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Antioxidant potential of solvent extracts of Kappaphycus alvarezii (Doty) Doty-An edible seaweed

  • University of Allahabad, Allahabad,India
  • Aquaculture Foundation of India, Madurai,Tamil Nadu,India

Abstract and Figures

Various solvent extracts of Kappaphycus alvarezii, an edible red seaweed (family Solieriaceae) were screened for total phenol content and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferrous ion chelating activity, reducing power and antioxidant activity assays in a linoleic acid system with ferrothiocyanate reagent (FTC). The total phenol content of different extracts of K. alvarezii varied from 0.683 ± 0.040% to 2.05 ± 0.038%. The radical-scavenging activity of ethanol extract was, as IC50 3.03 mg ml−1, whereas that of the water extract was IC50 4.76 mg ml−1. Good chelating activity was recorded for methanol extract (IC50 3.08 mg ml−1) wherein 67.0 ± 0.924% chelation was obtained using 5.0 mg ml−1 of extract. The reducing power of the samples was in the following order: BHT > methanol > ethanol > ethyl acetate > water > hexane. But, in the linoleic acid system, the ethanol extract proved superior to the synthetic antioxidants butylated hydroxytoluene (BHT). Hence, these extracts could be considered as natural antioxidants and may be useful for curing diseases arising from oxidative deterioration.
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Antioxidant potential of solvent extracts of Kappaphycus
alvarezii (Doty) Doty – An edible seaweed
K. Suresh Kumar, K. Ganesan, P.V. Subba Rao
Marine Biotechnology and Ecology Discipline, Central Salt and Marine Chemicals Research Institute (CSIR), Bhavnagar – 364 002, Gujarat, India
Received 11 May 2007; received in revised form 30 June 2007; accepted 6 August 2007
Various solvent extracts of Kappaphycus alvarezii, an edible red seaweed (family Solieriaceae) were screened for total phenol content
and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferrous ion chelating activity, reducing power and antioxidant
activity assays in a linoleic acid system with ferrothiocyanate reagent (FTC). The total phenol content of different extracts of K. alvarezii
varied from 0.683 ± 0.040% to 2.05 ± 0.038%. The radical-scavenging activity of ethanol extract was, as IC
3.03 mg ml
, whereas that
of the water extract was IC
4.76 mg ml
. Good chelating activity was recorded for methanol extract (IC
3.08 mg ml
) wherein
67.0 ± 0.924% chelation was obtained using 5.0 mg ml
of extract. The reducing power of the samples was in the following order:
BHT > methanol > ethanol > ethyl acetate > water > hexane. But, in the linoleic acid system, the ethanol extract proved superior to
the synthetic antioxidants butylated hydroxytoluene (BHT). Hence, these extracts could be considered as natural antioxidants and
may be useful for curing diseases arising from oxidative deterioration.
Ó2007 Elsevier Ltd. All rights reserved.
Keywords: Kappaphycus alvarezii; Antioxidant activity; Total phenolics; Free radicals; Reducing power
1. Introduction
All living organisms contain complex systems of antiox-
idant enzymes. Some of these systems, e.g. the thioredoxin
system, are conserved throughout evolution and are
required for life. Antioxidants in biological systems have
multiple functions, including defending against oxidative
damage and participating in the major signalling pathways
of cells. One major action of antioxidants in cells is to pre-
vent damage caused by the action of reactive oxygen spe-
cies. Reactive oxygen species include hydrogen peroxide
), the superoxide anion (O
2), and free radicals, such
as the hydroxyl radical (
OH). These molecules are unstable
and highly reactive, and can damage cells by chain reac-
tions, such as lipid peroxidation, or formation of DNA
adducts that could cause cancer-promoting mutations or
cell death. In order to reduce or prevent this damage, all
cells invariably contain antioxidants.
Lipid oxidation by reactive oxygen species (ROS), such
as superoxide anion, hydroxyl radicals, and hydrogen per-
oxide, causes a decrease in nutritional value of lipids, in
their safety and appearance. In addition, it is the predom-
inant cause of qualitative decay of foods, which leads to
rancidity, toxicity, and destruction of biochemical compo-
nents important in physiologic metabolism. Free radical-
mediated modification of DNA, proteins, lipids and small
cellular molecules are associated with a number of patho-
logical processes, including atherosclerosis, arthritis, diabe-
tes, cataractogenesis, muscular dystrophy, pulmonary
dysfunction, inflammatory disorders, ischemiareperfusion
tissue damage, and neurological disorders, such as Alzhei-
mer’s disease (Frlich & Riederer, 1995).
Antioxidants are classified by the products they form
on oxidation (these can be antioxidants themselves, inert,
0308-8146/$ - see front matter Ó2007 Elsevier Ltd. All rights reserved.
Corresponding author.
E-mail address: (P.V.S. Rao).
Available online at
Food Chemistry 107 (2008) 289–295
or pro-oxidant), by what happens to the oxidation prod-
ucts (the antioxidant may be regenerated by different
antioxidants or, in the case of ‘‘sacrificialantioxidants,
its oxidized form may be broken down by the organism)
and how effective the antioxidant is against specific free
radicals. Several synthetic antioxidants, such as butylated
hydroxyanisole (BHA), butylated hydroxytoluene (BHT),
and tert-butylhydroquinone (TBHQ), are commercially
available and currently used. However, these antioxidants
have been restricted for use in foods as they are sus-
pected to be carcinogenic. Some toxicological studies
have also implicated the use of these synthetic antioxi-
dants in promoting the development of cancerous cells
in rats. These findings, together with consumers’ interests
in natural food additives, have reinforced the efforts for
the development of alternative antioxidants of natural
origin (Huang & Wang, 2004). An immense number of
marine flora and fauna are reported to have a wide spec-
trum of interesting biological properties. In folk medi-
cine, seaweeds have been used for a variety of remedial
purposes, e.g. for the treatment of eczema, gallstone,
gout, crofula, cooling agent for fever, menstrual trouble,
renal problems and scabies (Chapman & Chapman,
Seaweeds are rich in polysaccharides, minerals, proteins
and vitamins. Documented antioxidant activity would ele-
vate their value in the human diet as food and pharmaceu-
tical supplements (Yan, Nagata, & Fan, 1998). Few reports
are available on the antioxidant potential of seaweeds
(Jimenez-Escrig, Jimenez-Jimenez, Pulido, & Saura-Cali-
xto, 2001). Ismail and Hong (2002) reported antioxidant
activity of four commercial edible seaweeds, namely Nori
(Porphyra sp.), Kumbu (Laminaria sp.), Wakame (Undaria
sp.) and Hijiki (Hijikia sp.).
The Rhodophyta (red algae) are a distinct eukaryotic
lineage, characterized by the accessory photosynthetic pig-
ments phycoerythrin, phycocyanin and allophycocyanins
arranged in phycobilisomes. They contain a large assem-
blage of species that predominate in the coastal and con-
tinental shelf areas of tropical, temperate and cold-water
regions. Red algae are ecologically significant as primary
producers, providers of structural habitat for other mar-
ine organisms, and they play an important role in the pri-
mary establishment and maintenance of coral reefs. Some
red algae are economically important as providers of food
and gels (Wilson, 2000). For this reason, extensive farm-
ing and natural harvest of red algae occur in numerous
areas of the world. Kappaphycus alvarezii, an economi-
cally important red tropical seaweed, which is highly
demanded for its cell wall polysaccharide, is the most
important source of kappa carrageenan. The world
production of Kappaphycus species is approximately
28000 tons per annum. This seaweed accounts for the
largest consumption worldwide (McHugh, 1987). It is eas-
ily accessible, in huge amounts, for food and pharmaceu-
tical applications. The present study deals with
antioxidant properties of K. alvarezii.
2. Materials and methods
2.1. Collection of samples
K. alvarezii was collected from a cultivation site at Port
Okha (L 22°28.5280N; L 069°04.3220E) located on the north
west coast of India during April, 2006. The sample was
thoroughly washed with seawater to remove epiphytes
and dirt particles, followed by shade-drying for two days.
It was then brought to the laboratory, oven-dried at 70 °C
for 4 h to obtain a constant weight and pulverized in the
grinder (size 2 mm). This sample was used for determina-
tion of phenolic content, as well as for antioxidant studies.
The chemicals used in these studies were of analytical grade.
2.2. Preparation of extracts
The pulverized moisture-free sample (20 g) was
extracted with 200 ml of individual solvents using a Soxhlet
extractor. The extraction was repeated many times to
obtain a sizable quantity of extract. Consequently, the
extract was concentrated in a rotary evaporator at 40 °C.
Different solvents were used for the preparation of extracts
to determine the antioxidant efficacy of K. alvarezii. All the
experiments were conducted in triplicate.
2.3. Determination of total phenol
Total phenolic content was estimated by Folin–Ciocal-
teau method (Singleton & Rossi, 1965). To 6.0 ml of
double-distilled water, 0.1 ml of sample and 0.5 ml of
Folin–Ciocalteau reagent were mixed, followed by the addi-
tion of 1.5 ml of Na
(20 g 100 ml
water) and the
volume was made up to 10.0 ml with distilled water. After
incubation for 30 min at 25 °C, the absorbance was
measured at 760 nm and the total phenolic content was cal-
culated with a gallic acid standard and expressed as a per-
centage of total phenols obtained on a dry weight basis.
2.4. DPPH radical scavenging assay
-scavenging potential of different fractions was
measured, based on the scavenging ability of stable 1,1-
diphenyl-2-picrylhydrazyl (DPPH) radicals by K. alvarezii
antioxidants. The ability of extracts to scavenge DPPH rad-
icals was determined by the method of Blois (1958). Briefly,
1 ml of 1 mM methanolic solution of DPPH
was mixed
with 1 ml of extract solution (containing 0.5–5.0 mg ml
of dried extract). The mixture was then vortexed vigorously
and left for 30 min at room temperature in the dark. The
absorbance was measured at 517 nm and activity was
expressed as percentage DPPH
-scavenging activity relative
to the control, using the following equation:
%Radical scavenging activity
¼AControl ASample=AControl
290 K.S. Kumar et al. / Food Chemistry 107 (2008) 289–295
2.5. Ferrous ion-chelating activity
Iron-chelating abilities of methanol, ethanol and ethyl
acetate extracts of K. alvarezii were used for the present
investigation. The chelating of ferrous ions by the extracts
and standards was estimated by the method of Dinis,
Madeira and Almeida (1994). Extracts were added to a
solution of 2 mM FeCl
(0.05 ml). The reaction was initi-
ated by the addition of 5 mM ferrozine (0.2 ml) and the
mixture was shaken vigorously and left standing at room
temperature for 10 min. After the mixture had reached
equilibrium, the absorbance of the solution was then mea-
sured at 562 nm. The percentage inhibition of ferrozine–
complex formation was determined using the follow-
ing formula:
%Inhibition ¼1A1Sample=A0Control
where A
was the absorbance of the control and A
was the
absorbance in the presence of the sample extracts and stan-
dards. The control contained FeCl
and ferrozine, with
complex formation molecules.
2.6. Reducing power
Extracts of K. alvarezii were prepared using methanol,
ethanol, water, ethyl acetate and hexane. The reductive
potential of extracts was determined by the method of
Oyaizu (1986). The different concentrations of extracts
(0.5–25 mg ml
) were mixed with phosphate buffer
(2.5 ml, 0.2 M, pH 6.6) and potassium ferricyanide
] (2.5 ml, 1%). The mixture was incubated at
50 °C for 20 min. A portion (2.5 ml) of trichloroacetic acid
(10%) was added to the mixture, which was then subjected
to centrifugation (10 min, 1000g). The upper layer of solu-
tion (2.5 ml) was mixed with distilled water (2.5 ml) and
(0.5 ml, 0.1%), and the absorbance was measured
at 700 nm. Higher absorbance of the reaction mixture indi-
cated greater reductive potential.
2.7. Antioxidant activity in the linoleic acid system with
ferrothiocyanate reagent (FTC)
Ethanolic extract of K. alvarezii was subjected to the
assay adopted by Osawa and Namaki (1983). The extract
(4 mg) was dissolved in 99.5% ethanol and mixed with
2.5% linoleic acid in 99.5% ethanol (4.1 ml), 0.05 M phos-
phate buffer (pH 7, 8 ml) and distilled water (3.9 ml) and
kept in screw-cap containers under dark conditions at
40 °C; 0.1 ml of this solution was added to 9.7 ml of 75%
ethanol and 0.1 ml of 30% ammonium thiocyanate. After
3 min, 0.1 ml of 0.02 M ferrous chloride in 3.5% hydrochlo-
ric acid was added to the reaction mixture, the absorbance
of the red colour was measured at 500 nm in the spectro-
photometer every two days. The control and standard were
subjected to the same procedure except that for the control,
there was no addition of sample and, for the standard,
4 mg of sample was replaced with 4 mg of butylated
hydroxy toluene (BHT), used as a positive control. Absor-
bance was measured at intervals of 2 days. The percent
inhibition of linoleic acid peroxidation was calculated as:
Inhibition ð%Þ
¼100 ðabsorbance increase of the sample½
=absorbance increase of the controlÞ100
The IC
value represented the concentration of the com-
pounds that caused 50% inhibition. All experiments were
carried out in triplicate.
2.8. Statistical analysis
For the extract, three samples were prepared for each
experiment. The data were presented as mean ± standard
3. Results and discussion
3.1. Antioxidant activity
The antioxidant activity is system-dependent. Moreover,
it depends on the method adopted and the lipid system
used as substrate (Singh, Maurya, de Lampasona, & Cata-
lan, 2006). Hence, the following different methods have
been adopted in order to assess the antioxidative potential
of K. alvarezii extracts.
3.2. Total phenol content
A number of studies have focussed on the biological
activities of phenolic compounds, which are potential anti-
oxidants and free radical-scavengers (Ka
¨nen et al.,
1999; Rice-Evans, Miller, Bolwell, Bramley, & Pridham,
1995; Sugihara, Arakawa, Ohnishi, & Furuno, 1999). The
total phenol content was maximum when a mixture of
chloroform and methanol (2:1) was used (2.05 ± 0.038%)
followed by ethanol (1.94 ± 0.029%), methanol
(1.79 ± 0.77%), n-propanol (1.40 ± 0.040%) and ethyl ace-
tate (1.09 ± 0.597%). Extracts obtained using other sol-
vents, namely acetone, n-hexane and chloroform, showed
<1% total phenol content (Table 1).
3.3. Scavenging effect on 1,1-diphenyl-2-picrylhydrazyl
radical (DPPH
The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical is a
stable radical with a maximum absorbance at 517 nm that
can readily undergo reduction by an antioxidant. Because
of the ease and convenience of this reaction, it has now
widespread use in the free radical-scavenging activity
assessment (Brand-Williams, Cuvelier, & Benset, 1995).
The radical-scavenging activity of K. alvarezii extract is
shown in Fig. 1 and expressed as percentage reduction of
the initial DPPH
absorption by the tested compound.
The best radical-scavenging activity could be obtained in
K.S. Kumar et al. / Food Chemistry 107 (2008) 289–295 291
the ethanol extract (IC
3.03 mg ml
), followed by meth-
anol (IC
4.28 mg ml
). Extracts obtained using water
also showed equivalent scavenging activity (IC
4.76 mg ml
). These values were lower than those
obtained using BHT (IC
2.83 mg ml
), but the IC
ues of the methanol and water extracts were comparable
with a-tocopherol (IC
4.55 mg ml
). The extracts of K.
alvarezii showed better radical-scavenging activity than
did the extract of Palmaria palmata (dulse) IC
12.5 mg ml
(Yuan, Carrington, & Walsh, 2005a), and
purified extract of Ecklonia cava IC
– 5.49 10
(c.f. Suja, Jayalekshmy, & Arumughan, 2005). Ragan and
Glombitza (1986) reported the radical-scavenging activity
of seaweeds to be mostly related to their phenolic contents.
On the other hand, Siriwardhana, Lee, Kim, Ha, and Jeon
(2003) and Lu and Foo (2000) reported a high correlation
between DPPH radical-scavenging activities and total poly-
phenolics r= (0.971). In the present study, the linear
regression analysis of DPPH
-scavenging (i.e EC
with the total phenol content (gallic acid equivalents) gave
an rvalue of 0.937, showing statistically significant correla-
tion. K. alvarezii is the main industrial source of carra-
geenan (having alternating D-galactose 4-sulphate and
3,6-anhydro D-galactose residues), which may also contrib-
ute to the antioxidant potential of this seaweed. Compo-
nents, such as low molecular weight polysaccharides,
pigments, proteins or peptides, also influence the antioxi-
dant activity (Siriwardhana et al., 2003).
3.4. Metal ion-chelating activity
All the extracts demonstrated reasonable ferrous ion che-
lating efficacy (Fig. 2). The ascorbic acid extract demon-
strated best ferrous chelating efficacy (IC
2.88 mg ml
followed by methanol, ethanol and ethyl acetate (IC
3.08, 3.83 and 4.38 mg ml
, respectively). Iron is known
to generate free radicals through the Fenton & Haber-Weiss
reaction. Metal ion-chelating activity of an antioxidant
molecule prevents oxyradical generation and the conse-
quent oxidative damage. Metal ion-chelating capacity plays
a significant role in the antioxidant mechanism since it
reduces the concentration of the catalyzing transition metal
in LPO. It is reported that chelating agents that form r-
bonds with a metal, are effective as secondary antioxidants
since they reduce the redox potential, thereby stabilizing the
oxidized form of the metal ion (Srivastava, Harish, & Shiva-
nandappa, 2006). Metal-binding capacities of dietary fibres
are well known, e.g. the inhibitory effects on ferrous absorp-
tion of algal dietary fibres such as carrageenan, agar and
alginate, were reported (Harmuth-Hoene & Schelenz,
1980). In this present study, the carrageenan might have
caused the decrease of ferrous ion in the assay system.
3.5. Measurement of reducing potential
The reducing power of K. alvarezii extracts was concen-
tration-dependent (Fig. 3). As the concentration increased
from 0.5 to 5.0 mg ml
, there was an increase in absor-
bance with all the solvents except hexane. However, the
reducing powers of the samples were found to be in the fol-
lowing order: BHT (0.23–0.879) > methanol (0.07–
Table 1
Percent phenol content of K. alvarezii in various solvents
Solvents Total phenol (%)
Acetone 0.963 ± 0.058
n-Propanol 1.40 ± 0.040
Ethyl acetate 1.09 ± 0.597
n-Hexane 0.83 ± 0.048
Chloroform 0.683 ± 0.040
Methanol 1.79 ± 0.77
Ethanol 1.94 ± 0.029
Chloroform:methanol (2:1) 2.05 ± 0.038
Values are means of three replicate determinations; SD, standard
Fig. 1. Antioxidant activities of different solvent extracts of K. alvarezii determined as DPPH radical-scavenging activity.
292 K.S. Kumar et al. / Food Chemistry 107 (2008) 289–295
0.74) > ethanol (0.333–0.44) > ethyl acetate (0.013–
0.467) > water (0.017–0.193) > hexane (0.017–0.16). It is
believed that antioxidant activity and reducing power are
related. Reductones inhibit LPO by donating a hydrogen
atom and thereby terminating the free radical chain reac-
tion (Srivastava et al., 2006).
3.6. Antioxidant activity in a linoleic acid system with
ferrothiocyanate reagent (FTC)
Peroxyl radicals are formed by a direct reaction of oxy-
gen with alkyl radicals. Decomposition of alkyl peroxides
also results in peroxyl radicals. Peroxyl radicals are good
oxidizing agents, having more than 1000 mV of standard
reduction potential (Decker, 1998). They can abstract
hydrogen from other molecules with lower standard reduc-
tion potentials. This reaction is frequently observed in the
propagation stage of lipid peroxidation. Cell membranes
are phospholipid bilayers with extrinsic proteins and are
the direct target of lipid oxidation (Girotti, 1998). As lipid
oxidation of cell membranes increases, the polarity of lipid
phase surface charge and formation of protein oligomers
increase; and molecular mobility of lipids, number of SH
groups, and resistance to thermal denaturation decrease.
Malonaldehyde, one of the lipid oxidation products, can
react with the free amino group of proteins, phospholipid,
and nucleic acids, leading to structural modifications,
which induce dysfunction of immune systems. The antiox-
idant effects of K. alvarezii extract and BHT on the perox-
idation of linoleic acid were investigated and the results are
presented in Fig. 4. The absorbance ranges recorded for
control, BHT and sample were 0.0087–0.0151, 0.0021–
0.0093 and 0.0037–0.0104, respectively. The ethanolic
extract of K. alvarezii showed higher inhibitory effect than
Fig. 2. Ferrous ion-chelating activities of different solvent extracts of K. alvarezii.
Fig. 3. Reducing powers of K. alvarezii extracts, along with a synthetic antioxidant.
K.S. Kumar et al. / Food Chemistry 107 (2008) 289–295 293
did the positive control, BHT. This might be due to the
presence of ascorbic acid and vitamin A (b-carotene) con-
tent in the extract of K. alvarezi (Fayaz et al., 2005).
Algal polysaccharides play an important role as free rad-
ical-scavengers in vitro and antioxidants for the prevention
of oxidative damage in living organisms. Their activity
depends on several structural parameters, such as the degree
of sulfation (DS), the molecular weight, the sulfation posi-
tion, type of sugar and glycosidic branching. Moreover,
some reports reveal that the sulfate and phosphate groups
in the polysaccharides lead to differences in their biological
activities. In vitro antioxidant activity of j-carrageenan oli-
gosaccharides and their oversulfated, acetylated, and phos-
phorylated derivatives have been reported by Yuan et al.
(2005b). They also reported that phosphorylated and sul-
fated glucans exhibited better antioxidant ability than did
glucans or other neutral polysaccharides, which indicates
that polyelectrolytes, such as glucan sulfate or phosphate,
might have increased scavenging activity. Moreover, the sul-
fate content of polysaccharides from Porphyra yezoensis
was reported to contribute to the antioxidant activity. The
cell wall of K. alvarezii is known to be constituted of carra-
geenan, a sulfated polysaccharide, which may contribute to
its antioxidant potential in addition to the presence of ascor-
bic acid, vitamin A and various phenolics.
4. Conclusion
In the present investigation, the various solvent extracts
of K. alvarezii exhibited excellent scavenging effect (%) by
assay, reducing power, ferrous ion-chelating activ-
ity and antioxidant property in the linoleic acid system.
Thus they could be used in nutraceutical and functional
food applications. Since this is a preliminary study, a
detailed investigation on the compositions of each compo-
nent involved is absolutely necessary to establish appropri-
ate applications which may open new frontiers for human
consumption of this seaweed world-wide.
The authors are grateful to Dr. Pushpito Ghosh, Direc-
tor, Central Salt & Marine Chemicals Research Institute,
Bhavnagar, Gujarat, India for his constant support and
encouragement. They also appreciate Discipline Co-ordi-
nator, Marine Biotechnology and Ecology Discipline, for
providing research facilities and profusely thank the
Department of Biotechnology (Sanction No: BT/PR
3309/PID/03/139/2002), New Delhi, India for providing
financial assistance.
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... Fucoxanthin is one of the most abundant carotenoids in nature and its content varies over the seasons and life cycles of the algae [58]. When present in the thallus of seaweeds, this accessory pigment is quite stable in the presence of organic ingredients, apart from surviving the drying process and storage at ambient temperature, however, fucoxanthin in pure form is susceptible to oxidation [59]. A. ensiformis also presented high levels of carotenoids and fucoxanthin, similar to those found in Sargassum linearifolium (Turner) C. Agardh and Spatoglossum asperum J. Agardh [41]. ...
The consumption of seaweed has grown notably due to its use in the food, cosmetic and pharmaceutical industries, as well as organic fertilizers and biofuel, among others. Species of Asperococcus have antioxidant and antitumor properties and synthesize abundant amounts of fucoidans with important anticoagulant properties. In this study, the biochemical characterization of the A. ensiformis sporophytes was performed: organic matter, alginates, fucoidans, total carbohydrates and proteins content, pigments, polyphenols and antioxidant activity. Also, its life cycle was described and the best culture conditions were identified to optimize the hatchery phase. Three incubation temperatures 8, 12 and 16 °C and six nutrient concentrations were evaluated: three with Provasoli culture medium (PES) and three with PES + Kelpak® (a commercial biostimulant based on algae). Asperococcus ensiformis presented a heteromorphic life cycle, alternating between microscopical branched filaments (gametophytic phase) and an erect macroscopic stage (sporophytic phase). The biochemical composition of the A. ensiformis sporophytes showed a relatively low carbohydrate and protein content, but a high yield of alginates and fucoidans, and high polyphenol content and antioxidant activity. In the culture assays, the highest survival and colonization on seed-rope of gametophytes were achieved at 12 °C and high PES concentrations. The colonization of sporophytes on the seed-ropes at the end of the experiment was similar at the different temperatures, but the highest survival and growth were at 8 °C and low PES and PES + Kelpak® concentrations. This study emphasizes the need to analyze the industrial potential of A. ensiformis, through its biochemical characterization and optimization of crops, using different temperatures and traditional nutrients, as well as biostimulants based on seaweeds.
... Their results showed that the phenolic compounds from red seaweed Kappaphycus alvarezii could exhibit excellent antioxidant activity. So the authors discussed and concluded that the antioxidant activity of κ-carrageenan oligosaccharides may result from the extracts of red algae [139]. Since this is a preliminary study, a detailed investigation to elucidate the relationship between the component structure and antioxidant activity is still in needed. ...
Carrageenan, a kind of water-soluble linear sulfated polysaccharide with excellent stability and gel-forming properties, has been widely used in food and cosmetic industries. Carrageenan oligosaccharides, as the degradation products of carrageenan, possessed versatile physiological activities as well as other excellent properties such as their lower molecular weight, better water solubility and higher absorption efficiency. Additionally, the biological activities of carrageenan oligosaccharides are closely related to their structure, especially the number and position of sulfate groups. This review aimed to comprehensively summarize the methods of preparation, structural characteristics, and the biological activities of carrageenan oligosaccharides. The biological mechanisms underlying the health benefits of carrageenan oligosaccharides are also elaborated in order to provide guidance for application of carrageenan oligosaccharides as marine sources in pharmaceutical and agricultural industries.
... The world production of Kappaphycus species is approximately 28000 tons per annum. This seaweed accounts for the largest consumption worldwide [5]. ...
Seaweed contains many biofunctional compounds such as pigment and antioxidants that have the utility to inhibit degenerative diseases that are caused by reactive species oxygen (ROS). This research aimed to measure the constituents of photosynthetic pigment and antioxidant activity of brown seaweed Sargassum sp. from North Sulawesi. Sargassum sp. was extracted using n-hexane, acetone, and ethanol by the maceration method. The research consisted of chlorophyll (a, b, and C1+C2), fucoxanthin, carotenoid, phycocyanin and phycoerythrin, total phenol content (TPC), scavenging radical activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP). The result exhibited that the hexane extract contained higher chlorophyll a and fucoxanthin than ethanol extract. The TPC values of acetone and ethanol extract of sargassum sp extract were 45.382 ± 3.023 and 44.885 ± 2.834 μg GAE (Galic Acid Equivalent) g-1 extract, respectively. Acetone extract of Sargassum sp. had a lower antioxidant activity of DPPH radical scavenger (IC50 2.966±0.178 mg mL-1) than ethanol extract IC50 2.684±0.256 mg mL-1 extract). The FRAP value of acetone and ethanolic extract of S.olygocystum were respectively 14.45±1.425 and 9.09±0.876 μM Fe2+ mg-1. The Sargassum extract is a potential natural source of natural pigment and antioxidant.
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Introduction: Arsenicis one of the heavy metals found in drinking water andone of the free radical generators. In
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Antioxidant potential, carbohydrate content, ash, minerals, proteins, and amino acids of Kappaphycus alvarezii farmed along the São Paulo coast, Brazil, were evaluated to support the best use of four strains and new applications with added value. Ash content ranged from 25.60 to 11.65%. Mineral contents varied from 10,130.90 ± 1,613.78 mg (100 g)⁻¹ DW (summer 2018) to 12,561.20 ± 2,190.72 mg (100 g)⁻¹ DW (summer 2017), and the highest mineral contents occurred in the green strain. Carbohydrate levels varied from 122.92 ± 15.11 mg g⁻¹ DW (summer 2017) to 231.79 ± 16.86 mg g⁻¹ DW (winter 2017), and the highest carbohydrate value was observed in the G11 strain. The highest protein amount was observed in the brown strain with 8.79 mg (100 g)⁻¹ DW. The highest antioxidant potential of K. alvarezii was in spring 2017 for the brown strain. Total phenolic content ranged from 41.77 ± 15.41 to 366.58 ± 109.17 mg GAE g⁻¹ DW, DPPH activity ranged from 13.29 ± 1.20 to 61.07 ± 3.43%, FRAP ranged from 58.73 ± 3.96 to 105.54 ± 6.60%, and ABTS varied from 95.29 ± 4.31 to 112.52 ± 1.41%. Therefore, nutritional and antioxidant properties of K. alvarezii varied according to strains and seasons, with the best result in the spring of 2017. In summer and autumn of 2017, the green strain had better nutritional and antioxidant profiles, whereas in the winter of 2017 and spring of 2017 it was the G11 strain and in the summer of 2018 it was the red strain.
Marine macroalgae and their derivatives have been studied for its potential biological activities to produce novel medicinally valued compounds. In the current study, the brown seaweed Sargassum wightii was studied for phytochemical screening FTIR analysis and potential antioxidative activities. Six different solvents namely petroleum ether, benzene, chloroform, ethyl acetate, methanol and ethanol were used to study the in vitro antioxidant activity using different assays viz; DPPH, hydroxyl, superoxide, ABTS and reducing power. Fourier Transform Infrared Spectroscopy (FTIR) analysis was carried out to identify the functional group present in the seaweed sample. Maximum DPPH (138.36% and IC 50 28.64 µg/ml) and Hydroxyl (119.19% and IC 50 21.89 µg/ml) radical-scavenging activity of ethyl acetate extract was recorded whereas methanol extract showed enhanced superoxide radical scavenging activity (139.90% and IC 50 24.56 µg/ml). Maximum ABTS radical scavenging activity (128.09% and IC 50 23.66 µg/ml) was recorded for ethanol extract. The reducing power of the sample was in the following order: methanol > ethanol > Petroleum ether > Ascorbic acid > ethyl acetate > Benzene > chloroform. Hence, these extracts could be considered as natural antioxidants and may be useful for curing diseases arising from oxidative deterioration.
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Background The exposure of crops to a variety of fungal and bacterial pathogens leads to huge economic losses. Different strategies are being adapted to control these diseases among which the application of chemicals fungicide is common. However, these chemicals are posing a serious threat to the environment. For biological management of root rot disease of tomato and better fruit quality, studies were conducted on the possible use of endophytic yeast as a biocontrol agent. Results Endophytic yeasts were isolated from healthy plants and identified. Identification of selected isolates was confirmed on the basis of 18S rDNA gene sequencing. They were evaluated for suppressive effect on root rotting fungi in vitro and also in vivo on tomato plants, used alone or under neem cake soil amendment. Seventy-six isolates of yeasts were evaluated against root rotting fungi Fusarium oxysporum, F. solani, Rhizoctonia solani and Macrophomina phaseolina using dual culture plate assay. Seventy-five isolates were found to suppress radial growth of F. oxysporum, F. solani and M. phaseolina by producing zones of inhibition or lysing the fungal hyphae. However, none of the isolates was found to inhibit R. solani in vitro . Most of the isolates also caused nematicidal activity at varying degree against Meloidogyne javanica. All test isolates produced indole acetic acid in vitro and solubilized phosphorus. In pots and field plot experiments, test isolates of yeasts were able to suppress root rotting fungi on tomato in natural soil and soil amended with neem cake with enhancement of growth of tomato plants. Yeasts were also found to ameliorate the plant resistance through enhancing polyphenolic contents, salicylic acid and antioxidant activity. Conclusions Endophytic yeasts were found effective against root rot disease of tomato and could be used as a potential biocontrol agent for the management of soil-borne diseases of tomatoes.
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Arsenic is one of the heavy metals found in drinking water and one of the free radical generators. In comparison, the blue protein C-phycocyanin occupies a unique role among the many bioactive components of Spirulina due to its applications in the food industry and the treatment of some diseases. AL-Yasiri T, Alchalabi SMM. Use Of C-phycocyanin‎‎ To Reduce The Toxicity Of Arsenic On Rats. Natural Volatiles and Essential Oils, 2021; 8(4): 4460-4471
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Research background. Microalgae represent an emergent sustainable source of bioactive compounds such as antioxidants, vitamins, minerals and polyunsaturated fatty acids that can ameliorate the nutritional characteristics of foods. The biochemical composition of microalgae could be modulated by varying the culture conditions to enhance the accumulation of biomolecules of interest. The aim of this work is to optimise the nutri-functional properties of two microalgae that can be used in food production. Experimental approach. Nannochloropsis gaditana L2 and Chlorella sp. SM1 were screened for growth, biochemical composition and radical scavenging activity employing four different growth media (algal, BG-11, f/2 and Conway) with different nutrient composition. The feasibility of using Chlorella sp. SM1 cultivated in BG-11 medium, in an under-investigated Mediterranean dairy product ricotta cheese and its effect on the sensory attributes was investigated. Additionally, Arthrospira platensis was used as reference in sensory analysis. Results and conclusions. Nitrate- and phosphate-rich media (BG-11 and algal) enhanced the biomass productivity. However, the highest lipid production (23.10 and 11.86 mg/(L·day) by strains SM1 and L2 respectively) and carbohydrate content (34.79 and 44.84% by SM1 and L2 respectively) were obtained with the nitrate-deficient f/2 medium. Regardless of the used medium, the lipid profile of Chlorella sp. SM1 and N. gaditana L2 remained adequate for different applications with >50% C16-18 as the main fatty acids. Significant increase in oleic acid (C18:1) content was recorded in response to nitrogen deficiency, being the highest in SM1 in f/2 medium (34%). Nitrogen deficiency was also found to enhance phenolic compound (expressed as gallic acid equivalents, 48.8 and 35.1 mg/g in SM1 and L2 respectively) and carotenoid contents (2.2 and 2.0 mg/g in SM1 and L2 respectively). Due to its interesting antioxidant potential, Chlorella sp. SM1 was used at different mass fractions (0.2, 1 and 1.5%) to enrich the ricotta cheese. The sample with 0.2% Chlorella sp. SM1 was found to give the most appreciated product. Novelty and scientific contribution. This study presents the production of an innovative ricotta cheese using Chlorella sp. as a functional ingredient, without altering the manufacturing procedure, while maintaining acceptable sensorial characteristics. The biochemical composition of the used strains varied depending on the culture medium composition, which enabled the accumulation of phytonutrients of interest.
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As a search for natural antioxidants from plant materials, strong antioxidative activity was observed in leaf waxes extracted from Eucalyptus species. A novel type of antioxidant was isolated from the leaf wax of Eucalyptus globulus and identified as n-tritriacontan-16, 18-dione. Antioxidative activities were determined by different methods; a thiocyanate method, a thiobarbituric acid method, a total carbonyl value method and a weighing test. The antioxidant showed remarkable antioxidative activity in a water/alcohol system and was more effective than α-tocopherol and BHA; however, it has no antioxidative activity in an oil system.
Water and organic extracts (diethyl ether, chloroform, ethyl acetate, acetone, ethanol and methanol) obtained from Hizikia fusiformis were screened on reactive oxygen species (ROS) scavenging assays (1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydrogen peroxide and hydroxyl radical) and lipid peroxidation (inhibition of linoleic acid oxidation) inhibitory assays. Water, methanol and ethanol extracts showed significant ROS radical scavenging activities. Water extracts showed high scavenging activities on hydrogen peroxide (around 76%) and DPPH radicals (around 75%) while it presented a moderate scavenging activity on hydroxyl radicals (around 54%). Comparatively higher ROS scavenging activities were recorded in hydroxyl radical and DPPH scavenging assays. DPPH radical scavenging activities were well correlated with the polyphenolic content. ROS scavenging and lipid peroxidation inhibition activities indicated that H. fusiformis might be a valuable natural antioxidative source containing both water and fatsoluble antioxidative components.