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.     

Role of glutamate and dopamine receptors in the psychopharmacological profile of the indole alkaloid psychollatine

Psychollatine (1), a new glycoside indole monoterpene alkaloid isolated from Psychotria umbellata, has shown an interesting psychopharmacological profile. This study aimed to investigate the role of NMDA glutamate and dopamine receptors in mediating the properties of 1. Psychollatine (1) was assessed for NMDA-induced seizures, MK-801-induced hyperlocomotion, amphetamine-induced lethality, and apomorphine-induced climbing behavior in mice. Psychollatine (1) (100 mg/kg) and MK-801 (0.3 mg/kg) prevented NMDA-induced seizures (P < 0.01), while 1 (100 mg/kg) attenuated the MK-801-induced hyperlocomotion (P < 0.05). Compound 1 (3 and 10 mg/kg), as well as chlorpromazine (4 mg/kg), prevented amphetamine-induced lethality (P < 0.05). Finally, 1 (10 mg/kg) (P < 0.05), MK-801 (0.2 mg/kg) (P < 0.01), and chlorpromazine (4 mg/kg) (P < 0.01) attenuated apomorphine-induced climbing behavior. The present results strongly support the involvement of NMDA glutamate receptors in the mode of action of psychollatine (1).     

Anti-inflammatory and analgesic properties of water-ethanolic extract from Pothomorphe umbellata (Piperaceae) aerial parts

Anti-inflammatory and analgesic activities as well as the median lethal dose (LD50) of water-ethanolic extract (PHE) of the aerial parts of Pothomorphe umbellata were evaluated in animal models. The ED(50) (oral) for the inhibition of carrageenan-induced rat paw edema assay was determined to be 550 mg/kg, while the LD(50) was higher than 2.0 g/kg. At a dose of 550 mg/kg, PHE inhibited the inflammatory process by 48.7% (P < 0.05) on the third hour of the assay (edema peak) when compared to the untreated control. Indomethacin, the positive control used in this test, inhibited the edema by 58.6% at a dose of 10 mg/kg, when compared to the untreated control (P < 0.05). All three fractions--hexane, methylene chloride and ethyl acetate--obtained by partition of PHE with respective solvents also showed inhibition of the edema induced by carrageenan over a period of 4h but the methylene chloride fraction showed the best activity. The activity shown by the methylene chloride fraction at 200 mg/kg was comparable to that exhibited by indomethacin at a dose of 10mg/kg. The number of writhings induced by a 0.6% acetic acid solution intraperitoneal injection was decreased by 22% (P < 0.05) in the group treated orally with Pothomorphe umbellata crude extract. PHE also inhibited the granulomatous tissue formation in rats by 6.2% (P < 0.05). In the same assay, topically applied dexamethasone decreased the granuloma formation by 14.2%. The above results suggest that Pothomorphe umbellata crude extract has analgesic and anti-inflammatory properties supporting its folkloric use for the treatment of these conditions.     

Biphasic effects of Morus alba leaves green tea extract on mice in chronic forced swimming model

In this study, the effects of an aqueous extract of Morus alba leaves green tea (ME) on mouse behaviors (depression, anxiety, climbing activity and thermal response), muscle coordination and muscle strength were studied. Male IRC mice received a single intraperitoneal injection of either the ME, desipramine or diazepam. Thirty minutes after injection, the mice were tested in all experimental models. A significant antidepressant-like effect could be detected in the animals receiving either 100 or 200 mg/kg ME. The effect of 200 mg/kg ME in decreasing the immobility time was comparable to 10 mg/kg desipramine. With higher dose (1000 mg/kg), a significant increase in immobility time could be observed. In the elevated plus maze, no increase in time in the open arm could be observed in mice treated with ME at either 100 or 200 mg/kg. However, high doses of ME (500 or 1000 mg/kg) decreased both time in the open arm and the number of entries in the maze. No change in thermal response could be seen in mice treated with ME at doses up to 500 mg/kg, however, at 1000 mg/kg, the response time to heat was increased significantly. The ME at either 500 or 1000 mg/kg also decreased muscle coordination, strength and climbing activity significantly when compared with the control. This study suggests that ME possesses an antidepressant- without an anxiolytic-like effect, however, at high doses, the extract might show the sedative effect and alter other functions such as muscle strength, animal activity in the maze and pain response.     

Hypoglycemic effect and chlorogenic acid content in two Cecropia species

The hypoglycemic effect of methanol leaf extracts from Cecropia obtusifolia and C. peltata was evaluated in healthy mice. A significant decrease (p < 0.05) in plasma glucose levels was recorded 2 and 4 h after a single oral administration of methanol extracts (1 g/kg). This effect was correlated with the chlorogenic acid contents in both species; C. peltata, containing 19.84 +/- 1.64 mg of chlorogenic acid/g of dried leaves produced the highest decrease (D(alpha 2,60) = 20.18, p < 0.05) of plasma glucose levels (52.8%). The extracts of C. obtusifolia from Tabasco and Veracruz, showed similar hypoglycemic effects (33.3% and 35.7%, respectively) and chlorogenic acid contents (Tukey(0.05) = 1.8859) (13.3 +/- 3.2 mg/g and 13.1 +/- 1.6 mg/g, respectively). The hypoglycemic effect produced by different doses (0.1, 0.25, 0.50, 0.75 and 1 g/kg body wt, p.o.) of C. peltata showed a lineal relationship with chlorogenic acid content, reaching an ED(50) = 0.540 g/kg body wt for extract, and an ED(50) = 10.8 mg/kg body wt for chlorogenic acid. These results suggest that C. peltata is a better hypoglycemic agent than C. obtusifolia, and it could be considered for developing a phytomedicinal product to carry out clinical trials.     

西洋参茎叶皂甙对小鼠学习记忆的易化作用

西洋参茎叶皂甙500mg/kg、100mg／kg给小鼠连续灌胃7天，可拮抗樟柳碱和戊巴比妥钠引起的记忆获得损害，对环己酰亚胺引起的记忆巩固障碍有显著改善作用。西洋参茎叶皂甙还可使常压、低压缺氧状态下小鼠存活时间有所延长。     

Analgesic and anti-inflammatory activities of the crude hydroalcoholic extract obtained from the bark of Hymenaea martiana

Experiments were designed to examine the analgesic and anti-inflammatory activities of the crude hydroalcoholic extract (CE) of Hymenaea martiana. The CE of H. martiana (25-200 mg/kg, i.p.) caused a graded inhibition of hindpaw oedema induced by carrageenan, PAF-acether (PAF), serotonin (5-HT), dextran and histamine (HIS). However, the CE given orally up to 500 mg/kg had no effect on the agonist-induced hindpaw oedema. The CE given intraperitoneally, but not orally, caused a graded and pronounced inhibition of His, 5-HT, bradykinin (BK) and PAF-induced increase of vascular permeability. When the CE was given orally (300 mg/kg) once a day for 15 days it caused a significant increase of agonist-induced increase of vascular permeability. The CE given either by p.o. or by i.p. routes (100-800 mg/kg) dose-dependently inhibited arachidonic acid (AA)-induced ear oedema in mice, being significantly more potent when it was given by the latter route. In contrast, CE at the same doses, failed to inhibit croton-oil-induced ear oedema in mice. The CE of H. martiana given by either i.p. or p.o. routes caused a marked and dose-dependent antinociceptive activity as revealed by its antagonistic action against acetylcholine, acetic acid or AA-induced writhing responses in mice, being more effective when given intraperitoneally. These results, and those previously reported with the CE of H. martiana in the isolated preparations, provide strong experimental support which argues in favour of the beneficial use of this plant extract in folk medicine. The exact mechanism that underlies its analgesic and anti-inflammatory profiles remains unclear, but may result from its ability to inhibit the generation of lipoxygenase and/or cyclooxygenase products of the arachidonic acid pathway.     

Hypoglycaemic activity of Anthocleista vogelii (Planch) aqueous extract in rodents

The hypoglycaemic effect of Anthocleista vogelii was studied in mice, rats and rabbits. Aqueous extract of the plant obtained by infusion from finely pulverized root was used. The extract (100, 400 and 800 mg/kg) induced significant hypoglycaemic activity in a dose-related fashion at 2 h after oral administration in mice and rats with ED₂₅ of 250 mg/kg and 350 mg/kg respectively. The extract (800 mg/kg, orally) similarly induced statistically significant lowering of blood glucose levels at 8 h in normoglycaemic rabbits. The extract (400 mg/kg and 800 mg/kg, orally) also caused reduction of blood glucose levels in alloxan-induced diabetic animals. The results of this study indicate that the aqueous extract of the roots of Anthocleista vogelii possess favourable hypoglycaemic activity both in normo and hyperglycaemic animals compared to chlorpropamide as a standard.     

Action of compounds from Mandevilla velutina on croton oil-induced ear oedema in mice. A comparative study with steroidal and nonsteroidal antiinflammatory drugs

The antioedematogenic activity of two natural pregnane compounds from Mandevilla velutina was evaluated against croton oil-induced ear oedema in mice. For comparison the effects of nonsteroidal (indomethacin, phenidone and BW 755C) and steroidal (dexamethasone) antiinflammatory drugs were analysed. The purified compounds from M. velutina MV8612 (3 and 30 mg/kg, i.p.) and to a lesser extent MV8608 (30 and 100 mg/kg; i.p.), given 30 min prior to the croton oil, significantly inhibited this oedema, maximal inhibition (MI) of 53% and 26%, respectively. However, given orally 180 min after, neither compound had any effect. Compound MV8612 but not MV8606 (200–600 μg/ear) given 180 min after the irritant significantly inhibited croton oil-induced oedema, MI of 29%. Indomethacin given topically (0.05–0.2 mg/ear) 180 min after, but not orally (1–10 mg/kg), significantly inhibited this oedema, MI of 30%, while phenidone administered either orally (100 and 300 mg/kg) or topically (2 mg/ear) 180 min after caused partial inhibition, MI of 24% and 18%, respectively. BW 755C, given topically (0.1 and 0.5 mg/ear) but not orally (10–300 mg/kg) 180 min after, was also effective in inhibiting croton oil oedema, MI of 18%. Dexamethasone given either topically (0.05–0.2 mg/ear) or orally (0.25-1 mg/kg) 30 and 60 min prior potently inhibited croton oil oedema, MI of 86% and 79%, respectively. These results indicate that the natural compounds MV8612 and to a lesser extent MV8608 isolated from M. velutina, besides their antibradykinin activity, exhibited both topical and systemic long-lasting antioedematogenic effects against croton oil-induced ear oedema in mice.     

Effect of Dianex, a herbal formulation on experimentally induced diabetes mellitus

Dianex, a polyherbal formulation consisting of the aqueous extracts of Gymnema sylvestre, Eugenia jambolana, Momordica charantia Azadirachta indica, Cassia auriculata, Aegle marmelose, Withania somnifera and Curcuma longa was screened for hypoglycemic activity in normal and streptozotocin induced diabetic mice. Dianex was administered in different doses of 100-500 mg/kg/day orally in acute (6 h) and long-term (6 weeks) studies. Blood glucose levels were checked 2-6 h after treatment in acute studies and every 2 weeks in long-term studies. Body weight was recorded on the first and final day of the treatment in the long-term studies with diabetic mice. After 6 weeks, high-density lipoprotein, triglycerides, total cholesterol, alanine transaminase (ALT), aspertate transaminase (AST), urea and creatinine were estimated in serum of the diabetic mice. Glycogen and total protein levels were estimated in the liver. Also, the liver and pancreas was subjected to histological examination. Oral glucose tolerance and in vitro free radical scavenging activity was also studied.Dianex produced significant (p<0.05) hypoglycemic activity at 250-500 mg/kg doses in both normal and diabetic mice in acute and long-term studies. The body weight of diabetic mice significantly (p<0.05) increased with all tested doses of Dianex. The elevated triglycerides, cholesterol, ALT, AST, urea and creatinine levels in diabetic mice were significantly (p<0.05) reduced at the doses of 250 and 500 mg/kg. The liver glycogen and protein levels were both significantly (p<0.05) increased in diabetic mice at 250 and 500 mg/kg doses. Dianex increased the glucose tolerance significantly (p<0.05) in both normal and diabetic mice at all the doses tested. Histopathological examination showed that the formulation decreased streptozotocin induced injury to the tissues at all the doses tested. It produced significant (p<0.05) free radical scavenging activity against ABTS+, DPPH and hydroxyl free radicals at the concentrations ranging between 10-1000 microg/ml.Thus, in the present study, Dianex produced significant hypoglycemic activity in both normal and diabetic animals. It also reversed other diabetic complications in diabetic mice at 250 and 500 mg/kg doses. In our earlier study, Dianex was well tolerated in laboratory animals at higher doses (upto 10 g/kg in mice, acute toxicity; up to 2.5 g/kg in rats, subacute toxicity studies for 30 days) without exhibiting any toxic manifestation. Hence, Dianex may be useful in the treatment of diabetes mellitus.     

In vivo antimalarial evaluation of Gomphostenins

Aim of the study

The present study aims to evaluate the in vivo antimalarial potential of the leaf extract of Gomphostemma niveum and two new compounds; named as Gomphostenin (GN–6) and acetyl Gomphostenin (GN–10) isolated and purified from this plant against Plasmodium berghei in mice.

Materials and methods

The blood schizontocidal activity was performed in early infection of Plasmodium berghei and also in established infection of Plasmodium berghei. The mice were orally administrated with various doses of water and chloroform extracts of leaves of Gomphostemma niveum (GN–W and GN–C, 300, 400 and 500 mg/kg/day), GN–6 and GN–10 (50, 100, 150 and 200 mg/kg/day). Chloroquine (8 mg/kg) used as a positive control, while an equal volume of saline plus 0.5% tween-80 was used as a negative control.

Results

GN–W, GN–C and pure compounds (GN–6 and GN–10) produced a dose dependent chemosuppression effect at various dose levels. GN–10 exhibited highest percent of chemosuppression i.e. 92.65% at a dose level of 200 mg/kg/day. In case of curative test, the survival period of the parasitized infected mice was significantly prolonged at 200 mg/kg dose of GN–10.

Conclusions

The studies have indicated that clerodane class of diterpenes GN–6 and GN–10 certainly holds great promise for malaria control and will be useful in antimalarial chemotherapy.     

Inhibition of chemical carcinogenesis by Psoralea corylifolia seeds

Psoralea corylifolia L. (Fabaceae) seeds are extensively used in Ayurvedic medicine. Topical application of 100 mg/kg body weight of the active fraction (AF) of P. corylifolia seeds inhibited the growth and delayed the onset of papilloma formation in mice, initiated with 7,12-dimethyl benz(a) anthracene and promoted using croton oil. The AF at the same dose, when administered orally, inhibited the growth of subcutaneously injected 20-methylcholanthrene (MCA)--induced soft tissue fibrosarcomas significantly. The AF has been shown by gas chromatography analysis to be composed of a mixture of glycerides of fatty acids.     

Effects of canthin-6-one alkaloids from Zanthoxylum chiloperone on Trypanosoma cruzi-infected mice

Canthin-6-one (1), isolated from Zanthoxylum chiloperone (Rutaceae), possesses a broad sprectum of antifungal and leishmanicidal activities. In this study, we have examined the antiparasitic effects of canthin-6-one (1), 5-methoxycanthin-6-one (2), canthin-6-one N-oxide (3), as well as that of the total alkaloids of Zanthoxylum chiloperone stem bark, in Balb/c mice infected either acutely or chronically with Trypanosoma cruzi. The compounds were administered orally or subcutaneously at 5mg/kg/day for 2 weeks, whereas the alkaloidal extract was given at 50mg/kg/day for 2 weeks. The antiparasitic activity was compared with that of benznidazole given at 50mg/kg/day for 2 weeks. In the case of acute infection, parasiteamia was significantly reduced following oral treatment with canthin-6-one (1). Moreover, the total alkaloids of Zanthoxylum chiloperone stem bark led to high levels of parasitological clearance. Seventy days post-infection, the serological response in the acute model was significantly different between oral canthin-6-one (1) and benznidazole-treated mice. Chronic model of the disease showed that both canthin-6-one (1) and the alkaloidal extract at the above dosage induced 80-100% animal survival compared to untreated controls. These results indicate that canthin-6-one (1) exhibits trypanocidal activity in vivo in the mouse model of acute or chronic infection. This is the first demonstration of anti-Trypanosoma cruzi activity for a member of this chemical group (canthinones). Considering the very low toxicity of canthin-6-one (1), our results suggest that long-term oral treatment with this natural product could prove advantageous compared to the current chemotherapy of Chagas disease.     

In vivo and in vitro antimalarial activity of 4-nerolidylcatechol

4‐Nerolidylcatechol (4‐NC) isolated from Piper peltatum L. (Piperaceae) was evaluated for in vitro antiplasmodial activity against Plasmodium falciparum (cultures of both standard CQR (K1) and CQS (3D7) strains and two Amazonian field isolates) and for in vivo antimalarial activity using the Plasmodium berghei‐murine model. 4‐NC exhibits significant in vitro and moderate in vivo antiplasmodial activity. 4‐NC administered orally and subcutaneously at doses of 200, 400 and 600 mg/kg/day suppressed the growth of P. berghei by up to 63% after four daily treatments (days 1–4). Also, 4‐NC exhibited important in vitro antiplasmodial activity against both standard and field P. falciparum strains in which 50% inhibition of parasite growth (IC₅₀) was produced at concentrations of 0.05–2.11 μg/mL and depended upon the parasite strain. Interestingly, healthy (non‐infected) mice that received 4‐NC orally presented (denatured) blood plasma which exhibited significant in vitro activity against P. falciparum. This is evidence that mouse metabolism allows 4‐NC or active metabolites to enter the blood. Further chemical and pharmacological studies are necessary to confirm the potential of 4‐NC as a new antimalarial prototype. Copyright © 2011 John Wiley & Sons, Ltd.     

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.     

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.     

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.     

In vivo antiplasmodial potential of three herbal methanolic extracts in mice infected with Plasmodium berghei NK65

Objective: The present study deals with the investigation of antiplasmodial potential of leaf methanolic extract of Aegle marmelos, Aristolochia indica and Cassia auriculata against Plasmodium berghei(NK65)infected mice.Methods: The chloroquine-sensitive parasites P. berghei(1 × 106) were inoculated into Swiss albino mice intraperitoneally. The methanol extracts of three herbal plants were orally administered in P. berghei infected mice which were further assessed using the four-day suppressive test at different doses of 150, 300 and 600 mg/kg per day. Chloroquine(CQ) was used as the standard drug with of 1.25, 2.5 and 5 mg/kg concentrations and was orally administered.Results: The leaves of A. marmelos, A. indica, and C. auriculata were found to suppress P. berghei parasitaemia in Swiss albino mice by(67.0 ± 4.02)%,(72.0 ± 8.44)% and(52.7 ± 2.06)% at 600 mg/kg/d with ED50 values of 284.73, 233.77 and 562.48 mg/kg, respectively. These herbal plants increased the mean survival time of infected mice and prevented body weight loss. GC-MS analysis revealed the presence of hentriacontan-16-one(C31 H62 O) in A. indica extract. The histopathology study showed non-toxic to kidney and liver at 600 mg/kg/body weight.Conclusions: Overall results revealed that herbal plants may be active in the development of novel and cheap antimalarial compounds.     

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%.     

Preventive and curative effects of Berberis aristata Fruit extract on paracetamol- and CCl4-induced hepatotoxicity

The effect of an aqueous-methanol extract of Berberis aristata fruits (Berberidaceae) was investigated against paracetamol- and CCl₄-induced hepatic damage. Paracetamol produced 100% mortality at a dose of 1 g/kg in mice while pre-treatment of animals with crude extract (500 mg/kg) reduced the death rate to 10%. Pre-treatment of rats with fruit extract (500 mg/kg, orally twice daily for 2 days) prevented (p<0.05) the paracetamol (640 mg/kg) as well as CCl₄ (1.5 mL/kg)-induced rise in serum transaminases (GOT and GPT). Post-treatment with three successive doses of extract (500 mg/kg, 6h) restricted the hepatic damage induced by acetaminophen (p<0.01) but CCl₄-induced hepatotoxicity was not altered (p>0.05). Plant extract (500 mg/kg) caused significant prolongation (p<0.01) in pentobarbital (75 mg/kg)-induced sleep as well as increased strychnine-induced lethality in mice suggestive of inhibitory effect on microsomal drug metabolizing enzymes (MDME). These results indicate that the crude extract of Berberis aristata fruits exhibits hepatoprotective action partly through MDME inhibitory action.