PHARMACOGNOSTIC AND BIOLOGICAL STUDIES OF THE LEAVES AND STEM-BARK OF HYMENOCARDIA ACIDA, TUL. (EUPHORBIACEAE)

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Department of Pharmaceutical Sciences

ABSTRACT
This study deals with the pharmacognostic and biological aspects of the leaves and stem bark of Hymenocardia acida Tul (Family Euphorbiaceae). Euphorbiceae is a large and heterogeneous family found mainly in the tropics and sub-tropics. H. acida is a savannah shrub or tree with twisted trunk usually less than 4.5 m high but sometimes attaining as much as 9m. it is commonly found in Senegal, Sierra Leone, Togo and Nigeria; widely spread in tropical Africa. In northern Nigeria and in Zaire, the leaves and stem-bark are used in the treatment of eye infection, chest pains, anaemia, diabetes and purulent sores. Macroscopical, microscopical and phytochemical studies were carried out on the leaves and stem-bark of the plant. Characteristic pharmacognistic features of the plant were found to be polygonal sclereids , frequent non-articulate laticifers and on the average brown (outer surface) of the bark. The sessile covering trichomes, orange or yellow coloured, could served as diagnostic features on the epidemis of the leaves. Other macroscopical and microscopical features could serve in the identification of the plant and provide monograph data for the plant. The various phytochemical tests revealed the presence of carbohydrates, tannins, alkaloids, flavonoids, terpenes and sterols, saponins and cardiac glycosides in both the stem-bark and leaves. Anthraquinones were present in the leaves but not in the stem-bark. Cyanogenic glycosides, resin and balsams were found to be absent. Evaluation of the crude drug was carried out. The moisture content for the leaves and stem-bark were 20.5%w/w, 8.0%w/w; ash value 4.8%w/w, 11.5; acid insoluble ash value 1.5 w/w, 7.5w/w; water soluble extractive value 42.0%w/w, 44.0%w/w; alcohol soluble extractive value 34.0 %w/w, 37.0 %w/w respectively. These established quantitative values can be used in the preparation of a monograph on the plant and provide indices for identification: The plant was found to be safe orally, there was no observable LD50 which is a dose effective for producing a certain sign in 50% of the animals of a group. The mice, survived the doses greater than 5000mg/kg up to 11000mg/kg. The Histopathological studies from the chronic administration of the plant leaves and stem-bark in rats showed a stimulating effect on haemopoiesis and lympocytes proliferation which could help in ameliorating anaemic conditions. It may also play a role in activating the immune system in the cause of prolong treatment. The result had also shown that the prolonged treatment with the leaves or stem-bark of H. acida can induce hepatoxicity. The results of analgesic activity studies showed a significant and doses dependent analgesic activity when compared to untreated controls (P< 0.05), this gave justification for the use of the plant in ethnomedicine for the treatment of pain.