الفهرس 
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Abstract
The current study entitled “Antitrypanosomal activity of rosemary (Rosmarinus officinalis) plant extract on Trypanosoma evansi experimental infection” aimed to evaluate the in vitro and in vivo anti-trypanosomal activity of rosemary (R. officinalis) plant extracts on T. evansi infection compared with diminazene aceturate drug.
The study design and plan of work were as follows:
Plant samples were collected from the aerial parts (stem, leaves, and flowers) of rosemary, and eight extracts were prepared using different solvents.
Petroleum ether, ethyl acetate, ethyl alcohol, and distilled water are organic and aqueous solvents used in ascending polarity.
The presence of phenols, saponins, tannins, flavonoids, and alkaloids were determined by phytochemical screening of the extracts.
The eight extracts using different solvents were prepared at concentrations of 4, 10, and 20 mg/ml (four from leaves and four from stem bark) of the rosemary plant collected from Matrouh Governorate, Egypt.
T. evansi parasites were isolated from a naturally infected camel, then identified as RoTat 1.2 strain and maintained in the laboratory by the continuous passage in white Swiss mice of mixed sexes (20–25 g) to give parasitaemia of approximately 105 parasites/ ml.
In vitro test for trypanocidal activity was carried out using a microtiter plate to evaluate the viability of T. evansi after treatments for different plant extracts to calculate LC50 –LC90 by using ELISA titer plates.
The toxicity test was assessed to the different solvents. However, groups of Albino rats were administrated extracts at the suitable in vitro concentration to notice toxicity and calculating LD50 – LD90.
After that, in vivo assays were performed using rats as a biological model for each selected extract at its suitable in vitro concentration and administration.
Parasitaemia levels were determined after two days of extracts and drug administrations in the controls and checked three times a week for clinical signs included: weight loss, oedema of the face, ocular discharges, encrustation of the lips, lethargy and mortality rate, in addition to prepatent period, longevity and animal mortality.
Blood samples were collected weekly for 6-9 weeks, by cardiac puncture, for potential haematological and biochemical abnormalities that may be associated with the administration of different extracts.
• Blood samples were collected from each group weekly until the end of the experiment by heart puncture for haematological and biochemical analyses.
• Gross lesions and histological changes were examined for pathological abnormalities by the end of the experiment.
• The increases and decreases in haematological and biochemical parameters were statically analyzed, and also LC50 and LC90.
The results revealed that:
Phytochemical screening showed significant differences (p≤0.05) between leaves and stem bark components.
The extracts of 20 mg/ml concentration have in vitro activity on T. evansi more than 4, 10 mg/ml concentrations that need more time than diminazene aceturate (DA), which complete immobilized the parasites within 20 minutes.
20 mg/ml concentration has lethal doses greater than 200 mg/kg, and there was no evidence of acute toxicity at the doses tested.
There was a significant reduction in infection-induced alterations in the treated groups relative to the untreated healthy group.
Significant differences (p<0.0001) between different treatments in all haematological and biochemical parameter values were observed compared to the healthy ones (N) and drug treatment (DA).
Significant decreases in RBCs count in all treated rats, except (AA), (DD), were nearly typical compared to the healthy group (-Ve).
Hb in all treatments decreased with significant differences within the normal range in three treatments (AA, B, and DD).
Mean values of WBCs significantly increased in all the treated groups except C and CC groups. It elevated with a significant difference in DD and DA compared to healthy control.
PLT, Lymph%, and HCT showed different treatments revolve around the normal range compared to the –ve group.
The treatment with some extracts did not achieve some selected biochemical indices to pre-infection state and could not prevent the disease-induced liver damage.
Hypoglycemia, hypoproteinemia, and normo-lipidemic were estimated in all treated groups.
Globulin levels were in the normal range and a highly significant increase (p<0.0001) in mean values of total bilirubin and kidneys function.
Serum ALT and ALP enzymes were significantly increased (p<0.0001), and AST was within normal, whilst LDH values decreased compared to controls and drug treatment.
Statistical analysis corroborated antitrypanosomal activity-specifically correlated to the treatment based on the type of solvent and part of the plant used in extraction.
Aqueous extract of R. officinalis (DD) caused reduction with a highly significant difference (p<0.0001) in parasite-induced biochemical changes evidenced in decreased LDH, bilirubin, creatinine, cholesterol, levels.
Treatment with ethanol and ethyl acetate extracts of the stem (C and B) decreased with a highly significant difference (p<0.0001) in Tp, Alb, and GLb levels as compared to its pre-treatment levels in all infected groups.
Ethanolic leaf extract (CC) was the best treatment that lowered the levels of urea, bilirubin, AST, and ALT liver enzymes with highly significant differences (p<0.0001).
Petroleum leaf extract (AA) had improved LDH, cholesterol, A/G%, and creatinine levels.
Chemical drug (DA) did not improve many parameters, except for WBCs and to less extent, ALP, Tg, TP, Alb, GLb, and A/G.
Macroscopical examination of different tissues particularly liver, kidney, and heart by naked eye showed no detectable abnormalities of the tissues in the animals treated compared to control groups. The changes were more evident in DA than others.
Concerning microscopical examination, pathological changes were unequal and not consistent with anemia compared to +ve controls.
The most changes recorded were observed in ethanol and ethyl acetate extracted treated groups (B, BB, C, and CC). It is expressed as oedema, congested blood, and hyperplastic bronchi together with peribronchial mononuclear cells infiltrations based on the type of treatment.
The leaf/ Petroleum ether extract was safe and the best and preferable extract has the most antitrypanosomal activity against T. evansi based on the score of legions.