Evaluation of neurotoxicity and hepatotoxicity effects of acute and sub-acute oral administration of unripe ackee (Blighia sapida) fruit extract

Abstract

Ackee (Blighia sapida) is a commonly eaten fruit that is indigenous to West Africa and Jamaica. Ackee poisoning in young children have been reported in parts of Nigeria due to consumption of the unripe fruits. This study was designed to identify potential mechanisms of acute and sub-acute toxicity of unripe B. sapida fruit extract (BSE). Acute toxic effect was investigated in mice of either sex administered BSE 2000 mg/kg. The sub-acute toxicity effects were investigated in mice of either sex that received 28 days repeated administration of BSE (100 and 500 mg/kg, p.o.). Locomotor activity and memory performance were measured as well as seizure vulnerability in PTZ-induced model. Liver enzymes were assessed in the serum. Acetylcholinesterase, oxidative stress parameters and histopathological changes were assessed in the brain and liver tissues. Signs and symptoms of toxicity such as urination, tremor, depressed locomotion and death were observed in acute toxicity test. Sub-acute dosing caused significant impairment in locomotor activity and memory performance in mice. Seizure threshold was shortened in BSE-treated compared to control mice. Brain acetylcholinesterase activity was significantly increased. Alkaline phosphatase (ALP) was significantly elevated in mice that received BSE (500 mg/kg). Furthermore, BSE caused significant increase in oxidative stress expressed in nitrite, malondialdehyde, reduced glutathione and catalase in the brain and liver tissues. Histological staining revealed neuronal damage of brain hippocampus and hepatocellular swelling and necrosis. Blighia sapida unripe fruit extract increased susceptibility to seizure and impaired locomotor and memory function. The biochemical and histopathological findings revealed potential toxicity mechanisms related to neurotoxicity and hepatotoxicity.

Keywords: Ackee; Brain; Liver; Oxidative stress; Seizure; Toxicity.

Graphical abstract

Fig. 1

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) on body weight (A) Percent change in body weight, (B) Area under the curve (% change in body weight/ 28 days). Values represents Mean ± SEM (n=10). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 2

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) locomotor activity (A) Horizontal activity count, (B) Vertical activity count. Values represents Mean ± SEM (n=5). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 3

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) memory performance on the Y-maze test. Values represents Mean ± SEM (n=5). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 4

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) on seizure latency in PTZ-induced model. Values represents Mean ± SEM (n=5). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 5

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) on brain acetylcholinesterase enzyme activities. Values represents Mean ± SEM (n=5). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 6

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) on brain nitroso-oxidative stress parameters. Values represents Mean ± SEM (n=5). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 7

Effect of sub-acute oral administration of unripe Blighia sapida fruit extract (BSE) on liver nitroso-oxidative stress parameters. Values represents Mean ± SEM (n=5). *p < 0.05, vs control in either sex, using 1-way ANOVA (Newmann Keuls test). Subscript M denotes male mice; F denotes female mice.

Fig. 8

Photomicrographs of histopathological changes in the brain hippocampal region (Heamatoxylin and Eosin Staining 400x). The cytoarchitecture of H&E of hippocampal (CA2) region revealed pyramidal neurons are normal and in a lamina arrangement in control male and female (A &D). The pyramidal neurons are normal except the disruption of the lamina arrangement in male (B) but moderate atrophy of pyramidal cells and increased eosinophilia of the neurons (necrosis, arrow) in females (E) mice treated with BSE 100 mg/kg. There is moderate atrophy and esinophilia of pyramidal neurons in males (C), and diffuse atrophy of pyramidal neurons in females (F) mice treated with BSE 500 mg/kg. A- Control male, B- BSE (100 mg/kg)-treated male, C- BSE (500 mg/kg)-treated male, D- Control female, E- BSE (100 mg/kg)-treated female, and F- BSE (500 mg/kg)-treated female.

Fig. 9

Photomicrographs of histopathological changes in the liver section (Heamatoxylin and Eosin Staining 400x). (A) Normal hepatocytes (B) There are diffuse hepatocellular swelling, degeneration (arrows) and coagulation necrosis, (C) There is vascular congestion, severe diffuse vacuolar degeneration (arrow) and necrosis of zone 1 hepatocytes. (D) The hepatocytes are normal, arranged in cords and with distinct nuclei (no observable lesion). (E) There is moderate vascular congestion, diffuse coagulation necrosis of hepatocytes and foci of inflammatory cells (arrows) within the parenchyma. (F) There is moderate congestion of central vein (blue arrow) and vacuolar degeneration of centrilobular to mid-zonal hepatocytes (arrows). A- Control male, B- BSE (100 mg/kg)-treated male, C- BSE (500 mg/kg)-treated male, D- Control female, E- BSE (100 mg/kg)-treated female, and F- BSE (500 mg/kg)-treated female.