Acute Toxicity and Erythrocyte Osmotic Fragility Studies of Methanol Leaf Extract of Asystasia vogeliana in Rats

Aim: To investigate the phytoconstituents of methanol and petroleum leaf extracts of Asystasia vogeliana (MLEAV and PLEAV), the median lethal dose (LD50) and the effects of MLEAV on body weight, organosomatic indices in vital organs and erythrocyte membrane of Albino Wistar rats during sub-acute administration.

Place and Duration of Study: Department of Veterinary Physiology and Pharmacology, University of Nigeria, Nsukka, in 2017.

Methodology: The crude extracts of MLEAV and PLEAV were used in determining the qualitative and quantitative analyses. The rats were assigned into four groups and dosed orally with distilled water (0.5 ml/100 g) as Group I, 62.5 mg/kg MLEAV (Group II), 125 mg/kg MLEAV (Group III) and 250 mg/kg MLEAV (Group IV) once daily for 28 days. Blood samples were collected from all the rats via the medial canthus into EDTA bottles for erythrocyte osmotic fragility (EOF) study on day 29. Relative organ-body weight indices of vital organs (spleen, heart, liver and kidney) were also evaluated.

Results: MLEAV and PLEAV showed the presence of saponins, flavonoids, phenols, alkaloids, anthraquinones and steroids. The total phenolic contents of MLEAV (3704.30 ± 44.00) significantly increase (P = 0.000) when compared with PLEAV (1349.46 ± 35.25). The LD50 of MLEAV is above 5000 mg/kg. There were significant (P < 0.05) decreases in the body weights of rats in Groups III and IV from 3rd to 4th week when compared with their baseline weights. There were significant (P < 0.05) increases in the relative spleen-body weight in Group IV when compared with other groups. There was no significant change (P > 0.05) in the hemolysis of rats in Group II when compared with the control group at 0.9% NaCl concentration.

Conclusions: The findings reveal that MLEAV showed better antioxidant capacity than PLEAV, and that 62.5 mg/kg of MLEAV is safe during the sub-acute administration.