Biomedical subjects

A O Onabanjo

Publications and source records attributed to A O Onabanjo.

At least 19 recordsLinked to original sources

PubMed1994

Toxicological study of the extracts of anti-malarial medicinal plant Enantia chlorantha.

Acute and sub-acute toxicity studies of the medicinal plant Enantia chlorantha were carried out in mice. The oral and s.c. routes of administration of both the aqueous and ethanolic extracts were employed. All the animals reacted to the medicinal plant, when given by both routes, with itching leading to body scratching lasting about 10 minutes. Fatality was not recorded in mice given 0.2g kg-1 s.c. and 20.0g kg-1 orally of both the ethanolic and aqueous extracts of E. chlorantha but larger concentration of both extracts resulted in deaths. Mean lethal dose (LD50) of 0.7g kg-1 was recorded for ethanolic, while 43.65g kg-1 was for aqueous preparations. In the sub-acute toxicity in which the animals were given 3 x 10(3)-5 x 10(-3)g kg-1 of the aqueous extract to drink at will for five weeks, no fatality was recorded and no significant damage to the body organs was observed. These data indicate that the plant drug when taken is safe in diseased states.

Acute Disease↗

PubMed1992

The in vitro and in vivo effects of mefloquine on Trypanosoma brucei brucei.

Blood stream forms of Trypanosoma brucei brucei were grown over mouse kidney (MK) cells in minimum essential medium with various concentrations of mefloquine. The drug was observed to inhibit multiplication of the parasites in vitro. Groups of male albino mice were treated with mefloquine at 24, 48 and hours after T. b. brucei infection. Mefloquine at 0.03 mg/kg body weight administered for 4 consecutive days cleared the infection. No trypanosomes were detected in the blood of these mice for 90 days and over after the clearance of parasite from the blood. The doses for both the in vitro and in vivo therapy, were well below those prescribed for humans.

Animals↗

PubMed1991

The effects of extracts of Enantia chlorantha in malaria.

The aqueous extract of the plant Enantia chlorantha was found effective in suppressing Plasmodium yoelii infection in mice if given orally in drinking fluid at 0.2-150 mg ml-1, but not if given by oral cannulation or subcutaneously. The animals given the extract in their drinking fluid survived for over 60 days. The ethanolic extract also was found to be effective in eliminating the parasites when administered subcutaneously in doses of 0.05-0.5 mg g-1. The chemoprophylactic action of the aqueous extract given in drinks prior to infection gave protection for almost 96 hours, but the ethanolic extract administered parenterally gave no such protection. The aqueous and ethanolic extracts have ED50 values of 6.9 mg g-1 and 0.34 mg g-1, respectively, and are schizonticidal in action. Phytochemical analysis of the plant extracts revealed the presence of alkaloids, saponins and simple sugars.

Animals↗

PubMed1991

Possible involvement of platelets in Plasmodium yoelii nigeriensis malaria infection in mice.

The possible involvement of platelets in the pathogenesis of malaria was examined by monitoring the changes in platelet function (bleeding time [BT] and thrombin time [TT]) concomitantly with changes in packed cell volume (PCV) and erythrocyte infection rate (EIR) in Plasmodium yoelii nigeriensis infection in mice. In untreated plasmodium-infected mice, there was a progressive reduction (day 1-7) in BT from 120.0 +/- 12.6 s to 77.5 +/- 5.9 s (p less than 0.005), a reduction in TT from 26.8 +/- 1.2 s to 17.8 +/- 1.2 s (p less than 0.005), an increase in EIR from 0 to 64.6 +/- 6.3% and a reduction in PCV from 44.9 +/- 1.9% to 21.5 +/- 3.9% (p less than 0.001). Mortality on day 9 was 100%. Antiplatelet serum treatment of plasmodium-infected mice protected against malaria and there was a blunting of the malaria-induced changes in platelet function, EIR and PCV. The values obtained in these rats were significantly higher than those of the untreated malarious mice. The respective values obtained on day 1 were comparable to those of control mice. Data obtained on day 7 were: BT, 106.4 +/- 7.4 s (p less than 0.05), TT, 22.7 +/- 1.1 s (p less than 0.05), EIR, 45.7 +/- 3.2% (p less than 0.01) and PCV, 39.5 +/- 2.0% (p less than 0.01). Mortality on day 9 of infection was 60%. The protection by antiserum was not due to its thrombocytopenic response as busulphan-induced thrombocytopenia did not have the same effect. These results suggest that platelets play an important role in malaria infection as well as in the attendant coagulopathic complications.

Animals↗

PubMed1990

Gastroprotective effects of an aqueous extract of Entandrophragma utile bark in experimental ethanol-induced peptic ulceration in mice and rats.

An aqueous extract of Entandrophragma utile bark was shown to be efficacious in preventing experimental ethanol-induced ulcers in rats. A therapeutic dose equivalent to 50 g/kg of bark orally caused total protection without lethality in the animals employed. The formation of a protective pellicle over the epithelial lining was observed, which may be due to the presence of tannins in the herbal medicine and this may prevent the absorption of noxious agents. In mice, a lethality dose-response curve could not be established orally. The maximum dosage administered was equivalent to 500 g/kg of the bark and produced 25% lethality.

Animals↗

PubMed1989

Chemotherapeutic effects of Annona senegalensis in Trypanosoma brucei brucei.

Mice infected with Trypanosoma brucei brucei 8/18 strain were treated orally and intramuscularly (im) with aqueous root extracts of Annona senegalensis, in doses of 27.8 mg kg-1 and 9.5 mg kg-1 respectively, for four consecutive days commencing 72 hours after the mice were infected. At these dosages the parasites were cleared from the circulation and no relapse was recorded over 60 days. The plant extract, however, had no effect on the trypanosomes when therapy was initiated at the late stages of infection, that is, about the sixth day when the parasitaemia level was 0.9 x 10(6); and all the animals died a day or two later. The herbal extracts also did not show any prophylactic action when given prior to infection. The root extract possesses different margins of safety in the mice depending on the route of administration. The therapeutic index for oral administration was 5.13, and that for im administration was 1.8. Chemical tests revealed that the plant extract contains alkaloids, saponins and tannins. Adverse reactions, especially to doses of 2.3-5.76 mg kg-1, were noted in animals that received the drug parenterally, but not when the drug was administered orally. However, A. senegalensis is shown to be therapeutically effective against T. b. brucei in mice, which agrees with the claims of Nigerian practitioners of Traditional Medicine that it is effective against trypanosomiasis in man.

Administration, Oral↗

PubMed1978

Studies on vasodilatation in the hand on exposure to heat.

In five subjects whose hands were exposed to heat, no depletion in the plasma kininogen level was observed when vasodilatation occurred. This might be due to the admixture of arterial and venous blood following the opening of arterio-venous (A--V) anastomoses. The small rise obtained by warming was not significant (P greater than 0.1). Consequently, the drop in kinonogen concentration recorded when the hand was allowed to cool to an ambient temperature of 23 degrees C as compared with the basal level and that during the period of warming, was also found to be non-significant. In another nine subjects whose A--V kininogen values were determined when their hands were immersed in a water bath at 37 degrees C, a significant A--V difference of the kininogen content was obtained. From this work, it is concluded that no appreciable depletion of venous kininogen concentration was obtained on hand warming. It is possible that sweat glands, vasodilator nerve fibres and the release of kinins contribute in part to the dilatation that occurs. Possible patho-physiological mechanisms involved are discussed.

Fingers↗

PubMed1978