Effects of dried Rose Petals (Rosa damascena) on the antioxidant capacity of Green and Black Tea

Abstract

The health benefits of green and black tea are mainly associated with their antioxidant potential and
phenolic compounds. The present study aimed to evaluate the effects of dried rose petals (Rosa
damascena) on the antioxidant capacity of green and black tea. Antioxidant capacities of tea and rose
infusions were assessed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2-azinobis-3-
ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging. In the DPPH method, various
concentrations of rose increased the radical scavenging activity of green tea, while the higher
concentrations (2 g) negatively influenced the radical scavenging activity of black tea. In the ABTS
assay, lower concentrations of rose (0.5 and 1 g) significantly increased the antioxidant activity of
green tea. Moreover, various concentrations of rose enhanced the ABTS radical scavenging activity
of black tea. According to the results, higher concentrations of rose decreased the DPPH radical
scavenging activity of black tea, while the lower concentrations exerted synergistic antioxidant effects
on the ABTS radical scavenging activity of green tea.

Full text

J Adv. Environ Health Res (2018) 6: 240-245 DOI: 10.22102/JAEHR.2018.135422.1085
ORIGINAL PAPER
MUK-JAEHR
Effects of dried Rose Petals (Rosa damascena) on the antioxidant
capacity of Green and Black Tea
Javad Aliakbarlu1, Shadieh Mohammadi2,3,, Saeed Dehestaniathar2,3, Surur Khalili Sadaghiani1
1. Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University,
Urmia, Iran
2. Environmental Health Research Center, Research Institute for Health Development, Kurdistan University
of Medical Sciences, Sanandaj, Iran
3. Department of Environmental Health Engineering, Faculty of Health, Kurdistan University of Medical
Sciences, Sanandaj, Iran
Date of submission: 10 Jun 2018, Date of acceptance: 06 Oct 2018
ABSTRACT
The health benefits of green and black tea are mainly associated with their antioxidant potential and
phenolic compounds. The present study aimed to evaluate the effects of dried rose petals (Rosa
damascena) on the antioxidant capacity of green and black tea. Antioxidant capacities of tea and rose
infusions were assessed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2-azinobis-3-
ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging. In the DPPH method, various
concentrations of rose increased the radical scavenging activity of green tea, while the higher
concentrations (2 g) negatively influenced the radical scavenging activity of black tea. In the ABTS
assay, lower concentrations of rose (0.5 and 1 g) significantly increased the antioxidant activity of
green tea. Moreover, various concentrations of rose enhanced the ABTS radical scavenging activity
of black tea. According to the results, higher concentrations of rose decreased the DPPH radical
scavenging activity of black tea, while the lower concentrations exerted synergistic antioxidant effects
on the ABTS radical scavenging activity of green tea.
Keywords: Rose, Antioxidant Activity, Tea
Introduction
Tea (Camellia sinensis L.) is the most
widely consumed beverage in the world next to
water. Depending on the manufacturing process,
several varieties of tea could be produced,
including white, yellow, green, red, and black
tea.1-4
Today, green tea has gained popularity
across the world owing to its numerous health
benefits, including antioxidant, antimicrobial,
anti-carcinogenic, and anti-inflammatory
properties.5, 6 Green tea is obtained from fresh
tea leaves and is often the preferred beverage in
Japan, China, and Western countries. Green tea
reduces the risk of free radicals and oxidative
stress,7, 8 which in turn decreases the potential
risk of life-threatening diseases such as cancer,
Shadieh Mohammadi
Shadiehmohammadi@yahoo.com
Citation: Aliakbarlu J, Mohammadi Sh, Dehestaniathar S,
Khalili Sadaghiani S. Effects of dried Rose Petals (Rosa
damascena) on the antioxidant capacity of Green and Black Tea.
J Adv Environ Health Res 2018; 6(4): 240-245
coronary heart disease, stroke, and obesity.9-11
Furthermore, green tea is an abundant source of
chemical components, such as polyphenols,
which are known to have potent antioxidant
properties.12, 13 The beneficial effects of black
and green tea are associated with the antioxidant
activities of their phenolic compounds.14
Black tea consumption constitutes
approximately 80% of the total tea beverage
industry.15 Among various types of tea, black
tea has a higher consumption rate compared to
green tea in different regions across the world.
Black tea is an abundant source of polyphenolic
compounds, which have numerous health
benefits considering their antioxidant, anti-
inflammatory, and antitumor properties.16 Tea
leaves contain various polyphenols and
flavonoids. Catechins are the main polyphenols
found in tea.13 Non-toxicity is another major
benefit of tea.17 Antioxidants play a key role in
regulating defense against oxidative stress.18
Rose (Rosa damascena) belongs to the
Rosaceae family and is an important ornamental

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Aliakbarlu et al.
plant used in foods and traditional medicines.19
Rose contains large amounts of phenolic
compounds, which are associated with
remarkable antioxidant capacity.9, 20 Addition of
dried rose petals to tea is a routine practice in
many regions in Iran, which provides a plausible
taste and a pleasant aroma. In other parts of the
world, it is common to drink tea with milk or
lemon. Reports are indicative of the effects of
whole and skimmed milk,21 milk and sugar,22
soy milk,23 and ascorbic acid 14 on the
antioxidant potential of tea.
The present study aimed to investigate the
effects of dried R. damascena petals on the
antioxidant activity of green and black tea.
Materials and Methods
Preparation of Plants
In this study, green tea, black tea, and dried
R. damascena petals were purchased from a
local market in Urmia, Iran (The origin of that is
unknown).
Experimental Chemicals
Potassium per sulfate, 2,2-azinobis-3-
ethylbenzothiazoline-6-sulphonic acid (ABTS),
2,2-diphenyl-1-picrylhydrazyl (DPPH), and
butylated hydroxytoluene (BHT) were
purchased from Sigma-Aldrich Chemie
(Steinheim, Germany). In addition, the
analytical grades of ethanol and methanol were
obtained from Merck (Germany).
Preparation of Tea and Rose Infusions
Rose infusions were prepared using various
concentrations of tea and dried rose petals,
which were similar to those commonly
consumed with tea. Green and black teas (2 g)
and dried rose petals (0.5-2 g) were added to hot
distilled water (500 ml) and brewed in an
Erlenmeyer flask at the temperature of 80 ºC for
10 minutes. Seven groups of samples were
prepared; one group had only two grams of tea,
three groups contained 0.5, one, and two grams
of dried rose petals, and three groups were
infusions of tea and dried rose petals (two grams
of tea, 0.5 gram of rose petals, two grams of tea
with one gram of rose petals, and two grams of
tea with two grams of rose petals). The infusions
were cooled at room temperature and were
filtered with Whatman grade 42 filter paper. The
filtrates were immediately used for the
antioxidant assays.
DPPH Radical Scavenging Assay
Scavenging activity of the samples was
determined using DPPH radical scavenging
assay.24 To do so, 50 microliters of each infusion
(dilution: 1:5) were added to two milliliters of
DPPH methanol solution (24 µg/ml). After
shaking, the samples were preserved at room
temperature in the dark for one hour.
Afterwards, the absorbance of the samples was
recorded against a blank at 517 nm using a
spectrophotometer (LKB Novaspec II;
Pharmacia, Sweden). Radical scavenging
activity of the samples was calculated based on
the following formula:
Radical Scavenging Activity (%)= (Ablank −
Asample)/(Ablank)×100
where Ablank is the absorbance of the blank
(DPPH solution), and Asample represents the
absorbance of the samples. In this process, BHT
(2 mg/ml) was used as the positive control.
ABTS Radical Scavenging Assay
The ABTS radical stock solution was
prepared by blending the aqueous solutions of
ABTS (7 mM) and potassium persulfate (2.45
mM), and the combination was preserved in the
dark for 16 hours.25 Following that, the green-
blue solution was diluted with ethanol in order
to obtain the absorbance of 0.7±0.02 at 734 nm
using a spectrophotometer (LKB Novaspec II;
Pharmacia, Sweden). In addition, 200
microliters of each sample (diluted with distilled
water 1:20) was mixed with two milliliters of
ABTS solution. After incubation at room
temperature for six minutes, the absorbance was
measured at 734 nm. ABTS radical scavenging
activity was calculated using the following
equation:
ABTS Radical Scavenging Activity (%)=
(Ablank− Asample)/(Ablank)×100
In this process, BHT (2 mg/ml) was used as
the reference compound.

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Statistical Analysis
In this study, all the measurements were
performed in triplicate. Data analysis was
performed in SPSS version 9.1 (SAS Institute,
Cary, NC) using Tukey’s multiple range test to
determine the significant differences between
the treatments at the significance level of
P≤0.05.
Results and Discussion
DPPH assay has been widely used to
examine the antioxidant activity of various
herbal extracts. This assay is a simple and quick
method for the assessment of radical scavenging
activity. In DPPH assay, the purple color of the
DPPH solution becomes yellowish due to
receiving hydrogen atoms or electrons from an
antioxidant.
The DPPH radical scavenging activity of
green tea, rose, and their infusions are depicted
in Figure 1. As can be seen, various
concentrations of rose (0.5, 1, and 2 g) increased
the radical scavenging activity of green tea. The
infusion of green tea with two grams of rose
(GT2R2) showed the strongest radical
scavenging effect (50.18%), while this rate was
estimated at 19.38% in green tea alone (GT2),
and the combination containing two grams of
rose (R2) had 28.07% radical scavenging
activity. In addition, the rate of radical
scavenging activity was estimated at 8.30% and
16.35% in the infusions with one and 0.5 gram
of rose (R0.5 and R1), respectively.
Fig. 1. DPPH Radical Scavenging Activity of Green Tea,
Rosa damascena, and their infusions (Small letters show
significant differences [P<0.05] among the DPPH
scavenging activity of the samples; BHT (2 mg/ml) as the
positive control)
The DPPH radical scavenging activity of
black tea, rose, and their infusions are illustrated
in Figure 2. According to the findings, lower
concentrations of R. damascena (0.5 and 1 g)
enhanced the radical scavenging activity of
black tea. On the other hand, the infusion of
black tea with two grams of rose (BT2R2)
showed the strongest radical scavenging effect
(51.20%), while two grams of black tea alone
(BT2) had a radical scavenging activity of
29.35%, and two grams of rose (R2) had a
radical scavenging activity of 28.07%.
Therefore, it could be inferred that the higher
concentrations of R. damascena negatively
influenced the radical scavenging activity of
black tea.
Fig. 2. DPPH Radical Scavenging Activity of Black Tea,
Rosa damascena, and their infusions (Small letters show
significant differences [P<0.05] among the DPPH
scavenging activity of the samples; BHT (2 mg/ml) as the
positive control)
In the ABTS assay, the green-blue color of
the ABTS solution became yellowish or
colorless due to receiving hydrogen atoms or
electrons from an antioxidant. The antioxidant
activity of lipid- and water-soluble compounds
could be measured using the ABTS assay.26
Figure 3 shows the ABTS radical scavenging
activity of green tea, R. damascena, and their
infusions. Various concentrations of rose (0.5, 1,
and 2 g) increased the radical scavenging
activity of green tea.
According to the results, GT2R2 had the
most significant radical scavenging effect
(98.63%), while this rate was 60.47% in GT2
and 69.77% in R2. Moreover, lower
concentrations of R. damascena (R0.5 and R1)
had the radical scavenging activity of 7.16% and

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Aliakbarlu et al.
24.75%, while GT2R0.5 and GT2R1 exhibited
78.77% and 91.77% of radical scavenging
activity, respectively. These values were higher
compared to the antioxidant activities of the
combination of green tea and R. damascena
(R0.5 and R1). Therefore, it could be concluded
that the lower concentrations of R. damascena
(0.5 and 1 g) exerted synergistic antioxidant
effects on the radical scavenging activity of
green tea.
Fig. 3. ABTS Radical Scavenging Activity of Green Tea,
R. damascena, and their infusions (Small letters show
significant differences [P<0.05] among the ABTS
scavenging activity of the samples; BHT (2 mg/ml) as the
positive control)
The ABTS radical scavenging activity of
black tea, R. damascena, and their infusions are
illustrated in Figure 4. In general, various
concentrations of R. damascena (0.5, 1, and 2 g)
enhanced the radical scavenging activity of
black tea. In addition, BT2R2 showed the
highest radical scavenging effect (97.38%),
while this rate was estimated at 56.71% in BT2
and 69.77% in R2.
Fig. 4. ABTS Radical Scavenging Activity of Black Tea,
R. damascena, and their infusions (Small letters show
significant differences [P<0.05] among the ABTS
scavenging activity of the samples; BHT (2 mg/ml) as the
positive control)
The present study aimed to assess the
effects of dried rose petals on the antioxidant
activities of green and black tea infusions.
According to the findings, R. damascena
increased the DPPH radical scavenging activity
of green tea, while the higher concentrations
decreased the radical scavenging activity of
black tea. Moreover, R. damascena improved
the ABTS radical scavenging activity of green
and black tea.
Several studies have investigated the
effects of various additives (e.g., ascorbic acid,
bovine milk, soy milk, and sugar) on the
antioxidant potential of tea. The findings have
demonstrated that the addition of ascorbic acid
could increase the total antioxidant activity of
black and green tea.14 In a study, Ryan and Petit
stated that the addition of various volumes of
whole milk and semi-skimmed or skimmed
bovine milk to tea infusions could reduce the
antioxidant capacity of black tea.21
Another research in this regard confirmed
that the addition of various volumes of soy milk
could decrease the total antioxidant capacity of
a black tea infusion.23 In the mentioned study,
the addition of milk and sugar was observed to
reduce the DPPH radical scavenging activity of
black tea.22 It has been argued that the addition
of whey proteins could decrease the antioxidant
activity of green tea.27 Previous studies have
also investigated the effects of various brewing
methods on the antioxidant properties of green
tea. According to the obtained results, water
temperature has a significant effect on the
extraction of antioxidant compounds, so that the
efficiency was higher with the use of hot water
extraction.28
Although the antioxidant activity of rose
flowers has been previously reported, there are
no data on the effects of rose infusions on the
antioxidant activity of tea. In a study in this
regard, Sagdic et al. claimed that the fresh
flower extract of R. damascena caused the
antiradical activity of 75.51% at 100 ppm.29 In
another research,30 the methanolic extract of
fresh R. damascena flowers was associated with
the antiradical activity of 89.44%.
In another study in this regard, the
antioxidant capacity of the methanolic extracts

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of three rose species (R. damascena, R.
bourboniana, and R. brunonii) was compared
using the DPPH assay. According to the
findings, the extract of R. brunonii exhibited the
maximum radical scavenging activity
(64.5±0.38%), followed by R. bourboniana
(51.8±0.46%) and R. damascena
(43.6±0.25%).19
Conclusion
The present study aimed to investigate the
effects of dried rose petals (R. damascena) on
the antioxidant capacity of green and black tea.
According to the results, higher concentrations
of R. damascena decreased the DPPH radical
scavenging activity of black tea, while the lower
concentrations exerted synergistic antioxidant
effects on the ABTS radical scavenging activity
of green tea.
Acknowledgements
Hereby, we extend our gratitude to Urmia
University in Urmia, Iran for the financial
support of this research project.
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