GAS CHROMATOGRAPHY-MASS SPECTROMETRY ANALYSIS AND ANTIOXIDANT ACTIVITY OF PUNICA GRANATUM L. PEELS AND ITS ROLE AS IMMUNOSTIMULANT AGAINST SCHISTOSOMA MANSONI INFECTION IN BIOMPHALARIA ALEXANDRINA

Abstract

Objective: To evaluate the antioxidant activity and chemical composition of Punica granatum L. and test it as immunostimulants against Schistosoma mansoni infection to Biomphalaria alexandrina snails.Methods: Antioxidant activity was evaluated by measuring the free radical scavenging activity of the 90% defatted methanol extract (90% DM) of P. granatum peels and its sub-derived fractions was evaluated via 2,2'-diphenyl-1-picrylhydrazyl and its chemical constituents were identified via gas chromatography-mass spectrometry (GC-MS) analysis. B. alexandrina snails were exposed to pomegranate extracts (PEs) for 1 month before their challenging with S. mansoni miracidia. Infection rates, immunological and histological parameters were, then, evaluated in PE-exposed snails and compared to controls.Results: The antioxidants activities of PE, expressed as scavenging concentration at 50%, were in the following order; 90% DM (12.45) ˃n-butanol(15.59) ˃ethyl acetate (21.36) ˃water (49.16) µg/ml, compared to 7.50 µg/ml for ascorbic acid. The infection rates of PE-exposed snails were 20%,50%, 60%, 70%, and 80%, respectively, for 90% DM, n-butanol, ethyl acetate, water, and dichloromethane extracts compared to 95% in control snails. The number of amoebocytes showed a significant increase, clear differentiation, and size increment in exposed snails compared to controls. Moreover, hermaphrodite glands histology shows a full maturity in the formation of reproductive cells in PE-exposed snails. The GC-MS analysis of the 90% DM extract revealed the presence of 36 compounds representing 93.1% of the total composition. Piperidin-4-ol, 1,3-dimethyl-2,4,6-triphenyl (19.87%), and 6,11-dihydroxy-5,12 naphthacenequinone-1-carboxylic acid (7.80%) were the major components.Conclusion: The identified compounds in 90% DM extract of P. granatum may be responsible for the high antioxidant activity of the fruit and it may account for its immunostimulatory effect against S. mansoni infection in B. alexandrina.Keywords: Punica granatum L., Antioxidant activity, Biomphalaria alexandrina, Schistosoma mansoni, Infection rate, Gas chromatography-mass spectrometry