Abstract:

Wild almonds of Iran show genetic diversity and have very a large distribution. Different species of these almonds have more variation in genes resistant to dryness, saltiness, diseases, pests, and other factors. In order to compare the antioxidant and antiradical activity of wild almond hull and shell phenolic extracts, 4 wild almond species (Amygdalus lycioides Spach, A. kotschyi Boiss. & Hohen, A. pabotti Browicz, A. trichamygdalus (Hand.-Mzt) Woronow) were selected from Shahindezh and Qasemloo Valley, West Azerbaijan province, Iran, in 2007. The fruits of these almonds were collected, their hulls and shells were dried and then ground, and then methanolic extracts were prepared from these hulls and shells. Total phenolic content was determined using the Folin-Ciocalteu (F-C) method. The extracts' reducing power and scavenging capacity for radical nitrite, hydrogen peroxide, and superoxide were evaluated. Hull and shell extracts, respectively, had a range of 122.2 ± 3.11-75.9 ± 1.13, 46.6 ± 0.94-18.1 ± 0.15 mg/g gallic acid equivalents/g extract in total phenolic content, 0.667-0.343, 0.267-0.114 AU at 700 nm in reducing power, 94.9 ± 0.97%-63.7 ± 1.14%, 65.7 ± 0.64%-24.2 ± 1.31% in hydrogen peroxide, 90.6 ± 1.11%-60.7 ± 2.13%, 56.7 ± 1.33%-28.5 ± 1.65% in superoxide, and 85.2 ± 1.21%-53.4 ± 2.69%, 53.5 ± 0.86%-24.9 ± 1.63% in nitrite radical scavenging percentage. The results show that the antioxidant and antiradical activities of the almond hull are higher than those of its shell phenolic extract among different species of almond. In addition, the reducing power of almond hull and shell phenolic extract was positively correlated with the phenolic content and radical scavenging capacities of wild almond hull and shell extracts in different species were positively correlated with phenolic content and reducing power.

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