Phytochemical screening, antimycobacterial activity and acute toxicity of crude extracts of selected medicinal plant species used locally in the treatment of tuberculosis in Uganda

Tropical Medicine and Health

Robert Byamukama¹  Jane Namukobe¹  Benson Oloya²  Willy Ssengooba³  Mathias Afayoa⁴ 

[1] Department of Chemistry, College of Natural Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda;Department of Chemistry, College of Natural Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda;Department of Chemistry, Faculty of Science, Muni University, P.O. Box 725, Arua, Uganda;Department of Medical Microbiology, College of Health Science, Makerere University, P.O. Box 7072, Kampala, Uganda;Department of Pharmacy, Clinical and Comparative Veterinary Medicine, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P.O. Box 7072, Kampala, Uganda;

关键词: Phytochemistry;    Antimycobacterial activity;    Acute toxicity;    Tuberculosis;    Medicinal plants;   

DOI  :  10.1186/s41182-022-00406-7

来源: Springer

【 摘 要 】

BackgroundTuberculosis (TB) is one of the leading causes of death globally, and the rise in drug-resistant forms of TB has become a significant threat. Subsequently, it is crucial to explore new, effective and safe anti-TB agents. This study aimed at conducting phytochemical screening, antimycobacterial activity, and acute toxicity of the selected plant species’ crude extracts to assess their toxicological potentials and efficacies against TB.MethodsThe aqueous and methanol/dichloromethane (DCM) (1:1) extracts of each selected plant species were subjected to phytochemical screening and antimycobacterial activity using microplate alamar blue assay. For acute toxicity, a single dose (2000 mg/kg) of the aqueous extracts was orally administered to each animal following the Organization for Economic Cooperation and Development (OECD) guidelines No. 425 and then observed for 14 days. The animals were closely observed on the general behavior and clinical signs of toxicity, and body weights were recorded. After the termination of the experiment, hematological, biochemical, and histopathological analyses were performed.ResultsThe extracts contained alkaloids, flavonoids, tannins, saponins, steroids, terpenoids, resins, cardiac glycosides, phenolic compounds, and coumarins. Aqueous extracts showed moderate to weak activity against the susceptible (H37Rv) M. tuberculosis strain and weak activity against the MDR-TB strain with Minimum Inhibitory Concentrations (MIC μg/mL) ranging from 293.0–2344.0 and 1172.0–4688.0, respectively. Methanol/DCM extracts showed significant to moderate activity against the susceptible TB strain and moderate to weak activity against the MDR-TB strain with MIC (μg/mL) ranging from 98.0–586.0 and 293.0–781.0, respectively. One mortality was recorded from the A. coriaria treated group following the acute toxicity tests, but the LD50 of all the extracts was estimated to be above 2000 mg/kg. Histopathological analyses did not show any significant lesions in the examined organs except those from the A. coriaria treated group.ConclusionPhytochemical screening of the extracts revealed the presence of alkaloids, tannins, saponins, flavonoids, steroids, terpenoids, resins, cardiac glycosides, phenolic compounds, and coumarins. All the methanol/DCM extracts of the plant species studied have promising antimycobacterial activity. The selected plant extracts studied exhibited low acute toxicity levels except for A. coriaria and could be safe for formulations into herbal products.

【 授权许可】

CC BY