Histopathological Effect of Oral Administration of Aqueous Extract of Red Calyces of Hibiscus Sabdariffa on the Lungs, Heart and Stomach of Albino Rats

Herbal medicine is an integral part of healthcare management systems in most developing countries of the world. Industrialized societies have also recognized the value of medicinal plants in recent time for the treatment of both human and animal diseases; however, some medicinal plants exhibit toxicity, emphasizing the need for toxicity testing. This study was designed to determine the histopathological effects
of aqueous extracts of dry calyces Hibiscus sabdariffa on the lungs, heart, and stomach of albino rats in a subacute toxicity study. Experimental rats were divided into four groups; A to D of three rats each. Group A was the controlled group and the rats were administered distilled water per os for 21 days while in group B to D the rats were administered the extract at the graded dose of 200 mg/kg, 400 mg/kg
and 800 mg/kg respectively per os for 21 days. The lungs, heart and stomach were harvested after 21 days treatment for histopathological examination. The
histopathology revealed a dose-dependent toxic effects, at higher doses, the lungs showed alveolar wall thickening, congestion of pulmonary vessels, and necrosis.
The heart tissues showed necrosis and fibrosis of the muscle tissues, and the stomach tissues exhibited gastric epithelial necrosis, fibrosis, and hypertrophy of the muscularis mucosa. These findings revealed that the safety of aqueous extract of dry calyces Hibiscus sabdariffa is dependent on dose and duration of the extract administration.