Toxicity of Methanol Extract of Lasiosiphon kraussianus Root

Abstract

The toxicity of a methanol extract of roots of Lasiosiphon kraussianus (lg = 20 g dried root) was investigated in mice, rats, rabbits, dogs and isolated rabbit ileum and heart. In acute toxicity studies carried out in mice, LD₅₀ of the extract was 27.1 g/kg and 330 mg/kg after oral and intraperitoneal administrations respectively. Clinical signs of peritoneal irritation, tachypnoea and listlessness and post mortem lesions of haemorrhagic enteritis were observed. In chronic toxicity studies with rats fed the extract at 2, 4 and 8 mg/kg/day for six months, no clinical signs of toxicity were observed and no gross lesions were detected at post mortem examinations. Haematological studies carried out in rabbits given 2 to 16 mg/kg of the extract per os showed no significant changes in the blood parameters measured. There was also no effect on blood pressure and respiration in the dog. On isolated rabbit ileum and heart however, high concentrations of the extract (2-32 mg/ml) inhibited intestinal rhythmic contractions and had negative inotropic and chronotropic effects on the heart.

It was concluded that a methanol extract of root of Lasiosiphon kraussianus when given at the dose of 2 mg (equivalent to 0.4 g dried root)/kg per os does not cause any toxic effects in mice, rats and rabbits.

A further study is required to confirm its efficacy in the treatment of leprosy and viral diseases.

Key Word Index

Lasiosiphon kraussianus - Toxicity - Ileum - Heart