Curative Test Research Articles

Evaluation of the anti-malarial activity of crude extract and solvent fractions of the leaves of Olea europaea (Oleaceae) in mice

BackgroundDrug resistance poses a challenge to malaria control measures. This calls for discovery & development of new chemotherapeutic agents. This study therefore was initiated to investigate the antimalarial activity of Olea europaea against Plasmodium berghei infected mice and to further ascertain in which fraction (s) the constituents responsible for anti-malarial activity are concentrated.MethodsThe leaves of Olea europaea were extracted by maceration using 80% methanol and the crude extract was then successively fractionated with solvents of differing polarity (chloroform, n-butanol and water). The anti-malarial activity of various doses of the extract and fractions (200, 400 and 600 mg/kg) was evaluated using chemo-suppressive, curative, and repository tests. Parameters, including parasitemia, rectal temperature, body weight, and packed cell volume were determined to establish the activity.ResultsThe acute oral toxicity test result revealed that the LD50 values of the extract and fractions were greater than 2000 mg/kg in mice. The crude extract significantly reduced parasitemia (p < 0.001) and prolonged survival time (p < 0.001), in a dose-dependent manner, in all tests, as compared to the negative control group. Higher parasitemia suppression (58%) was achieved with the larger dose (600 mg/kg) in the 4-day suppressive test, suggesting that the crude extract has largely a chemo-suppressive activity.Parasitemia was significantly reduced (p < 0.001) by all fractions in all doses used when compared to the negative controls, with the rank order of n-butanol (51%) > chloroform>aqueous (21%) fractions. Larger (600 mg/kg) and middle (400 mg/kg) doses of the crude extract as well as the fractions ameliorated all the other parameters in a consistent manner, with the crude being more active than the fractions. Preliminary phytochemical analysis revealed the presence of secondary metabolites that were differentially distributed in the fractions.ConclusionThe findings collectively indicate that the plant is endowed with antimalarial activity, the activity being more in the crude extract than the fractions, owing to the presence of secondary metabolites that act independently or in synergy. The varying degree of antimalarial activity in the fractions suggests that non-polar and medium polar principles could be responsible for the observed activity.

Toxicological Effects, Prophylactic and Curative Activity of Rauwolfia vomitoria Leaf Extracts on Plasmodium Berghei NK 65 infected Swiss albino mice

This study evaluates prophylactic and curative antiplasmodial effects of <i>Rauwolfia vomitoria</i> leaf extracts on Plasmodium berghei NK 65. The extracts of the leaves at 100, 200 and 400 mg kg-1 body weight/day dose levels were used to treat the test groups 72 hours before infection for the prophylactic test and 72 hours post infection for the curative test while a standard antimalarial drug, chloroquine, at a dose of 5 mg kg-1 body weight was administered on the positive control group. The negative control groups were left untreated. The level of parasitemia, Percentage Packed Cell Volume (% PCV), erythrocytes (RBC) and leukocytes (WBC) counts in the different groups were monitored also, bicarbonate, creatinine, uric acid, urea, calcium level and histological effects of extracts were determined during the period of study. Qualitative and quantitative phytochemicals of water and ethanol leaf extracts were determined.

English

The study evaluates the in vivo antiplasmodial activity of ethanol leaf extract and fractions of Jatropha gossypifolia in Plasmodium berghei infected mice. Phytochemical, physicochemical analyses, median lethal dose (LD50), effects on biochemical parameter were evaluated and the schizonticidal effects during early and established infections were investigated. The extract (50-200 mg/kg) was screened for antimalarial prophylactic and curative activities against 50 (20-30 g) P. berghei infected mice using standard method. The prophylactic and curative activity tests were repeated for the fractions of the extract. The phytochemical analysis done on J. gossypifolia leaves showed presence of tannins, saponins, phlobatannins, alkaloids, flavonoids, terpenoids and cardiac glycosides. It contained total ash (6.3%); acid insoluble ash value (3.8%), water soluble ash value (2.5%), ethanol extractive value (4.5%) and moisture content (7%). LD50 was 4472.14 mg/kg. There was significant increase in alanine transaminase (ALT), alanine phosphatase (ALP) and aspartate aminotransferase (AST) at 500 mg/kg on the 28th day, indicating liver injury at high dose and prolonged administration. The crude extract of J. gossypifolia (50-200 mg/kg) exhibited moderate prophylactic and significant (P &lt; 0.05) curative activities in both day 4 and 7 tests with a mean survival time comparable to the standard drug, quinine 100 mg/kg. The fractions of the leaf extract of J. gossypifolia exhibited moderate to good prophylactic and curative activities, with ethyl acetate fraction eliciting the best activity in both test models. The leaf extract and fractions of J. gossypifolia administration are safe and possess good antiplasmodial activity, which confirmed its folkloric antimalarial medicinal use. Key words: Malaria, antimalarial, Plasmodium berghei, Jatropha gossypifolia, toxicity, biochemical parameters. &nbsp

Chemical Composition of Essential Oil of Mondia whitei and Antifungal Activities Against Aspergillus flavus and Penicillium sp., The Mold Associated on Yams (Dioscorea rotundata Poir.) Tuber Rot

The aim of this work was to determine the chemical composition of essential oil of roots of Mondia whitei and to evaluate their antifungal potential against Aspergillus flavus and Penicillium sp. Oil was obtained by hydro-distillation and gas chromatography was used to analyze their chemical constituents. The fungi were isolated from post-harvest yams (Dioscorea rotundata) showing typical symptoms of tuber rot. Antifungal activities of the oil were tested in vitro against mycelia growth and conidia germination. In situ test was carried out on healthy yams by application of the oil after (preventive test) and before (curative test) infection with pathogens. Results showed that yield of root Mondia whitei essential oil was 2.57 % and the Menth-1-en-7-al <3-oxo-P-> was found to be the main component. Significant reduction of mycelia growth was obtained with minimal inhibitory concentration (MIC) at 500 μl/l and 525 μl/l respectively for Aspergillus flavus and Penicillium sp. This oil completely inhibited the conidia germination of Penicillium sp. with MIC at 525 μl/l while 65.38 % inhibitory was obtained at 1000 μl/l against Aspergillus flavus. In situ test showed significant reduction of necrosis of yam tuber rot. At 2500 μl/l we obtained 47.41 % and 72 % of necrosis inhibition respectively, for preventive and curative healing for Aspergillus flavus, while for Penicillium sp., we obtained at 2625 μl/l, 31.8 % and 43.07 % of the necrosis inhibition, respectively. This study demonstrated that essential oil from roots of Mondia whitei could be promising alternative for management yam tuber loose induced by mold.

Therapeutic potential of selected micronutrients in malaria: an in vivo study in Plasmodium berghei infected mice

The study involves an in vivo evaluation of the role of some antioxidant micronutrients in the therapeutics of malaria. Rodent malaria model using Plasmodium berghei NK-65 strain (chloroquine sensitive) was used. In the first stage of the experiment, a 4 day suppressive test was conducted using 40 mice of either sex weighing 20.05 6 0.02 g which were inoculated intraperitoneally with 1 3 107 million P. berghei infected erythrocyte and were administered with 0.2 ml of distilled water, 0.2 ml of vehicle, Tween 80 (control and vehicle group), chloroquine 25 mg/kg (standard drug group), vitamin A 60 mg/kg, vitamin E 100 mg/kg, selenium 1 mg/kg, zinc 100 mg/kg, and vitamin C 200 mg/kg (test groups D, E, F, G, and H respectively) 3 hours post-inoculation. Similarly, 35 mice of either sex were used to conduct a 4 day curative test after the initial screening test. Selenium demonstrated significant ( p , 0.05) chemosuppressive (82.01%) and schizonticidal activity (76.16%) when compared with negative control during the 4 day suppressive and 4 day curative test respectively. Mean parasitemia was significantly reduced ( p , 0.05) in the micronutrient treated groups after the 4 day curative test when compared with negative control. This was also significant between groups (F 5 7.04; p  0.05). Conclusively, antioxidant micronutrients have potential antimalarial activity and may be of benefit in malaria therapeutics.

Hepato-protective and haematological assessment of Morinda lucida ethanolic leaf extract on Plasmodium berghei parasitized mice

Development of antimalarial drugs from medicinal plants continues to be a very appealing option. Morinda lucida, commonly known as ‘Oruwo’ or ‘Erewo’ by the Yoruba people of South Western Nigeria, is used in the treatment of malaria, fever, amongst other ailments. Therapeutic efficacy of the ethanolic leaf extract was evaluated in Plasmodium berghei infected mice. Percentage suppression of parasitaemia for the ethanolic leaf extract was 54.68, 60.84, 84.89 and 96% for doses of 100mg/kg, 200mg/kg, and 400mg/kg body weight of the extract and 5 mg/kg Leonart DS respectively. Effective dose which depends on the inhibition of parasitaemia was also observed in the curative test. The hepatoprotective activity of the ethanolic leaf extract was determined through liver enzyme tests (AST, ALT, and ALP) for 100, 200, and 400 mg/kg body weight of the extract. Morinda lucida ethanolic leaf extract possesses no lethality in mice at 400mg/kg body weight. It is concluded that the ethanolic leaf extract of Morinda lucida is potentially useful as antimalarial drug.

Antiplasmodial activities of the combined leaves extracts of Morinda lucida, Phyllantus Amarus, Vernonia Amygdalina and Newbouldia laevis

The development of resistance to some synthetic antimalarial drugs and the spread of counterfeit antimalarial drugs, has become a global problem. It has affected effective malaria treatment, making the development of new drugs exigent. Certain medicinal plants contain potent ingredients such as alkalloids, flavonoids, glycoside and volatile oils, which suppress the spread of plasmodial infections, and are widely used within the tropics for treatment of malaria. This study was designed to investigate the antiplasmodial activities of the combined aqueous extract of Morinda lucida, Phyllantus amarus, Vernonia amygdalina and Newbouldia laevis at variable doses in Swiss albino mice infected with Plasmodium berghei (NK65). Fifty mice were randomized into ten groups which were divided equally for suppressive and curative test. Four days suppressive and 5 days curative test were used to assess the antiplasmodial activities of the extract in mice infected with chloroquine sensitive P. berghei at concentration of 200mg/kg, 400mg/kg and 800mg/kg body weight. Furthermore the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphate (ALP), urea and creatinin were determined by standard procedural methods to evaluate impact of extracts on hepatic and kidney function. The results of the 4 days suppressive test revealed that the test extract achieved percentage suppression of 9.8%, 58.3% and 60.2% for 200mg/kg, 400mg/kg and 800mg/kg concentration respectively. The curative test achieved the highest parasitaemia reduction with 800mg/kg (29.5±29.1 x 103) which was comparable to the standard antimalarial drug, chloroquine. There were significant elevation in the values of AST and ALT at 400mg/kg and 800mg/kg respectively suggesting hepatic dysfunction. However, ALP and urea showed no significant different (P&gt;0.05), but creatinin showed significant difference (P&lt;0.05) only at 200mg/kg. This study shows that the combined leaves extract demonstrated antimalarial activities.

Inhibitory effects of essential oils from Ocimum basilicum and Ocimum gratissimum on Colletotrichum musae: The causal agent of bananas anthracnose

AbstractThis study aimed to investigate the fungicidal effects of essential oils (EO) from Ocimum sp. on Colletotrichum musae. The fungus was isolated from bananas that showed typical symptoms of anthracnose followed by molecular identification. Oils were obtained by hydro‐distillation, and the chemical constituents were analysed using gas chromatography. The antifungal activity of the oils was tested in vitro against mycelia growth and conidia germination. In situ tests were carried out by spraying the oil on healthy bananas followed by the inoculation with C. musae conidia and the assessment of the necrosis symptoms. The obtained results revealed that the yield of the oil extracted from Ocimum basilicum and Ocimum gratissimum were 0.17% and 0.40%, respectively. Thujanol (24.38%), eugenol (23.78%) and (Z)‐ß‐ocimene (16.59%) were the main components found in O. basilicum while thymol (42.65%), trans‐sabinene hydrate (21.63%) and limonene (8.68%) were the major components found in O. gratissimum. The total reduction in the C. musae mycelial growth was observed at 800 and 275 µl/L, for the O. basilicum and O. gratissimum oils, respectively. These oils also inhibited completely the conidia germination at 400 and 185 µl/L. In situ tests showed the necrosis reduction bananas anthracnose. The minimum inhibitory concentration (MIC) for the preventive and curative test after the application of O. basilicum oil was 6,000 and 4,000 µl/L, respectively, whereas for the O. gratissimum oil, the MIC was 3,000 and 1,000 µl/L, jointly. Positive correlations were identified between the oil concentration and the reduction in bananas necrosis. These results indicated that the O. gratissimum EOs might be used as a biocide for the control of bananas anthracnose disease.

Antimalarial activities of butanol and ethylacetate fractions of Combretum nigricans leaf

Objective: To evaluate the antimalarial activity of the ethylacetate and butanol fractions of Combretum nigricans (C. nigricans) leaf extract in mice. Methods: C. nigricans solvent (butanol and ethylacetate) fractions were screened for their phytochemical constituents using standard procedures illustrated by Harborne and Evans. The Peters’ 4-day suppressive test against early malaria infection, Rane’s curative test against established malaria and prophylactic test for residual activity were employed for evaluating the antimalarial potential in mice. Results: The phytochemical screening revealed the presence of alkaloids, terpenoids, saponins, and flavonoids in both fractions at different intensity. Both fractions exhibited significant antimalarial activity in all test models (P Conclusions: Both solvent fractions of C. nigricans possess antimalarial activity, and may be useful at different stages of malaria therapy.

Cysteine Protease Inhibitors from the Methanol Extract of the Root Bark of Securidaca longepedunculata with Antimalarial Potentials in Chloroquine-Resistant P. berghei Parasite

Malaria parasite resistance against Artemisinin-based Combination Therapy (ACT) in some parts of the world necessitates the search for antimalarial compounds or plant extracts with novel mode of action and active against the chloroquine-resistant strain of the parasite to serve as alternative to ACT. Cysteine protease inhibitors' fraction of the methanol extract of the root bark of Securidaca longepedunculata (CPI) was investigated for antiplasmodial activity against chloroquine-resistant P. berghei-infected mice and its inhibitory effect on papain, P. berghei cysteine proteases and heme biocystallization were also evaluated. The methanol extract of the root bark was obtained by soxhlet extraction with 1,000 mL of 70% (v/v) methanol for 48 hours and concentrated to dryness at 45∘C. CPI was obtained using PBS (pH 7) extraction followed by cold acetone precipitation. Peter's four-day suppressive and Rane's four-day curative test was employed to assess the antimalarial potentials of CPI. Data was analysed with one way ANOVA followed by Dunnett's post hoc test, differences were considered significant at p≤0.05. The suppressive effect of CPI was significant (p≤0.05) at 34 and 23 mg/kg doses. Doses of 34, 23 and 11 mg/kg produced significant (p≤0.05) dose-dependent curative effect. CPI inhibited the proteolytic activity of papain enzyme and P. berghei cysteine proteases in vitro with IC50 values of 20.1 and 5.6 μg/mL respectively. The present study showed that cysteine protease inhibitors fraction of the methanol extract of the root bark of Securidaca longepedunculata is a potential source of novel antimalarial agents that could target malaria parasite cysteine proteases.

The Modulatory Activity of &lt;i&gt;Justicia carnea&lt;/i&gt; in Plasmodium Infected Mice

The study investigated the antiplasmodial potency of Justicia carnea in plasmodium infected mice. The aqueous leaf extract of Justicia carnea was subjected to phytochemical screening using GC-FID. The suppressive, prophylactic and curative activity of the studied plant was accessed after oral administration of standard drugs (5mgkg-1 choroquine and 4mgkg-1 artesunate) and 400-800mgkg-1 of the extract. The effect of the aqueous leaf extract of the studied plant was also explored in the activities of liver enzymes, oxidative stress markers and hematological indices of plasmodium infected mice using spectrophotomertic methods and a hematology auto analyzer (BC 5300 Mindray England) respectively. The aqueous leaf extract of Justicia carnea showed considerable dose dependent antiplasmodial activity in the suppressive, prophylactic and curative test conducted. The suppressive activity of (92%) of the aqueous leaf extract of the studied plant at 800mgkg-1 was comparable to the standard drugs used while the mean survival time of plasmodium infected mice at 800mgkg-1 was beyond the mean survival time of the infected untreated group. The aqueous leaf extract of the studied plant also exhibited significant improvements in the activities of liver enzymes, oxidative stress markers and some hematological parameters at 800mgkg-1 of the extract when compared with the infected and untreated group. The results of the study exhibited the antiplasmodial activity of the studied plant, nonetheless, the crude extracts of the studied plant can be further purified for synergistic use with other potent antimalarial drugs to combat and achieve total clearance of plasmodium resistant infections.

ANTIPLASMODIAL ACTIVITY OF CAESALPINIA CRISTA SEED EXTRACTS

Objective: To evaluate antiplasmodial activity of Caesalpinia crista seed extracts&#x0D; Methods: Antiplasmodial activity of the seed extracts of Caesalpinia crista against rodent malaria infections in chloroquine sensitive Plasmodium falcipuram strain was investigated, and oral acute toxicity of seed extracts of Caesalpinia crista was also evaluated.&#x0D; Results: The findings of this study revealed significant (P &lt; 0.05) and dose dependent decrease in parasitaemia in the parasitized groups treated with varying doses of the extract (50-200 mg/kg p.o.) in both suppressive and curative tests. There was also significant decrease in parasitaemia density in the chloroquine treated group. The alcoholic extract was found no toxicity in wistar rats and the oral LD50 was determined to be greater than 5000 mg/kg.&#x0D; Conclusion: Seed extracts of Caesalpinia crista extract possesses potent antiplasmodial activity and may therefore, serve as potential sources of new antimalarial agents&#x0D; Keywords: Plasmodium falcipuram, Caesalpinia crista, Plant extracts, Phytochemicals, Toxicity tests, malaria.

English

Malaria is a major debilitating disease caused by Plasmodium species and spread by female Anopheles mosquitoes. This research was conducted to determine the efficacy of ethanolic leaf extracts of Ricinus communis L. against Plasmodium berghei (NK65) infection in mice. Phytochemical components of the extract were analyzed and elucidated in order to reveal the constituents with antimalarial potentials. The safety of the extract in the experimental mice was ascertained by determining the median lethal dose (LD50). Result of the phytochemical screening revealed the presence of compounds notable for antimalarial effects such as alkaloids, flavonoids and anthraquinones. From the findings, it was established that a dosage of 141.42 mg/kg of the extract represents the acute lethal dose (LD50) in mice. Hence, three separate doses of the extract (10, 20 and 40 mg/kg) were prepared for the curative test. All the three doses portrayed a remarkable antimalarial activity as compared to the standard reference drug (chloroquine, 5 mg/kg). The extract dosage of 20 mg/kg showed the highest average suppression of 81.6% among the treatments. No significant differences were however observed among the treated groups (P&gt;0.05). On the other hand, a highly significant difference was observed between the treated and control groups (P&le;0.001). The leaf extracts of R. communis thus possess antimalarial properties and is therefore recommended as a new candidate for antimalarial drug development. Key words: Ricinus communis, chloroquine, phytochemical compound, antimalaria, dose, Plasmodium berghei. &nbsp

EVALUATION OF HEPATOPROTECTIVE EFFECT OF ETHANOLIC EXTRACT FROM RED BETEL (PIPER CROCATUM RUIZ AND PAV.) LEAVES

Objective: The objective of this study is to identify the effect of red betel (Piper crocatum Ruiz and Pav.) leaves ethanolic extract on hepatoprotective effect on CCl4-induced liver damage in rats.Methods: Standard phytochemical screening method was done for preliminary phytochemical screening. Hepatotoxic rats were induced with CCl4 and treated with ethanolic extract of red betel leaves. The hepatoprotective test was divided into two groups (curative and preventive test). In the curative test, the rats which have been induced with CCl4 were given ethanol extract 600 mg/kg bw each day for 15 days. In the preventive test, the induced rats were given ethanol extract 600 mg/kg bw each day and CCl4 each 4 h for 45 days. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) parameters were also measured.Result: The phytochemical screening showed an ethanolic extract of red betel leaves which contain a lot of phytochemical compounds. The result of hepatoprotective study showed that the ALT, AST, and ALP registered a significant (p&lt;0.05) alteration in CCl4treated rats.Conclusion: The ethanolic extract of red betel leaves had the curative and preventive test.

Pharmacological characteristics of the novel fungicide pyrisoxazole against Sclerotinia sclerotiorum

Pyrisoxazole is a pyridine compound of demethylation inhibitor fungicides. In this study, baseline sensitivity of Sclerotinia sclerotiorum to pyrisoxazole was determined using 166 strains from the oilseed rape fields in 2014, 2015 and 2016. The EC50 values for mycelial growth inhibition ranged from 0.0214 to 0.5443 μg mL−1, with a mean EC50 value of 0.2329 ± 0.1048 μg mL−1 and were normally distributed. The EC50 values had no significant difference among three populations from 2014, 2015, and 2016. There was no correlation with sensitivity between pyrisoxazole and carbendazim or iprodione. After treated with pyrisoxazole, we observed increased cell membrane permeability, and decreased exopolysaccharide and oxalic acid production, which can contribute to reduced virulence of S. sclerotiorum and lead to failure of disease infection. Protective and curative activity tests showed that pyrisoxazole exhibited excellent protective and curative activity against S. sclerotiorum in oilseed rape, and protective activity was better than curative activity. Compared with the currently used fungicides, pyrisoxazole not only exhibited excellent control efficacy on Sclerotinia stem rot, but also dramatically reduced the doses of fungicides in the field trials. Overall, these data provide more references for revealing pharmacological effect of pyrisoxazole against S. sclerotiorum and managing Sclerotinia stem rot on oilseed rape caused by benzimidazole- and dicarboximide-resistant populations.

Efficacy of citronella essential oil for the management of chilli anthracnose

The potential of citronella essential oil for the management of chilli anthracnose caused by Colletotrichum acutatum was investigated. In in vitro tests, citronella essential oil inhibited mycelial growth at 0.25, 1.25 and 2.5 μL citronella/mL water, reduced conidial germination, and inhibited germ tube elongation at 1.25 μL/mL. Citronella essential oil applied as a protective or curative treatment to chilli cv. Django fruits reduced anthracnose infection. Efficacy of citronella essential oil was substantially effective to chemical fungicides and relatively superior to a biofungicide in both protective and curative tests. However, citronella essential oil at 2.5 μL/mL was phytotoxic to chilli fruits. Therefore, the most effective rate of citronella essential oil was at 1.5 μL/mL with inhibition of pathogen growth, reduction of anthracnose symptoms, and no observable phytotoxic response on chilli fruits. Citronella essential oil may be a viable alternative to chemical fungicides for the management of chilli anthracnose.

Effects of a novel SDHI fungicide pyraziflumid on the biology of the plant pathogenic fungi Bipolaris maydis

Pyraziflumid is a novel member of succinate dehydrogenase inhibitor (SDHI) fungicide. Southern corn leaf blight (SCLB) caused by Bipolaris maydis is an important foliar disease of maize crop. In this study, baseline sensitivity of B. maydis to pyraziflumid was determined using 100 strains of B. maydis collected from different geographical regions in Jiangsu Province of China during 2015 and 2016, and EC50 values ranged from 0.0309 to 0.8856 μg/ml with the average value of 0.2780 ± 0.2012 μg/ml for mycelial growth, and 0.032 to 0.9592 μg/ml with the average value of 0.3492 ± 0.2450 μg/ml for conidium germination. After treatment with pyraziflumid, the distribution of cell nucleus and septum of mycelium was not changed, but hyphae of offshoot and conidia production decreased, cell secretion decreased, the cell membrane was damaged, mycelium electrolyte leakage increased, and organelles in mycelial cell dissolved and vacuolated. The protective and curative activity test of pyraziflumid suggested that pyraziflumid had great control efficiency against B. maydis on detached corn leaves. In protective activity assay with application of pyraziflumid at 5 μg/ml and 10 μg/ml, the control efficacy reached to 87.32% and 100% respectively. In curative activity assay with application of pyraziflumid at 20 μg/ml and 50 μg/ml, the control efficacy reached to 82.10% and 100% respectively.

Evaluation of In vivo Antimalarial Activities of leaves of Moringa oleifera against Plasmodium berghei in Mice

Background: In addition to resistance against drugs, no new drugs have reached the market during the last decade for malaria treatment. This implies the urgent need to search for new drugs from different sources. Medicinal plants are one of such sources for novel drugs. Therefore, the aim of the current study was to investigate antimalarial activity of crude extract of leaves of Moringa oleifera Lam (Moringaceae) in Plasmodium berghei in a mice model. Methods: The acute toxicity test was used as per standard guidelines. To determine parasite inhibition, 4-day Peter’s suppressive test was done. Curative and prophylactic tests were done by applying standard methods. Windows SPSS version 16 was used to analyse the data and analysis of variance (ANOVA) followed by Post Hoc Tukey’s HSD to compare results between groups. Results: Death was not observed up to a dose of 2000 mg/kg of the plant extract. In all mice treated with the extract, the level of parasitaemia was significantly reduced in comparison with the control group (P < 0.001) and also a very significant difference was observed in comparison with the chloroquine treated group (P < 0.0001) with lower doses. Mean survival time was significantly increased at all treatment doses. It reduced parasitemia in a dose-dependent manner in both curative and prophylactic activity tests resulting in a significant (P < 0.05) reduction of parasitaemia in comparison with the control group. Conclusions: The result of the current study revealed that the extract possessed significant anti-plasmodial activity as displayed by its ability to suppress P. berghei infection in mice. The present study can be considered as confirmation for traditionally claimed use of the plant against malaria treatment.

Antimalarial activity of selected Ethiopian medicinal plants in mice

Context: Parasites are the leading killers in subtropical areas of which malaria took the lion share from protozoan diseases. Measuring the impact of antimalarial drug resistance is difficult, and the impact may not be recognized until it is severe, especially in high transmission areas. Aims: To evaluate the in vivo antimalarial activities of hydroalcoholic extracts of the roots of Piper capense and Adhatoda schimperiana, against Plasmodium berghei in mice. Methods: Four-day suppressive and curative test animal models were used to explore the antimalarial activities of the plants. 200, 400, and 600 mg/kg of each plant extract was administered to check the activities versus vehicle administered mice. Mean survival time and level of parasitemia were the major variables employed to compare the efficacy vs. negative control. Results: In both models the 400 and 600 mg/kg doses of Adhatoda schimperiana and the 600 mg/kg dose Piper capense. showed significant parasitemia suppression and increased in mean survival time at p≤0.05. The middle dose of Piper capense had a border line inhibition where the extracts were considered active when parasitemia was reduced by ≥ 30%. Conclusions: The hydroalcoholic extracts of the roots of Adhatoda schimperiana and Piper capense possess moderate antimalarial activities, which prove its traditional claims. Thus, further studies should be done to isolate the active constituents for future use in the modern drug discovery.

Activity of a novel succinate dehydrogenase inhibitor fungicide pyraziflumid against Sclerotinia sclerotiorum

Pyraziflumid is a novel member of succinate dehydrogenase inhibitor fungicides (SDHI). In this study, baseline sensitivity of Sclerotinia sclerotiorum (Lib.) de Bary to pyraziflumid was determined using 105 strains collected during 2015 and 2017 from different geographical regions in Jiangsu Province of China, and the average EC50 value was 0.0561 (±0.0263)μg/ml for mycelial growth. There was no cross-resistance between pyraziflumid and the widely used fungicides carbendazim, dimethachlon and the phenylpyrrole fungicide fludioxonil. After pyraziflumid treated, hyphae were contorted with offshoot of top increasing, cell membrane permeability increased markedly, oxalic acid content significantly decreased and mycelial respiration was strongly inhibited. But the number and dry weight of sclerotia did not change significantly. The protective and curative activity test of pyraziflumid suggested that pyraziflumid had great control efficiency against S. sclerotiorum on detached rapeseed leaves, and protective activity was better than curative activity. These results will contribute to us on evaluating the potential of the new SDHI fungicide pyraziflumid for management of diseases caused by S. sclerotiorum and understanding the mode of action of pyraziflumid against S. sclerotiorum.