Journal of Veterinary and Biomedical Sciences
(ISSN: 2659 – 0743)
Volume 1, No. 2, 2018
Pages 29-47
DOI:10.36108/jvbs/8102.10.0240
In Vitro Antileishmanial, Antitrypanosomal And Cytotoxic —Assessment of Extracts of Three Nigerian Medicinal Plants Using Alamar Blue Assay And Cell Counting Methods.
Alawa J.N.1 , Kwanashie H. O.2*, Nok A. J.3 , Alawa C. B. I. 4*, Carter K.C.5° and Clements C. J.6 .
1Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Abuja, Giri, Nigeria
2Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Ahmadu Bello University, Zaria, Nigeria
3Department of Biochemistry, Faculty of Science, Ahmadu Bello University, Zaria, Kaduna State, Nigeria
4Department of Animal Production, Faculty of Veterinary Medicine, University of Abuja, Giri, Nigeria
5Department of Immunology, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
6Department of Pharmacognosy, Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
ABSTRACT
Infections caused by protozoan species are major worldwide health problems resulting in over three million deaths annually in developing countries. Extracts of three selected plants used as medicinal plants by indigenous local communities in Nigeria were screened against Trypanosoma brucei brucei bloodstream isolates and amastigotes forms of Leishmania major and for cytotoxic activity against normal cell lines (macrophages and L929 fibroblasts) and cancer cell lines (Jurkat and SH-SY5Y) using alamar blue assay and conventional cell counting methods. Results demonstrated that two extracts, aqueous extract of Vernonia amygdalina (VA) and methanolic extract of Annona senegalensis (AS) showed significant antileishmanial activity against macrophage infectivity (=50%) without cellular damage. The percentage suppression with VA was significantly higher (p<0.05) while that of AS was comparable to the standard drug, sodium stibogluconate (SSG) (% suppression with VA=65.1; AS=48.4; SSG=40.2). Two extracts showed strong antitrypanosomal activity with EC,, and MIC,, values of less than I10ug/ml namely hexane extract of AS (2.88 and 3.12) and methanolic extract of VA (8.04 and 6.25) which were more effective than the reference drug Cymelarsan, while other extracts showed moderate to low activity with values ranging from 10 to above 20 ug/ml. Cytotoxicity studies showed that only methanolic extracts were toxic to L929 fibroblasts and macrophages while no toxicity was observed on the Jurkat and SH-SY5Y cancer cells at this concentration. Phytochemical screening using GC-MS showed the presence of polyacetylenes, ethers, fatty acids, alkaloids, flavonoids, sulphur and alcohol compounds in the active extracts. The findings of this study has shown that extracts of AS and VA contain active compounds which could serve as alternative agents in the development of antileishmanial and antitrypanosomal drugs and warrants further investigation.
Keywords: Trypanosoma brucei brucei, Leishmania major, Nigerian plants, Alamar blue test