Antibacterial, Acute Toxicity and Histological Study of Dodonaea viscosa, Eucalyptus camaldulencis and Senna siamae: Ethnobotanical Plants for Typhoid Fever in Kano State, Nigeria

This study evaluated the antibacterial activity, acute toxicity, and histological effects of Eucalyptus camaldulensis, Dodonaea viscosa, and Senna siamae, three ethnobotanical plants traditionally used to treat typhoid fever in Kano State, Nigeria. Antibacterial activity against Salmonella typhi was assessed using the agar well diffusion method, followed by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Acute toxicity was evaluated using a single oral limit dose of 5000 mg/kg in mice, and histological assessment of the liver, kidney, and heart was performed using hematoxylin-eosin staining. At 100 mg/ml, E. camaldulensis exhibited the largest inhibition zone (20.3 ± 2.52 mm), followed by S. siamae (15.0 ± 0.00 mm) and D. viscosa (13.0 ± 0.00 mm) which showed a statistically significant (p < 0.05) with the control. MIC and MBC values confirmed that E. camaldulensis had the highest antibacterial potency (MIC 6.25 mg/ml; MBC 12.5 mg/ml), whereas D. viscosa and S. siamae showed MIC 12.5 mg/ml and MBC 25 mg/ml. Acute toxicity assessment revealed no mortality at 5000 mg/kg for all the extracts (LD50 > 5000 mg/kg). Histological evaluation showed normal heart tissues in all the tested groups, normal liver and kidney tissues in E. camaldulensis and S. siamae-treated mice, but slight tubular necrosis in the kidney and minimal hepatic necrosis in the liver of D. viscosa-treated mice. Lesions were graded as minimal and observed in 1 out of 3 mice per group.