There has been a growing interest in medicinal plants by the locals of the Pacific Islands since it is readily available. Annona muricata, commonly called soursop is one of such plants which is popular because it is being used to treat initial stages of cancer due to its antioxidant properties. This study investigated various extraction methods which could be used to compare and see the effectiveness of each on the chromosomes. The cytotoxicity and genotoxicity effect were studied using Allium cepa root tip cells. Eight onion bulbs were subjected to the treatment groups which were made using methanol, water and hexane extracts of A. muricata. Three different concentrations from each extraction solvent were used. The A. cepa root tip cells were subjected for 24 h to three different leaf extractions after left to grow in water. Concentrations of 12.5, 25 and 50 g/L were used. After the treatment, onion bulbs were put back in water to recover. Hence, 5 root tips from each bulb were removed (before treatment, treatment and recovery) with cells undergoing mitosis counted under 400x of a compound microscope. All studied concentrations of A. muricata methanol extract showed significant (p≤0.05) drop in the mean mitotic index when compared with control (mean MI reduced by 9.9, 44.4 and 54.2% for 12.5, 25 and 50 g/L respectively). A. muricata water extract also showed significant differences at 12.5 g/L where mitotic index (MI) was reduced by 8.6%. At 25 g/L, the reduction was by 35.3% and by 42.8% at 50 g/L. Drastic effect (p≤0.05) was observed with the soursop-hexane extract that reduced the MI significantly in 12.5 g/L by 5.0% and by 29.7% at 25 g/L. A huge reduction in MI was observed at 50 g/L where MI declined by 72.8%. Chromosomal aberrations were also observed which indicates the genotoxicity of the extracts. All the extraction methods contributed significantly towards the drop in total MI. Compounds in the extracts is mitodepressive.
Key words: Allium cepa, Annona muricata, chromosome aberration, cytotoxicity, mitosis, mitotic index.