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6Ann Dermatol (Seoul)
Received April 21, 2008, Accepted for publication July 20, 2008
*A grant by Korea Food and Drug Administration (2004∼2005).
Reprint request to: Jin Ho Chung, M.D., Department of Dermatology,
Seoul National University Hospital, 28, Yeongeon-dong, Jongno-gu,
Seoul 110-744, Korea. Tel: 82-2-2072-2414, Fax: 82-2-742-7344, E-mail:
j
hchung@snu.ac.kr
Ann Dermatol (Seoul) Vol. 21, No. 1, 2009
ORIGINAL ARTICLE
Dietary Aloe Vera Supplementation Improves Facial
Wrinkles and Elasticity and It Increases the Type I
Procollagen Gene Expression in Human Skin in vivo
Soyun Cho, M.D., Ph.D.1,2,4, Serah Lee, M.S.3,4, Min-Jung Lee, M.S.3,4, Dong Hun Lee, M.D.2,
Chong-Hyun Won, M.D., Ph.D.1,4, Sang Min Kim, Ph.D.3,4, Jin Ho Chung, M.D., Ph.D.2,3,4
Department of Dermatology, 1Seoul National University Boramae Hospital, 2Seoul National University College of Medicine, 3Laboratory
of Cutaneous Aging Research, Clinical Research Institute, Seoul National University Hospital, 4Institute of Dermatological Science,
Medical Research Center, Seoul National University, Seoul, Korea
Background: No studies have yet been undertaken to
determine the effect of aloe gel on the clinical signs and
biochemical changes of aging skin. Objective: We wanted to
determine whether dietary aloe vera gel has anti-aging
properties on the skin. Methods: Thirty healthy female
subjects over the age of 45 were recruited and they received
2 different doses (low-dose: 1,200 mg/d, high-dose: 3,600
mg/d) of aloe vera gel supplementation for 90 days. Their
baseline status was used as a control. At baseline and at
completion of the study, facial wrinkles were measured
using a skin replica, and facial elasticity was measured by an
in vivo suction skin elasticity meter. Skin samples were taken
before and after aloe intake to compare the type I procollagen
and matrix metalloproteinase 1 (MMP-1) mRNA levels by
performing real-time RT-PCR. Results: After aloe gel intake,
the facial wrinkles improved significantly (p＜0.05) in both
groups, and facial elasticity improved in the lower-dose
group. In the photoprotected skin, the type I procollagen
mRNA levels were increased in both groups, albeit without
significance; the MMP-1 mRNA levels were significantly
decreased in the higher-dose group. Type I procollagen
immunostaining was substantially increased throughout the
dermis in both groups. Conclusion: Aloe gel significantly
improves wrinkles and elasticity in photoaged human skin,
with an increase in collagen production in the photopro-
tected skin and a decrease in the collagen- degrading MMP-1
gene expression. However, no dose- response relationship
was found between the low-dose and high-dose groups.
(Ann Dermatol (Seoul) 21(1) 6∼11, 2009)
-Keywords-
Aging, Aloe vera, Matrix metalloproteinase, Procollagen,
Wrinkles
INTRODUCTION
Skin aging is attributed to intrinsic (chronological) aging
and photoaging (extrinsic aging). Photoaging and intrinsic
aging are induced by damage to human skin by repeated
exposure to ultraviolet (UV) irradiation and the damage
due to the passage of time, respectively. An alteration in
collagen, which is the major structural component of skin,
has been considered to be a cause of skin aging in
naturally aged and photoaged skin. With increasing age,
there is a sustained reduction of collagen and an elevated
secretion of matrix-degrading enzymes called matrix
metalloproteinases (MMP) in old skin as compared with
young skin1. UV causes photoaging by generating reactive
oxygen species, and this subsequently triggers a cascade
of signaling mechanisms and this eventually causes a
decrease of collagen, and an increase of MMP, inflam-
mation, epidermal DNA damage and apoptosis. During
this process, activator protein 1 (AP-1) is activated by UV
irradiation and so AP-1-driven MMPs such as MMP-1 and
MMP-9 are induced. The UV-induced MMPs can degrade
collagen, which results in a collagen deficiency in pho-
todamaged skin and eventually skin wrinkling2.
Aloe Supplementation for Aging Skin
Vol. 21, No. 1, 2009 7
The discovery or development of a novel agent that can
delay the appearance of wrinkles and other features of
cutaneous aging has been the quest of the pharmaceutical
and cosmeceutical industries. Aloe barbadensis is com-
mercially known as aloe vera, and it is a substance for
which claims have been made about its anti-inflammatory,
healing, moisturizing, antibacterial, antifungal and anti-
viral properties3-5. The gel is obtained from the pulp of
aloe vera, a tropical cactus that belongs to the lily family,
and aloe has been used as folk remedy since Roman times
and it is now a familiar ingredient in a wide range of
healthcare and cosmetic products. The gel comprises the
inner, colorless part of the aloe vera leaf, and the exudate
from the outer layers is also used for therapeutic purposes.
Different gel constituents, including salicylates4, mag-
nesium lactate3, bradykinin or thromboxane6, and poly-
saccharides7,8 have been presented as the reasons for aloe
gel's efficacy. However, the biochemical basis for its
action or influence on tissue repair is just beginning to be
understood.
The reports concerned with the wound-healing effect of
aloe in experimental animals or humans have been
contradictory. In one such study, the incision wounds in
rats were rapidly healed by aloe gel and the effect was
attributed to more rapid maturation of collagen5. Other
researchers have suggested that aloe increases the oxygen
access of tissues as a result of an increased blood supply9
and others have suggested that aloe stimulates fibroblast
activity and collagen proliferation10. Mannose-6-phosphate
was identified as a cause of significant wound healing by
aloe11, and the healing by aloe was found to be accom-
panied by higher levels of hyaluronic acid and dermatan
sulfate, which were suggested to stimulate collagen
synthesis and fibroblast activity12. On the other hand,
controlled clinical trials in humans demonstrated no
benefit when aloe vera was incorporated into topical
therapy13, and one study demonstrated delayed wound
healing when aloe vera was incorporated14. Many of the
inconsistent clinical results obtained for the therapeutic
efficacy of aloe gel might have been caused by the history
of the sample after removal from the leaf, or even the
growing conditions of the plant15. No studies have yet
been undertaken to determine the effect of aloe gel on the
clinical signs and biochemical changes of cutaneous aging
and photoaging.
In this study, we investigated whether dietary aloe vera gel
supplementation affects facial wrinkles, elasticity and the
mRNA levels of type I procollagen and MMP-1 in human
skin in vivo, and we used a skin surface analyzing system
and biochemical methods to determine this.
MATERIALS AND METHODS
Subjects
A total of 30 healthy female subjects over the age of 45
and who passed a screening exam were randomized to
receive a low dose or a high dose of aloe. The exclusion
criteria included topical corticosteroid or retinoid use 2
weeks prior to study entry and use of systemic steroid,
vitamins or phototherapy 1 month prior to the study. The
subjects were not allowed to use anti-wrinkle/whitening
cosmetics, topical retinoids or chemical peels, or to take
any other functional food or vitamins during the study.
They were allowed to use sunscreen lotion with a Sun
Protection Factor of 30 or higher.
Aloe vera gel intake
The aloe vera gel liquid we used (manufacturer: Univera
Company, Seoul, Korea) is obtained by dissolving con-
centrated aloe vera gel powder in distilled water with
flavors. Two different concentrations of liquid were made
from the aloe vera gel powder (lower-dose: 1%, higher-
dose: 3%). The lower-dose group received 120 ml of 1%
aloe vera liquid, which is equivalent to 1,200 mg of aloe
vera gel/day; the higher-dose group received 120 ml of
3% aloe vera liquid, which translates to 3,600 mg of aloe
vera gel/day.
A complete blood count (CBC), liver function tests (LFT)
and urinalyses were conducted at baseline and at 90 days
after beginning the study. The subjects were instructed to
report any cutaneous or systemic adverse events after the
initiation of the study. For the subjects who agreed to
biopsies, skin samples were taken from the buttock skin
before and after aloe intake. The specimens for RT-PCR
analysis were snap-frozen in liquid nitrogen, and the
specimens for immunohistochemical staining were oriented
immediately in a cryomatrix (Shandon, Pittsburgh, PA,
USA) and then this was stored at −70oC.
This study was conducted according to the principles of
the Declaration of Helsinki. This study was approved by
the Institutional Review Board at Seoul National Uni-
versity Hospital, and all the subjects gave their written
informed consent.
Wrinkle and elasticity measurements
At baseline and after 90 days, facial wrinkles were mea-
sured in the crow's feet area using a skin replica and a
Visiometer SV 600 (Courage＋Khazaka Electronic, Köln,
Germany). The Visiometer is a computerized instrument
that makes a skin microrelief map from the replica using a
light transmission method. It has 5 roughness parameters:
depth of roughness (R1), mean depth of roughness (R2),
SY Cho, et al
8Ann Dermatol (Seoul)
maximum roughness (R3), depth of smoothness (R4) and
arithmetic average roughness (R5).
Facial elasticity was measured with a non-invasive, in vivo
suction skin elasticity meter Cutometer MPA 580 (Courage
＋Khazaka Electronic, Köln, Germany). The Cutometer
takes measurements based on the principle of suction
elongation, using an optical measuring unit. Of the mea-
sured and calculated R-parameters taken with the Cuto-
meter, certain ratios of the parameters are biologically
meaningful and these do not depend on skin thickness,
and so they can be compared between different skin sites
and subjects. In particular, R2 (gross elasticity), R5 (net
elasticity) and R7 (elasticity/complete curve) are known to
be indicators of skin elasticity, and the closer each value is
to 1, the more elastic the skin is.
All the measurements were performed in a controlled
environment room, with a constant room temperature
between 20 and 25oC and the humidity was between 45
and 55%, at the Clinical Research Institute, Seoul National
University Hospital.
Quantitative real-time RT-PCR
The total RNA was extracted from tissues using TRIZOL
reagent (Invitrogen Life Technologies, Carlsbad, CA, USA),
and 1μg of the total RNA was converted to cDNA using a
First Strand cDNA Synthesis Kit (Roche Applied Science,
Indianapolis, IN, USA). Quantitation of the procollagen α1
(I), the MMP-1 cDNA and the endogeneous reference
GAPDH cDNA was performed using a fluorescence de-
tection method (ABI PRISM 7000 Sequence Detection
System, Perkin Elmer Applied Biosystems, Foster City, CA,
USA). The sequence-specific PCR primer sets and a
TaqMan MGB probe (FAMTM dye-labeled) were purchased
from Applied Biosystems. The cycling conditions were
50oC for 2 min, 95oC for 10 min, followed by 40 cycles at
95oC for 15 sec and 60oC for 1 min. To quantify the
relative changes in the gene expression between each
sample, we used the comparative CT method, as was
previously described16. In the comparative CT method, the
ΔCT mean value obtained in the control sample is 0 and
the fold difference is 1.
Immunohistochemical staining
The samples were sectioned 4μm thick and fixed in
acetone (5 min at −20oC). The sections were blocked
with blocking solution (85-9043, Zymed, San Francisco,
CA, USA) for 30 min and then they were incubated in a
humidified chamber at 4oC for 18 hours with monoclonal
anti-human PIP antibody, which detects procollagen type I
C-terminal peptide (M011, 1：1,000, Takara, Shiga, Japan).
After washing in PBS, the sections were incubated with
biotinylated secondary antibody (85-9043, Zymed) for 15
min. The sections were incubated with streptavidin
(85-9043, Zymed) for 15 min, and the color reaction was
performed with AEC (3-amino-9-ethylcarbazole; 00-2007,
Zymed) developing solution for 5 to 10 min. The cell
nuclei were then counterstained with Mayer's hema-
toxylin (S3309, Dako), and the samples were mounted
using Faramount Aqueous Mounting Medium (S3025,
Dako, USA).
Statistical analysis
The significance of differences between the higher and
lower dose groups was analyzed by using the Mann-
Whitney U-test for comparison of the baseline values
between the two groups; Wilcoxon's signed rank test was
used for comparison of the before- and after-aloe vera gel
intake values in each group. For all the tests, a p value＜
0.05 was considered significant.
RESULTS
All 30 subjects completed the trial without any adverse
events. The ages of the 30 subjects ranged from 49 to 74
years (average age: 56.2 yrs), and their body weights
ranged from 47 to 75 kg (average weight: 58.8 kg). In the
lower-dose group (n=15), the average age was 57.8±7.1
years and the average weight was 55.9±5.8 kg; in the
higher-dose group (n=15), the average age was 54.5±6.3
years and the average weight was 61.8±8.8 kg. By the
Mann-Whitney test, there was no significant difference in
the ages and body weights between the 2 groups, and so
the selection of subjects was deemed appropriate. No
subjective adverse events were reported. The laboratory
evaluations revealed no significant abnormalities in the
CBC, the LFTs and the urinalysis.
Aloe improves facial wrinkles and elasticity in pho-
toaged human skin in vivo
Comparison of the facial wrinkles before and after aloe gel
intake, as measured by the skin replica and the Visio-
meter, is shown in Table 1. The Visiometer R values R1
thru R5 decrease as the wrinkles diminish, that is, the skin
surface roughness decreases. Hence, the facial wrinkles in
both groups were shown to have significantly decreased
after 3 months of aloe vera supplementation, with the
Visiometer R1 thru R4 values being decreased (p＜0.05,
Wilcoxon's signed rank test) in the lower-dose group, and
the R1, R3-R5 values were significantly decreased in the
higher-dose group.
The Cutometer was used to measure changes in skin
elasticity. The closer the value is to 1, the more elastic the
Aloe Supplementation for Aging Skin
Vol. 21, No. 1, 2009 9
Table 2. Changes in the skin elasticity as measured by the Cuto
-
meter in each treatment group
Group R
values* Baseline
After aloe vera
gel intake
(90 days)
p
value
Lower-dose
Higher-dose
R2
R5
R7
R2
R5
R7
0.725±0.046
0.737±0.165
0.399±0.057
0.729±0.054
0.854±0.164
0.451±0.054
0.755±0.062
0.958±0.228
0.471±0.073
0.751±0.053
0.900±0.177
0.474±0.057
0.140
0.004
0.011
0.394
0.363
0.211
*The closer the value is to 1, the more elastic the skin is.
Fig. 1. The type I procollagen mRNA levels measured by real-time RT-PCR before and after aloe vera gel intake in the lower-dose
group (n=6) and the higher-dose group (n=6). Wilcoxon’s signed rank test was used for statistical analysis.
Fig. 2. The collagen-degrading MMP-1 mRNA levels before and after aloe vera gel intake in the lower-dose group (n=6) and the
higher-dose group (n=6). Statistical significance was tested by Wilcoxon’s signed rank test.
Table 1. Changes in facial wrinkles as measured by the Visio-
meter in each treatment group
Group R
values* Baseline
After aloe vera
gel intake
(90 days)
p
value
Lower-dose
Higher-dose
R1
R2
R3
R4
R5
R1
R2
R3
R4
R5
1.37±0.30
1.11±0.29
0.69±0.15
0.38±0.08
0.16±0.05
1.39±0.90
1.12±0.72
0.68±0.34
0.44±0.30
0.21±0.23
1.14±0.22
0.91±0.22
0.56±0.11
0.32±0.07
0.14±0.04
1.15±0.48
0.97±0.48
0.60±0.31
0.34±0.24
0.16±0.15
0.007
0.036
0.012
0.041
0.299
0.024
0.078
0.033
0.004
0.015
*Visiometer R values R1 thru R5 decrease as the wrinkles
diminish.
skin is. After 90 days of aloe vera supplementation, the R5
and R7 values were increased significantly in the lower-
dose group (Table 2), indicating increased cutaneous
elasticity. In the higher-dose group, the Cutometer R
values all increased, but this was without statistical
significance.
Aloe increases the type I procollagen gene expression
in photoprotected human skin in vivo
The type I procollagen and collagen-degrading MMP-1
SY Cho, et al
10 Ann Dermatol (Seoul)
Fig. 3. Type I procollagen (Takara) immunostaining in the buttoc
k
skin before and after aloe vera intake (original magnification
×200). The results are representative of 6 biopsied subjects in
each group.
gene expressions were compared by performing real-time
RT-PCR. In the lower-dose group (n=6), the type I pro-
collagen mRNA levels increased to 4.74±1.25 times the
baseline level (p＞0.05); in the higher-dose group (n=6),
these levels increased 1.75±0.41 fold (p＞0.05) (Fig. 1).
The MMP-1 mRNA levels were nearly unchanged in the
lower-dose group, with a 1.41±0.31 fold increase after
aloe intake (n=6); however, in the higher-dose group, the
MMP-1 mRNA transcripts were significantly (p＜0.05, n=
6) decreased to 0.51±0.13 times the baseline level (Fig. 2).
Type I procollagen immunostaining with anti-PIP antibody
demonstrated substantially increased intracellular and
extracellular procollagen expressions throughout the
dermis after aloe vera gel intake in both treatment groups
(Fig. 3).
DISCUSSION
This is the first clinical research to determine the effects of
dietary aloe supplementation on facial wrinkles/elasticity
and the type I procollagen and MMP-1 gene levels in aged
human skin. In this study, we found that aloe vera gel
supplementation clinically improved facial wrinkles and
elasticity, while it increased type I procollagen and it
decreased the MMP-1 gene expressions in the photo-
protected skin.
In this study, the degree of clinical wrinkles was ob-
jectively measured by using a device (the Visiometer) that
converts the skin surface roughness to numerical values.
The facial wrinkles decreased in both the lower-dose and
higher-dose groups; however, no dose-response relation-
ship was seen in this study. This may be partially
attributed to the small number of subjects in this study and
a relatively short time period of aloe gel supplementation.
The decrease in facial wrinkles as measured by the
Visiometer reflects increased type I procollagen in both
dosing groups. At the gene level, lower-dose aloe was
shown to increase type I procollagen mRNA in the
photo-protected buttock skin, albeit without statistical
significance, whereas no change was seen in the MMP-1
mRNA levels. In the higher-dose group, while aloe gel
had little effect on the type I procollagen mRNA levels, it
caused a significant decrease in the MMP-1 mRNA levels.
As a result, both dosing groups would have a net gain of
procollagen that would correlate clinically with the
improvement of wrinkles, as measured by the Visiometer.
Type I procollagen immunostaining also demonstrated an
upregulated protein expression in both groups.
The mechanism by which aloe exerts its anti-aging effects
is unknown. The therapeutic action of aloe has been
studied mostly for wound healing. When wounded
diabetic rats were treated orally and topically with aloe
gel, increased collagen formation was later demonstrated17,
and the collagen formed had a higher degree of cross-
linking, indicating enhanced levels of type III collagen18.
According to the literature on the therapeutic effect of
aloe, immunostimulation frequently appears as a con-
tributory factor. Aloe gel extracts, when applied after UV
exposure, were found to prevent suppression of local and
systemic immunity to haptens and delayed type hypersen-
sitivity responses to Candida albicans and alloantigens8,19.
This was attributed to the presence of polysaccharides in
the aloe vera gel. They have no significant anti-oxidant
activity; the immune-protective action of aloe polysac-
charides takes place at a step downstream from DNA
damage and repair, possibly by modulating the DNA-
damage-activated signal transduction pathways20. These
compounds may act by novel mechanisms to block the
signal transduction pathways and the production of
immunosuppressive cytokines. An acetylated glucoman-
nan in aloe was found to be the biologically active,
dominant polysaccharide, so much so that it was named
acemannan5. Acemannan from aloe was shown to
increase collagen biosynthesis, and perhaps this occurred
through macrophage stimulation21. In addition, active
glycoproteins have been demonstrated in aloe gel and
they may well play some part in aloe's therapeutic
activity, either immunologically as lectins or as proteases
such as anti-bradykinins. Superoxide dismutase activities
have also been reported from Aloe vera gel22.
There are 3 cases of oral aloe vera-induced hepatitis in the
medical literature23-25. In this study, no toxicity was
observed in association with oral aloe intake. The doses
used in the study were determined arbitrarily based on the
Aloe Supplementation for Aging Skin
Vol. 21, No. 1, 2009 11
daily recommended dosage of aloe by the manufacturer of
the study material. From the two doses used in this study,
no dose-response relationship could be demonstrated
clinically (wrinkles and the elasticity measures), biochemi-
cally (procollagen and the MMP-1 gene levels) or micro-
scopically (procollagen staining). Our results indicate no
added advantage of high-dose aloe vera gel ingestion for
cutaneous anti-aging purposes. The limitations of the
study include the lack of a control group. In addition,
daily sunblock use may have added to the protective
effects of aloe; however, sunblock alone does not actively
increase procollagen production or reduce the MMP-1
gene expression. It only renders skin less susceptible to
further photodamage that would occur with the passage of
time. Therefore, the role of sunblock as an active anti-
aging substance could be excluded. For determining the
optimal effective daily dosage of aloe, a placebo-con-
trolled study with a larger number of subjects and a longer
study period is warranted.
Since aloe significantly decreased wrinkles and it
increased elasticity in photoaged human skin in vivo with
an increase of the net procollagen, oral aloe gel sup-
plementation may be a novel anti-aging strategy that
prevents and repairs cutaneous photoaging. A future
challenge will be to determine the mechanism of action of
aloe gel in preventing cutaneous aging.
ACKNOWLEDGMENTS
The authors are indebted to Ae-Kyong Woo and Joo-Mi
Shim for coordinating the study and procuring the cu-
taneous tissues. This research was supported by a grant
from the Korean Food and Drug Administration.
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