Antimycoplasmal activity of some plant species from northern Nigeria compared to the currently used therapeutic agent.

CONTEXT: Mycoplasma spp. are obligate parasites of humans and animals. But due to the special requirements needed to culture Mycoplasma in the laboratory, little or no research has been done to evaluate the efficacy of medicinal plants on the organism. OBJECTIVE: To screen medicinal plants traditionally used to treat infections for possible antimycoplasmal and cytotoxic activities. MATERIALS AND METHODS: Acetone extracts of 21 Nigerian medicinal plants were analyzed for antimycoplasmal and cytotoxicity activities using the metabolic inhibition and colorimetric methods, respectively. The extract with the best antimycoplasmal activities was also analyzed for its phytochemical constituents using the desktop method. RESULTS: Calotropis procera (Aiton) R.Br (Asclepiadaceae) extract had the best antimycoplasmal effect with a minimum inhibitory concentration (MIC) of 80 µg/mL and minimum mycoplasmacidal concentration (MMC) of 160 µg/mL. This extract contained saponins, tannins, cardiac glycosides, alkaloids, and flavonoids. The extract of Vernonia amygdalina Delile (Compositae) was the most cytotoxic with median lethal concentration (LC(50)) of approximately 17 µg/mL, and that of Anacardium occidentale L. (Anacardiaceae) was the least cytotoxic with an LC(50) of approximately 1919 µg/mL. DISCUSSION: Calotropis procera is a promising plant for an alternative antimycoplasmal agent because the crude acetone extract had a higher mycoplasmacidal activity than the conventional drug tylosin, which is currently used in treatment of the disease in Nigeria. CONCLUSION: The crude extract of Calotropis procera is worth investigating for the development of a potent agent against cattle Mycoplasma, which has long defied solution by conventional chemotherapy.

Toxicological screening of lyophilized extract of some Nigerian wild mushrooms in mice.

Mushrooms are macrofungi widely consumed as food. However, many mushrooms rot away in the wild because of fear of toxicity. Therefore, lyophilized aqueous extracts of 6 mushroom species collected from Zaria, Nigeria and taxonomically identified as Chlorophyllum molybdites, Panaeolus subalteatus, Macrolepiota procera, Leucopaxillus albissmus, Hygrophoropsis aurantiacus and Pholiota aurea were screened for toxicity in mice. Lyophilized aqueous extract of each of these mushrooms was administered to three groups of 3 mice intraperitoneally (i.p.) at doses of 100, 1000 and 10, 000 mg kg(-1), respectively. Another group of three mice given distilled water served as control. The mice were examined for clinical signs of toxicity over a period of 72 h and pathological examinations conducted on dead animals. The severity of clinical signs, onset of death and pathological lesions were dose dependent. Death occurred within 10 min in all the mice dosed at 10,000 mg kg(-1) with the lyophilized extracts of all the mushrooms screened, with the exception of that of H. aurantiacus, which produced death 21-23 h post administration. This result showed that all the screened mushrooms, including the popular edible M. procera were found toxic. Therefore, since all the mushrooms screened were found toxic, it is recommended that extreme caution should be exercised in their consumption. Furthermore, in view of the regional differences in the toxicity of mushrooms, there is the need to screen more wild mushrooms found in Nigeria for toxicity. This will boost mushroom mycophagy, reduce poisoning incidence and reduce wastage of edible mushrooms in the wild.

Effects of anticonvulsants on acute cypermethrin poisoning in mice and rats.

Male albino mice were given 35 mg cypermethrin/kg bw followed immediately by 1.0, 2.5 or 5 mg diazepam/kg, 5, 10 or 20 mg phenobarbitone/kg, or 10, 25 or 50 mg diphenylhydantoin/kg ip in dose groups of 10 mice each. Effectiveness of therapy was assessed by alleviation of effects and survival percentage. Rat brains implanted with electroencephalographic (EEG) and electromyograhic electrodes were given 58 mg cypermethrin/ kg followed by 5 mg diazepam/kg, 20 mg phenobarbitone/kg, or 50 mg diphenylhydantoin/kg. Diazepam at 5 mg or 20 mg phenobarbitone/kg produced 100% survival and alleviated all the signs of poisoning while diphenylhydantoin produced 80% survival at 50 mg/kg. The antidotes antagonised desynchronization of EEG waves produced in rats exposed to cypermethrin. These results suggest involvement of GABA in the mechanism of cypermethrin action in addition to its established effect on the sodium ion channel.

Trypanocidal activity of organotin chlorides on Trypanosoma brucei-infected mice.

The organotin compounds dibutyltin (DBTC) and diphenyltin dichlorides (DPTC) were tested for trypanocidal activity on a Trypanosoma brucei-infected mice model. At a dose of 10 mg DBTC and 15 mg DPTC/kg/day for five consecutive days, they cleared the parasites from the peripheral blood of the infected mice. Subinoculation of some healthy mice with the homogenates of liver, spleen, kidney, cerebrospinal fluid and blood from the mice considered cured, showed a few cases of relapse. The LD50 of DBTC and DPTC are 90 mg/kg and 75 mg/kg respectively.

Acute toxicity studies of tri-n-butyltin and triphenyltin acetates in rats.

Two organotin compounds, tri-n-butyltin acetate (TBTA) and triphenyltin acetate (TPTA), that have antifungal potentials and are intended for use on yam root crops to prevent rot were evaluated for acute mammalian toxicity in rats. The median lethal doses po were 297.54 mg TBTA/kg and 402.38 mg TPTA/kg. Both compounds produced significant central nervous system and respiratory depressions at single doses of 200 mg TBTA/kg or 300 mg TPTA/kg. The histopathological findings due to TBTA included pulmonary, hepatic and renal congestion, brain hemorrhages, and destruction of the intestinal mucosa. TPTA produced brain congestion, and hepatic and pulmonary petechial and generalized hemorrhages.

Subchronic toxicity studies of tri-n-butyltin and triphenyltin acetates in rats.

The effects of a moderate but prolonged exposure of rats to tri-n-butyltin acetate (TBTA) and triphenyltin acetate (TPTA), as might be encountered as residues in yam peel diets, were investigated in rats. These subchronic toxicity studies (16, 8, or 4 mg TBTA/kg and 20, 10 or 5 mg TPTA/kg) showed histopathologic lesions in lungs, liver, intestine and kidney. The hematologic parameters in the groups treated with either compound fell within the normal range for the rats. However, there was a reduction in mean lymphocyte count for rats receiving 10 or 20 mg TPTA/kg, and a reduction in monocyte count in the 20 mg TPTA/kg group. These data indicate a need for further toxicologic studies and cautionary measures to avoid ingestion, inhalation or contamination of dietary materials by these fungicides.

The lead content of plants and animals as indicators of environmental contamination.

Lead content of tissues from some edible plants, pigeons and a vulture, and from human and cattle blood were determined to gain insight into the extent of environmental lead contamination in Zaria and Kaduna environs of Kaduna state of Nigeria. The results suggest that environmental lead contamination in these areas was insignificant when compared to values from developed countries like US. However, there is need for more work of this nature on a regional basis to ascertain the true picture of total environmental lead pollution in Nigeria.

An activated charcoal hemoperfusion system for the treatment of barbital or ethylene glycol poisoning in dogs.

The efficacy of activated charcoal (AC) hemoperfusin therapy was studied in dogs acutely poisoned with lethal doses of barbital or ethylene glycol (EG). Two of three barbital-poisoned dogs treated with AC hemoperfusion survived; the dog tha died was only hemoperfused for 1.5 h. Although AC hemoperfusion of EG-poisoned dogs reduced the blood level of the toxicant considerably, this was not enough to effect survival. The use of AC hemoperfusion was an effective therapeutic measure for dogs poisoned with lethal doses of barbital. The use of the AC hemoperfusion system with existing drugs of therapy for EG poisoning may be beneficial.

Urinary delta-aminolevulinic acid (ALA) excretion in humans and cattle as an index of exposure to lead.

Disposable ion-exchange chromatographic columns were used to determine delta-aminolevulinic acid (ALA) concentrations in 11 bovine and 184 human urine samples. The mean urinary ALA concentrations in persons working as battery charges, autopainters, automechanics, and urban first-grade pupils were 11.61 +/- 14.23, 6.51 +/- 3.31, 6.48 +/- 3.36, and 5.71 +/- 2.91 micrograms/ml respectively. These values were higher than those found in urine from gasoline station attendants, university students and laboratory assistants, rural adult farmers, and rural first-grade pupils, which were 4.90 +/- 1.95, 4.93 +/- 1.76, 4.40 +/- 1.79 and 4.51 +/- 2.65 micrograms/ml respectively. In cattle (Holstein Friesian/White Fulani cross) the mean urinary ALA concentration was 1.84 +/- 0.04 micron/ml. The data indicates that persons working around automobile, lead batteries and leaded gasoline had elevated ALA concentrations in urine. Rural humans and cattle did not have significant elevations of urinary ALA.

Acute toxicity of the leaves and extracts of Dichapetalum barteri (Engl.) in mice, rabbits and goats.

Acute toxicity of the leaves and extracts of Dichapetalum barteri for mice, rabbits and goats was investigated. Consumption of 0.5 g/kg and 2.2 g/kg body weight of dried leaves was lethal to rabbits and goats, respectively, within 4 h. Plants collected in the dry season were more toxic than those collected during the wet season. Clinical signs observed were initial depression followed by restlessness, convulsions, and death. The main lesions observed were acute vasculitis and congestion of the liver, lung, kidney, spleen as well as extensive oedema and congestion of the myocardium. The water extract of the leaves was lethal to mice at 2.0 g/kg, to rabbits at 0.1 g/kg and toxic to isolated rabbit heart at 2 mg/ml of Locke's solution. Monofluoroacetate was detected in the plant material and is probably the toxic principle of D. barteri.