ANTI-TYPHOID ACTIVITIES OF ETHANOLIC PULP EXTRACT OF UNRIPE ANONNA MURICATA (LINN.) FRUITS IN SWISS ALBINO RATS INFECTED WITH SALMONELLA TYPHI.

Abstract

Study was carried out to investigate the anti-typhoid activity of ethanolic pulp extract of unripe Anonna muricata fruits in Swiss albino rats infected with Salmonella typhi. Phytochemical and proximate screenings were carried out on the extract. The result of the phytochemical screening revealed the presence of saponin, tannin, terpernoid, flavonoid, anthraquinone and cardiac glycoside however, alkaloid and phlobatannin were absent. The proximate analysis showed the presence of carbohydrate (48%), moisture content (24.51%), ash (0.58%), crude protein (9.09%) and fat (17.13%) but crude fibre was not detected. For in vitro testing, pure clinical and typed S. typhi were obtained and their identity were confirmed using standard microbiological methods. The extract was reconstituted with dimethylsulphoxide (DMSO) to make concentrations of 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500mg/ml. The in-vitro activity of the extract against typed and clinical isolates of S. typhi did not show any zone of inhibition (ZI) at concentrations of 50-200mg/ml for clinical isolates but at higher concentration, a significant increase (P<0.05) was recorded (4.93-11.37mm). The 100mg/ml of the extract did not inhibit the typed isolates. However, a progressive increase (3.03-14.03mm) was observed at higher concentrations. The Minimum Inhibitory Concentration (MIC) values for typed and clinical isolates were 150 and 250mg/ml respectively while Minimum Bactericidal Concentration (MBC) values were 350 and 400mg/ml respectively. The antibiotic sensitivity test showed that ciprofloxacin (10μg) had the highest antibacterial activity against the typed (11mm) and clinical S. typhi (16mm) while both organisms were resistant to amoxicillin (30μg). Moreover, the in-vivo bioassay was done to evaluate the antibacterial and prophylactic effect of the extract as well as its effect on haematological parameters and various organs. Forty-two healthy Swiss albino rats (170-220g) between 5-7weeks old were used for the in vivo assay. The rats were fed with standard rat pellets and were acclimatized for 7days before the treatment started. The result showed that infectious dose of the test organism on experimental rats was 6.8x106cfu/ml. Faecal shedding of S. typhi by rats treated with extract decreased with increasing days of treatment while faecal shedding in group given prophylactic treatment significantly increased (P<0.05). There was no significant change (P<0.05) in body weight in all groups when compared to weights before treatment but in group infected without treatment, a significant decrease (P<0.05) was recorded. Also, the relative weight of liver, kidney and spleen in all groups observed was not significantly different (P<0.05) from the control. There was significant decrease (P<0.05) in White Blood Cell (WBC) of group given extract while there was significant increase (P<0.05) in the Packed Cell Volume (PCV) and Haemoglobin (Hb) levels. Restorative effects were observed in the histopathological examination carried out on liver and kidney but it had a protective effect on the spleen. The demonstration of antibacterial activity of unripe fruit extract against both clinical and typed isolates as well as the reduction observed in the faecal shedding of S. typhi provides a scientific basis for its use in the treatment of typhoid infection. However, the high Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) may indicate the capacity to develop resistance against the plant extracts. The extract is non-toxic to vital organs, did not interfere with rat metabolism and also stimulated haemoglobin production. However, it still lacks prophylactic activity. Conclusively, the phytochemicals detected in the extract of A. muricata fruit was responsible for the various activities exhibited.