A comparative study of the antioxidant, antibacterial and cytotoxic activities of different varieties of imported ripe cavendish banana

Abstract

Abstract Banana is one of the most delicious and energetic crops among the agricultural crops. Traditionally, Omanis used bananas to treat gastrointestinal disorders, constipation and diarrhea. The present study aims to determine different pharmacological and toxicological activities of extracts of two varieties of imported ripe banana which was collected in the local fruits and vegetable market. Extracts from ipe bananas imported from India and the Philippines were prepared separately l by soaking the bananas in methanol for seventy-two hours. The prepared banana extracts were fractionated with various solvents with increasing pattern of polarity to give corresponding banana crude extract, respectively. All prepared crude extracts were used to determine their antioxidant, antibacterial and cytotoxic activities by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), agar gel diffusion and brine shrimp lethality methods. In case of the Indian ripe banana, the highest antioxidant activity was obtained from the ethyl acetate extract and the water crude extract showed the lowest activity. However, in the ripe banana from the Philippines, the highest activity was obtained from the chloroform crude extract and the lowest activity was obtained from the water extract. Both extracts with different polarity displayed moderate antibacterial activity at different working concentrations. The zone of inhibition range was 0-19 mm against one Gram-positive bacterial strain such as Staphylococcus aureus (S. aureus) and three Gram-negative bacterial strains such as Escherichia coli (E. coli), Haemophilus influenza (H. influenza) and Enterococcus faecalis. Both banana extracts with different polarity showed significant cytotoxic activity at all working concentrations. Both banana crude extracts killed all shrimp nauplii at the highest concentration of 500 μg/ml. In Indian ripe banana, the highest cytotoxic activity was found in water crude extract with an LC50 value of 27.35μg/ml and the lowest was in ethyl acetate and methanol extract with an LC50 value of 57.54 μg/ml. Almost similar results were obtained from the bananas from the Philippines. In conclusion, the polar crude extracts prepared from both varieties of ripe bananas have significant pharmacological and toxicological activities. Therefore, the polar banana extracts might be agents to be used as antibiotics.