Effects of Allium Sativum Ethanolic Extract on Trypanosoma brucei brucei Parasites’ Morphometric Parameters and Clinical Outcome in White Albino Laboratory Rats

Abstract

Background: Trypanosomosis affects humans as well as wild and domestic vertebrates, yet has no successful prophylaxis, chemotherapy nor cure.
Objectives: The study was to investigate the effects of Allium sativum extract on Trypanosoma brucei brucei parasites’ morphometric parameters, parasitemia and the clinical outcome in white infected Albino laboratory rats in order to determine its trypanocidal effects.
Methodology: The study was conducted at the department of Biological Sciences Laboratory of the Moi University Eldoret. Thirty two (32) mature rats randomly divided into four groups (M, N, P and Q) were kept in four (4) cages in a well ventilated room, with adequate light supply in the day.
Sixteen (16) rats were infected with T. b. brucei (1.0 x 104 parasites per rat); eight (8) of which (Group N) were treated with the A. sativum ethanolic  extract on day 5 and day 9 after infection, while the other eight (8)rats (Group Q) received saline treatment on the same days.
Sixteen (16) non-infected rats (controls) were also divided into two groups of eight rats each (P and M) and treated as in group N and Q, respectively. The rats were obtained from University of Nairobi, Chiromo Campus.
Results: All infected rats became parasitemic two days after infection and reached peak levels on day 4 and 5 post infection. Parasitemia in saline treated infected rats fluctuated between 4025.5 ± 0.05 - 5544.4 ± 0.05 parasites per 200WBC whereas in the extract treated rats parasitemia declined
from 6976.6 ± 0.05 - 311.0 ± 0.05 parasites per 200WBC after the first treatment. Uninfected saline treated rats maintained normal Hb level (10.6g/L to 11.8g/L) as compared to the uninfected extract treated rats’ whose Hb levels was at 13.41g/L to 14.36g/L. The haemoglobin level changed to 8.0g/L four days after the infection in the group N rats before rising to 10.2g/L on day 8 post-infection following the extract treatments. Group Q
rats’ Hb declined to 6.43g/L by the end of the study. RBC count of the infected saline treated rats declined to 3.38 x 106/μL as compared to 4.93-7.61 x 106/μL in the normal rats by 11 days postinfection. There was however no significant change in WBC, temperature and weight between the saline extract treated rats. The extract produced a shrinking effect on the parasite's body with some of the morphometric parameters appearing  significantly (P<0.05) reduced as observed under a microscope with ocular and stage micrometer scale. The mean nucleus, posterior ends to nucleus centre, the nucleus centre to the anterior end and the body length were reduced from 2.41μm to 1.42μm(P=0.00), 4.42μm to  3.68μm(P=0.017) , 4.65μm to 4.18μm(P=0.001) and 8.58μm to 7.19μm(P=0.001) respectively.
Conclusion: In conclusion it was evident that, A. sativum ethanolic extract exhibited Trypanocidal effects that can be exploited to control clinical progression of Trypanosomosis in rats. In addition, the data presented demonstrates the plant extract had the potential to improve the red and white blood cell indices reducing parasitaemia following T. b. brucei infection. These findings suggest that, the garlic extract affected the plasma membrane of the parasites since shrinking was only possible with disrupted membrane biochemistry.

Key words:  Trypanosoma brucei brucei, Allium Sativum, Parasitemia, Morphometric parameters,