Acute Toxicity Evaluation of Magnolia Officinalis Bark on Swiss Albino Mice

ABSTRACT Magnolia officinalis (of the family Magnoliaceae) is a traditional Chinese medicine also referred as Houpu Magnolia, Kara-Koboku or Magnolia bark since the bark of the tree is the main active ingredient. Magnolia officinalis has been used for thousands of years in Chinese pharmacopoeia. The bark of Magnolia officinalis known under the pinyin name “Houpo” has been traditionally used in Chinese and Japanese medicines for the treatment of anxiety, asthma, depression, gastrointestinal disorders, headache and more. This research was carried out to evaluate the acute toxicity of Magnolia officinalis bark on Swiss albino mice, in order to determine the median lethal dose (LD₅₀) and the behavioral pattern of the mice exposed to the extract. Acute toxicity test was carried out using nine (9) mice which were marked on their tails for easy identification and were acclimatized for two weeks. The animals were fed with animal feed and water. The experiment was carried out in two phases. In phase one, nine (9) mice were fasted with free access to water. They were divided into three groups and given 10 mg/kg, 100 mg/kg and 1000 mg/kg of Magnolia officinalis bark extract respectively. No mortality was observed after 24 hours. In the second phase, three animals were used and each was given 1600, 2900 and 5000 mg/kg respectively. No mortality was recorded in the mouse given 1600 mg/kg of the extract. However, the mice that received 2900 mg/kg and 5000 mg/kg all died. The median lethal dose (LD₅₀) was calculated to be 2154.07 mg/kg. The result shows that Magnolia officinalis could be toxic at higher doses.