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1.
In this study, we are reporting antileishmanial activity of a marine sponge Haliclona exigua, belonging to phylum Porifera. The crude methanol extract and its three fractions were tested both in vitro and in vivo.
The crude extract exerted almost complete inhibition of promastigotes at 50 μg/ml and 76.4 ± 6.5% inhibition of intracellular
amastigotes at 100 μg/ml concentration with IC50 values of 18.6 μg/ml and 47.2 μg/ml, respectively. When administered to Leishmania donovani infected hamsters at a dose of 500 mg/kg × 5, p.o., it resulted in 72.2 ± 10.4% inhibition of intracellular amastigotes.
At a lower dose (250 mg/kg), it exhibited 43.9 ± 5.1% inhibition. Among the fractions, highest antileishmanial activity both
in vitro (>90%) and in vivo (60.9 ± 18.3%) was observed in n-butanol (soluble) fraction with IC50 values of 8.2 μg/ml and 31.2 μg/ml against promastigotes and intracellular amastigotes, respectively. Hexane fraction also
showed comparatively good activity against both the stages of parasites in vitro but was moderately active in leishmania-infected
hamsters. Chloroform fraction resulted in 45 ± 10.2% inhibition in vivo at a dose of 500 mg/kg × 5, p.o., whereas it was inactive
in vitro. n-Butanol (insoluble) fraction was inactive both in vitro and in vivo. Araguspongin C, an alkaloid isolated from n-butanol (soluble) fraction exhibited moderate inhibition of promastigotes and intracellular amastigotes at 100 μg/ml but
showed weak antileishmanial action in vivo. Our findings indicate that this marine sponge has the potential to provide new
lead toward development of an effective antileishmanial agent and, hence, calls for more exhaustive studies for exploiting
the vast world of marine resources to combat the scourge of several parasitic diseases. 相似文献
2.
Misra S Verma M Mishra SK Srivastava S Lakshmi V Misra-Bhattacharya S 《Parasitology research》2011,109(5):1351-1360
The present study is aimed to evaluate antifilarial activity of Xylocarpus granatum (fruit from Andaman) against human lymphatic filarial parasite Brugia malayi in vivo. The in vitro antifilarial activity has already been reported earlier for this mangrove plant which has traditionally
been used against several ailments. Aqueous ethanolic crude extract, four fractions (ethyl acetate fraction, n-butanol fraction, water-soluble fraction and water-insoluble fraction) and pure molecule/s of X. granatum (fruit) were tested in vitro on adult worms and microfilariae (mf) of B. malayi and the active samples were further evaluated in vivo in B. malayi (intraperitoneally) i.p. transplanted in the jird model (Meriones unguiculatus) and Mastomys coucha subcutaneously infected with infective larvae (L3). The crude aqueous ethanolic extract was active in vitro (IC50: adult = 15.46 μg/ml;
mf = 13.17 μg/ml) and demonstrated 52.8% and 62.7% adulticidal and embryostatic effect on B. malayi, respectively, in Mastomys at a dose of 5 × 50 mg/kg by oral route. The antifilarial activity was primarily localized in the ethyl acetate-soluble fraction
which revealed IC50 of 8.5 and 6.9 μg/ml in adult and mf, respectively. This fraction possessed moderate adulticidal and embryostatic
action in vivo in Mastomys. Out of eight pure molecules isolated from the active fraction, two compounds gedunin (IC50 = 0.239 μg/ml, CC50 = 212.5 μg/ml,
SI = 889.1) and photogedunin (IC50 = 0.213 μg/ml, CC50 = 262.3 μg/ml, SI = 1231.4) at 5 × 100 mg/kg by subcutaneous route
revealed excellent adulticidal efficacy resulting in to the death of 80% and 70% transplanted adult B. malayi in the peritoneal cavity of jirds respectively in addition to noticeable microfilaricidalo action on the day of autopsy.
The findings reveal that the extract from the fruit X. granatum contains promising in vitro and in vivo antifilarial activity against human lymphatic filarial parasite B. malayi which could be attributed to the presence of two pure compounds gedunin and photogedunin. 相似文献
3.
The chemotherapeutic interventions against visceral leishmaniasis (VL) are limited and facing serious concerns of toxicity,
high cost, and emerging drug resistance. There is a greater interest in new drug developments from traditionally used medicinal
plants which offers unprecedented diversity in structures and bioactivity. With this rationale, ethanolic extract of Tinospora sinensis Linn and its four fractions were tested in vitro against promastigotes and intracellular amastigotes and in vivo in Leishmania donovani infected hamsters. Ethanolic extract exhibited an appreciable activity against promastigotes (IC50 37.6 ± 6.2 μg/ml) and intracellular amastigotes (IC50 29.8 ± 3.4 μg/ml). In hamsters, it resulted in 76.2 ± 9.2% inhibition at 500 mg/kg/day × 5 oral dose level. Among fractions,
n-butanol imparted highest in vitro and in vivo activities. Ethanolic extract and butanol fraction also enhances reactive oxygen
species (ROS) and nitric oxide (NO) release. The results indicate that T. sinensis may provide new lead molecules for the development of alternative drugs against VL. 相似文献
4.
Shuaibu MN Wuyep PA Yanagi T Hirayama K Tanaka T Kouno I 《Parasitology research》2008,102(6):1119-1127
In vitro antiplasmodial activity of methanolic extracts of 16 medicinal plants was evaluated by fluorometric assay using PicoGreen.
The IC50s, as determined by parasite DNA concentration, ranged from <11 to >200 and <13 to >200 μg/ml for Plasmodium falciparum 3D7 and K1, respectively; and the most active extracts were those from Anogeissus leiocarpus and Terminalia avicennoides (<11–≥14 μg/ml). Aqueous, butanolic, ethyl acetate, and methanolic fractions of these two extracts revealed butanolic fraction
to have a relatively better activity (IC50, 10–12 μg/ml). Activity-guided chromatographic separation of the butanolic fraction on Sephadex LH-20 followed by nuclear
magnetic resonance and correlation high-performance liquid chromatography revealed the presence of known hydrolysable tannins
and some related compounds—castalagin, ellagic acid, flavogallonic acid, punicalagin, terchebulin, and two other fractions.
The IC50s of all these compounds ranged between 8–21 μg/ml (8–40 μM) against both the strains. Toxicity assay with mouse fibroblasts
showed all the extracts and isolated compounds to have IC50 ≥ 1500 μg/ml, except for Momordica balsamina with <1500 μg/l. All the extracts and isolated compounds did not affect the integrity of human erythrocyte membrane at the
observed IC50s. However, adverse effects manifest in a concentration-dependent fashion (from IC50 ≥ 500 μg/ml). 相似文献
5.
Pujals G Suñé-Negre JM Pérez P García E Portus M Tico JR Miñarro M Carrió J 《Parasitology research》2008,102(6):1243-1247
The aim of the present study was to evaluate the in vitro activity and cytotoxicity of meglumine antimoniate microspheres
produced by spray drying on Leishmania infantum and the effect of the excipients used in them. The parasite strain shows sensitivity to the meglumine antimoniate microspheres
prepared. All the antimony IC50 values from encapsulated meglumine antimoniate (3.80 ± 0.34 to 9.53 ± 0.70 μg SbV/ml for promastigotes assay) are considerably
lower compared to the mean value of IC50 in Glucantime solution (112 ± 12.74 μg SbV/ml). Interesting IC50 values for the excipient chitosan (112.64 ± 0.53 mg/ml for promastigotes and 100.81 ± 26.45 mg/ml for amastigotes) were obtained
(without cytotoxic activity), whereas the rest of the excipients did not show any activity. This new delivery system could
offer a new pharmacological tool for the treatment of leishmaniosis that reduces the doses required, lowering toxic side effects
because of meglumine antimoniate. 相似文献
6.
Santoro GF das Graças Cardoso M Guimarães LG Salgado AP Menna-Barreto RF Soares MJ 《Parasitology research》2007,100(4):783-790
In the present work, we have investigated the effect of essential oils obtained from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) on growth and ultrastructure of diverse evolutive forms of Trypanosoma cruzi. Culture epimastigotes and bloodstream trypomastigotes were incubated for 24 h with different concentrations of oregano or
thyme essential oils and with thymol (the main constituent of thyme), and the inhibitory concentration (IC)50 was determined by cell counting. Crude extract of oregano essential oil inhibited epimastigote growth (IC50/24 h = 175 μg/ml) and also induced trypomastigote lysis (IC50/24 h = 115 μg/ml). Thyme essential oil presented IC50/24 h values of 77 μg/ml for epimastigotes and 38 μg/ml for trypomastigotes, while treatment with thymol resulted in an IC50/24 h of 62 μg/ml for epimastigotes and 53 μg/ml for trypomastigotes. Scanning electron microscopy of treated cells showed
few morphological alterations at the plasma membrane. Observation by transmission electron microscopy showed cytoplasmic swelling
with occasional morphological alterations in plasma and flagellar membrane. Our data indicate that oregano and thyme essential
oils are effective against T. cruzi, with higher activity of thyme, and that thymol may be the main component responsible for the trypanocidal activity. 相似文献
7.
Moon HI 《Parasitology research》2007,100(5):1147-1149
Samples of Carpesium genus used as traditional remedies for the treatment of parasite infections were collected, and methanol extracts were obtained
by sonication. The ethylacetate-, n-butanol- and H2O-soluble fractions exhibited weak antiplasmodial activity (IC50 > 100 μg/ml; IC50, 50% inhibitory concentration). However, the chloroform fraction exhibited more impressive antiplasmodial activity (IC50 = 8.2 μg/ml). The antiplasmodial activity of the chloroform fractions was evaluated in vitro against the chloroquine-resistant
D10 strain of Plasmodium falciparum. Bioactivity-guided isolation of the chloroform fractions of the whole plants of Carpesium rosulatum has led to the isolation of a sesquiterpene lactone, ineupatorolides A, displaying high antiplasmodial activity (IC50 = 0.007 μg/ml). This is the first report of the isolation of ineupatorolides A from this species and of its remarkable antiplasmodial
activity. 相似文献
8.
Passero LF Castro AA Tomokane TY Kato MJ Paulinetti TF Corbett CE Laurenti MD 《Parasitology research》2007,101(3):677-680
The crude methanolic extract from leaves of Jacaranda puberula showed activity against Leishmania (Leishmania) amazonensis. The extract presented active against promastigote forms with an inhibitory concentration 50% (IC50) value of 88.0 μg/ml, but only moderated activity against amastigote forms; however in higher concentrations the extract
showed cytotoxic effects. The bio-guided chromatographic fractionation the crude methanolic extract against amastigotes yielded
a fraction with an IC50 value of 14.0 μg/ml (without cytotoxic activity) in relation to the crude extract (IC50 value, 359.0 μg/ml). These data indicate that J. puberula leaves contain active compounds, which should be further investigated for the development of new potential drugs against
cutaneous leishmaniasis. 相似文献
9.
Shokri A Sharifi I Khamesipour A Nakhaee N Fasihi Harandi M Nosratabadi J Hakimi Parizi M Barati M 《Parasitology research》2012,110(3):1113-1117
Pentavalent antimonials are the standard treatment for cutaneous leishmaniasis (CL) with low efficacy and resistance is emerging.
CL is increased significantly in respect to incidence rate and expanding to new foci. In the present study, the effect of
verapamil on in vitro susceptibility of promastigote and amastigote stages of Leishmania tropica to meglumine antimoniate (MA, Glucantime) was evaluated using colorimetric assay (MTT) and in a macrophage model, respectively.
Verapamil, as a calcium channel blocker, affects drug uptake by preventing of drug efflux from the cells. In promastigote
form, several concentrations of MA with or without verapamil showed significant decrease (P < 0.05) in optical density. The overall mean IC50 value with combination of MA plus verapamil (IC50 = 116.03 μg/ml) was significantly less than MA (IC50 = 225.14 μg/ml) alone
(P < 0.05) for promastigote stage. Similarly, the amastigote stage was more susceptible to treatment with MA plus verapamil
to that of MA alone (P < 0.05). Analysis of overall effect of different concentrations of MA alone, compared with combination of MA plus verapamil
by mean infection rate of amastigotes in each macrophage showed a significant difference (P < 0.05).These findings indicated some degree of synergistic effects between MA and verapamil on in vitro susceptibility of
L. tropica to MA. Further works are required to evaluate this synergistic effect on animal model or volunteer human subjects. 相似文献
10.
The objective of this study was to develop a herbal formulation to control dengue vector mosquitoes. PONNEEM, a novel herbal
formulation prepared using the oils of neem (Azadirachta indica), karanj (Pongamia glabra) and their extracts, was tested for larvicidal, ovicidal and oviposition deterrent activities against Aedes aegypti and Aedes albopictus at 1, 0.5, 0.3 and 0.1 ppm concentrations. Cent percent larvicidal and ovicidal activities were observed at 0.1 ppm in the
two mosquito species under laboratory and sunlight-exposed conditions up to 12 months from the date of manufacture. Oviposition
deterrent activity of 69.97% and 71.05% was observed at 1 ppm concentration of PONNEEM against A. aegypti and A. albopictus, respectively. Reduction in enzyme levels for α-esterase was 0.089 ± 0.008 and 0.099 ± 0.140 μg napthol produced/min/mg larval
protein; for β-esterase, it was 0.004 ± 0.009 and 0.001 ± 0.028 μg napthol produced/min/mg larval protein; for glutathione
S-transferase, it was 10.4814 ± 0.23 and 11.4811 ± 0.21 μmol/min/mg larval protein and for total protein, it was 0.177 ± 0.010
and 0.008 ± 0.005 mg/individual larva in treated groups of A. aegypti and A. albopictus, respectively. The nontarget organisms such as Gambusia affinis and Diplonychus indicus were not affected. No mortality was observed in control. PONNEEM can be used effectively for the management of human vector
mosquitoes. 相似文献
11.
Experiments on Wistar rats showed that exenatide (0.015–0.5 nmol per 100 g body weight) somewhat increased renal excretion
of potassium from 7 ± 1 to 16 ± 1 μmol/h/100 g body weight (p < 0.05) in animals with normal serum concentration of glucose (4.6 ± 0.4 mM) and potassium (4.3 ± 0.1 mM). Exenatide dramatically
enhanced excretion of potassium under conditions of hyperkalemia (11.4 ± 0.4 mM) produced by intraperitoneal injection of
1.25% KCl solution (5 ml per 100 g body weight). During the fi rst postinjection hour, potassium excretion increased 2-fold
and attained 97 ± 11 μmol/h/100 g body weight in comparison with potassium load alone (47 ± 9 μmol/h/100 g body weight, p < 0.05). The data attest to a possible role of peptide regulators in normalization of potassium balance via renal mechanisms. 相似文献
12.
Olounladé PA Azando EV Hounzangbé-Adoté MS Ha TB Leroy E Moulis C Fabre N Magnaval JF Hoste H Valentin A 《Parasitology research》2012,110(4):1427-1433
The need for new anthelmintic with no chemical residues is becoming urgent. In a program aiming at the evaluation of plant
as sources of new active molecules, the anthelmintic activities of the essential oils (EOs) obtained from either Zanthoxylum zanthoxyloides seeds or Newbouldia laevis leaves were evaluated against Strongyloides ratti by analyzing the results of two in vitro bioassays. These two plants and their tested parts were retained after an ethnopharmacology
survey that confirmed their use by small-scale farmers for treatment of small ruminants affected by digestive helminths. The
plants were harvested in Benin, and their EO were obtained by hydrodistillation. The EO yield of extraction was 0.65% (w/w)
of for Z. zanthoxyloides seeds and 0.05% (w/w) for N. laevis. The chemical compositions of the two EOs were analyzed by gas chromatography coupled with mass spectrometry. The major constituents
of the EO from Z. zanthoxyloides consisted of the following compounds: γ-terpinene (18 %), undecane (15 %), valencene (8.3 %), decanal (8.3 %), and 3-carene
(6.7 %). In contrast, the major constituents of the EO from N. laevis leaves consisted of the following compounds: β-caryophyllene (36 %) and eugenol (5.8 %). An egg-hatching inhibition (EHI)
assay was developed and a larval migration inhibition assay was used on S. ratti to examine the effects of the EOs and to evidence their inhibitory concentrations (IC50 and IC90) values on this nematode. Furthermore, the toxicity of the two EOs on Vero cell line was evaluated. When tested on S. ratti egg hatching, the two EOs resulted in similar IC50 values (19.5 and 18.2 μg/ml for Z. zanthoxyloides and N. laevis, respectively), which were about sevenfold higher than that of the control (thiabendazole, IC50 = 2.5 μg/ml). Larval migration was inhibited at similar concentrations for: Z. zanthoxyloides (IC50 = 46 μg/ml), N. laevis (IC50 = 51 μg/ml), and the control [levamisole (IC50 = 36 μg/ml)]. No cytotoxicity was found on Vero cells because both EOs had IC50 values higher than 50 μg/ml. Therefore, we have concluded that the EOs from two plants, used in folk medicine, may contain
compounds with anthelmintic activity and could be used as improved traditional medicines or, at least, as food additives in
a combined treatment for the control of helminth infections. 相似文献
13.
Myxobolus honghuensis n. sp. is described from allogynogenetic gibel carp Carassius auratus gibelio (Bloch), during a survey of myxosporean parasites in Honghu Lake, Hubei Province, China. It is characterized by the presence
of round plasmodia of 5–12 mm in diameter in the pharynx of host. Mature spores of M. honghuensis were pyriform in frontal view and anterior pointed with bluntly round posterior, they measured 16.9 ± 0.5 (15.1–19.5) μm
long, 10.4 ± 0.4 (9.0–11.3) μm wide, and 8.4 ± 0.4 (7.9–9.1) μm thick. Two polar capsules were pyriform and slightly unequal
with larger polar capsule 8.4 ± 0.4 (7.6–10.2) μm × 3.9 ± 0.2 (3.0–4.5) μm and smaller capsule 7.9 ± 0.2 (7.0–9.3) μm × 3.7 ± 0.3
(2.8–4.1) μm. Polar filaments coiled with seven to eight turns. Both morphology and DNA sequence data revealed that M. honghuensis n. sp. was distinct from other described Myxobolus species. Phylogenetic analysis placed M. honghuensis n. sp. in a clade of gill-infecting myxobolids. 相似文献
14.
Ashish Rastogi Zhiquan Luo Zhuojie Wu Paul S. Ho Phillip D. Bowman Salomon Stavchansky 《Biomedical microdevices》2010,12(5):915-921
A drug delivery system that consists of microperforated polyimide microtubes was developed and characterized. Two groups of
polyimide tubes were used. One set consisted of microtubes (I.D. = 125 μm) with 32.9 ± 1.7 μm size holes. The second set consisted
of larger tubes (I.D. = 1000 μm) with 362–542 μm holes. The number of holes was varied between 1 and 3. The small tubes were
loaded with crystal violet (CV) and ethinyl estradiol (EE) and the drug release studies were performed in 0.01 M phosphate
buffered saline (PBS) (pH 7.1–7.4) at 37.0 ± 1.0°C for upto 4 weeks. The large tubes were loaded with CV and the drug release
was studied in vitro in PBS and also ex vivo in rabbit’s vitreous humor. Linear release rates with R2 > 0.9900 were obtained for all groups with CV and EE. Release rates of 7.8 ± 2.5, 16.2 ± 5.5, and 22.5 ± 6.0 ng/day for CV
and 30.1 ± 5.8 ng/day for EE were obtained for small tubes. For large tubes, a release rate of 10.8 ± 4.1, 15.8 ± 4.8 and
22.1 ± 6.7 μg/day was observed in vitro in PBS and a release rate of 5.8 ± 1.8 μg/day was observed ex vivo in vitreous humor. 相似文献
15.
The leishmanicidal activity of Aloe vera leaf exudate (AVL) has been demonstrated in promastigotes and axenic amastigotes, but its effectiveness in animal models
has not been evaluated. The presence of alkaloids, triterpenes, cyanidines, proanthocyanidines, tannins, and saponins in AVL
was identified. Its effectiveness in four Leishmania donovani strains was studied both in promastigotes (IC50 ranged from 70–115 μg/ml) and amastigotes (IC50 ranged from 3.1–11.4 μg/ml). In amastigotes, the killing by AVL was facilitated through its induction of nitric oxide in
leishmania-infected macrophages. The safety index was good as AVL up to 300 μg/ml remained non-toxic to monocytes and macrophages. In
a L. donovani BALB/c mouse model, oral or subcutaneous administration of AVL (15 mg/kg body weight × 5 days) reduced parasitemia by >90%
in the liver, spleen, and bone marrow without impairment of hepatic and renal functions. Collectively, we conclude that AVL
shows promising antileishmanial activity and may provide a new lead agent in the treatment of Leishmaniasis.
Chitra Mandal and Mitali Chatterjee should be considered as joint senior authors. 相似文献
16.
Considering the snake venoms’ pharmacological properties and chemotherapeutic potential as well as the need for new alternatives
for Giardia infection treatment, the present study was carried out aiming to evaluate the in vitro effects of crude Crotalus durissus terrificus and Bothrops jararaca venoms on the growth and adherence of Giardia duodenalis trophozoites. Trophozoites (106) were exposed to serial twofold dilutions of C. durissus terrificus and B. jararaca venoms that ranged from 3.125 to 200 μg/ml and from 5 to 320 μg/ml, respectively. The two venoms inhibited the growth of
trophozoites, and the level of inhibition varied according to the assayed concentrations and incubation times. The highest
reduction of parasite growth was observed with increasing concentrations of the venoms. No effect on parasite adherence was
observed. Light microscope observations revealed changes of the pear-shape aspect of the cell and reduction of flagellar beating
frequency in the great part of the trophozoites. This is the first attempt to evaluate the in vitro effects of snake venoms
on Giardia trophozoites. The findings stress the need for more investigations and prompt us to perform further studies to identify active
principles with antigiardial effect. 相似文献
17.
Shuaibu MN Pandey K Wuyep PA Yanagi T Hirayama K Ichinose A Tanaka T Kouno I 《Parasitology research》2008,103(6):1333-1338
Stem barks of Anogeissus leiocarpus and Terminalia avicennoides widely used in Africa for treatment of some parasitic diseases were collected and made into methanolic extracts. The extracts
were tested on four strains of promastigote forms of Leishmania in vitro. Solvent fractionation in aqueous, butanolic, and ethyl acetate layer indicated butanol and aqueous fractions to
have a superior leishmanicidal activity. Chromatographic separation of the butanolic fraction on Sephadex LH-20 followed by
nuclear magnetic resonance and correlation high-performance liquid chromatography revealed the presence of known hydrolyzable
tannins and some related compounds—with castalagin as the major compound. The observed activity ranged from 62.5 to ≥150,
112.5 to ≥500, and 55 to >150 μg/ml for the crude methanolic extract, different solvent fractions, and the isolated compounds,
respectively, on the four different Leishmania strains. 相似文献
18.
Borges A Silva S Op den Camp HJ Velasco E Alvarez M Alfonzo MJ Jorquera A De Sousa L Delgado O 《Parasitology research》2006,99(2):167-173
Leishmania parasites are sensitive to peptides with antimicrobial and ion-channel inhibitory activity. Because scorpion venoms are rich sources of such peptides, the leishmanicidal effect of Tityus discrepans venom was investigated. A negative correlation between cell growth and venom concentration was observed for venom-treated cultures of Leishmania (L.) mexicana mexicana promastigotes; 50% growth inhibition was obtained at 0.4 μg/ml. Light microscopy showed rounded, highly vacuolated L. (L.) m.
mexicana cells with impaired flagellar motion after 15 min of incubation at 35 μg/ml. Ultrastructural studies confirmed an intense cytoplasm vacuolation and also enlargement of the flagellar pocket. Survival rates for New World Leishmania promastigotes (75% venom effective concentration, μg/ml) obtained after acute (1 h) venom toxicity tests were: L. (L.) m. mexicana (2.3), Leishmania (V.) braziliensis (11.3), and Leishmania (L.) chagasi (56.2). Heat (90°C) treatment of venom and fraction TdII abolished most of their leishmanicidal effect. Acute toxicity assays performed with Sephadex G-50 fractions indicated that leishmanicidal activity is associated with the venom lowest molecular mass components (2.8–7.4 kDa), as determined by MALDI-TOF mass spectrometry. 相似文献
19.
In order to assess the potential of the stem bark of Kigelia africana (Lam.) Benth as source of new anti-malarial leads, n-hexane and ethyl acetate (EtOAc) extracts and four compounds isolated
from the stem bark were screened in vitro against the chloroquine-resistant W-2 and two field isolates of Plasmodium falciparum using lactate dehydrogenase assay. The products were also tested for their cytotoxicity on LLC/MK2 monkey kidney cells. The
EtOAc extract exhibited a significant antiplasmodial activity (IC50 = 11.15 μg/mL on W-2; 3.91 and 4.74 μg/mL on field CAM10 and SHF4 isolates, respectively), whereas the n-hexane fraction
showed a weak activity (IC50 = 73.78 μg/mL on W-2 and 21.85 μg/mL on SHF4). Three out of the four compounds showed good activity against all the three
different parasite strains (IC50 < 5 μM). Specicoside exhibited the highest activity on W-2 (IC50 = 1.54 μM) followed by 2β, 3β, 19α-trihydroxy-urs-12-en-28-oic acid (IC50 = 1.60 μM) and atranorin (IC50 = 4.41 μM), while p-hydroxycinnamic acid was the least active (IC50 = 53.84 μM). The EtOAc extract and its isolated compounds (specicoside and p-hydroxycinnamic acid) were non-cytotoxic (CC50 > 30 μg/mL), whereas the n-hexane extract and two of its products, atranorin and 2β, 3β, 19α-trihydroxy-urs-12-en-28-oic
acid showed cytotoxicity at high concentrations, with the last one being the most toxic (CC50 = 9.37 μg/mL). These findings justify the use of K. africana stem bark as antimalaria by traditional healers of Western Cameroon, and could constitute a good basis for further studies
towards development of new leads or natural drugs for malaria. 相似文献
20.
F. Fuentes M. J. Giménez F. Marco L. Alou L. Aguilar J. Prieto 《European journal of clinical microbiology & infectious diseases》2000,19(2):137-139
The in vitro susceptibility to trovafloxacin and gemifloxacin of Streptococcus pneumoniae strains exhibiting decreased susceptibility to ciprofloxacin (MIC ≥2 μg/ml; 30 strains with intermediate resistance [MIC
2 μg/ml] and 43 strains with complete resistance [MIC ≥4 μg/ml]) was determined. Seventy-three strains collected in a surveillance
study carried out from May 1996 to April 1997 in Spain (prior to commercialisation of trovafloxacin and gemifloxacin) from
patients with respiratory tract infections were tested. The antibacterial activity of gemifloxacin was affected to a lesser
extent than that of trovafloxacin by the increase in the MIC of ciprofloxacin, with gemifloxacin showing significantly (P≤0.001) better antibacterial activity than trovafloxacin in all ciprofloxacin MIC categories (MIC50/MIC90 values of 0.015/0.03,
0.015/0.06, 0.03/0.06 and 0.12/0.25 μg/ml for gemifloxacin vs 0.12/0.12, 0.12/1, 0.25/0.5 and 2/4 μg/ml for trovafloxacin
in the 2, 4, 8 and ≥16 μg/ml ciprofloxacin MIC categories, respectively). Nine (12.3%) of these 73 strains exhibited decreased
susceptibility to trovafloxacin (≥2 μg/ml), whereas all strains were inhibited by 0.25 μg/ml of gemifloxacin. 相似文献