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 1,2,4
3,4
3,4
2
Soyun Cho, M.D., Ph.D. , Serah Lee, M.S. , Min-Jung Lee, M.S. , Dong Hun Lee, M.D. , 1,4 3,4 2,3,4 Chong-Hyun Won, M.D., Ph.D. , Sang Min Kim, Ph.D. , Jin Ho Chung, M.D., Ph.D. 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 photoprotected skin and a decrease in the collagen- degrading MMP-1
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: jhchung@snu.ac.kr
6 Ann Dermatol (Seoul)
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) -KeywordsAging, 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, inflammation, 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 photodamaged skin and eventually skin wrinkling2.
Aloe Supplementation for Aging Skin
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 commercially known as aloe vera, and it is a substance for which claims have been made about its anti-inflammatory, healing, moisturizing, antibacterial, antifungal and antiviral 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, magnesium lactate3, bradykinin or thromboxane6, and poly7,8 saccharides 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 accompanied 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 14 healing when aloe vera was incorporated . 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 concentrated 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%, higherdose: 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 University Hospital, and all the subjects gave their written informed consent.
Wrinkle and elasticity measurements At baseline and after 90 days, facial wrinkles were measured in the crow's feet area using a skin replica and a Visiometer SV 600 (Courageďź‹Khazaka Electronic, KĂśln, 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), Vol. 21, No. 1, 2009
7