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Studies on the therapeutic properties of Roselle (Hibiscus sabdariffa) calyx: A popular ingredient in the cuisine of North East India

Authors:
  • ICAR-RC for NEHR, umiam
  • ICAR Research Complex - NEH Region, Umiam
  • Indian Council of Agricultural Research- Research Complex for North Eastern Hill Region

Abstract and Figures

Roselle plant (Hibiscus sabdariffa) of Malvaceae family finds its mention in folk medicine of North East India for its use in various ailments. In the present study, the proximate value and nutritional quality, antioxidant activity, antimicrobial properties, anti-proliferative activity and apoptosis-inducing capacity of roselle found in North East India was evaluated. Nutritional evaluation of the calyx establishes it as a good source of dietary antioxidants and ascorbic acid. Antimicrobial activity of the aqueous extract upto 25mg/ml concentration showed complete growth inhibition of both gram positive (Staph. aureus) and gram negative (E. coli, K. pneumoniae) bacteria while antioxidant activity with 100 mg/ml concentration was high (90% scavenging activity) that gradually decreases with dilution in concentration. The antiproliferative and apoptotic activities were evaluated in cervical (HeLa) cancer cell lines. It exhibited anti-proliferative activity in a concentration-dependent manner; the concentration @100mg/ml can induce upto 51.8% apoptosis. The studies indicated its potential benefits for health which can further be tested and validated for use as supplement in the food.
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International Journal of Food Science and Nutrition
ISSN: 2455-4898
Impact Factor: RJIF 5.14
www.foodsciencejournal.com
Volume 2; Issue 5; September 2017; Page No. 01-06
Studies on the therapeutic properties of Roselle (Hibiscus sabdariffa) calyx: A popular ingredient in
the cuisine of North East India
*1 Kekungu-u Puro, 2 Chubasenla Aochen, 3 Sandeep Ghatak, 4 Samir Das, 5 Rajkumari Sanjukta, 6 Kamal Prasad
Mahapatra, 7 Anjani Kumar Jha, 8 Ingudam Shakuntala, 9 Arnab Sen
1, 3, 4, 5, 8, 9 Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India
2 Biotechnology Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India
6 Agroforestry Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India
7 Horticulture Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India
Abstract
Roselle plant (Hibiscus sabdariffa) of Malvaceae family finds its mention in folk medicine of North East India for its use in
various ailments. In the present study, the proximate value and nutritional quality, antioxidant activity, antimicrobial properties,
anti-proliferative activity and apoptosis-inducing capacity of roselle found in North East India was evaluated. Nutritional
evaluation of the calyx establishes it as a good source of dietary antioxidants and ascorbic acid. Antimicrobial activity of the
aqueous extract upto 25mg/ml concentration showed complete growth inhibition of both gram positive (Staph. aureus) and gram
negative (E. coli, K. pneumoniae) bacteria while antioxidant activity with 100 mg/ml concentration was high (90% scavenging
activity) that gradually decreases with dilution in concentration. The antiproliferative and apoptotic activities were evaluated in
cervical (HeLa) cancer cell lines. It exhibited anti-proliferative activity in a concentration-dependent manner; the concentration
@100mg/ml can induce upto 51.8% apoptosis. The studies indicated its potential benefits for health which can further be tested
and validated for use as supplement in the food.
Keywords: Hibiscus sabdariffa, cancer cells, antioxidant, antimicrobial activity
Introduction
The roselle plant, with an attractive flower believed to be
native to Africa, is cultivated in Sudan, India, Malaysia and
Taiwan. It is also one of the signature food ingredients of
indigenous delicacies such as Jingtah jajewsaw in Meghalaya,
Masor tenga in Assam, Gakro ghapha in Nagaland, Silok
sougri Mapan Metpa in Manipur etc. The flowers are also
used as a dye by virtue of its bright red colour. In addition to
their use in food, various parts of the roselle plant have been
used in traditional medicine for the prevention of diseases. It
has been used in herbal tea to treat hypertension, pyrexia and
liver damage although the pharmaceutical components are
poorly defined [1].Various workers reported the roselle calyx
possesses various beneficial effects in human health as
mediated through its antioxidant property [2, 3].
Supplementation of roselle calyx extract in ex vivo murine
hematopoietic stem cells culture increased the survivability of
cells [4]. It also had an inhibitory effect on biofilm formation
of oral pathogenic bacteria [5].
The calyces are also rich in vitamins, especially ascorbic acid
[6]. Ascorbic acid is an essential dietary component. Various
workers have reported variable content suggesting the type of
soil influences its ash and mineral content causing variations
within the same species [7, 8, 9, 10]. The antimicrobial activity,
antibacterial and cytotoxicity studies in dose-dependent
manner have also been studied [11, 12]. Moreover, the
antimicrobial activity on isolates from food, veterinary, and
clinical samples have indicated that roselle extract contain
potential antimicrobials in foods [13].Antioxidative activity of
the extract was also reported in cancerous cell lines while the
antioxidant potential in the form of scavenging free radical
and inhibitory effect on XO activity has been evaluated [14, 15].
The effects of roselle-anthocyanins (HA) on human cancer
cells (HL-60) showed apoptosis of cells in a dose and time-
dependent manner [16]. It has also been reported to induce
apoptosis in leukemic cells via reduction of retinoblastoma
phosphorylation and Bcl2 expression [17].
In the present study, the nutritional constituents, antioxidant
activity, antimicrobial properties, antiproliferative activity and
apoptotic potential of locally available roselle plant,
commonly used in the indigenous cuisines, is evaluated to
determine its therapeutic benefits.
Materials and Method
Sample collection and preparation
The roselle calyces (Figure 1) were harvested between
November-December from Bhoirymbong village in Ri-Bhoi
district, located between 25°40´ to 25°21´N latitude and
90°55´15´´ to 91°16´E longitude in the state of Meghalaya,
India. The calyces were dried and powdered for proximate
analysis of nutrient contents and others. The extracts @100
mg/ml (w/v) concentration with water was prepared,
homogenized and clarified by centrifugation at 10000 rpm for
30 min at 4°C. The aqueous extract was collected and filtered
International Journal of Food Science and Nutrition
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with 0.45 µm syringe filter for further in vitro studies. One
gram of the powder was extracted overnight in 80% methanol
and filtered. The filtered extract was used for estimation of
Total antioxidant capacity (TAC) and phenols, respectively.
Fig 1: Roselle plant (a) flowering stage and (b) calyces
Tables and Figures
Estimation of Proximate analysis
The proximate analysis of roselle calyces was done as per the
method prescribed by AOAC for estimating moisture content,
dry matter (DM), total ash (TA), crude protein (CP), ether
extract (EE) and crude fibre (CF) [18]. The nitrogenous free
extract (NFE) was calculated from 100 - (% moisture + % CF
+ % CP + % EE + % TA).
Total phenols content
Phenol content was determined with Folin-Ciocalteau reagent
by the method described by Singleton et al. [19]. 0.5 ml of
extract was initially made up to 3 ml with 80% methanol. 1 ml
of DMSO and 1 ml of 10% Folin-Ciocalteau reagent was
added and mixed. 3 ml of 1% Na2CO3 was finally added after
3 minutes, and the tubes were incubated for 2 h at room
temperature. A standard curve was plotted using different
concentrations of gallic acid (50-300 μg/ml). Absorbance was
measured at 760 nm. The phenolic contents were calculated
on the basis of the calibration curve of gallic acid (50-300
ug/ml) and expressed as gallic acid equivalents (GAE), in
milligrams per gram of dry weight.
Ascorbic Acid content
Vitamin C content was determined by the method described
by Sadasivam and Manickam [20]. Two gram of the powder
was extracted with 4% oxalic acid overnight. The extract was
filtered and used for the analysis. To 10 ml of the extract, a
few drops of bromine water was added until the solution
became coloured, confirming the completion of the oxidation
of ascorbic acid to dehydroascorbic acid. The final volume
was then made to 50 ml with 4% oxalic acid. 2 ml of sample
aliquots was made up to 3 ml of distilled water. To this 1 ml
of 2, 4-Dinitrophenylhydrazine reagent was added and 1-2
drops of 10% thiourea was added to remove excess bromine.
The reaction mixture was mixed and incubated at 37oC for 3
h. 5 ml of 80% sulphuric acid was then added to dissolve the
osazone crystals formed. A standard curve was plotted using
different concentrations of Ascorbic acid (20-120 μg/ml).
Absorbance was measured at 540 nm. The total phenolic
content was expressed in milligrams per gram of dry weight.
Total Antioxidant Capacity
Total antioxidant capacity was estimated with
phosphomolybdenum reagent by the method described by
Prieto et al. [21]. To 0.3 ml of sample extract, 3 ml of
phosphomolybdenum reagent solution (0.6 M sulphuric acid,
28 mM potassium phosphate and 4 mM ammonium
molybdate) was added. The tubes were then incubated at 95oC
for 1 h. After cooling at room temperature the absorbance was
measured at 695 nm. A standard curve of ascorbic acid was
plotted (20-100 µg/ml) to calculate the values. Total
antioxidant capacity was expressed as Ascorbic acid
equivalents (AAE), in milligrams per gram of dry weight.
Free radical scavenging activity assay
Antioxidants are compounds with free radical scavenging
activity and its activity in the extract was measured using 2, 2-
Diphenyl-1-picrylhydrazyl (DPPH) assay as per the method
described by Yamasaki et al. [22]. 20 µl of plant extracts (five
serial dilutions RD1-RD5 of 100, 50, 25, 12.5 and 6.25
mg/ml) or standard solution (BHT) is added to 200 µl of
DPPH reagent in 96 well plates in triplicates. Absolute
methanol is used as reagent blank. All reagents is mixed and
incubated for 30 min at room temperature, protected from
light. The absorbance is measured at 490 nm with an ELISA
reader (Lab systems Multiskan Plus, Thermo Fisher Scientific,
USA).The percentage of DPPH free radical scavenging
activity is calculated as % inhibition = 100 - [(As-Ab)/Ac x
100] Where As is the absorption of extract, Ab is the
absorption of the blank sample and Ac is the absorption of the
control.
Antimicrobial assay
The activity of antimicrobial properties was studied using agar
dilution method [23]. One ml of 0.5 McFarland microbial
inoculum preparation by direct colony suspension (CLSI
guidelines) of Escherichia coli (E.coli) -ATCC 25922,
Staphylococcus aureus (Staph. aureus) -ATCC 25923 and
Klebseilla pneumoniae (K. pneumoniae) - ATCC 700603
having approximately 106 bacterial/ml was added to 1 ml of
serial two-fold dilution (100, 50, 25, 12.5, 6.25, 3.125 mg) of
aqueous extract of roselle in tubes and incubated at 37°C for
24 h. The incubated tubes were poured into agar plates in
duplicate and incubated at 37°C for 24-48 h. The minimum
inhibitory concentration (MIC) endpoint is recorded as the
lowest concentration of roselle extract that completely inhibits
growth under suitable incubation conditions using methanol
and non-treated control.
Anti-proliferative assay
Two-fold serial dilution of the aqueous extract was prepared
and upto five dilutions (100, 50, 25, 12.6 and 6.25 mg/ml)
were used for studying the anti-proliferative effects in HeLa
cells by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium
Bromide (MTT) assay as per Mosmann with slight
modification [24]. The cells @1x106/ml in Earle’s Minimum
Essential Medium (EMEM), (Sigma-Aldrich, USA) with 10%
FBS were suspended in a 96 well plate @100 µl/well and 100
µl of each dilution were added in triplicates with mitogen-
Concanavalin A (ConA) and Phytohaemagglutinin A (PHA)
@ 10mg/ml as positive control. The cells were incubated at
International Journal of Food Science and Nutrition
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37°C with 5% CO2 for 72 h. 10 µg MTT dye was then added
to each well and further incubated for 4 h. The supernatants
were removed and dimethyl sulfoxide (DMSO) @150 µl was
added to each well and incubated at room temperature by
gentle shaking for 30 min. The supernatants were collected
and the absorbance was measured at 570 nm with an ELISA
reader (Lab systems Multiskan Plus, Thermo Fisher Scientific,
USA).
Apoptosis assay
The apoptosis assay was done using Annexin V- FITC
apoptosis detection kit (Calbiochem, Germany) in flow
cytometer (BD LSR Fortessa, USA). Two-fold five serial
dilution (100, 50, 25, 12.6 and 6.25 mg/ml) of the aqueous
extract was prepared for studying apoptosis in HeLa cells
along with non-treated control. The cells @1x106/ml in
Earle’s Minimum Essential Medium (EMEM), (Sigma-
Aldrich, USA) with 10% FBS were suspended in a 96 well
plate @100 µl/well and 100 µl of each dilution were added in
triplicates. The control wells were treated with 100 ml PBS
(pH 7.2). The cells were incubated at 37°C with 5% CO2 for
24 h. The cells were then processed using apoptosis detection
kit following manufacturer’s instructions. The percentage of
apoptosis was measured in flow cytometer with setting of
unstained cells and cells stained with isotype control. Samples
were acquired taking 10000 cell counts.
Statistical analysis
The experiment were done in triplicates and the results were
expressed as mean ± SD. Statistical difference compared
between various treated and untreated groups were analyzed
by one way analysis of variance (ANOVA) followed by
Tukey test for significance. Statistical analysis was considered
significant if P< 0.05.
Results and Discussion
Nutritive value
Proximate composition of dried calyces is presented in Table
1. Dry matter, crude fibre, crude protein, ash and moisture
content were 40.45, 20.83, 27.32, 4.67 and 6.79%,
respectively. The NFE was calculated as 64.14% which
represent the soluble carbohydrate and other easily utilizable
non-nitrogenous components. The analyses present a
comparable proximate composition. The nutritional content of
the calyx was in the range as reported in three varieties found
in Sudan with the moisture content range from 6.19 -12.07%,
CP between 5.5 to 9.76%, CF from 10.74 and 12.17% and
carbohydrate between 60.43 and 61.76% [25]. Carbohydrate
content as high as 68.7% followed by crude fibre (14.6%) and
ash content (12.2%) has also been reported [26].
Table 1: Proximate composition of roselle calyces
Content
Values (%)
Moisture
09.53 ± 1.796
Dry matter (DM)
90.47 ± 1.796
Crude protein (CP)
08.31 ± 0.360
Crude fiber (CF)
11.53 ± 0.608
Ether extract (EE)
00.80 ± 0.035
Total ash (TA)
05.69 ± 0.431
Nitrogen free extract (NFE)
64.14 ± 1.294
Values are mean of triplicates + SD
Biochemical properties
Table 2 presents the biochemical properties of the calyx
analyzed. The total phenol content of methanolic extract was
measured at 7.12 mg GAEg-1, and total antioxidant capacity at
3.39 mg AAE g-1. A lower value of 2.91 mg GAE g-1 has also
been reported [27]. The presence of polyphenols in the plants in
itself is indicative of the presence of antioxidative function,
due to their inherent high redox potentials which make them
efficient reducing agents, hydrogen donors and singlet oxygen
quenchers [28]. The total antioxidant capacity measured in the
methanolic extract was 3.39 + 0.25 mg AAE g-1. Clear
correlations have also been established between antioxidant
activity and phenolic content in plant extracts [29]. The results,
therefore, reinforce the potential of Roselle as an important
source of natural dietary antioxidants. Roselle calyces in the
study exhibited an Ascorbic acid content of 0.801 mg g-1; the
dietary conversion is 80 mg/100 g edible portion. Duke and
Atchley had reported an ascorbic acid content of 14 mg/100g
in fresh calyces6. Tee et al. also established that roselle
calyces had higher ascorbic acid content than orange [30]. The
calyces in this study exhibited a dietary ascorbic acid value of
80 mg/100 g; this value is higher than the established average
values of 42.7 and 43 mg/100 g for orange and papaya,
respectively [31]. Roselle calyces are, thereby a nutritionally
viable source of food and condiment because of its high
antioxidant capacity and an appreciable amount of ascorbic
acid content.
Table 2: Biochemical Properties of calyces
Parameter
Value
Total Phenol content (mg GAEg-1)
7.12 + 0.20
Total Antioxidant capacity (mg AAEg-1)
3.39 +0.25
Total Ascorbic Acid content (mg g-1)
0.801 + 0.05
Values are mean of triplicates + SD
Free radical scavenging assay
The scavenging activity ranged from 89.7% in RD1 to 57.02%
in RD5 indicating the concentration-dependent inhibition
(Table 3). The standard BHT showed 99.56% inhibition.
Antioxidant activity of roselle also represents the free radical
scavenging activity which was found to be dose-dependent.
The 100 mg/ml concentration of roselle extract exhibited
89.70% scavenging activity compared to 99% standard BHT,
thereby indicating high antioxidant potentials. The ethanol
crude extract from the dried flowers have capacity of
quenching free radical and inhibiting xanthine oxidase (XO)
International Journal of Food Science and Nutrition
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activity [32]; in animal models, calyces extracts have
demonstrated hypocholesterolemic and antihypertensive
properties [33].
Table 3: Inhibition/scavenging activity of serial dilution RD1-RD5
of roselle extract, C Standard BHT contral (n=3)
Dilution
Conc (mg/ml)
% inhibition/scavenging activity
RD1
100
89.70 ± 0.639
RD2
50
63.56 ± 2.132
RD3
25
60.69 ± 1.350
RD4
12.6
58.38 ± 2.286
RD5
6.25
57.01 ± 4.045
C
Std BHT
99.56 ± 0.638
Values are mean of triplicates + SD
Antimicrobial assay
The MIC of two-fold dilution exhibited a complete growth
inhibition of both gram positive (Staph. aureus) and gram
negative (E. coli, K. pneumonia) bacteria up to 2nd dilution (25
mg/ml). Numerous colonies (> 300 colonies) were observed
from the 3rd dilution onwards indicating non-inhibition of
growth (Table 4). There is no growth in methanol control
plates while non-treated control plates have numerous
colonies present. The antimicrobial effect on both gram
positive and gram negative bacteria was dose-dependent as
observed by Chau et al. against food spoilage bacteria using
ethanolic extract [12]. The antimicrobial activity was reported
by other workers on isolates from food, veterinary, and
clinical samples and suggested that it might be potent agents
as food additives to prevent contamination from these bacteria
[13].
Table 4: Antimicrobial pattern of various concentration of roselle
(n=3)
Concentration (mg/ml)
Staph. aureus
E. coli
K. pneumoniae
100
-
-
-
50
-
-
-
25
-
-
-
12.5
+
+
+
6.25
+
+
+
MC
-
-
-
NTC
+
+
+
+ = growth present, - = no growth. MC = methanol control, NTC =
non-treated control
Anti-proliferative assay
The anti-proliferative effect of the extract on the cells was
visualized by microscope at high power magnification. The
formation of formazan crystal on adding MTT dye was
observed (Figure 2). The stimulation index (SI) of roselle-
treated cells was calculated (Figure 3). A gradual decrease in
SI up to third dilution (@ 25mg/ml) was first observed, which
then increased with dilutions. The initial decrease and
subsequent increase of SI perhaps correspond to the apoptosis
of cells in the different concentration of extract compared to
SI of non-treated control which showed non-inhibition of cell
growth while the standard mitogen ConA show higher
stimulation than PHA. The antiproliferative activities of
roselle extract on cervical (HeLa) cancer cell lines showed
dose dependent inhibitory effects. Similar observations was
reported on its activities on different cell lines like ovarian
(Caov-3), breast (MCF-7, MDA-MB-231) and cervical
(HeLa) cancer cell lines found that it exhibit the strongest
anti-proliferative potency towards the MCF-7 cancer cells [14].
Fig 2: Photograph showing (a) inhibition of HeLa cell growth and (b)
formazan crystal formation (20 X)
Fig 3: Stimulation index of antiproliferative assay with serial dilution
(RD1-RD5) of roselle extract in HeLa cells. C - Non-treated control,
Mitogen-Con A and PHA @10mg/ml. (n=3)
Apoptosis in HeLa cells
The fractions of the cells as early apoptosis, late apoptosis,
necrotic and healthy cells were calculated in percentage from
the total population of cells counted. The result showed the
induction of apoptosis is concentration dependent (Table 5)
ranges from 51.8% to 9.4 % in decreasing order of
concentration in roselle-treated HeLa cells. The apoptotic
activity of roselle was found to be concentration dependent in
cervical (HeLa) cancer cell lines. Similar report on effects in
human cancer cells (HL-60) using roselle-anthocyanins (HA)
show apoptosis of cells in a dose- and time-dependent manner
[16]. The 6.3% apoptosis in non-treated control cells probably
represent the percentage of necrotic cell death. Therefore, the
use of roselle calyces in the dietary habits definitely offers
benefits in terms of its antioxidant properties, antimicrobial
effects, antiproliferative and apoptotic activities against
cancerous cells. The other parts of the plant, viz. leaves and
seeds needs further investigation in this regard.
Table 5: Apoptosis of HeLa cells treated with various concentration
of rosells extract (n=3)
Concentration (mg/ml)
Apoptosis (%)
100
51.8 ± 0.6364
50
25.8 ± 0.3536
25
20.5 ± 0.2121
12.5
10.6 ± 0.5657
6.25
9.4 ± 0.1414
Non-treated control
6.3 ± 0.0707
International Journal of Food Science and Nutrition
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Conclusions
The oral indigenous traditional knowledge on therapeutic uses
of traditional foods ingredient have been supported by
research studies and documentation. Besides the regular
dietary use of roselle in popular delicacies in North east region
of India, the current study also reiterates roselle as a source of
natural antioxidants and a good and cheaper source of
Ascorbic acid, more than most fruits and vegetables. The
promising preliminary results with its extracts on cancerous
cells studies also provide new avenues for natural therapeutic
research on cancer. Therefore, with many enriching chemical-
biological knowledge from animal and human models using
plant extracts, future focused studies with greater scientific
robustness in terms of standardization of dose for its
effectiveness, safety and tolerability will permit the
formulation of safe, effective therapeutic herbal formulations
which can be used as an acceptable source for curing many
health issues and restoring general health.
Acknowledgement
The research work is done under the project “Investigation
and evaluation of ethno-veterinary medicines through
biological activity screening of medicinal plants” Code no.
IXX08847 of the institute. The authors thank the Director,
ICAR-RC for NEH Region and Umiam for providing
necessary facilities to carry out the work.
References
1. Hou D, Tong X, Terahara N, Luo D, Fujii M. Dephinidin
3-sambubioside, a Hibiscus anthocyanin, induces
apoptosis in human leukemia cells through reactive
oxygen species-mediated mitochondrial pathway. Arch.
Biochem. Biophy. 2005, 440:101-109.
2. Lin TL, Lin HH, Chen CC, Lin MC, Chou MC, Wang C.
et al. J. Hibiscus sabdariffa extract reduces serum
cholesterol in men and women. Nut. Res. 2007, 27(3):140
145.
3. Kuriyan R, Kumar DR, Kurpad AV. An evaluation of the
hypolipidemic effect of an extract of Hibiscus Sabdariffa
leaves in hyperlipidemic Indians: a double blind, placebo
controlled trial. BMC Complementary and Alternative
Medicine. 2010; 10:27.
4. Hamid ZA, Lin HL, Abdalla BJ, Yuen OB, Latif ES,
Mohamed J, et al. Rajab NF, Wah CP, WakHarto MKA,
Budin SB. The role of Hibiscus sabdariffa L. Roselle in
maintenance of ex vivo murine bone marrow-derived
hematopoietic stem cells. The Scientific World Journal
2014, http://dx.doi.org/10.1155/2014/258192.
5. Sulistyani H, Fujita M, Miyakawa H, Nakazawa F. Effect
of roselle calyx extract on in vitro viability and biofilm
formation ability of oral pathogenic bacteria. Asian Pacific
J. Tropical Med. 2016, 9(2):119-124.
6. Duke JA, Atchley AA. Proximate analysis. In: Christie,
B.R., Ed.; The handbook of plant science in agriculture.
CRC Press, Inc., Boca Raton, FL, 1984.
7. Nnam NM, Onyeke NG. Chemical compositions of two
varieties of sorrel Hibiscus sabdariffa L., calyces and the
drinks made from them. Plant Foods Hum. Nutr. 2003,
58:1-7.
8. Ojokoh AO. Roselle Hibiscus sabdariffa calyx diet and
histopathological changes in liver of albino rats. Pak J
Nutr. 2006, 5:110-113.
9. Adanlawo IG, Ajibade VA. Nutritive value of the two
varieties of roselle Hibiscus sabdariffa calyces soaked
with wood ash. Pak. J. Nutr. 2006, 5:555-557.
10. Carvajal O, Maria D, Dremitriz B, Flores ZO, Margaret P,
Jones H. Hibiscus sabdariffa L., roselle calyx, from
ethnobotany to pharmacology. J. Expt. Pharmacol. 2012,
4, 25-39.
11. Olaleye MT. Cytotoxicity and antibacterial activity of
methanolic extract of Hibiscus sabdariffa. J. Med. Plant.
Res. 2007, 1:9-13.
12. Chao C, Yin M. Antibacterial effects of roselle calyx
extracts and protocatechuic acid in ground beef and apple
juice. Foodborne pathogen and disease 2008, 6(2):201-
206.
13. Fullerton M, Khatiwada J, Johnson US, David S, William
LL. Determination of antimicrobial activity of sorrel
Hibiscus sabdariffa on E.coli O157:H7 isolated from food,
veterinary and clinical samples. J. Med. Food. 2011,
14(9):950-956.
14. Akim A, Lim CH, Asmah R, Zanainaul AZ. Antioxidant
and anti-proliferative activities of Roselle juice on Caov-3,
MCF-7, MDA-MB-231 and HeLa cancer cell lines. Afri. J.
Pharma. Pharmacol. 2011, 5(7):957-965.
15. Tseng TH, Kao ES, Chu CY, Chou FP, Lin WHW, Wang
CJ. et al. Protective effects of dried flower extracts of
Hibiscus sabdariffa L. against oxidative stress in rat
primary hepatocytes. Food Chem. Toxic. 1997, 35:1159-
1164.
16. Chang YC, Huang HP, Hsu JD, Wang CJ. Hibiscus
anthocyanins rich extract-induced apoptotic cell death in
human promyelocytic leukemia cells. Texaco Appl Pharm.
2005, 205, 201-212.
17. Tseng TH, Kao TW, Chu CY, Chou FP, Lin WL, Wang
CJ. et al. Induction of apoptosis by Hibiscus
protocatechuic acid in human leukemia cells via reduction
of retinoblastoma RB phosphorylation and Bcl-2
expression. Biocheml. Pharmaco. 2000, 60(3):307-315.
18. Association of Official Analytical Chemist AOAC.
Official methods of analysis of the association of official
analytical chemist. Washington DC, 1980.
19. Singleton VL, Orthofer R, Lamuela-Raventós RM.
Analysis of total phenols and other oxidation substrates
and antioxidants by means of Folin-Ciocalteu reagent.
Methods in Enzymology 1999, 299:152-178.
20. Sadasivam S, Manickam A. Biochemical Methods. 3rd
Edition, New Age International Publishers. 1996, pp 194-
195.
21. Prieto P, Pineda M, Aguilar M. Spectrophotometric
quantitation of antioxidant capacity through the formation
of phosphomolybdenum complex: specific application to
the determination of vitamin E. Anal. Biochem. 1999,
269(2):337-341.
22. Yamasaki K, Hashimoto A, Kokusenya Y, Miyamoto T,
Sato T. Electrochemical method for estimating the
antioxidative effects of methanol extracts of crude drugs.
Chemical Pharmaceutical Bull. 1994, 42(8):1663-5.
23. Balouiri M, Sadiki M, Ibnsouda SK. Methods for in vitro
evaluating antimicrobial activity: A review. J.
International Journal of Food Science and Nutrition
6
Pharmaceutical Analysis 2016, 6:71-79.
24. Mosmann T. Rapid colorimetric assay for cellular growth
and survival: Application to proliferation and cytotoxicity
assays. J. Immunol. Methods 1983, 65(1-2):55-63.
25. Wafa AS. Chemical composition of some roselle Hibiscus
sabdariffa genotypes. M. Sc. thesis submitted to
University of Khartoum. 1997.
26. Luvonga WAL, Njorge MS, Makokha A, Ngunjiri PW.
Chemical characterization of Hibiscus sabdariffa Roselle
calyces and evaluation of its functional potential in the
food industry. Proceeding of JKUAT Scientific and
Industrial Conference, Kenya. 2010, 631-638.
27. Mohd-Esa N, Hern FS, Ismail A, Ye CL. Antioxidant
activity in different parts of roselle Hibiscus sabdariffa L.
extracts and potential exploitation of the seeds. Food
Chem. 2010, 122:1055-1060.
28. Kahkonen MP, Hopia AI, Vuorela HJ, Rauha JP, Pihlaja
K, Kujala TS. et al. Antioxidant activity of plant extracts
containing phenolic compounds. J. Agril. Food Chem.
1999, 47:3954-3962.
29. Piluzza G, Bullitta S. Correlations between phenolic
content and antioxidant properties in twenty-four plant
species of traditional ethnoveterinary use in the
Mediterranean area. Pharmaceutical Biol. 2011, 49(3):240-
247.
30. Tee ES, Mohd Ismail N, Mohd Nasir A, Kahtijah I.
Nutrient composition of Malaysian foods, 4th Edition.
Institute for Medical Research, Kuala Lumpur. 1997
31 Longvah T, Ananthan R, Bhaskarachary K, Venkaiah K.
Indian Food Composition Tables, 2017, National Institute
of Nutrition, ICMR, Hyderabad India.
32 Tseng TH, Kao ES, Chu CY, Chou FP, Lin WHW, Wang
CJ. et al. Protective effects of dried flower extracts of
Hibiscus sabdariffa L. against oxidative stress in rat
primary hepatocytes. Food Chem. Toxic. 1997; 35:1159-
1164.
33 Mckay DL, Chen CY, Saltzman E, Blumberg JB. Hibiscus
sabdariffa L. tea tisane lowers blood pressure in
prehypertensive and mildly hypertensive adults. J. Nutr.
2010; 140:298-303.
... Nowadays, roselle and its juice have been popular among the consumer since it is rich in antioxidant content which may possess health benefits to the consumers (Islam, 2019). Roselle or Hibiscus sabdariffa Linn. is a plant originally from Asia (India to Malaysia) or Tropical Africa, which has been widely cultivated in Sudan, Taiwan, India and Malaysia (Puro et al., 2017;Shruthi and Ramachandra, 2020). Roselle also was reported to contain many other chemical compositions such as bioactive compounds and organic acids. ...
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Gum Arabic (GA) is the dried exudate obtained from the tree of Acacia senegal and Acacia seyal that possess a prebiotic effect on humans. Meanwhile, roselle is a popular juice that is rich in antioxidants. However, as a complex polysaccharide, the addition of GA in roselle juice may affect the antioxidant properties of the final product. Therefore, this study aimed to determine the effect of different types of GA (Acacia senegal or Acacia seyal) addition, at different concentrations (0%, 2%, 4% and 6%) on the antioxidant properties and antioxidant stability of roselle juice during storage. The most accepted formulation of juice for each GA type along with the control sample (0% GA) was analysed for their oxidative stability during five weeks of chill storage (4±1oC). Results showed that the addition of GA increased or at least maintained the vitamin C and total phenolic content (TPC) in the range of 11.35±1.26-25.18±1.70 mg/100 mL and 21.04±1.55-45.08±4.76 mg GAE/100 mL, respectively. Nevertheless, the addition of more than 2% of GA significantly reduced (p<0.05) about 7% to 25% of total anthocyanin content. Variation of results was shown by ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging activity (DPPH) assay. For storage study, all juices (0% GA, 4% A. senegal and 2% A. seyal) exhibited fluctuation in trend for all the antioxidant properties except for TPC which remained stable. In conclusion, overall findings showed the addition of GA may increase or at least maintain the antioxidant properties of the juices except for anthocyanin content and antioxidant activity (DPPH assay). Meanwhile, the addition of GA had a variation that resulted in the oxidative stability of juices during storage
... Data show the total anthocyanin content in the dried powdered calyces was 112.28 to 196.61 mg/100g on a dry weight basis. This value is in the range as reported in other studies in the literature 0.760 to 622.91 mg/100g (Puro et al. 2017;Sinela et al. 2017). The compost with biofertilizer significantly increased total anthocyanin and total flavonol. ...
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ABSTRACT Use of compost and biofertilizer provides nutrients to crops and improves the chemical and physical properties of soils. A pot and incubation experiment was conducted to evaluate the effects of compost and Azotobacter chroococcum and Azospirillum brasiliense as biofertilizer on the carbon dioxide emission, nutrient availability under various incubation periods (0-time, 3, 7, 14, 30, 45, and 60 days) and growth, quality, and yield of roselle plants in pots. The treatments were control (C), compost 14 ton ha À1 (T1) and compost þ biofertilizer (T2). Results showed that the soil CO 2 flux was increased by 24.38, 33.16, 68.46, 70.17, 62.62, 50.34, and 47.49% over the control for 0-time, 3, 7, 14, 30, 45, and 60-days incubation periods, respectively , at compost þ biofertilizer treatments. Available N was increased by increasing incubation period to two months 71.07, 63.67, 63.17, 57.77, 62.57, 57.89, and 58.01%, respectively, under treatment of compost þ biofertilizer. The heaviest sepals of fresh and dry weights of sepals were gained by compost þ biofertilizer treatment. Total anthocyanin and total flavonol increased by 29.68 and 32.45%, respectively, above the untreated plants. Also, the available N, P, and K content in the soil after the harvesting stage of roselle plants increased by 174.85, 178.24, and 50.96%, respectively, using compost with bio fertilizer treatment. Compost application with biofertilizer may, therefore, be a good strategy for increased to nutrient availability, growth parameter, and yield.
... Protein content ranged between 8.81-6.96g, fat content ranged between 1.60 -1.23g, ash between 5.36 -6.74g, crude fibre between 7.25 -5.76g Puro et al. (2017). The trend in change in the proximate composition of moisture and fat was found to be similar with Zaman et al. (2017). ...
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A field experiment was conducted from December 2020 to March 2021 in a rice fallow under the Department of Agronomy, College of Agriculture, Vellanikkara to develop a viable weed management strategy in green gram. The lowest weed dry matter production was recorded in hand weeded plots, which was followed by the treatments where pre- mergence application of oxyfluorfen, imazethapyr, imazethapyr + imazamox and diclosulam was integrated with hand weeding. Grain yield and haulm yield was the highest in hand weeding,which was statistically on par with all the treatments where pre-emergence herbicide application was followed by hand weeding. The application of pre-emergence herbicides resulted in a reduction in the soil microbial count at flowering as compared to the untreated plots, however, the microbial population was recovered by harvest stage in the plots treated with oxyfluorfen, imazethapyr and imazethapyr + imazamox. Only diclosulam was found to have a pronounced inhibitory effect on the soil microbial population at harvest stage. Soil nutrient status was found to be higher in any of the weed management treatments as compared to unweeded control.
... Protein content ranged between 8.81-6.96g, fat content ranged between 1.60 -1.23g, ash between 5.36 -6.74g, crude fibre between 7.25 -5.76g Puro et al. (2017). The trend in change in the proximate composition of moisture and fat was found to be similar with Zaman et al. (2017). ...
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Sandalwood (Santalum album L.), a root hemiparasite, endemic to Southern India, is a tree of great commercial value globally. Considering the growing demand and the diminishing supply of sandalwood from its naturalhabitat, there is a great potential for cultivating sandal trees in agricultural land, home gardens and other agro forestry systems. The cultivation of sandalwood is challenging because of the poor understanding of host parasite relationship as sandalwood is a root parasite. In this context a study was carried out to understand the relationship of sandalwood with its two primary hosts, Cajanus (legume) and Alternanthera (nonlegume).The results showed that sandalwood grown with Cajanus (T3) have greater plant height (176.57 cm), stem girth (12.01 cm) chlorophyll content (3.29 mg/g FW of leaves) in contrast to sandalwood grown with Alternanthera (T2) and control (T1) without a host. The variations in activity of SOD, Peroxidase (POX) and accumulation of phenols, flavonoids, proline in sandalwood indicates differences in sandalwood response at molecular level towards the two hosts. There was a clear shift in SOD isozyme bands in sandalwood when it interacted with Cajanus as compared to Alternanthera (T2 ) and control (T1). The increase in peroxidases observed in T3 (11.30g/mg protein) was significantly higher compared to the T2 and T1 . The same trend was observed for the phenols, flavonoids and prolines. The greater reduction in defense response in the host plant Cajanus in comparison to Alternanthera when planted with sandalwood signifies the deliberate vulnerability of Cajanus towards sandalwood parasitism, making it a superior host. Indeed, a polybag experiment to evaluate the direction of root growth shows a clear preference of sandalwood root to Cajanus, as compared to Alternanthera. Overall from the phenotypic observations and also from the biochemical estimations, the leguminous host Cajanus was found to be a better primary host than Alternanthera in the field condition. The insights gained from the present investigation can be used for sandalwood cultivation in large scale in the natural habitat as well as in other agroforestrty region.
... The calyces of roselle are used in the preparation of a local refreshing beverage in Nigeria called Zobo. Roselle calyces have been reported to contain dry matter, crude fibre content, crude protein content, ash content and moisture content values were 40.45%, 20.83%, 27.32%, 4.67% and 6.79%, respectively [6]. Roselle calyx is considered to be good sources of invaluable antioxidants. ...
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This study investigated the effects of Saccharomyces cerevisiae-induced fermentation on the antioxidant properties of Roselle calyx aqueous extract and determined the physicochemical changes of the fermented extract. Total phenolics, total flavonoid, ascorbic acid content, total monomeric anthocyanin content and DPPH radical scavenging activity of roselle aqueous extract were investigated before and after fermentation. Roselle calyx aqueous extract was fermented for period of 10 days. During fermentation, the extract was evaluated for pH, alcohol (%), titratable acidity (%) and total soluble solids (oBrix). Total soluble solids and pH significantly decreased at the end of the fermentation whereas titratable acidity and alcohol content significantly increased. Fermentation caused significant reduction in total monomeric anthocyanin content from an initial value of 3518±30.8 to 1075±28.2 CGE/100 g dry extract whereas significant increase was observed in total phenolic content from 195.75±76.01 to 455.5±1.41 mgGAE/100 g dry extract and ascorbic acid content from 1392±101 to 2028±108 mg AAE/100 g dry extract and total flavonoids increased from 193.0±74.25 to 291.5±4.95 mgQE/100 g dry extract but it was not significant. There was also a significant increase in 1-1-diphenyl-2-picryl hydrazyl (DPPH) scavenging activity of roselle calyx aqueous extract from an initial value of 44.15% to final value of 71.10% after fermentation, leading to an increase in antioxidant activity. Therefore, the quantity of phenolic compounds increased with fermentation process. This study showed that roselle calyx aqueous extract fermented by Saccharomyces cerevisiae has a better antioxidant activity.
... The biocidal activities of HS extracts have widely been acclaimed by several researchers. Puro et al. [126] found that aqueous extract of HS at a concentration (mg/mL) of 100, 50, and 25 was able to inhibit the growth of S. aureus, E. coli, and Klebsiella pneumoniae. In a similar study, [127] demonstrated the antimicrobial action of HS extracts on E. coli strain O157:H7, a major bacterial foodborne pathogen isolated from food, veterinary, and clinical samples. ...
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Sorghum beer (pito) is an indigenous alcoholic beverage peculiar to northern Ghana and parts of other West African countries. It is overwhelmed with calories, essential amino acids (such as lysine, etc.), B-group vitamins, and minerals. In recent years, there has been a growing demand for highly flavoured yet functional pito in Ghana; however, the local producers lack the prerequisite scientific expertise in designing such products. We propose the utilization of Tetrapleura tetraptera (TT) and Hibiscus sabdariffa (HS) as cheap and readily available materials in designing functional flavoured pito. The addition of TT and HS would not alter the fermentation profile but rather augment the starter with nutrients, thus improving the fermentation performance and shelf life of the final pito. In vitro and in vivo studies provide substantive evidence of antioxidant, nephro-and hepato-protective, renal/diuretic effect, anticholesterol, antidiabetic, and antihypertensive effects among others of the TT and HS, hence enriching the pito with health-promoting factors and consequently boosting the health of the consumer. Herein, we summarise the phytochemical, biological, pharmacological, and toxicological aspects of TT and HS as well as the technology involved in brewing the novel bioactive-flavoured pito. In addition, we also report the incidence of heavy metal in conventional pito.
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Roselle calyces ( Hibiscus sabdariffa L.) were evaluated through a critical study of existing research works on health benefits, mineral compositions, bioactive compositions, mechanisms, and possible research gaps. The use of roselle calyces as an alternative to synthetic food dyes, addressing growing global challenges of overweight, obesity, and cardiovascular diseases, was evaluated and encouraged. Studies indicate the attenuation of obesity by chlorogenic acid (the predominant phenolic compound in roselle calyx) via mechanisms associated with the UCP-1 and PGC-1α pathways, resulting in reduced blood lipid levels, reduced fat accumulation in the liver, and increased thermogenesis through fat metabolism. Minimum inhibitory concentration (MIC) of known bacteria and fungi, such as Listeria monocytogenes, Escherichia coli, Bacillus cereus, Salmonella typhimurium , Candida tropicalis , and Candida krusei , were studied. More research, however, needs to be conducted on organic acids present in roselle calyces to look into their possible applications and maximize their possible benefits.
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The “Indian Food Composition tables (IFCT 2017)” provides nutritional values for 528 key foods. Each food was compositely sampled from six different regions covering the entire country thus representing the national food supply and consumption pattern. The nutrient mean of six regions represents the national value, and SD represents the national variability. There are 12 tables providing nutrient data on proximate principles and dietary fibre, water soluble vitamins, fat-soluble vitamins, carotenoids, mineral and trace elements, starch and individual sugars, complete fatty acid profile, amino acid profile, organic acids, polyphenols, oligosaccharides, phytosterols, saponin, phytate and complete fatty acid profile of edible oils and fats. Number of food entries in each food group are: Cereals and millets (24), grain legumes (25), green leafy vegetables (34), other vegetables (78), fruits (68), roots and tubers (19), condiments and spices (33), nuts and oil seeds (21), sugars (2), Mushrooms (4), Miscellaneous foods (2), milk and milk products (4), egg and egg products (15), poultry (19), animal meat (63), marine fish (92), marine shellfish (8), marine mollusks (7), fresh water fish and shell fish (10). Data on vitamin D2, oligosaccharides, phytosterols, organic acids and individual polyphenols are hall mark contribution of the new IFCT 2017. Pictoral description of foods along with scientific nomenclature and names in 17 Indian official languages are provided. The new IFCT 2017 is expected to bring about paradigm change in nutrition research in the country.
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Objective: To investigate the effect of the roselle calyx extract (RCE) (Hibiscus sabdariffa L.) on the in vitro viability and biofilm formation ability of oral pathogenic bacteria. Methods: RCE was prepared by soaking roselle calyx powder with ethyl alcohol for 24 h at room temperature. After centrifugation, the extract was lyophilized. Then, the extract was dissolved in phosphate-buffered saline, the pH was adjusted, and the extract was aseptically filtered. We used Streptococcus mutans, Streptococcus sanguinis, Lactobacillus casei, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia in this study. The antibacterial activity of the RCE was determined by treating the cells of these bacteria with the extract for 10 or 20 min at room temperature. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration was determined using the microdilution method, and the effect of the RCE on the ability to form biofilm was determined using a polystyrene micro plate assay. In addition, we used the WST-1 assay to determine the cytotoxicity of the RCE on HGF, Ca9-22 and KB cells. Results: The RCE had antibacterial activity against oral bacteria used in this study. In particular, most significant antibacterial activity was observed against Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas gingivalis. The MIC and minimum bactericidal concentration were 7.2 mg/mL-28.8 mg/mL and 14.4 to >57.6 mg/mL. The RCE had an inhibitory effect on biofilm formation at the MIC and sub-MIC levels. In addition, the RCE had low cytotoxic effects on HGF, Ca9-22 and KB cells. Conclusions: Thus, our results indicate that the RCE may be used for preventing oral diseases.
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In recent years, there has been a growing interest in researching and developing new antimicrobial agents from various sources to combat the emergence of the microbial resistance. Therefore, a greater attention was paid on antimicrobial activity screening and evaluating methods. Several bioassays are well known and commonly used such as disk-diffusion, well diffusion and broth or agar dilution, but others are not widely used such as flow cytofluorometric and bioluminescent methods because they require specified equipment and further evaluation for reproducibility and standardization, even if they can provide a rapid results of the antimicrobial agent’ effects and a better understood of their impact on the viability and cell damage inflicted to the tested microorganism. In this present review article, an exhaustive list of in vitro antimicrobial susceptibility testing methods and detailed information on their advantages and limitations are reported.
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Hematopoietic stem cells- (HSCs-) based therapy requires ex vivo expansion of HSCs prior to therapeutic use. However, ex vivo culture was reported to promote excessive production of reactive oxygen species (ROS), exposing HSCs to oxidative damage. Efforts to overcome this limitation include the use of antioxidants. In this study, the role of Hibiscus sabdariffa L. (Roselle) in maintenance of cultured murine bone marrow-derived HSCs was investigated. Aqueous extract of Roselle was added at varying concentrations (0-1000 ng/mL) for 24 hours to the freshly isolated murine bone marrow cells (BMCs) cultures. Effects of Roselle on cell viability, reactive oxygen species (ROS) production, glutathione (GSH) level, superoxide dismutase (SOD) activity, and DNA damage were investigated. Roselle enhanced the survival (P < 0.05) of BMCs at 500 and 1000 ng/mL, increased survival of Sca-1(+) cells (HSCs) at 500 ng/mL, and maintained HSCs phenotype as shown from nonremarkable changes of surface marker antigen (Sca-1) expression in all experimental groups. Roselle increased (P < 0.05) the GSH level and SOD activity but the level of reactive oxygen species (ROS) was unaffected. Moreover, Roselle showed significant cellular genoprotective potency against H2O2-induced DNA damage. Conclusively, Roselle shows novel property as potential supplement and genoprotectant against oxidative damage to cultured HSCs.
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Roselle (Hibiscus sabdariffa Linn) extract has been scientifically proven to possess high antioxidant activity, anti-proliferation and anti-carcinogenic properties. This study was conducted to evaluate the antioxidative capacity of commercialized Roselle juice (RJ) at three storage periods and its anti-proliferative effect on breast (MCF-7 and MDA-MB-231), ovarian (Caov-3) and cervical (HeLa) cancer cell lines. The antioxidant activity of 1 week (WRJ), 1 month (MRJ) and 1 year (YRJ) juice samples each at 0.001 to 10% concentration range were determined through 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay with L-ascorbic acid as positive control. EC 50 values of WRJ, MRJ, and YRJ were found to be 3.733±0.247, 3.717±0.637 and 3.383±0.711%, respectively. These values were compared to 0.217±0.616% for positive control. The difference in antioxidant activity between different storage periods of RJ was not significant (p>0.05) but all samples exhibited increasing activity with increasing concentrations. RJ at the same concentrations were tested using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay on the four cell lines to obtain the percentage viability of the cells. The cells were incubated for 72 h after inoculation with RJ and the control group was without treatment. The IC 50 was found to be highest for Caov-3 cells (2.267±1.193%) whereas MCF-7 cells exhibited the lowest (0.432±0.278%) IC 50 value after treatment with MRJ. All determinations were analyzed using ANOVA through SPSS with p<0.05 considered as significant. Increasing concentrations of sample corresponded to lower percentage viability of cells for all samples, however the interaction within and between cell type and storage period was not significant (p>0.05). The study showed that commercialized Roselle juice has strong antioxidant capacity and anti-proliferative activity on the four cancer cell lines despite different storage periods. However, further study should be conducted to establish its anti-cancer mechanisms.
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a b s t r a c t The calyx of the roselle plant has long been recognised as a source of antioxidants. The objective of this study was to evaluate antioxidant activity, free radical-scavenging and total phenolic content in other parts of the roselle plant. Roselle seed extracts were found to have the highest antioxidant activity and strongest radical-scavenging activity of all plants tested. Methanol extracts showed a positive correlation between phenolic content and antioxidant activity, as measured by b-carotene bleaching assay and DPPH radical-scavenging activity. The antioxidant efficacy of roselle seeds in a whole food system was investi-gated by testing the effect on lipid oxidation in cooked beef patties stored at 4 °C for 14 days. Results showed that patties treated with roselle seeds had reduced lipid oxidation compared to patties treated with BHT. This study suggests that roselle seeds have the potential to be used as food antioxidants.
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Hibiscus sabdariffa Linne (Malvaceae), a plant long used as a soft drink and medical herb in Taiwan, has been found to reduce blood lipids in animals. To investigate the cholesterol-lowering potential of H. sabdariffa extract (HSE) in human subjects, a clinical study was conducted using an oral preparation of HSE capsules. The study consisted of 42 volunteers who were observed over a period of 4 weeks. The volunteers ranged from 18 to 75 years old with a cholesterol level of 175 to 327 mg/dL. Subjects were randomly assigned to 3 groups: group I (1 capsule of HSE during each meal), group II (2 capsules), and group III (3 capsules). Serum cholesterol levels were determined at baseline before the study commenced and at 2 and 4 weeks of the treatment period. In general, taking HSE led to a significant decrease in serum cholesterol level in subjects from groups I and II after 4 weeks. After HSE had been administered for 2 weeks, serum cholesterol levels were found to be lower in all groups (P < .05 for groups I-III) compared with baseline values by 7.8% to 8.2%. A similar response was observed, a reduction in serum cholesterol level by 8.3% to 14.4%, after 4 weeks of taking the supplement. It is important to note that the serum cholesterol level for 71% of group II volunteers was significantly lowered with a mean reduction of 12% (P < .05). We conclude that a dosage of 2 capsules of HSE (with a meal) for 1 month can significantly lower the serum cholesterol level. The observation of lowered serum cholesterol in these subjects suggests that HSE may be effective in hypercholesterolemic patients.
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Publisher Summary This chapter discusses the analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Analyses of the Folin-Ciocalteu (FC) type are convenient, simple, and require only common equipment and have produced a large body of comparable data. Under proper conditions, the assay is inclusive of monophenols and gives predictable reactions with the types of phenols found in nature. Because different phenols react to different degrees, expression of the results as a single number—such as milligrams per liter gallic acid equivalence—is necessarily arbitrary. Because the reaction is independent, quantitative, and predictable, analysis of a mixture of phenols can be recalculated in terms of any other standard. The assay measures all compounds readily oxidizable under the reaction conditions and its very inclusiveness allows certain substances to also react that are either not phenols or seldom thought of as phenols (e.g., proteins). Judicious use of the assay—with consideration of potential interferences in particular samples and prior study if necessary—can lead to very informative results. Aggregate analysis of this type is an important supplement to and often more informative than reems of data difficult to summarize from various techniques, such as high-performance liquid chromatography (HPLC) that separate a large number of individual compounds .The predictable reaction of components in a mixture makes it possible to determine a single reactant by other means and to calculate its contribution to the total FC phenol content. Relative insensitivity of the FC analysis to many adsorbents and precipitants makes differential assay—before and after several different treatments—informative.