ASPECTS OF HISTOPATHOLOGICAL EFFECTS OF HIBISCUS SABDARIFFA EXTRACTS ON ALBINO RATS
ABSTRACT
The effect of oral administration of aqueous and methanolic extracts of dried calyx of Hibiscus sabdariffa on the histological features of some tissues of Rattus norvegicus was studied for a period of 28 days. One hundred and eight (108) adult male and female albino rats aged 4 weeks, weighing 120g to 295g were used. The one hundred and eight (108) adult male and female albino rats were randomly divided into 9 groups of 8 treatment groups and one control with each comprising of 12 rats per group. The eight treatment groups were sub-divided into two based on extract type administered. They were experimentally exposed to oral administration of aqueous and methanolic extracts at 100mg/kg, 200mg/kg, 400mg/kg and 800mg/kg respectively whereas the control was given normal saline. The weights of the animals were measured weekly and the liver, kidney, heart, ovary and testis were dissected out and processed using standard histological procedures. Similarly, blood was collected using standard methods to determine the serum levels of such liver enzymes like Aspartate Transaminase (AST), Alanine Transaminase (ALT) and Alkaline Phosphate (ALP). There was an overall non-dependent dosage and duration significant decrease (p<0.05) in weights of the treated rats in comparison with the control. Similarly, there were significant histological alterations in the heart and liver of Rattus norvegicus exposed to aqueous and methanolic extract of Hibiscus sabdariffa while the histology of the ovary, testis and kidney had no observable pathological alterations. The pathological alterations observed in the heart of the experimental rats administered with aqueous extract of Hibiscus sabdariffa such as hyperaemia myocardial, inflammatory infiltrates, necrosis, fragmentation and hyalinization were less severe when compared to those administered with the methanolic extract of 100mg/kg, 200mg/kg, 400mg/kg and 800mg/kg. Similarly, more severe histopathological changes were observed in the liver of rats exposed to methanolic extract of Hibiscus sabdariffa such as severe hepatocellular vacuolar degeneration, mononuclear leucocyte infiltration and necrosis especially in the 200mg/kg, 400mg/kg and 800mg/kg treatment groups. There was a significant increase (p<0.05) in the serum concentrations of Alanine Transaminase (ALT), Aspartate Transaminase (AST) and Alkaline phosphatase (ALP) of the rats administered with both extracts when compared with that of the control. The results obtained in this study therefore suggest that methanolic and aqueorus calyx extracts of Hibiscus sabdariffa have the potentiality to cause deleterious effects in the tissues of consumers if not moderately taken.