In vitro screening of extracts from some Egyptian plants for their radical scavenging and oxidant reducing properties

The damaging effect of free radicals and oxidative species in a number of disease states has prompted a sustained interest in screening medicinal plants with antioxidant constituents. In the present study, extracts from medicinal plants growing in South Sinai, Egypt, were screened for their antioxidant properties using chemical assays. The study included methanolic extracts of Alkanna orientalis (L.) Boiss. roots, Cucumis prophetarum Jusl. ap. L, Cleome droserifolia (Forssk.) Del., and Crataegus sinaica Boiss. (and its ethyl acetate and butanol subfractions). Screening for the radical scavenging was performed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay [1], whereas the oxidant reducing properties were determined using the ferric reducing antioxidant power (FRAP) assay [2]. Data were expressed as Trolox® equivalents, at an extract concentration of 62.5µg/ml. In the DPPH scavenging assay the Crataegus and Alkanna extracts produced similar strong radical scavenging activity (Trolox equivalents ranging between 37.9–38.3µM), whereas the Cucumis and Cleome extracts exhibited relatively weak antiradical properties. In the FRAP assay the extracts produced ferric reducing ability in the following order: Crataegus (ethyl acetate fraction) > Crataegus (butanol fraction) > Alkanna > Crataegus > Cleome, while the Cucumis extract was devoid of activity. The antioxidant activity produced by extracts of C. sinaica and A. orientalis are in agreement with previous reports with these species/genus [3, 4]. These data suggest further evaluation in a suitable cell-based assay to test for the intracellular antioxidant potential of these extracts.

Acknowledgements: Alison Holmes, Holly Matthews and Tina Shah.

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