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Indian Journal of Pharmacology, Vol. 38, No. 5, September-October, 2006, pp. 359-360 Research Letter Toxicological studies of aqueous stem bark extract of Boswellia dalzielii in albino rats Etuk EU, Agaie BM, Onyeyili PA, Ottah CU Department of Pharmacology, College of Health Sciences, Usmanu Danfodiyo University, Sokoto Code Number: ph06100 Boswellia dalzielii (Frankincense) is a tree plant. It is abundantly found in north-western Nigeria, where the Hausa speaking people refer to it as Hano or Harrabi. This plant is very popular among the locals as a potent source of ethnomedicine.[1] The extract from its leaves is used for the treatment of diarrhea in poultry.[2] The root decoction of B. dalzielii and Daniella oliveri is used for wound healing. The fresh bark is eaten to induce vomiting and relieve symptoms of giddiness and palpitations. The root decoction of the plant boiled along with Hibiscus sabdariffa is used for the treatment of syphilis. The fragrant gum resin from the plant is used locally for fumigation of clothes and houses and as a deodorant.[2] Despite the widespread uses of this plant in treating a plethora of human and animal diseases in this environment, neither its phytochemistry nor toxicological profile has been studied and reported to our knowledge. The present effort is, therefore, aimed at investigating the chemical constituent and the toxicity profile of the stem bark extract of the plant following oral administration in rats. The plant material was collected from Zuru in Kebbi state of Nigeria in September 2004. A Botanist in the Biological Sciences Department of Usmanu Danfodiyo University, Sokoto confirmed the identity of the plant and a voucher specimen was deposited at the department's Herbarium. The stem bark was carefully separated, air dried to a constant weight and pulverised to a dry powder using a wooden mortar. About 200 g of the powder was macerated in 1500 ml of distilled water for 24 h. The liquid filtrate was concentrated in vacuum at 40oC and the percentage yield of the extract was found to be 6.8% (w/w). The extract was chemically tested for the presence of different chemical constituents using standard methods.[3] The up and down procedure was adopted to evaluate the acute toxicity of the extract after oral administration in the rats.[4] Five adult, female, non-pregnant rats were randomly selected for this experiment. The animals were marked and housed individually in cages. They were fasted overnight, but allowed free access to water before the administration of a freshly prepared extract orally at a single dose of 3000 mg. kg -1. Each rat was sequentially dosed with the extract and observed for 48 h for signs of acute toxicity or instant death. This was followed by repeated dose (subchronic) study for 28 days. Twenty-four rats were randomly selected, weighed and divided into four groups of six rats each. The animals in group 1 (control) received 2 ml of normal saline daily, while those in groups II, III and IV received 900, 1800 and 2700 mg.kg -1 of the extract, respectively, through the oral route for 28 days. The extract was administered at the same time daily and the doses were adjusted as necessary to reflect the changes in the weights of the animals. The animals were fed and watered adequately during the treatment period. They were weighed weekly and constantly observed for signs of morbidity and mortality. At the end of the study period (28 days), the animals were anaesthesised with chloroform and blood samples immediately collected by cardiac puncture for haematological and biochemical analysis. Necropsy of all the animals was carried out and selected organs like the heart, lungs, liver and kidneys were removed and preserved. The organs were physically examined and weighed and samples were collected for histopathological examinations. All the data collected during this study were expressed as the mean±SEM. One-way analysis of variance (ANOVA) with subsequent Dunnett's test was used to detect further differences between groups. P < 0.05 was considered significant. The aqueous stem bark extract of Boswellia Dalzeilii contained various pharmacologically active compounds, such as, alkaloids, tannins, saponins and anthraquinones. The oral administration of 3000 mg.kg -1 of the extract did not produce any sign of acute toxicity or instant death in any of the five rats tested during the observation period. This suggests that the median lethal dose (LD 50 ) of the extract using the revised up and down procedure is greater than 3000 mg.kg -1. The fact that the LD 50 of aqueous extract of Boswellia dalzeilii is above 3000 mg.kg -1 is an indication that the extract could be considered relatively safe, especially when given orally. Absorption may not be complete due to inherent factors limiting absorption from the gastrointestinal tract. In the subchronic toxicity studies, the extract did not produce any lethality among the tested animals when varying doses of 900, 1800 and 2700 mg.kg -1sub , were administered orally, daily for 28 days. The rats treated with the highest dose of the extract (2700 mg.kg -1sub ), however, recorded significant ( P > 0.05) reductions in the percentage weight gain as compared with those in the control group. In addition, the organs' weight (kidney, liver, heart and lungs) of the animals treated with 2700 mg.kg -1 of the extract showed significant decease when compared with that of the control and the other treatment groups. The haematological analysis provided the results presented in [Table - 1]. There were no significant ( P >0.01) changes in the packed cell volume (PCV), white blood cell count (WBC) and red blood cell count (RBC) between the groups of rats treated with 900 and 1800 mg.kg -1 of the extract and the control group. There were significant ( P < 0.01) reductions, however, in the packed cell volume and red blood cell count ( P < 0.05) of the rats treated with the highest dose of the extract (2700 mg.kg -1). The extract treatment did not change the values of serum electrotypes (sodium and potassium) in the treated animals when compared with the control group. There was a significant increase ( P < 0.01) in the serum urea level of the rats treated with 2700 mg.kg -1 of the extract when compared with the control and the other treated groups. The other biochemical indices like hepatic enzymes and serum proteins remained unchanged. [Table - 2] Histopathological examinations of the tissue samples taken from the kidneys, heart, lungs and liver of both the rats treated with the extract and the untreated rats revealed no pathological lesions. The above findings suggest that prolonged oral administration of very high doses of the aqueous stem bark extract of Boswellia dalzielii may be associated with increased risk of toxicity.[5] References
Copyright 2006 - Indian Journal of Pharmacology The following images related to this document are available:Photo images[ph06100t1.jpg] [ph06100t2.jpg] |
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