimbi(IC_(50): 4.881 μg/mL) showed very good antiplasmodial activity. Conclusions: Crude extracts of Mangifera indica and Hyptis suaveolens demonstrated the most efficacious antimalarial activity. A bioassay-guided fractionation of these extracts to identify the lead compound is proved to be useful. The results validate the traditional use of the selected plants as antimalarials.

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.

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.

Apocynaceae species with antiproliferative and/or antiplasmodial properties: a review of ten genera

Apocynaceae is a large family of tropical trees, shrubs and vines with most species producing white latex. Major metabolites of species are triterpenoids, iridoids, alkaloids and cardenolides, which are known for a wide range of biological and pharmacological activities such as cardioprotective, hepatoprotective, neuroprotective, anti-inflammatory, anticancer and antimalarial properties. Prompted by their anticancer and antimalarial properties, the current knowledge on ten genera （Allamanda, Alstonia, Calotropis, Catharanthus, Cerbera, Dyera, Kopsia, Nerium, Plumeria and Vallaris） is updated. Major classes of metabolites are described using some species as examples. Species with antiproliferative （APF） and/ or antiplasmodial （APM） properties have been identified. With the exception of the genus Dyera, nine genera of 22 species possess APF activity. Seven genera （Alstonia, Calotropis, Catharanthus, Dyera, Kopsia, Plumeria and Vallaris） of 13 species have APM properties. Among these species, Alstonia angustiloba, Alstonia macrophylla, Calotropis gigantea, Calotropis procera, Catharanthus roseus, Plumeria alba and Vallaris glabra displayed both APF and APM properties. The chemical constituents of these seven species are compiled for assessment and further research.