Acute toxicity studies and antibacterial evaluation of Bombax costatum stem bark extracts

Bombax costatum belongs to the family Bombacaceae and is commonly called red-flowered silk-cotton tree or red kapok tree, the plant occurs from Senegal. In Nigeria, different parts of B. costatum are employed for various purposes. The extract from the bark is drunk or applied on the head for dizziness; and the gum resin from the bark is pulverized, mixed with oil and used to manage skin diseases such as “craw-craw”. This study showed that the, median lethal dose (LD50) via oral route of the extracts was found to be greater than 5000 mg/kg when administered orally in albino rats. The extracts of B. costatum stem bark was observed to posses s antibacterial activity against four out of the seven bacterial isolates that were used for the study. Ciprofloxacin was used as a control, and it has higher antibacterial activity as compared to the plant extracts. Although, the three extracts showed app reciable zones of inhibition (18-28 mm), the ethyl acetate extract exhibited a wider dimension (26-28mm) and prove to be the best as compared to the hexane and methanol extracts which showed (18-20 mm) and (22-25 mm) respectively. The results from the MIC and MBC also revealed that the ethyl acetate extract (6.25 and 12.5 mg/ml) had higher inhibitory strength than the hexane (25 and 50 mg/ml) and methanol (12 and 25 mg/ml) extracts. The results of this study provide scientific justification for the traditional uses of the stem bark in the treatment of infectious diseases and food poisoning.Keywords: Bombax costatum; Stem bark; Antibacterial activity; Toxicity studies