In vivo antimalarial effect of Ananas comosus (L) Merr (Bromeliaceae) fruit peel, and gas chromatography-mass spectroscopy profiling: A possible role for polyunsaturated fatty acid

Purpose: To evaluate the antimalarial effect of Ananas comosus extract and fractions and also to identify the likely bioactive compounds. Method: The fruit peel of the plant was extracted with methanol, and the extract successively fractionated with n-hexane, dichloromethane, ethyl acetate, methanol and water. The n-hexane fraction was further subjected to vacuum liquid chromatography to afford four sub-fractions, one of which was also analyzed using gas chromatography-mass spectroscopy (GC-MS). Plasmodium berghei-infected mice were treated orally with three doses (100, 200 and 400 mg/kg) of the plant extract and a single dose (200 mg/kg) of each of the fractions and sub-fractions in a curative antimalarial model using artemisinin combination therapy (ACT) as the reference drug. Results: The extract exhibited significant (p < 0.001) non-dose dependent parasitemia inhibitory activity in the range of 44.84 to 76.09 %. All fractions displayed inhibitory effect (p < 0.001) in the range of 46.44 to 87.58 % with the dichloromethane fraction displaying the highest effect (87.58 %). The sub-fractions exhibited significant inhibitory effect (p < 0.001) in the range of 84.14 to 92.54 %. The ACT produced significant (p < 0.001) inhibitory effect of 83.92 %. GC-MS analysis revealed the presence of 17 bioactive compounds, the most abundant of which were linoleic acid and palmitic acid. Conclusion: A. comosus displays strong antimalarial activity which supports the folkloric use of the plant for malarial treatment. A polyunsaturated fatty acid (linoleic acid) was the most abundant phyto-constituent identified.