Reproductive Impairment Associated With The Ethanolic Extract Of Alstonia Boonei (De-Wild) Stem Bark In Male Rats

摘要

The aqueous ethanolic extract of Alstonia boonei stem bark was studied on the reproductive characteristics of 60 male albino rats for 2 and 4 weeks. The rats were randomly assigned to 6 groups of 10 animal each for the 2 weeks segment: group 1 received 1ml/kg normal saline, group II and III got 50 and 200mg/kg of the extracts respectively. For the 4 weeks segment, group IV received 0.5ml/kg normal saline, while groups V and VI got 50 and 200mg/kg of the extract respectively. At the end of the 2 weeks 50mg/kg extract significantly decreased the sperm count, motility, viability and adversely charged the morphology of the sperm. These results were replicated dose and time dependently in the 200mg/kg by the 4th week. However no significant changes on the blood level of testosetorone and body weight were observed. It is concluded from this study that the extract may have toxic potentials on reproductive function without the involvement of plasma testosterone. Thus the dose and duration of application of the extract in folk medicine should be regulated to forestall possible reproductive impairment. The active constituent associated with this effect and the mechanism of action are subjects to further investigation. Introduction The application of natural medicinal products to manage the diseases of man is primordial. Man has often depended on natural substances to treat some ailments, especially in the developing economies. The trend is being reversed in recent times in some advanced countries because of the perceived long term toxicity of some synthetics drugs. Some of the natural products have provided the lead for researches, discovery, development and synthesis of many orthodox drugs in current use; for instance the 4-aminoquinolines for malaria and the cardiac glycoside, digitalis for arrhythmias.Alstonia boonei grow wild as a lactiferous tree, and belongs to the family, Apocynaceae. It is widely distributed, but thrives best in the tropics and subtroprical regions. Studies reveal that most components of the plant have medicinal values. The phytochemical analysis shows that the plant contains alkaloids, terpenes, sterols and porphyrines. Some of them have been isolated and characterized. They include echitamine, astonine, ditanine, chlorogenine, alstovenine, etc. The pharmacological screening of the plant extract reveals the following actions. Antimalarial antipyretic (Ojewole, 1984); analgesic, antiinflamatory (Kweifio-Okai, 1996, Olajide et. al., 2000) antipsychotic, lactogenic (Yinusa et.al., 2005, ) diuretic, antihypertensive (Kucera et al., 1972) anthelmintic, spasmolytic (Makinde, 1996) antidote, antimicrobial (Olajide, 2000). Studies exist to show that some antimalarial drugs possess antifertility properties. This has been documented for quinine, and chloroquine by Sairam(1978), Meisel et al (1993), and Adeeko and Dada (1998). Lohiya et al., (1994), Raji and Bolarinwa (1997) and Raji et al., (2003) have also reported the reversible antifertility activities of extracts of Carica papaya, quassia amara and Azaridichta indica respectively. Medicinal substances emanating from extracts of Alstonia boonei are widely used in folk medicine, especially in the management of febril illness, pyrexia and malaria syndrome. This informed the study of the plant extract on reproductive function in order to generate information about the possible reproductive effect of the extract, especially in developing economy such as Nigeria where the rural population depend on the extract. The information will also be useful as a guide to folk medicine. practitioners who use the plant extract, regularly. Materials And Methods Plant Material The stem bark of Alstonia bonnie was collected from Imo State University Owerri Campus and was identified by Dr. S. E. Okeke (plant Taxonomist) Department of Plant Biology and Biotechnology, Faculty of Science, Imo State University, Owerri. The voucher specimen is deposited in the departmental herbarium. Preparatio