Oral Safety Evaluation of the Aqueous Fruit Extract of Annona Muricata in Wistar Rats

Annona muricata fruit (i.e. Soursoup or custard apple a tropical plant species known for its edible fruit)has been attributed with numerous medicinal benefits (including antimicrobial, anti-inflammatory, anti-protozoan, antioxidant, anxiolytic, anti-stress, anti-ulcerogenic, wound healing, hepato-protective, anti-icteric, hepatoprotective, anticancer and antihyperglycemic activities) as well as some toxicological effects (neurotoxicity and neurodegeneration). Despite its ancestral use and wide applications in human health, scientific information on its oral safety remains scanty. In this study, the oral safety of 100 mg/kd/day, 200 mg/kg/day and 400 mg/kg/day of the aqueous fruit extract of Annona Muricata (AFAM) was evaluated in young adult, male and female white albino Wistar rats using standard acute and 42-days sub-chronic oral toxicity testing guidelines on anthropometric, biochemical, hematological and histo-pathological endpoints. In addition, preliminary qualitative and quantitative analyses of AFAM were undertaken using standard procedures. Results of the study showed that the estimated LD50 value for the acute oral toxicity study of AFAM calculated to be greater than 5 g/kg body weight/oral route although the testing was associated with transient but reversible behavioral toxicities. For its sub-chronic oral toxicity testing, AFAM treatment resulted in profound %weight gain, decreases in the serum triglycerides and very low density lipoprotein cholesterol and liver enzymes. Similarly, prolonged oral AFAM treatments caused significant decrease and increase in the differential neutrophils and platelet counts, respectively while the hist-opathological features of hepatic steatos is and renal tubule collapse in the AFAM-treated livers and kidneys, respectively suggested possible increased intrahepatic lipids biosynthesis and nephrotoxicity. The preliminary phytochemical analyses of AFAM showed the presence and relative amount of flavonoids, alkaloids, tannin, glycosides, saponin, and reducing sugars while the Gas Chromatography-Mass spectroscopy showed the relative abundance of thirteen compounds. Composite analyses conducted on the extract showed the presence of carbohydrate (64.65%), protein (2.14%), moisture content (8.07%), ash value (6.73%), lipid (14.22%) and fiber (4.19%). Overall, the study suggested that the prolonged AFAM oral treatments could predispose to the development of fatty liver disease from de novo intrahepatic biosynthesis of triglycerides, nephrotoxicity and hematotoxicity. In conclusion, the results of this study showed that prolonged consumption of AFAM should be with a great caution as it could pose serious health concerns.