Histological Evaluation of Ethanol Leaf Extract of Syzygium aromaticum on Stomach and Colon of Wistar Rats

The use of food additives or herbs has consistently received attention from researchers globally. One of these substances, Syzygium aromaticum, is used for medicinal purposes and food spices. This work evaluated the histological effect of ethanol leaf extract of Syzygium aromaticum on the stomach and large intestine of adult Wistar rats. Twelve-four (24) adult Wistar rats with average weight of 200 g were randomly divided into four groups of six rats each. Group A served as the control and received 1 ml of water, Group B, C and D received 200, 400 and 800 mg/kg body weight of ethanol leaf extract of Syzygium aromaticum respectively. All administrations were done through oral route for 21 days. After sacrifice, the stomach and colonic tissues were harvested, fixed in 10% neutral buffered formalin andprocessed for haematoxylin and eosin staining. Histological findings in stomach showed normal mucosal crypts, activation of lamina propria lymphocytes, mural active vascular congestion and dilatation in the 200 mg/kg body weight treated group; heavy mural infiltrates of eosinophils, mural vasodilatation and congestion in the 400 mg/kg body weight treated group; heavy mural infiltrates of inflammatory cells, mural vasodilatation and congestion in the 800 mg/kg body weight treated group. Histological findings in colon at all doses revealed normal colonic architecture of mucosa crypts, increased goblet cells, muscularis propria and activation of lamina propria lymphocytes. Conclusively, Syzygium aromaticum could be considered toxic on the stomach at a dose exceeding 200 mg/kg body weight, but with no significant effect on the colon. Thus its culinary and medicinal consumption should be monitored.