Subchronic toxicity of aqueous extract of Alstonia boonei de wild. (apocynaceae) stem bark in normal rats
Keywords:Alstonia boonei, Aqueous Extract, Rats, Subchronic Toxicity.
Methodology: Wistar rats were randomly assigned into eight groups of five animals each: four male groups and four female groups. Each sex group had a control group receiving distilled water and three test groups receiving 200, 500 and 1000mg/kg respectively. Animalâ€™s body weights were recorded on the first day and once a week for the four experiment weeks. The hematological analysis included total WBC count, total RBC count, Hb, %HCT, MCV, MCH and MCHC. Biochemical/serum profile studies include TG, TC, ALT, AST, urea and TP. Tissue specimens of the liver, kidney and lung were subjected to histological examination using standard hematoxylin-eosin staining.
Results: In male rats, aqueous extract showed significant decreases in relative weight of liver with extreme significance P<0.001 at a dose of 200mg/kg (vs. control group), P<0.001 of lung at all the doses, P<0.05 (200 and 500mg/kg) and P<0.01 (1000mg/kg) in heart weight. In relative kidney weight, only the dose of 1000mg/kg showed a significant increase vs. normal control male rats. Unlike male rats, only relative kidney weight in female rats was significantly different from the control group in a dose-dependent manner. The aqueous extract treated male groups showed significant increases P<0.001 (1000mg/kg) of total WBC count and MCHC, significant decreases of %HTC (dose response manner), P<0.05 total RBC count (at doses of 500 and 1000mg/kg) and Hb P<0.01 (500mg/kg) vs. normal male rats. In female rats, the haematological study showed significant increase P<0.01 of total WBC count (at the doses of 500 and 1000mg/kg), significant decreases P<0.05 and P<0.01 of total RBC respectively at the doses of 200 and 1000mg/kg, significant decrease of Hb with extreme significance P<0.001 at the dose 1000mg/kg, %HTC also decrease dose response manner vs. control female rats. Biochemical study showed in male rats significant decreases in level of TG P<0.001 (at the doses of 200 and 500mg/kg) and urea, although it showed any dose-dependent effect vs. control male rats. AST also decreases (P<0.05) in male rats at the dose of 200mg/kg but significantly increase P<0.001 at the dose of 500mg/kg. In the female rats, biochemical study revealed significant increases in level of TG P<0.001 and urea P<0.01 at the dose of 200mg/kg and significant decreases in level of TG P<0.01, AST P<0.05 and urea P<0.05 at the dose of 500mg/kg (vs. control female rats). Microscopically, there were mild hepatic and renal tissue injuries supporting the hematological analysis.
Conclusion: The results indicated that aqueous extract of Alstonia boonei De Wild is toxic in high doses.
 Asuzu IU & Anaga AO (1991), Pharmacological screening of the aqueous extract of Alstonia boonei stem barks. Fitoterapia 63, 411-417.
 Awodele O, Osunkalu VO, Akinde OR, Teixeira da Silva JA, Okunowo WO, Odogwu EC & Akintonwa A (2010), Modulatory Roles of Antioxidants against the Aqueous Stem Bark Extract of Alstonia boonei (Apocynaceae)-induced Nephrotoxicity and Testicular Damage. International Journal of Biomedical and Pharmaceutical Sciences 4, 76-80.
 Cullen JM (2007), Liver, Biliary system and Exocrine pancreas. In: Pathologic Basis of Veterinary Disease, 4th Edn., McGavin MD, Zachary JF. (Eds.). Mosby, London, 403-406. http://www.elsevier.com/wps/find/bookdescription.cws_home/708252/description#description.
 Dalsiel JM (1997), Botany, uses of Alsonia boonei stems bark. In: The useful plants of West Africa. Crown agents for overseas government and administration, London. 260-264.
 Ghai CL (2004), A Text Book of Practical Physiology. 6th Ed. Jaypee Brothers Medical Publishers, New Delhi. 130-175. http://www.nbcindia.com/Descriptions.asp?6v6yr_vq=GHIMG&Buy+Book+Online=A+Textbook+of+Practical+Physiology&by=Ghai.
 Iwu MM (1993), Handbook of Africa Medicinal Plants. CRC Press, Boca Raton, FL, USA. 116-118.
 Kamgang R, Youmbi M, Mengue Nâ€™GPR, Ngogang & Yonkeu J (2005), Cameroon local diet-induced glucose intolerance and dyslipidemia in adult Wistar rat. Diabetes Research and Clinical Practice 69, 224-230. http://dx.doi.org/10.1016/j.diabres.2005.02.005.
 Kasote DM, Badhe YS, Zanwar AA, Hegde MV & Deshmukh KK (2012), Hepatoprotective potential of ether insoluble phenolic components of n-butanol fraction (EPC-BF) of flaxseed against CCl(4) -induced liver damage in rats. Journal of Pharmacy and Bioallied Sciences 4, 231-235. http://dx.doi.org/10.4103/0975-7406.99064.
 Kucera M, Marquis VO & Kucerovah (1972), Contribution to the knowledge of Nigerian Medicinal plants. JLC separation and quantitative evaluation of Alstonia boonei alkaloids. Planta Medica 21, 343-346. http://dx.doi.org/10.1055/s-0028-1099562.
 Maurica MI (1993), Handbook of African Medicinal plants. CRC Press, Boca Raton, FL. 116-118.
 Mohajeri D, Mousavi G & Mesgari M (2007), Sub-acute toxicity of Crocus sativus L. (Saffron) stigma ethanolic extract in rats. American Journal of Pharmacology and Toxicology 2(4), 189-193. DOI: 10.3844/ajptsp.2007.189-193.
 Nkono Ya Nkono BL, Sokeng SD, Dzeufiet Djomeni PD & Kamtchouing P (2014), Antihyperglycemic and Antioxydant Properties of Alstonia boonei De Wild. (Apocynaceae) Stem Bark Aqueous Extract in Dexamethasone-Induced Hyperglycemic Rats. International Journal of Diabetes Research 3(3): 27-35.
 OCDE (1995), Etude de toxicitÃ© orale Ã dose rÃ©pÃ©tÃ©e pendant 28 jours sur les rongeurs. Ligne directrice de lâ€™OCDE pour les essais de produits chimiques. 407-409. French.
 Ojo OA, Ajiboye B, Oyinloye BE & Akintayo CO (2014), Prophylactic Effects of Ethanolic Extract of Alstonia boonei Stem Bark Against DDVP-induced Toxicity in Albino Rats. Journal of Pharmaceutical and Biomedical Sciences 4(07), 650-657. www.jpbms.info.
 Oliver-Bever B (1986), Medicinal Plants in Tropical West Africa. Cambridge University Press, London. 89-90. http://dx.doi.org/10.1017/cbo9780511753114.
 Oze GO, Nwanjo HU & Onyeze GO (2007), Nephrotoxicity caused by the extract of Alstonia boonei (De wild) stem bark in Guinea pigs. The Internet Journal of Nutrition Wellness 3(2).
 Raji Y, Salman TM & Akinsomisoye OS (2005), Reproductive Functions in Male Rats Treated with Methanolic Extract of Alstonia boonei Stem Bark. African Journal Biomedical Research 8, 105-111.
 Reitman S & Frankel S (1957), A colorimetric method for the determination of serum glutamic oxaloacetic and glutamic pyruvic transaminase. American Journal of Clinical Pathology 28, 56-63.
 Rej R (1997), Liver diseases and the clinical laboratoryâ€”the twentieth Arnold O. Beckman conference in clinical chemistry. Clinical Chemistry 43(8), 1473â€“1475.
 Tsague M, Fokunang C, Ngameni B, Tembe-Fokunang E, Guedje N, Tom E, et al. (2015), Pre-clinical Evaluation of the Hypotensive and Anti Atherogenic Activity of Hydroethanolic Extract of Eribroma oblongum (Malvaceae) Stem Bark on Wistar Rats Models. British Journal of Pharmaceutical Research 5(1), 1â€“14. doi:10.9734/BJPR/2015/12782. http://dx.doi.org/10.9734/BJPR/2015/12782.