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J. Cosmet. Sci., 64, 193–205 (May/June 2013)
193
Effects of seaweed
Laminaria japonica
extracts on skin
moisturizing activity
in vivo
JAE-SUK CHOI, WOI SOOK MOON, JI NA CHOI,
KEE HUN DO, SUN HWA MOON, KWANG KEUN CHO,
CHAE-JEONG HAN, and IN SOON CHOI, RIS Center,
Industry-Academic Cooperation Foundation, Silla University, Republic of
Korea (J.-S.C., K.H.D, S.H.M., I.S.C.), Ecomine Co., Ltd., Republic of
Korea (W.S.M., J.N.C.), Department of Animal Resources Technology,
Gyeongnam National University of Science and Technology, Republic of
Korea (K.K.C), Department of Beauty Art, Graduate School of Beauty
Art, Youngsan University, Republic of Korea (C.-J.H.) Department of
Biological Science, Silla University, Republic of Korea (I.S.C).
Accepted for publication August 29, 2012.
Synopsis
Twelve species of edible seaweed from the coast of Korea were screened for skin moisturizing activity. We
placed the lead of a Corneometer on an approximately 6-cm2 test area of the forearm and measured both un-
treated skin (control) and skin treated with test moisturizing creams either containing or not containing 5%
water:propylene glycol (50:50) extracts of seaweeds. Over the 8-h observation period, the strongest activity
of the Laminaria japonica extracts occurred at the 2-h period. For the 10% extract, hydration with the L. ja-
ponica extract increased by 14.44% compared with a placebo. Transepidermal water loss (TEWL) was also
measured using a test cream with 10% L. japonica extract. For up to 8 h after applying the creams, TEWL
was decreased to 4.01 g/cm2, which was approximately 20% of that seen with the control. We suggest that
the L. japonica extract hydrates skin via the humectants and hydrocolloids that it contains. To confi rm the
safety of L. japonica extracts, we performed a patch test on human skin. The results suggested that at moder-
ate doses humans can safely use the extracts. For commercial applications, we evaluated the physicochemical
characteristics of the test cream products, including Hunter L, a, and b values; pH; refractive index; and coef-
fi cient of viscosity. L. japonica extract did not affect overall formulations of the test cream product in any of
the tested aspects. These results suggest that L. japonica extract is a promising ingredient in moisturizing
formulations.
INTRODUCTION
Skin is the most exposed organ of the human body and acts as the fi rst line of defense
against external insults. The appearance and function of skin are maintained by an important
Address all correspondence to In Soon Choi at ischoi@silla.ac.kr .
JOURNAL OF COSMETIC SCIENCE194
balance between the water content of the stratum corneum and skin surface. At least 10%
water is needed in the skin to keep it soft and fl exible. When the water content falls below
this level, keratin becomes progressively less fl exible. A variation in water content of only
1% can signifi cantly change its elasticity and permeability (1,2).
Moisturizer prevents the skin from drying and chapping, thus slowing the aging process.
A wide variety of moisturizing components are available in different formulations, such
as vegetable glycerin, rose water, jojoba oil, vitamin E oils, and sorbitol. However, there
remains a demand for a highly effective moisturizer with an excellent safety and effi cacy
profi le. Thus, for many years, there have been numerous attempts to develop new agents
capable of preventing and/or treating dry skin (2–4).
Interest in marine organisms as potential and promising sources of pharmaceutical
agents has increased in recent years (5,6). Seaweeds can act as a source of bioactive
compounds and are able to produce a great variety of secondary metabolites with dif-
ferent activities. Several cosmetic ingredients from seaweeds were recently shown to
have whitening (7), antiaging (8), and antiwrinkle effects (3), and can protect against
ultraviolet light (9).
However, few studies have measured the moisturizing effects of seaweed extracts (10).
In addition, there has been no report on the skin moisturizing activity of indigenous
seaweed species in Korea. Therefore, to develop a new moisturizer, we measured the
moisturizing effects of Korean indigenous seaweed extracts using a Corneometer and a
Tewameter. To confi rm the safety of the extract, we conducted a patch test for human
skin. For possible commercial application, we also measured the physiochemical char-
acteristics of the test cream products such as Hunter L, a, and b values; pH; refractive
index; and coeffi cient of viscosity.
MATERIALS AND METHODS
SEAWEED EXTRACTS
Seaweed thalli were collected from the coast of Korea from November 2005 to April
2006. Twelve edible seaweed species (four of Chlorophyta, six of Phaeophyta, and two
of Rhodophyta) were used in this study. Seaweed tissues were dried for 1 day at room
temperature using an electric fan and then ground into powder using a coffee grinder
for 10 min. For the water/propylene glycol extraction, we used the methods described
by Mekideche and Briand (10). To each 5 g of powder, 100 mL of 50% water/50%
propylene glycol was added at room temperature for 1 day to extract the water/propylene
glycol-soluble components. This procedure was repeated two times, and the combined
extracts were stored at −20°C until use.
TEST CREAM WITH SEAWEED EXTRACT
To determine in vivo skin moisturizing activity, test creams were made with the 12
seaweed extracts. The test creams were kindly supplied by Silla B&H Co., Ltd. (Busan,
Korea). The formulations studied (Table I) were prepared in a PRIMIX RM homomixer
L. JAPONICA EXTRACTS AS A MOISTURIZER 195
(PRIMIX Co., Ltd., Osaka, Japan) at 3000 rpm within 10 min and supplemented with
different concentrations (%) (W/W) of seaweed extract. A placebo formulation was prepared
without seaweed extract. The proximate compositions, free amino acid compositions and
mineral contents of the selected seaweed water/propylene glycol extracts were also measured
following the Korea Food and Drug Administration guidelines (KFDA) (11).
MEASUREMENT OF SKIN MOISTURIZING ACTIVITY USING A CORNEOMETER
We measured the skin moisturizing effects of the extracts using a Corneometer based on
the methods of Dal’Belo et al. (4). The water content of the stratum corneum was mea-
sured with a skin capacitance meter (Corneometer CM 825; Courage & Khazaka Elec-
tronic GmbH, Cologne, Germany). This device determines the water content of the
superfi cial epidermal layers down to a depth of approximately 0.1 mm and expresses the
values in arbitrary units. Therefore, the moisture level of the treated skin was expressed
as increased hydration (%) compared with untreated skin (10).
Ten women (median age, 27 years; range, 24–31 years) participated in the study after provid-
ing informed consent. Biophysical measurements were made on the inner forearm. We placed
a Corneometer lead on a test area of approximately 6 cm2 on the forearm. The dose in each
case was 8 µl/cm2. All data were obtained on the same day from each individual, and the
average values of 10 measurements per site were used in subsequent calculations. Prior
to all measurements, each subject washed her forearm with a liquid hand wash and then
Table I.
Formulation of the Test Cream Containing Seaweed Extract
INCI Percentage of components (W/W)
Water (aqua), demineralized as 100%
Seaweed extract 0–15.00
Disodium EDTA 0.10
Butylene glycol 6.00
Methylparaben 0.20
Triethanolamine 0.25
Sorbitan stearate, sucrose cocoate 4.50
Sorbitan sesquioleate 0.50
Polysorbate 60 0.50
Stearic acid 1.50
Cetearyl alcohol 1.50
Cetyl ethylhexanoate 8.00
Captylic/capric triglyceride 2.00
Gyclomethicone 4.00
Limnanthes alba seed oil 2.00
Dimethicone 0.50
Tocopheryl acetate 0.20
Propylparaben 0.10
Carbomer 0.25
JOURNAL OF COSMETIC SCIENCE196
allowed at least 30 min for full skin acclimation to room temperature (20°C ± 2°C) and
humidity (45%–60%) (12).
First, to screen for potential skin moisturizing activity, test creams with 5% of each of the
12 seaweed extracts were used for treatment. At 2 h after application of the creams, the in-
creased hydration status of the treated skin compared with that of the untreated skin was
measured, and the seaweed that exhibited the strongest moisturizing activity was selected.
To fi nd the best concentration, the moisturizing activity of the selected seaweed that showed
the highest activity was determined at 0%, 1%, 3%, 5%, 7%, 10%, and 15% concentra-
tions. At 2 h after application of the creams, the increased hydration compared with un-
treated skin was measured. To confi rm the hydration-lasting effect of the test cream
containing 10% of the selected seaweed extract, we measured skin moisturization at 0, 3, 5,
10, 15, and 30 min, and 1, 1.5, 2, 4, 6, and 8 h after application of the creams.
TEWL MEASUREMENTS USING THE TEWAMETER
To assess skin barrier function, the transepidermal water loss (TEWL) of the test cream
with the selected seaweed extract was measured with an evaporimeter (Tewameter
TM210; Courage & Khazaka Electronic GmbH, Cologne, Germany). TEWL measure-
ments were performed according to the relevant guidelines (13,14), and the instrument
was registered in g/m2h for 2 min after probe equilibration on the skin for 30 s. To deter-
mine the best concentration, the TEWL of the selected seaweed was determined at 0%,
1%, 3%, 5%, 7%, 10%, and 15% concentrations 2 h after application of the creams. To
confi rm the hydration-lasting effect of the test cream containing 10% of the selected
seaweed extract, we measured TEWL at 0, 3, 5, 10, 15, and 30 min, and 1, 1.5, 2, 4, 6,
and 8 h after application of the creams.
PATCH TEST
The patch test procedure was conducted as previously described (15) to confi rm safety of
the extracts for human skin. The patch test was performed using the test cream contain-
ing 10% L. japonica extract on 25 human volunteers, of whom 20 were female and 5 were
male. Subject age varied from 22 to 28 years, and the average age was 25.5 years. The
quantity of test cream applied per test patch was 20 µl (20 mg for solid test materials).
The test articles were dispensed onto Finn Chambers (Epitest, Ltd., Tuusula, Finland) on
Scanpor tape (Alpharma, Oslo, Norway), and the patch was applied to normal skin on the
forearm. The patch was removed up to 48 h after patch application. The treatment
sites were assessed for the presence of irritation using a 5-point scale 6 h after patch removal.
The degree of irritation was evaluated by visual scoring according to the following scale
with grading defi ned as: 0 = no reaction; 0.5 = barely perceptible, very weak spotty erythema;
1 = slight erythema, either spotty or diffuse; 2 = moderate erythema; and 3 = intense
erythema, infi ltration, and possible vesicles (16).
PHYSIOCHEMICAL CHARACTERISTICS OF THE TEST CREAM PRODUCTS
For possible future application in moisturizing agents and cosmetic products for dry skin,
the physiochemical characteristics of the test cream products containing 10% L. japonica
L. JAPONICA EXTRACTS AS A MOISTURIZER 197
were measured, including Hunter L, a, and b values; pH; refractive index; and coeffi cient
of viscosity. Test cream color was measured by a color difference meter (Spectrophotometer
CM-700d; Konica Minolta Sensing, Inc., Tokyo, Japan). The numerical value of the
color was expressed by Hunter L, a, and b values. The Hunter values were monitored by
a computerized system using SpectraMagic software (version 2.11; Minolta Cyberchrom
Inc., Osaka, Japan). The overall color difference (ΔE) was calculated using the equation
1
222
2
ªº
' ' ' '
¬¼
EL a b
. According to the Cosmetic Standard and Experimental Method
(No. 2007-45) by the KFDA (17), after 10-fold dilution with distilled water, the pH of the
cream was measured at 25°C using the pH meter SevenEasy pH S20K (Mettler-Toledo
GmbH, Greifensee, Switzerland). The refractive index of the cream was measured at 25°C
using an ABBE Refractometer DR-A1 (ATAGO Co., Ltd., Tokyo, Japan). The viscosity of
the cream was measured in spindle No. SC4-25 at 1 rpm and 25°C using a Brookfi eld
viscosity meter (Brookfi eld programmable DV-III+RHEOMETER, Stoughton, MA).
STATISTICAL ANALYSES
All experiments were performed at least three times independently. Differences between
groups were calculated using a Student’s t-test. Results were deemed statistically signifi -
cant at p < 0.05.
RESULTS
SCREENING OF SKIN MOISTURIZING ACTIVITY
Of the 12 seaweed species screened for their potential skin moisturizing activity, the test
creams containing 5% Codium fragile, Ecklonia cava, Enteromorpha linza, and Undaria pinnatifi da
extracts showed no skin moisturizing effect compared with the placebo cream (17.05%;
Figure 1). Test creams containing 5% Capsosiphon fulvescens, Hizikia fusiformis, and Sargassum
horneri exhibited 19.09%, 18.95%, and 18.16%, respectively, showing slight moisturizing
effects. The test cream containing 5% Gracilaria verrucosa, Laminaria japonica, Porphyra yezoen-
sis, S. sagamianum, and Ulva pertusa showed considerable moisturizing activity; the increased
hydration percentage compared with untreated skin was 20.32%, 28.71%, 23.46%, 24.27%,
and 19.99%, respectively. Among them, the strongest activity was exhibited by L. japonica.
For this reason, we selected and tested this species for the next assay. Analysis of the L. japonica
water/propylene glycol extracts revealed various nutritional components, such as carbohy-
drates, proteins, crude fat, free amino acids, sugars, minerals, etc. (Table II).
SKIN MOISTURIZING ACTIVITY OF L. JAPONICA EXTRACT
To identify the concentration that showed the highest activity, we measured the
moisturizing activity of the cream containing L. japonica at different concentrations.
These results are shown in Figure 2. In the test cream without the extract, the mois-
ture level of skin was increased by 17.02%; when the same cream with 1%, 3%, 5%,
7%, 10%, and 15% extract was used for treatment, the moisture level of skin was
increased by 21.31%, 24.21%, 27.31%, 29.16%, 31.46%, and 30.72%, respectively.
In the L. japonica cream-applied group, the increased concentration of seaweed
JOURNAL OF COSMETIC SCIENCE198
extracts reasonably and dose-dependently increased the hydration compared with un-
treated skin from 0% to 10%. However, with the 15% concentration, the moisture
level decreased.
To confi rm the length of hydration from the test cream containing 10% L. japonica ex-
tract, we measured skin hydration at different times after application of the creams. Both
with and without the extract, the hydration percentage was increased immediately and
continued to decrease over time (Figure 3). The hydration percentage of skin was 73.78%
with the test cream without the extract; when the same cream containing 10% extract
was used for treatment, the hydration percentage of skin was 94.22%, which was 20.44%
higher than that in the placebo. From 1 to 2 h, the moisturizing cream containing L.
japonica extract increased skin hydration approximately 1.5 times more than did the same
cream without the extract. At 8 h after application, the increased skin hydration percent-
age of skin treated with the test cream containing the extract was 18.70%, and that of the
test cream without the extract was 15.81%. Namely, the hydration effect of the test
cream containing 10% L. japonica extract lasted for 8 h, the time tested, showing the
strongest activity at the 2-h period.
TEWL OF L. JAPONICA EXTRACT
To determine the best concentration, the TEWL of the treated skin was determined for
0%, 1%, 3%, 5%, 7%, 10%, and 15% concentration test creams with L. japonica at 2 h
after application. These results are shown in Figure 4. In the test cream without the ex-
tract, the TEWL of skin was 8.67 g/cm2; when the same cream containing 1%, 3%, 5%,
7%, 10%, and 15% extract was used for treatment, the TEWL of the skin was 8.25, 7.90,
7.06, 6.76, 6.54, and 6.70 g/cm2, respectively (Figure 4). The TEWL of skin without any
test cream was 12.22 g/cm2. Among these test groups, the lowest TEWL was exhibited
Figure 1. The 12 seaweed species from which extracts were obtained (Pla: Placebo control, Cfr: Codium frag-
ile, Cfu: Capsosiphon fulvescens, Eca: Ecklonia cava, Eli: Enteromorpha linza, Gve: Gracilaria verrucosa, Hfu:
Hizikia fusiformis, Lja: Laminaria japonica, Pye: Porphyra yezoensis, Sho: Sargassum horneri, Ssa: S. sagamianum,
Upe: Ulva pertusa, and Upi: Undaria pinnatifi da). The moisture content of skin was measured 2 h after apply-
ing the formulations containing 5% seaweed extract. All measurements were performed in triplicate, and
values are an average of three replications. Differences were considered signifi cant at *p < 0.05, and **p < 0.01
versus the placebo control.
L. JAPONICA EXTRACTS AS A MOISTURIZER 199
at a concentration of 10% L. japonica. However, at a concentration of 15%, the TEWL of
skin was slightly increased.
To confi rm the duration of TEWL-preventing effects, we measured TEWL at 0, 3, 5, 10,
15, and 30 min, and 1, 1.5, 2, 4, 6, and 8 h after application of the creams containing
10% L. japonica extracts. Within 5 min after application of the creams, the TEWL level
was very large both with and without the cream. From 10 min to 2 h, the TEWL was
dramatically reduced. Overall, in the testing group, the TEWL of skin treated with the
test cream containing the extract was lower than that without cream (Figure 5). At 8 h
after application, the TEWL of skin treated with the test cream containing the extract
was 4.01 g/cm2, and that of the test cream without the extract was 5.10 g/cm2.
PATCH TEST
To confi rm safety of the extracts for human skin, a patch test was performed on 25 human
volunteers. When the 20 mg per test patch was applied with the test cream, none of the 25
subjects developed erythema, cellular infi ltration, or vesicles. Based on these results, we
suggest that the L. japonica extract is not irritating to normal human skin at moderate doses.
Table II.
Proximate Compositions, Free Amino Acid Compositions and Mineral Contents
of the L. japonica Water/ Propylene Glycol Extracts
Compositions Unit Contents
Proximate compositions Carbohydrate g/100g 0.6
Sugars g/100g 0.5
Proteins g/100g 0.2
Crude fat g/100g 0.2
Saturated fatty acid g/100g 0.1
Unsaturated fatty acid g/100g -
Free amino acids Alanine mg/100mL 4.23
Ammounium chloride mg/100mL 1.62
Arginine mg/100mL 2.03
Aspartic acid mg/100mL 42.47
Glutamic acid mg/100mL 68.94
Glycine mg/100mL 0.17
Hydroxyproline mg/100mL 38.14
Phosphoserine mg/100mL 0.37
Serine mg/100mL 0.86
Threonine mg/100mL 0.42
Minerals Na mg/100g 40.4
Ca mg/100g 30.0
K mg/100g 102.2
Mg mg/100g 3.5
Fe mg/100g 0.05
Zn mg/100g 0.02
JOURNAL OF COSMETIC SCIENCE200
PHYSIOCHEMICAL CHARACTERISTICS OF THE TEST CREAM PRODUCTS CONTAINING 10% L. JAPONICA
For possible future application in cosmetic products and therapeutic agents for skin hy-
dration, the physiochemical characteristics of the test cream products containing 10% L.
japonica were measured, including chromaticity (as Hunter L, a, and b values), pH, refrac-
tive index, and coeffi cient of viscosity. These results are shown in Table III. Whereas the
L value and Hunter color a value of the test cream without extract were 86.12 and −0.14,
respectively, the L and a values of the test cream containing 10% L. japonica extract were
80.64 and −0.84, respectively, a notable decrease. Although the Hunter color b value of
the creams increased from 1.01 to 4.91, adding 10% L. japonica extract showing b values
Figure 2. Effect of Laminaria japonica extract on skin moisturization at different concentrations. The mois-
ture content of skin was measured 2 h after applying the formulations containing different concentrations of
the seaweed extract. All measurements were performed in triplicate, and values are an average of three repli-
cations. Differences were considered signifi cant at *p < 0.05 and **p < 0.01 versus the control.
Figure 3. Moisturizing profi le of creams without ( ) and with (䊏) 10% Laminaria japonica extract. The
moisture content of skin was measured at different times after applying the formulations containing 10%
seaweed extract. All measurements were performed in triplicate, and values are an average of three replica-
tions. Differences were considered signifi cant at *p < 0.05, **p < 0.01, and ***p < 0.001 versus the control.
L. JAPONICA EXTRACTS AS A MOISTURIZER 201
was notably increased. The overall color difference (ΔE) was 6.76, which was not a dra-
matic color change. With the addition of 10% L. japonica extract, the pH of the test
cream changed from 6.35 to 5.91, perhaps as a result of the lower pH (5.60) of L. japonica
extract itself. According to Notifi cation No. 2009-158 of the KFDA, the normal pH
range of cosmetics is between 3.0 and 9.0. Therefore, L. japonica extracts are suitable for
cosmetic products. The refractive index of the cream with and without 10% L. japonica
extract was 1.3543 and 1.3727, respectively. The coeffi cient of viscosity was 68, 945 Cp
(centipoise) and 124,333 Cp, respectively, and this may have resulted from the lower
viscosity of L. japonica extract itself. For all tested aspects, L. japonica extract did not affect
the overall formulations of the test cream product.
Figure 5. TEWL of cream without ( ) and with (䊏) 10% Laminaria japonica extract over time. The TEWL
of skin was measured at different times after applying the formulations containing 10% seaweed extract. All
measurements were performed in triplicate, and values are an average of three replications. Differences were
considered signifi cant at **p < 0.01 and ***p < 0.001 versus the control.
Figure 4. Effect of different concentrations of Laminaria japonica extract on TEWL. The TEWL of skin was
measured 2 h after applying the formulations containing different concentrations of seaweed extract. All
measurements were performed in triplicate, and values are an average of three replications. Differences were
considered signifi cant at *p < 0.05 versus the control.
JOURNAL OF COSMETIC SCIENCE202
DISCUSSION
Because skin is the most exposed organ of the human body, and because water determines
the softness and smoothness of skin, moisturizers are most commonly used to treat dry
skin. Skin hydration depends on the equilibrium between water transferred by osmosis
from the dermis to the epidermis and water lost from the surface by evaporation. Dehy-
dration of the upper layer of the skin results when water is lost from the stratum corneum
more rapidly than it is received from the lower layer of the skin. Dry skin is also the result
of loss of the horny layer of lipids. Dry skin is brittle and rough, although it is constantly
supplied with water from inside the body (18).
Moisturizers are used to treat dry and irritated skin as well as atopic dermatitis and ich-
thyosis. A wide variety of moisturizers are currently available, but there remains a de-
mand for a highly effi cacious moisturizer with an excellent safety and effi cacy profi le.
Thus, for many years, there have been numerous attempts to develop new agents capable
of preventing and/or treating dry skin.
Intertidal seaweeds are periodically exposed to air and experience a variety of potentially
stressful environmental conditions, including nutrient limitation, high light, high and
low temperatures, desiccation, and osmotic stress (19). To overcome these situations,
seaweeds produce a great variety of secondary metabolites with different activities. These
biologically active secondary metabolites are valuable natural ingredients for cosmetics
(7–9,20). In particular, seaweed polysaccharides such as fucoidan, carrageenan, alginates,
and agar have been used as excipients in cosmetic formulae because of their high gelling,
bonding, and viscosity-increasing properties (3). However, until now, few studies have
measured the moisturizing effects of seaweed extracts (10). In addition, there has been no
report on the skin moisturizing activity of indigenous seaweed species in Korea. For these
reasons, we evaluated the skin moisturizing activities in easily collectible and edible in-
tertidal seaweeds.
It is generally accepted that there are two major strategies for the measurement of skin
moisturizing effects. The fi rst is to assess skin hydration by measuring the water content
of the stratum corneum using a Corneometer. The second is to assess skin barrier function
by measuring the TEWL using a Tewameter.
Table III.
Physiochemical Characteristics of Test Cream Without (a) and With (b) Laminaria japonica Extract.
All Measurements Were Performed in Triplicate, and Values are an Average of Three Replications.
Differences Were Considered Signifi cant at p < 0.05
Test cream products
ab
pH 6.35 5.91
Refractive index(nD) 1.3543 1.3727
Viscosity (cps) 124,333 68,945
Color value
(Lightness, L) 86.12 80.64
(Redness, a)−0.14 −0.84
(Yellowness, b) 1.01 4.91
ΔE Value — 6.76
L. JAPONICA EXTRACTS AS A MOISTURIZER 203
First, we compared the skin moisturizing activity of 12 seaweed species collected in Korea;
L. japonica showed the highest activity and was chosen for this study. In a previous study
(10), Codium fragile collected in France showed potent skin moisturizing activity; how-
ever, in our results, Codium fragile from Korea did not show any effects. These results may
be caused by variations in cellular chemical compositions and biological activities accord-
ing to season, habitat, and different thalli in seaweed (21).
When we were measured the increased skin hydration abilities of L. japonica creams at
different concentrations, the highest activity was shown at 10%. When we measured the
moisture level at different times after application of the 10% L. japonica extract cream,
the moisturizing effect lasted up to 8 h, which was an increase of >15% compared with
the placebo cream, showing the strongest activity at the 2-h period. It is generally ac-
cepted that when a new challenger agent is tested, if the skin moisturizing property is
greater than 10%–20% compared with the placebo, the new agent is regarded as having
moisturizing activity (22). In our results, 10% L. japonica extract showed favorable mois-
turizing capacity of >15% compared with the placebo.
When we evaluated the skin barrier function of L. japonica cream at different concentra-
tions, the lowest TEWL was exhibited by the 10% extract. TEWL was dramatically re-
duced beginning immediately after the cream application to 10 min, and did not decrease
until 2 h. After applying moisturizer, there are two types of TEWL measurements that
can be done. One is when lipid formulations such as petrolatum are applied to the skin,
evaporative water loss is immediately reduced due to closing of the stratum corneum by
a specifi c lipid(s). Another is that within 15 min after applying a moisturizer, a large
amount of water evaporation from the skin surface occurs in the oil-in-water (O/W)
emulsion or an aqueous cosmetic solution (23,24). In this study, because the formulation
of the test cream was an O/W emulsion, this tendency was observed.
Although the effi cacy and mechanisms underlying the effects of moisturizers remains a
topic of controversy, occlusives, humectants, and hydrocolloids can be used to improve
skin moisturization. Occlusive moisturizers (e.g., petrolatum, lanolin, mineral oil, vege-
table oil, acetyl alcohol, cholesterol, ceramides, and silicones) are oily substances that
retard TEWL. Humectants (e.g., glycerin, propylene glycerol, polysorbate 30, polyglyceryl-3,
sorbitol, gelatin, urea, sodium lactate, vitamins, and proteins) are hydroscopic substances
that draw water from the viable epidermis/dermis to the stratum corneum. Hydrocolloids
(e.g., colloidal oatmeal and proteins in moisturizers) are large molecular weight sub-
stances that form an artifi cial membrane (25).
L. japonica is commonly used as a foodstuff in Korea and Japan and is reported to contain
various nutritional contents (26). In our study, the solids content of L. japonica water/
propylene glycol extracts was 25.2 mg/ml. We found that there are several different nu-
tritional components, such as carbohydrates, proteins, free amino acids, sugars, and min-
erals, in the L. japonica water/ propylene glycol extracts (Table II). In our results, the test
cream containing 10% L. japonica increased skin moisture immediately and over time.
We suggest that the L. japonica extract addresses skin hydration via two mechanisms.
First, hydroscopic substances such as free amino acids, sugars, and minerals that draw
water from the viable epidermis/dermis to the stratum corneum, and the diffusion of
these materials through the superfi cial epidermal layers, reinforces the activity of the
natural moisturizing factors in skin that help to retain appropriate moisture levels in the
epidermis. Second, phycocolloids such as alginate and protein in seaweed extracts attach
JOURNAL OF COSMETIC SCIENCE204
to skin proteins to form a protective barrier for both immediate and long-term regulation
of moisture loss.
To confi rm the safety of the L. japonica extracts, we performed a patch test for human skin. The
results suggest that the extracts can be safely used by humans at moderate doses. In addition,
for commercial applications, we evaluated the physiochemical characteristics of the test cream
products, including Hunter L, a, and b values; pH; refractive index; and the coeffi cient of
viscosity. L. japonica extract did not affect overall formulations of the test cream product in any
of the tested aspects. Regarding odor, we confi rm that the extract added no objectionable odor
to the cream, but the cream itself has a mild odor, which likely masks that of the seaweed.
In conclusion, L. japonica extract used at 5%–10% in cosmetic formulations may consti-
tute an effective hydrating agent; it may become a promising and effective moisturizing
ingredient in face- and body-care product formulations. In addition, it has been reported
that L. japonica has additional benefi ts for the skin, such as antimicrobial (27), antioxi-
dant (28), and anti-infl ammatory activities (29). Therefore, it is expected that L. japonica
will be used as a promising cosmetic ingredient that possesses various biological activities
as well as skin moisturizing activity.
ACKNOWLEDGMENTS
This work was supported by the Global Healthcare Industry RIS Center, Ministry of
Knowledge Economy, Republic of Korea. Kwang Keun Cho was also supported by the
Priority Research Centers Program through the National Research Foundation of Korea
(NRF) funded by the Ministry of Education, Science and Technology (2012-006683),
Republic of Korea.
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