3.3. Antioxidant activity of Senjed peel aqueous extracts
The free radical (DPPH) scavenging activity (%) of aqueous extracts
obtained from exocarp (peel) of Senjed (Elaeagnus angustifoliaL.) fruits was 58.17%. The free radical (DPPH) scavenging activity DPPH
of aqueous, acetone and methanolic extracts of the mesocarp and exocarp
in oleaster fruit are measured as 28.03, 27.16, 27.82; and 27.62, 27.95,
27.84 (μmol Trolox/g FW), respectively ((Cansev et al., 2011). In the
study of Hassanzadeh & Hassanpour (2018), the mean antioxidant capacity
of peel and pulp extracts obtained by 85% methanol based on the DPPH
assay was 74.71 and 53.76%, respectively. According to Faramarz et al.
(2015), the mean antioxidant capacity of peel, pulp and seed based on
the DPPH assay in different genotype of E. angustifolia L. was
86.95, 91.78 and 35.83%, respectively. Also, according to Incilay
(2014), the antioxidant capacity for leaf, flower, peel and fruit ofE. angustifolia L. fruit was 1.036, 1.65, 1.28 and 2.51 μg
trolox/g, respectively.
Velmurugan et al. (2018) reported that the aqueous extract of P.
amurense possesses good DPPH scavenging activity. When compared to the
positive control of L-ascorbic acid it has less activity but there is
little difference at a concentration of 500 μg. DPPH activity results
reveal that the Senjed peel aqueous extract possesses hydrogen donating
ability and, may act as primary antioxidants. The effectiveness of
antioxidant activity depends on the inhibition reaction between a
peroxyl radical and the antioxidant. The electron-attractive inductive
effect of the alpha carbonyl group in the para position should in fact
destabilize the phenoxyl radical and reduce the radical scavenging
ability of compounds (Kajiyama & Ohkatsu, 2001). The following possible
mechanism can be applied for DPPH radical scavenging activity. The dimer
formation during the reaction between two phenoxyl radicals can
influence the antioxidant property of the extract. These dimers may
initially reduce DPPH radical scavenging (Bortolomeazzi et al., 2007).