Antiplasmodial activity of Setaria megaphylla

The antimalarial activity of an ethanol leaf extract of Setaria megaphylla was studied in vivo in mice infected with Plasmodium berghei berghei during early and established infections. Setaria megaphylla (100-300 mg/kg/day) exhibited a significant (p < 0.05) blood schizonticidal activity in 4-day early infection and in established infection with a significant (p < 0.05) mean survival time comparable to that of the standard drug, chloroquine, 5 mg/kg/day. The leaf extract possesses a promising antiplasmodial activity in vivo which can be exploited in malaria therapy.     

Antiplasmodial activity of Homalium letestui

The in vivo antiplasmodial activity of the ethanol root extract of Homalium letestui used as a malaria remedy in Southern Nigeria was evaluated in Plasmodium berghei berghei infected mice. Homalium letestui root extract (500-1000 mg/kg/day) exhibited significant (p < 0.05) blood schizontocidal activities both in a 4-day early infection test and in an established infection with a considerable mean survival time comparable to that of the standard drug, chloroquine, 5 mg/kg/day. The root extract possesses significant (p < 0.05) antiplasmodial activity, which can be exploited in malaria therapy.     

Evaluation of antiplasmodial activity of ethanolic seed extract of Picralima nitida

The in vivo antiplasmodial activity of the ethanol seed extract of Picralima nitida grown particularly for the leaf and seed in Niger Delta region of Nigeria was evaluated in Plasmodium berghei berghei infected mice. Picralima nitida (35-115 mg/kg day) exhibited significant (P<0.05) blood schizonticidal activity both in 4-day early infection test and in established infection with a considerable mean survival time though not comparable to that of the standard drug, chloroquine, 5 mg/kg day. The seed extract possesses significant (P<0.05) antiplasmodial activity which correlate with it reported in vitro activity.     

Antimalaria activity of ethanolic extract of Tetrapleura tetraptera fruit

The in vivo antiplasmodial activity of the ethanol fruit extract of Tetrapleura tetraptera used as spice and in the treatment of various ailment in Niger Delta region of Nigeria was evaluated in Plasmodium berghei infected mice. Tetrapleura tetraptera (300-900 mg/kg day) exhibited significant (P < 0.05) blood schizonticidal activity both in 4-day early infection test and in established infection with a considerable mean survival time comparable to that of the standard drug, chloroquine, 5 mg/kg day. The fruit extract possesses significant (P < 0.05) antiplasmodial activity with may have contributed to the immune status of the Nigerians against malaria in addition to its nutritive value.     

Antimalarial activities of Tithonia diversifolia (Asteraceae) and Crossopteryx febrifuga (Rubiaceae) on mice in vivo

Ethanolic extracts of the aerial part of Tithonia diversifolia and the stem bark of Crossopteryx febrifuga were investigated against early, residual (repository) and established malaria infections in vivo using Swiss albino mice at a dose range of 50-400 mg/kg per day. Chloroquine at 5 mg/kg per day was used as the positive control for the early and established infections while Pyrimethamine at 1.2 3/kg per day was used as the positive control for the residual infection test. Dose dependent chemo suppressive activities were obtained at the different levels of the infection tested. Tithonia diversifolia and Crossopteryx febrifuga gave some level of suppression of parasitaemia in the early and established infection stages. Tithonia diversifolia was active at 200 mg/kg per day in the repository test. The mean survival period of the mice treated with the extract in the established infection test was low, a possible indication of toxicity as a result of sub chronic administration of the extract. Crossopteryx febrifuga was inactive in the repository test. Beside the above limitations, the suppression of parasitaemia by the extracts at the highest dose was similar to chloroquine and pyrimathamine.     

Effect of Khaya grandifoliola extract on Plasmodium berghei berghei in mice

Khaya grandifoliola stem bark extract was tested for antimalarial action against Plasmodium berghei berghei in mice. The schizontocidal activity of the extract was assessed on early and established infections using chloroquine as a standard drug. The repository activity was also investigated and pyrimethamine was used as the standard. In the early infection test (like the chloroquine group), K. grandifoliola extract was effective in suppressing the malaria infection. However, on the established infection, the extract failed to effectively suppress the infection. The extract also demonstrated residual activity.     

In vivo antimalarial activities of Quassia amara and Quassia undulata plant extracts in mice

Extracts obtained from two Nigerian Simaroubaceae plants, Quassia amara L. and Quassia undulata (Giull and Perr) D. Dietr were screened for antimalarial properties using a total of six extracts. The plant extracts showed significant antimalarial activities in the 4 day suppressive in vivo antimalarial assay in mice inoculated with red blood cells parasitized with Plasmodium berghei berghei. Plant extracts were studied at 100 mg and 200 mg per kg body weight mouse per day, respectively. At a concentration of 100 mg/kg of mouse, Q. amara leaf hexane extract had the highest suppressive activity with a parasite density of 0.16 +/- 0.001%. Q. amara leaf methanol extract had an outstanding activity; of 0.05 +/- 0.03% at 200 mg/kg. Chloroquine (10 mg/kg, positive control) had a suppressive activity of 0.34 +/- 0.02 in the same assay on day 4.     

In vivo antiplasmodial activity of Bombax buonopozense root bark aqueous extract in mice infected by Plasmodium berghei

OBJECTIVE: To evaluate the in vivo antiplasmodial activity and the oral acute toxicity of the Bombax buonopozense root bark aqueous extract.METHODS: The in vivo antiplasmodial activity of the root bark aqueous extract of Bombax buonopozense against early and established rodent malaria infections in chloroquine sensitive Plasmodium berghei strain in mice was investigated, and oral acute toxicity of the aqueous root bark extract of Bombax buonopozense was also evaluated in mice.RESULTS: The findings of this study revealed significant(P 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 aqueous extract was found no toxicity in mice and the oral LD50 was determined to be greater than 5000 mg/kg.CONCLUSION: Bombax buonopozense root bark aqueous extract possesses potent antiplasmodial activity and may therefore, serve as potential sources of new antimalarial agents.     

In vivo antimalarial activities of Enantia polycarpa stem bark against Plasmodium berghei berghei in mice

Ethnopharmacological relevance

Enantia polycarpa (PC) Engl. Et Diels (Annonaceae) is used in traditional medicine as an antimalarial remedy in Southern Nigeria.

Aim of the study

The antimalarial activities of ethanolic stem bark extracts of Enantia polycarpa was studied in vivo, in mice infected with Plasmodium berghei berghei.

Materials and methods

The ethanolic stem bark extract of Enantia polycarpa was administered at doses ranging from 200 to 600 mg/kg/day to Plasmodium berghei infected mice in both early and established models of antiplasmodial studies.

Results

The extract of Enantia polycarpa exhibited promising antimalarial activity against both early and established infections. At a dose of 600 mg/kg the extract achieved a 75.8% and 72% chemosuppression of parasitaemia in the study of acute and established infections, respectively. The extract also prolonged mean survival time of Plasmodium berghei infected mice during the study of established infection. The mean survival time of mice administered Enantia polycarpa extract at 600 mg/kg/day (27 days) was significantly longer than infected/untreated control (12 days). For the acute toxicity study the extract had an intraperitoneal LD₅₀ of 186 mg/kg but caused no mortality when administered orally at doses as high as 2,000 and 4,000 mg/kg.

Conclusions

Collectively, the results indicate that Enantia polycarpa is safe when administered orally and possesses promising antimalarial activity, thus supporting its use in traditional medicine for the treatment of malaria.     

The schizontocidal activity of Spathodea campanulata leaf extract on Plasmodium berghei berghei in mice

Effects of extracts of Spathodea campanulata on Plasmodium berghei berghei in mice have been investigated. Schizontocidal activity of the plant in blood was determined on both the early and established infections. The repository action of the plant was also investigated. Chloroquine and pyrimethamine were used as reference drugs. The alcoholic extract of the leaves of the plant demonstrated antiplasmodial activity. The plant extract was more effective in treating the early infection than the established one. This report provides scientific data for the use of the aqueous alcoholic decoction of the leaves of Spathodea campanulata for the treatment of malaria.     

Screening Azadirachta indica and Pisum sativum for possible antimalarial activities

Solvent-free extracts obtained from the leaves of Azadirachta indica and Pisum sativum were screened for antimalarial action using Plasmodium berghei in mice. Four days of oral dosing with 500 mg/kg and 125 mg/kg of the methanol extract of A. indica showed a parasite suppression which was statistically significant although all test animals died after 5 days, just 1 day longer than the untreated control group. A 50 mg/kg oral dose of the aqueous extract of P. sativum was found to have significant prophylactic activity by producing a parasite suppression of 31.9%.     

Combination effects of chloroquine with the febrifugine and isofebrifugine mixture against a blood-induced infection with chloroquine-resistant Plasmodium berghei NK65 in ICR mice

The combination effects of chloroquine with a mixture of febrifugine and isofebrifugine were evaluated against a blood-induced infection with chloroquine-resistant P. berghei NK65 in ICR mice. Mice in the untreated control showed a progressively increasing parasitemia leading to mouse death. A two-day dosage of 20 mg base/kg of chloroquine alone showed little effect against P. berghei NK65 infection, and all mice died from day 13 to 14 with an increasing parasitemia. A four-day dosage of 1 mg/kg of the febrifugine and isofebrifugine mixture alone showed a little antimalarial activity, but all mice died from day 19 to 27 with an increasing parasitemia. On the other hand, mice treated with chloroquine plus alkaloids survived during the experiment. All mice treated with chloroquine alone or the alkaloid mixture alone showed low parasitemia levels during a drug administration and following a few days, but then malaria parasites increased in the bloodstream of the treated mice until death. On the other hand, malaria parasites in the mice given chloroquine plus alkaloids decreased on day 6 and then were not detected by a microscopic examination during observation period.     

Antimalarial 4-phenylcoumarins from the stem bark of Hintonia latiflora

The EtOAc extract of the stem bark of Hintonia latiflora showed the suppression of total parasitemia and the chemosuppression of schizont numbers, when tested in vivo against Plasmodium berghei infection in mice. Bioassay-directed fractionation of the EtOAc extract, using the in vitro 16 h and the in vivo 4-day suppression tests on P. berghei schizont numbers, led to the isolation of the new compound 5-O-beta-D-glucopyranosyl-7,4'-dimethoxy-3'-hydroxy-4-phenylcoumarin (1), along with the known 5-O-beta-D-glucopyranosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin (2). The structure of compound 1 was established on the basis of spectroscopic data interpretation. Compounds 1 and 2 suppressed the development of P. berghei schizonts in vitro with IC50 values of 24.7 and 25.9 microM, respectively. Compound 2 suppressed the development of schizonts at the dose of 40 mg/kg by 70.8% in the in vivo assay.     

The central nervous effects of Mitragyna africanus (Willd) stembark extract in rats

The acute toxicity and the central effects of Mitragyna africanus (M. africanus) stembark methanol extract were studied in rats. The extract did not produce any death in the treated rats even at the highest dose (6400 mg kg(-1)) used. It produced depressant effects on the central nervous system. The stembark extract potentiated amylobarbitone sleeping time in rats dose-dependently, induced sleep in rats and also produced significant local anaesthetic effect on rabbits, the effects being comparable to that of xylocaine. The extract protected rats treated with a convulsive dose of strychnine (2 mg kg(-1)) and increased the period of onset of convulsions and decreased the number of spasms.     

Toxicological evaluation of ethyl acetate extract of Cylicodiscus gabunensis stem bark (Mimosaceae)

The toxicity profile of the ethyl acetate (EA) extract of the stem bark of Cylicodiscus gabunensis (CG) was studied in Wistar rats. The rats were administered graded doses (0.75, 1.5, 3 and 6 g/kg p.o.) of the extract daily for 6 weeks and the effects on clinical signs, body weight, food and water consumption, organ weight, haematology, histology as well as serum, hepatic and renal biochemical parameters were measured. Body weight of dosed and control rats increase throughout the duration of treatment but food and water consumption were not significantly affected. The relative weights of the liver, lungs, heart and kidneys remained normal whereas a significant change was observed in that of the spleen. The hematocrit level was increased in treated animal. Our data demonstrates a significant increase in serum concentrations of aspartate amino-transferase, alanine amino-transferase, total cholesterol and glucose with high-dose of CG treatment tested (3-6 g/kg). CG also caused a significant reduction in hepatic malondialdehyde concentration. Renal urea and creatinine levels were reduced significantly in test groups. Histological findings reveal a characteristic progression treatment-related effect on liver, kidneys and lungs. The acute toxicity LD50 was estimated at 14.5 and 11 g/kg body weight (b.w.) for male and female respectively, but dose-related mortality of 30 and 50% were observed during the sub-acute toxicity. These findings have once more highlighted the limitations of the acute toxicity LD50 testing and suggest that CG may exert varied toxicological effects when administered orally in rats.     

Antiplasmodial activity of root extract and fractions of Croton zambesicus

Aim of the study

Antiplasmodial activity of root extract and fractions of Croton zambesicus were evaluated to ascertain the folkloric claim of its antimalarial activity and elucidate its antiplasmodial mechanism of action.

Material and method

The crude ethanolic root extract (27–81 mg/kg) and gradient fractions ( n- hexane, chloroform, ethyl acetate and methanol; 54 mg/kg) of Croton zambesicus were investigated for antiplasmodial activity against chloroquine - sensitive Plasmodium berghei infections in mice. The antiplasmodial activity during early and established infections as well as the prophylactic activity were investigated. Chloroquine (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. Oxidant generation potentials of the crude extract and fractions was also evaluated to elucidate their mechanism of action.

Results

The crude root extract (27 – 81 mg/kg) demonstrated significant (P < 0.01–0.001) schizonticidal activity during early and established infections and also had prophylactic activity. The activity was comparable to that of the standard drug used (chloroquine 5 mg/kg, pyrimethamine 1.2 mg/kg). Methanol, ethyl acetate and chloroform fractions had comparative in vivo antiplasmodial activity and oxidant generation potentials.

Conclusion

The antiplasmodial activity of this root extract and fractions which is likely to be through peroxidation confirms the folkloric use of this plant.     

Analgesic and antimalarial activities of crude leaf extract and fractions of Acalypha wilkensiana

Aim of the study

Antiplasmodial and analgesic activities of leaf extract and fractions of Acalypha wilkensiana were evaluated to ascertain the folkloric claim of its antimalarial and analgesic activities.

Materials and methods

The crude leaf extract (220–659 mg/kg) and fractions (chloroform and aqueous; 440 mg/kg) of Acalypha wilkensiana were investigated for antiplasmodial activity against chloroquine sensitive Plasmodium berghei infections in mice and for analgesic activity against chemical and heat-induced pains. The antiplasmodial activity during early and established infections as well as prophylactic activity were investigated. Chloroquine (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. Analgesic activity of the crude extract was also evaluated against acetic acid, formalin and heat-induced pains.

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 < 0.001). They also improved the mean survival time (MST) from 16 to 22 days relative to control (p < 0.01–0.001). The activities of extract/fractions were incomparable to that of the standard drugs used (chloroquine and pyrimethamine). 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.

Conclusion

The antiparasitaemic and analgesic effects may in part be mediated through the chemical constituents of the plant.     

In vivo antimalarial activity and toxicological effects of methanolic extract of Cocos nucifera (Dwarf red variety) husk fibre

OBJECTIVE: Phytochemical constituents as well as antimalarial and toxicity potentials of the methanolic extract of the husk fi bre of Dwarf Red variety of Cocos nucifera were evaluated in this study.METHODS: The dried powdered husk fi bre was exhaustively extracted with hexane, ethyl acetate and methanol successively and the methanolic extract was screened for fl avonoids, phenolics, tannins, alkaloids, steroids, triterpenes, phlobatannins, anthraquinones and glycosides. A 4-day suppressive antimalarial test was carried out using Plasmodium berghei NK65-infected mice, to which the extract was administered at doses of 31.25, 62.5, 125, 250 and 500 mg/kg body weight(BW). Toxicity of the extract was evaluated in rats using selected hematological parameters and organ function indices after orally administering doses of 25, 50 and 100 mg/kg BW for 14 d.RESULTS: Phytochemical analysis revealed the presence of alkaloids, tannins, phenolics, saponins, glycosides, steroids and anthraquinones in the extract. Moreover, the extract reduced parasitemia by 39.2% and 45.8% at doses of 250 and 500 mg/kg BW respectively on day 8 post-inoculation. Various hematological parameters evaluated were not significantly altered(P0.05) at all doses of the extract, except red blood cell count which was signifi cantly elevated(P0.05) at 100 mg/kg BW. The extract significantly increased(P0.05) urea, creatinine, cholesterol, high-density lipoprotein-cholesterol and bilirubin concentrations in the serum as well as atherogenic index, while it reduced albumin concentration significantly(P0.05) at higher doses compared to the controls. Alanine aminotransferase activity was reduced in the liver and heart signifi cantly(P0.05) but was increased in the serum signifi cantly(P0.05) at higher doses of the extract compared to the controls.CONCLUSION: The results suggest that methanolic extract of the Dwarf red variety has partial antimalarial activity at higher doses, but is capable of impairing normal kidney and liver function as well as predisposing subjects to cardiovascular diseases.     

Effects of Piper longum fruit, Piper sarmentosum root and Quercus infectoria nut gall on caecal amoebiasis in mice

The anti-amoebic effects of crude methanol extracts of Piper longum fruit, Piper sarmentosum root and Quercus infectoria nut gall against Entamoeba histolytica infecting the caecum of mice were studied. Caecal amoebiasis in mice was induced by injection of Entamoeba histolytica trophozoites directly into the caecum. The mice were then treated orally with the extract, a standard drug (metronidazole), or vehicle p.o. for five consecutive days, beginning 24 h after the infection and were examined on the sixth day. At a dose of 1000 mg/kg per day, the extracts of Piper longum fruit, Piper sarmentosum root and Quercus infectoria nut gall had a curative rate of 100, 40 and 26%, respectively. At a concentration of 500 and 250 mg/kg/day, extract from Piper longum fruit was still effective in 93 and 46% of the cases, respectively, while extract from Piper sarmentosum root at a dose of less than 1000 mg/kg per day did not cure any mice from amoebiasis. Extract of Quercus infectoria nut gall at a concentration of 500 and of 250 mg/kg per day cured 26 and 13% of mice, respectively. Metronidazole at a concentration of 125 and of 62.5 mg/kg per day had a curative rate of 100 and 60%, respectively. The severity of caecal wall ulceration was reduced in mice which received the extract and metronidazole as compared to the control animals.     

Effects of American ginseng berry extract on blood glucose levels in ob/ob mice

In this study, we evaluated antihyperglycemic effects of American ginseng berry extract in diabetic ob/ob mice. Animals received daily intraperitoneal (IP) injections of the extract 150 mg/kg for 12 days. On days 5 and 12, the extract-treated ob/ob mice had significantly lower fasting blood glucose levels compared to day 0 (both p < 0.05). Glucose tolerance improved significantly, which was shown by overall glucose excursion, calculated as area under the curve (AUC) during the two-hour IP glucose tolerance test. The AUC decreased by 31.8% on day 12 compared to day 0 (p < 0.01). In addition, after 12 days of the berry extract treatment, a significant reduction in body weight (p < 0.01 compared to day 0) and a significant increase in body temperature (p < 0.01 compared to day 0) was noticeable. Our results support in vivo antihyperglycemic and antiobese activity of American ginseng berry extract that may prove to be of clinical importance in the prevention and treatment of Type 2 diabetes.