Is a combine therapy of aqueous extract of azadirachta indica leaf (neem leaf) and chloroquine sulphate toxic to the histology of the rabbit cerebellum?

Background: Herbal medication is commonly employed in treatment of diseases. Aqueous extract of Azadirachta indica leaf (A. indica) is commonly used in treatment of malaria by Nigerians. Most often, aqueous extract of A. indica leaf is taken in combination with chloroquine in order to cure malaria infection without knowledge of the side effect especially by the rural dwellers in Nigeria.

Objectives: This study is designed to investigate the effects of aqueous extract of A. indica leaf, and concomitant administration of chloroquine phosphate + aqueous extract of A. indica leaf on the Brain tissue (cerebellum) of rabbit.

Methods: Eight adult male Rabbits with average weight range between 1.29kg - 1.52kg obtained from Department of Zoology University of Ekpoma, Edo state were used for this study. They were weighed at intervals of five days before and after the experiment. They were randomly divided into four groups (A- D) of two rabbits each. The chloroquine and aqueous extract of A. indica leaf was administered to the animals orally via a cannula inserted through the oral cavity. They were treated as follows; group A received (100mg ml(-1) dry extract solution of aqueous extract of A. indica), group B received (15mg kg(-1) of chloroquine sulphate), group C received (100mg ml(-1) dry extract solution of aqueous extract of A. indica + 15mg kg(-1) of chloroquine sulphate and the control animals (group D) were given normal saline. Both the treatment and control animals were sacrificed at the end of the experiment. The cerebellum was carefully dissected out and immediately fixed in Bouin's fluid for histological studies.

Results: Groups A-C animals showed normal Cerebellar histoarchitecture and average weight gain of 2.1% (group A), 1.4% (group B), 0.7% (group C) and 1.4% (group D) respectively. When the average weight gain by the treated animals was compared to the average weight gain by the control animals, it was statistically not significant (P>0.06).

Conclusion: Our findings revealed that aqueous extract of A. indica has no effect on the histology of the Cerebellum and weight of adult male rabbits, even when it is administered concomitantly with Chloroquine Sulphate at a reported and recommended safe dose.