3.2. Total phenolic and flavonoid content of extracts
The active compounds of natural sources such as phenolic and flavonoids
compounds have shown to have antioxidant activities due to their ability
to donate the electrons and scavenge the free radicals. Many factors
such as climate, soil and ecological conditions are involved in the
amount of these plants secondary metabolites (Saboonchian et al., 2014).
Average TPC of aqueous extracts of the exocarp (peel) of Senjed fruit
were measured as 573.31 ± 3.57 mg GAE/100 g FW. Hassanzadeh &
Hassanpour (2018) reported that TPC of peel and pulp methanolic extractof Elaeagnus angustifolia L. fruits from different locations of
East and West Azerbaijan provinces of Iran was in the range of 444.74 –
669.86 and 423.91 – 561.00 (mg GAE/100 g FW), respectively. Cansev et
al. (2011) reported that average TPC of aqueous, acetone and methanolic
extracts of the mesocarp and exocarp in oleaster fruit was 778.11,
558.52, 390.44; and 361.24, 413.95, 524.40 (mg GAE/100 g FW),
respectively. They concluded that extraction procedures using water
showed much more antioxidant capacity and total phenolic content
compared to methanol and acetone extraction procedures for tested
samples (p<0.05 ).
TPC of oleaster fruits crust and crumb methanolic extracts grown in
different locations of Turkey reported as in the range of 13.43-22.30
and 10.58-16.44 (mg GAE/g DM), respectively (Simsek & Sufer, 2021). TPC
in seed, flesh and peel of different genotype of oleaster methanolic
extracts ranged from 2.14 to 6.26 ± 0.04, 0.14 to 1.54, and 0.12 to 2.59
(mM QE/mg extract), respectively (Faramarz et al., 2015). A review of
literature shows that the content of phenolic compounds in the exocarp
(peel or crust) of Elaeagnus angustifolia L. fruit is higher than
its mesocarp (flesh, pulp or crumb). The nature and polarity of solvent
systems markedly influenced the phenolic contents of extracts. The
results imply that the aqueous extract of Senjed peel could be effective
in the antioxidant and free radical scavenging activity. The amount of
the total phenolics of the aqueous extract of Phellodendron
amurense was 70 μg mg-1 (Velmurugan et al., 2018).
TFC of the extracts obtained from the peel of Senjed fruit was 151.33 ±
2.67 mg CAE /100 g FW. Hassanzadeh & Hassanpour (2018) reported that
TFC of Elaeagnus angustifolia L. fruits peel and pulp methanolic
extract in five different locations of East and West Azerbaijan
provinces of Iran was in the range of 73.69 – 226.5 and 94.27 – 209.42
mg CAE/100 g FW, respectively. TFC of the methanolic extracts obtained
from the crust and crumb of oleaster fruit varied between 5.99 ± 0.45
and 16.24 ± 1.49 mg CE/g DM, and 3.10 ± 0.01 and 6.54 ± 2.68 mg CE/g DM,
respectively (Simsek & Sufer, 2021). The TFC in methanolic extracts of
seed, flesh and peel of different genotype of oleaster fruit ranged from
4.7 to 17.6, 0.62 to 1.90, 0.64 to 1.13 (mM QE/mg extract), respectively
(Faramarz et al., 2015). TFC of the extracts obtained from the crust and
crumb of oleaster fruit varied between 5.99 to 16.24, and 3.10 and 6.54
(mg CE/g DM), respectively (Simsek & Sufer, 2021).
After 24 days of storage, the trolox equivalent (TE) of soybean and
cottonseed oils fortified with 400 mg/kg rosemary extract was
significantly higher than the TE of oils fortified with 200 mg/kg of the
synthetic antioxidants BHA and BHT (Yang et al., 2016).