Acute and sub-chronic oral toxicity assessment of the leaf aqueous extract of Kalanchoe crenata (Crassulaceae)

Abstract

Previous studies demonstrated that the leaves of Kalanchoe crenata (Crassulaceae) possess analgesic, anti-inflammatory, anticonvulsant and cardiovascular activities but nothing is known about the toxicity of this plant material. The objective of the present study was to evaluate the acute and sub-chronic toxicities of the aqueous extract of the leaves of K. crenata (AEKC) prepared as a dry leaves decoction. Acute oral toxicity of the AEKC was evaluated in mice at doses 2, 4, 6, and 8 g/kg. Animals were observed for 3 hours post administration for signs and symptoms of intoxication. Survivors were followed up for 14 days after treatment. Wistar rats of both sexes were used for sub-chronic toxicity. They were orally treated with the AEKC at doses of 300, 600 and 1200 mg/kg/day for 4 consecutive weeks. They were further euthanized and blood was collected for biochemical and hematological analyses. A single acute administration of AEKC reduced the sensitivity to pain and the mobility of animals. These behavioral modifications disappeared 3 hours after administration. Only the dose of 8 g/kg caused the death of one female mouse out of 6, inferring a LD₅₀ greater than 8 g/kg. The daily administration of AEKC did not induce mortality, behavioral modifications, significant variations of body weight, relative weights of the liver and kidney and plasma content of Alanine amino transferase (ALAT) and aspartate amino transferase (ASAT). Besides, no significant difference was observed on glomerular filtration rate and other parameters of renal excretion. Meanwhile, at the dose of 300 mg/kg/day, a significant increase in total bilirubin, free bilirubin and a significant decrease in conjugated bilirubin and plasma creatinine were registered. These results suggest that the aqueous extract of the leaves of K. crenata can be classified as a non-toxic substance. However, attention should be paid on the hepatic function.

Keywords: Acute and sub-chronic toxicity, aqueous extract, Kalanchoe crenata, Crassulaceae