Antioxidant and antiplatelet activities of flavonoid-rich fractions of three citrus fruits from Korea
Biotech
Antioxidant and antiplatelet activities of flavonoid-rich fractions of three citrus fruits from Korea
Awraris Derbie Assefa 0 1
Eun Young Ko 0 1
So Hyun Moon 0 1
Young-Soo Keum 0 1
0 Department of Bioresources and Food Science, Konkuk University , Seoul 143-701 , South Korea
1 Awraris Derbie Assefa
Three different fractional (methanol, ethyl acetate and hexane) extracts from yuzu (Citrus junos Sieb ex Tanaka), hallabong [(C. unshiu Marcov 9 C. sinensis Osbeck) 9 C. reticulata Blanco] and orange (C. sinensis) were evaluated for their antioxidant activity and antiplatelet effects. 2,2-Diphenyl-1-Picrylhydrazyl (DPPH), cupric reducing antioxidant capacity (CUPRAC) and ferric-reducing antioxidant power (FRAP) methods were used for the antioxidant activity tests. Total flavonoids and total phenolics were also evaluated spectrophotometrically. The ethyl acetate fraction contained the highest total flavonoid and total phenolic content and exhibited the highest antioxidant activities (185.2 ± 14.5 and 208.7 ± 17.5 mg/ g dry extract for FRAP and CUPRAC values, respectively). The total phenolic and total flavonoid content ranged from 58.2 ± 1.4 to 102.4 ± 8.6 and 19.6 ± 0.5 to 64.3 ± 0.8 mg/g dry extract, respectively. The results of DPPH assay showed that ethyl acetate fractions had the least IC50 values (0.12 ± 0.002, 0.04 ± 0.0006, in mg/mL for orange and hallabong samples, respectively) followed by the hexane fraction (0.19 ± 0.007 mg/mL) of the orange sample. For all fractions, the antioxidant activity and contents of total phenolics and total flavonoids correlated well with each other. In vitro investigation of the antiplatelet effect showed that ethyl acetate fraction has the highest inhibition (84.3 ± 5.8 to 96.1 ± 1.8 %). Hexane and MeOH fractions of hallabong and orange samples
FRAP; DPPH phenolics; Citrus fruits
-
inhibited platelet aggregations by less than or equal to
41 %.
Introduction
Platelet aggregation
Total
Because of the unhealthy lifestyle and aged population,
mortality associated with cancer and cardiovascular
diseases has increased
(Fuentes et al. 2013a)
. Reactive oxygen
species (ROS) are known to play a dual role, being either
harmful or beneficial to living systems. ROS have
beneficial effect in defense against infectious agents, in the
function of a number of cellular signaling systems and in
the induction of a mitogenic response at low
concentrations. At high concentrations, ROS can be important
mediators of damage to cell structures, including lipids and
membranes, proteins and nucleic acids
(Valko et al. 2006)
.
ROS play an important role in degenerative or pathological
processes such as cancer
(Valko et al. 2006)
, coronary
heart disease
(Watt et al. 2012)
, neurodegenerative
disorders
(Roy et al. 2008)
, atherosclerosis
(Patel et al. 2000)
and inflammation
(Kielland et al. 2009)
. The development
of cardiovascular diseases such as acute myocardial
infarction, cerebrovascular disease and peripheral arterial
thrombosis is related to the interaction process of
atherosclerotic lesions and thrombus formation. This
interaction is basically established with the participation of
platelets
(Fuentes et al. 2013b)
. Platelets adhere to
endothelial cells and contribute to the recruitment of
leukocytes involved in the local vascular inflammation and
thrombosis formation (Jackson et al. 2009). Several
synthetic drugs such as aspirin and triflusal are used to inhibit
the aggregation of platelets
(Cruz et al. 1998; Yu et al.
2011)
. However, it has been reported that synthetic drugs
are accompanied by several adverse side effects. Low-dose
aspirin increases the risk of major bleeding and intestinal
ulceration (Schror 1997). The term ‘aspirin resistance’ has
been used to describe the failure of aspirin to inhibit
platelet activity. Between 8 and 45 % of patients who suffered
an ischemic stroke or cardiovascular disease are aspirin
resistant
(Ohmori et al. 2006)
. Therefore, the development
of safe, alternative therapeutic agents with antiplatelet
activity is crucial. Reports show that plant-derived foods
like spinach, which is rich in nitrates, apple rich in
flavonoids and tomato in lycopene exhibit antiplatelet activity
(Bondonno et al. 2012; Fuentes et al. 2013a)
. Plants are
believed to be valuable sources of antioxidants.
Epidemiological studies suggest that consumption of fruits and
vegetables is associated with significantly lower risk of
coronary artery disease and stroke (Hu 2003).
The health benefits of citrus fruits are largely attributed
to the presence of the relatively high concentrations of
antioxidant compounds, such as ascorbic acid and phenolic
compounds, mainly flavonoids
(Gonza´lez-Molina et al.
2010; Kawaii et al. 1999)
. Various studies showed that
extracts from citrus peels exhibited antiplatelet activities
besides their antioxidant activity
(Sagdic et al. 2011; Yu
et al. 2005)
. Although it is believed that citrus fruits have
several be (...truncated)