Total phenolic contents and free radical scavenging activity of certain Egyptian Ficus species leaf samples

Abstract

The antioxidative phytochemicals in grains, vegetables, fruits and medicinal plants have received increasing attention for their potential role in prevention of human diseases. The methanol extracts of the leaves of eleven Ficus species growing in Egypt were subjected to free radical scavenging activity using 1,1-diphenyl picrylhydrazyl (DPPH ) method. Six methanol extracts of six species showed high activity in order: Ficus lyrata Warb. > Ficus afzelli G. > Ficus nitida L. > Ficus virens Ait. > Ficus sycomorus L. > Ficus decora Hort. with SC 50 38.37, 60.22, 61.67, 74.00, 79.50 and 81.62 μg/ml, respectively. The free radical scavenging activity of different fractions obtained from successive fractionation of the six methanol extracts with organic solvents of different polarities; petroleum ether, CHCl 3, EtOAc and n-BuOH; showed that, the EtOAc and n-BuOH fractions have the high activity with SC 50 < 50 μg/ml whereas petroleum ether and CHCl 3 fractions have weak activity at SC 50 > 200 and 100 μg/ml, respectively. The EtOAc and n-BuOH fractions of F. lyrata showed the strongest free radical scavenging activity on DPPH with SC 50 = 8.27 and 12.14 μg/ml, respectively and also the highest antioxidant capacity monitored by phosphomolybdenum method (928.48 and 728.53 mg equivalent to ascorbic acid/g extract). Preliminary phytochemical investigation of the six active EtOAc and n-BuOH fractions guided by review of literatures of this genus showed that phenolic compounds constitute the major components of it. The total phenolic, tannin, flavonoid and flavonol contents of the six active EtOAc and n-BuOH fractions were measured using the well established methods. Linear correlation between the total antioxidant capacity of the six active EtOAc and n-BuOH fractions and the total phenolic and flavonoid contents were observed. More in vivo and in vitro studies along with detailed photochemical investigation are needed in the hope to can use these species (crude extract, fractions, sub-fractions or pure compounds) in the prevention and therapies of diseases in which oxidants or free radicals are involved.