Jude E. Okokon

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.

Pharmacological screening and evaluation of antiplasmodial activity of Croton zambesicus against Plasmodium berghei berghei infection in mice

Objective: To evaluate the antiplasmodial activity of leaf extract of Croton zambesicus on chloroquine-sensitive Plasmodium berghei berghei infection in mice and to confirm its traditional use as a malarial remedy in Africa. Materials and Methods : The ethanolic leaf extract of Croton zambesicus (50-200 mg/kg) was screened for blood schizontocidal activity against chloroquine-sensitive Plasmodium berghei berghei infection in mice. The schizontocidal activity during early and established infections as well as the repository activity were investigated. Results: The extract demonstrated a dose-dependent chemosuppression or schizontocidal effect during early and in established infections, and also had repository activity. The activity was lower than that of the standard drugs (chloroquine 5 mg/kg, pyrimethamine 1.2 mg/kg/day). Conclusion: The leaf extract possesses considerable antiplasmodial activity, which can be exploited in malaria therapy.

Hypoglycemic activity of aqueous leaf extract of Persea americana Mill

Persea americana mill (lauraceae) is a tree plant also called avocado or alligator pear. It is chiefly grown in temperate regions and sparsely grown in tropical regions of the world. It is recommended for anemia, exhaustion, hypercholesterolemia, hypertension, gastritis, and gastroduodenal ulcer. The leaves have been reported as an effective antitussive, antidiabetic, and relief for arthritis pain by traditional medicine practitioners of Ibibio tribe in South Nigeria. Analgesic and antiinflammatory properties of the leaves have been reported. Although there are reports of the medicinal uses of this plant, there is no report on its antidiabetic activity. Therefore, it was thought worthwhile to evaluate its antidiabetic effects in alloxan-induced diabetic rats. In November 2004, the fresh leaves of Persea americana were collected from the farm of the Faculty of Agriculture, University of Uyo, Uyo, Nigeria. The plant was identified and authenticated by Dr. (Mrs) Margaret Bassey, a taxonomist in the Department of Botany, University of Uyo, Uyo, Nigeria. The leaves were shade dried for a period of 10 days. It was pulverized in wooden mortar and 100 g of the powder was macerated in 300 mL of water in a conical flask for 72 h. The liquid filtrate was concentrated in vacuo at 40 C. The yield was 2.67%. The dried extract was formulated as suspension in distilled water using Tween 80 as suspending agent. The extract was chemically tested for the presence of different chemical constituents using standard methods. Adult albino Wistar rats (150-180 g) of either sex obtained from University of Uyo, animal house, Uyo, Nigeria were used for the study. The animals were acclimatized for a period of 10 days to room temperature (28 ± 5 C) with a relative humidity of 50%. They were housed in standard cages and maintained on standard pellets and water ad libitum. Approval for animal studies were obtained from the College of Health Sciences Animal Ethics Committee, University of Uyo. Hypoglycemic activity of aqueous leaf extract of Persea americana Mill

Evaluation of the in vivo antimalarial activity of ethanolic leaf and stembark extracts of Anthocleista djalonensis.

Objective: To evaluate the in vivo antimalarial activities of ethanolic leaf and stembark extracts of Anthocleista djalonensis used traditionally as malarial remedy in Southern Nigeria in mice infected with Plasmodium berghei berghei. Methods: The ethanolic extracts of the A. djalonensis leaf (1000 – 3000 mg/kg/day) and stembark (220 – 660 mg/kg/day) were screened for blood schizonticidal activity against chloroquine-sensitive P. berghei in mice. The schizonticidal effect during early and established infections was investigated. Results: The A. djalonensis leaf extract (1000 – 3000 mg/kg/day) exhibited a significant antiplasmodial activity both in the 4-day early infection test and in the established infection with a considerable mean survival time, which was incomparable to that of the standard drug, chloroquine (5 mg/kg/day). The stembark extract (220 – 660 mg/kg/day) also demonstrated a promising blood schizontocidal activity in early and established infections. Conclusion: These plant extracts possess considerable antiplasmodial activities, which justify their use in ethnomedicine and can be exploited in malaria therapy.

Anti-inflammatory and analgesic activities of Melanthera scandens.

OBJECTIVE To evaluate the anti-inflammatory and analgesic activities of leaf extract of Melanthera scandens (M. scandens). METHODS The crude leaf extract (39-111 mg/kg) of M. scandens was investigated for anti-inflammatory and analgesic activities using various experimental models. The anti-inflammatory activity was investigated using carragenin, egg-albumin induced oedema models, while acetic acid, formalin-induced paw licking and thermal-induced pain models were used to evaluate the antinociceptive property. RESULTS The extract caused a significant (P<0.05 - 0.001) dose-dependent reduction of inflammation and pains induced by different agents used. CONCLUSIONS The leaf extract possesses anti-inflammatory and analgesic effects which may be mediated through the phytochemical constituents of the plant.

Antiplasmodial and antiulcer activities of Melanthera scadens.

OBJECTIVE To evaluate the antimalarial and antiulcerogenic activities of leaf extract and fractions of Melanthera scandens (M. scandens). METHODS The crude leaf extract (37-111 mg/kg) and fractions (chloroform, ethylacetate and methanol; 78 mg/kg) of M. scadens were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei infections in mice and for antiulcer activity against experimentally-induced ulcers. The antimalarial activity during early and established infections as well as prophylactic was investigated. Artesunate (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Antiulcer activity of the crude extract was also evaluated against indomethacin, ethanol and histamine induced ulcers. RESULTS The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine-sensitive Plasmodium berghei infection in prophylactic, suppressive and curative models in mice. These reductions were statistically significant (P<0.001). They also improved the mean survival time (MST) from 9.28 to 17.73 days as compared with the control (P<0.01-0.001). The activities of extract/fractions were incomparable to that of the standard drugs i.e. artesunate and pyrimethamine. On experimentally-induced ulcers, the extract inhibited indomethacin, ethanol and histamine induced ulcers. These inhibitions were statistically significant (P<0.001) and in a dose-dependent fashion. CONCLUSIONS The antiplasmodial and antiulcerogenic effects of this plant may in part be mediated through the chemical constituents of the plant.

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 (5mg/kg) and pyrimethamine (1.2mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. 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.

Antiplasmodial and antipyretic studies on root extracts of Anthocleista djalonensis against Plasmodium berghei

Abstract Objective To evaluate the antimalarial activities of ethanolic root extract/fractions of Anthocleista djalonensis (A. djalonensis) in Plasmodium berghei (P. berghei) infected mice. Methods A. djalonensis root extract (175–1 000 mg/kg) and fractions (chloroform, ethyl acetate and methanol; 250 and 500 mg/kg) were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei infections in mice and for antipyretic activity against dinitrophenol, amphetamine and yeast-induced pyrexia. The antiplasmodial activity during early and established infections as well as prophylactic were investigated. Artesunate (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Antipyretic activity of the crude extract was also evaluated against dinitrophenol, amphetamine and yeast-induced pyrexia. 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 Conclusions A. djalonensis root extract has antiplasmodial and antipyretic activities which may in part be mediated through the chemical constituents of the plant.

In vivo antimalarial activity of ethanolic leaf extract of Stachytarpheta cayennensis.

OBJECTIVE To evaluate the in vivo antiplasmodial activity of the ethanol leaf extract of Stachytarpheta cayennensis in the treatment of various ailment in Niger Delta region of Nigeria, in Plasmodium berghei infected mice. MATERIALS AND METHODS The ethanolic leaf extract of Stachytarpheta cayennensis (90-270 mg/kg/day) was screened for blood schizonticidal activity against chloroquine sensitive Plasmodium berghei berghei in mice. The schizonticidal effect during early and established infections was investigated. RESULT Stachytarpheta cayennensis (90-270 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. CONCLUSION The leaf extract possesses significant (P< 0.05) antiplasmodial activity which confirms its use in folkloric medicine in the treatment of malaria.

Antiplasmodial and Antidiabetic Activities of Ethanolic Leaf Extract of Heinsia crinata

The ethanolic leaf extract of Heinsia crinata, grown particularly for the leaf in Niger Delta region of Nigeria, was evaluated for antiplasmodial activity in Plasmodium berghei-infected mice as well as for hypoglycemic and antidiabetic activities in alloxan-induced diabetic rats. H. crinata (450-1,350 mg/kg/day) exhibited significant (P < .05) blood schizonticidal activity in both the 4-day early infection test and established infection with a considerable mean survival time, though not comparable to that of the standard drug, chloroquine (5 mg/kg/day). Treatment of alloxan-induced diabetic rats with the leaf extract caused a significant (P < .01) reduction in fasting blood glucose levels of normal and alloxan-induced diabetic rats both in an acute study and with prolonged treatment (2 weeks). The activity of the extract was comparable to that of the reference drug, glibenclamide, during the acute study but was not comparable to that of the standard drug during prolonged treatment. The results suggest that the leaf extract of H. crinata possesses significant (P < .05) antiplasmodial as well as hypoglycemic and antidiabetic effects that can be employed in health care.