Oat beta-glucan, a structural component of subaleurone and endosperm cell walls of the seeds of oats, is a linear polysaccharide composed of beta-D-glucopyranose (beta-D-glcp) as the primary building block. Furthermore, the linear chain of oat beta-glucan is arranged as blocks of two or three consecutive (1,4)-linked units separated by a single (1,3)-linkage. The long history application of oat beta-glucan as functional food component and pharmaceutical agent was due to its beneficial physiological effect and functional properties. It has been shown that oat beta-glucan can work as anti-irritant and to speed up the healing of shallow abrasions and partial thickness burn through several mechanisms that remains unclear to us. A recent finding that oat beta-glucan may be capable of penetrating deep into the skin and delivering significant skin benefits, indicated that the skin care actions of oat beta-glucan such as anti-radiation, anti-wrinkle, anti-aging were most likely attributed to its long-lasting and film-forming property, activation of immune cells, and stimulation of deposition of collagen. In this article, the research conducted by a well-known lab was introduced and discussed with regards to the experimental materials, design of experiments and proposed mechanism of action of oat beta-glucan.
Study on the Anti-Radiation, Anti-Wrinkle and Anti-Aging Bioactivity of Oat beta-Glucan
The utility of oat beta-glucan in anti-radiation, anti-wrinkle, anti-aging, moisturizing and healing minor wounds and burns has been fairly well established[1-2], however, the mechanism of actions remained unclear to cosmetic industries until the evidence of its effects on the intact skin emerged only recently. It has long been considered that the large biopolymers, such as protein and glocusaminoglycan and glycoproteins, are very hard to penetrate deeply into the skin when applied in cream. An interesting research conducted by Dr Pillai and his colleagues was published in 2005 in the magazine of International Federation of Societies of Cosmetic Chemists, indicated that oat beta-glucan was capable of skin penetration and such penetration was related to the skin care activities including anti-radiation, anti-wrinkle and anti-aging effects[3]. Dr. Pillais applied the penetration experiment on an isolated skin sections, and found that beta-glucan penetrated the epidermis and reached the dermis by passing in the gaps between cells. Their experiment showed that 28% of the applied oat beta-glucan entered the skin and around 4% reached the dermis (i.e. the layer where wrinkles form) after 8 hours of treatment with 0.5% beta-glucan solution. The figure below was cited form Dr. Pillai¡'s publication and demonstrated the proposed mechanism for the skin penetration of beta-glucan. As shown in the figure, after the entery to skin, oat beta-glucan forms a thin film above the stratum corneum (horny layer) and epidermis so that a promoted moisturization is achieved. For the 4% beta-glucan that is able to reach the dermis, it activates immune cells, mainly macrophage, through an interaction between glucan and glucan receptors on the surface of macrophage. This triggers several indirect, cytokine-mediated reactions with fibroblasts that stimulate collagen synthesis. As a result of promoted collagen synthesis, the negative effect of radiation is minimized, elasticity of the skin is enhanced, wrinkle is reduced and aging process is largely delayed. The effect of beta-glucan on facial fine-lines and wrinkles was also evaluated by performing a clinical trial with 27 subjects. A significant reduction of wrinkle depth, height and overall roughness was observed by microscopic image analysis of silicon replicas after the oat beta-glucan solution was treated to the subjects for 8 weeks in a continue manner.
Figure: Proposed mechanism for the skin penetration of beta-glucan.
(cited from Ravi Pillai, Mark Redmond, Joachim Röding, 2005)
Discussion on Penetration Study
Although the skin penetration of beta-glucan and its activity were supported by the research conducted by Dr. Pillai, there were many things need to be clarified before came to the final conclusion. First of all, the beta-glucan solution used in their studies, was extracted with mild alkali (pH 9.2) aqueous solution followed by the removal of protein. Such prepared oat beta-glucan solution demonstrated to be a mixture with the purity of oat beta-glucan less than 50%. Noted that the impurities can not be ignored when the solution was applied for the skin penetration evaluation because they were in a high percentage. Secondly, the beta-glucan contained in the extracted solution was glucans with different molecular weights that varies from several thousand to several million. It has been reported that the purity and molecular weight of polysaccharide largely influence the biological activity because the impurities cause physiological disturbances and the immune cell surface receptor can only recognize glucan with certain range of molecular weights. Therefore, in order to investigate the activity of oat beta-glucan and the molecule mechanism at molecular level, oat beta-glucan with high purity and certain molecular weights are required. Such high quality oat beta-glucan will help to elucidate the interaction between beta-glucan and macrophage surface receptors at molecular level, establish the structure-bioactivity relationship, and create highly active beta-glucan agents based on structural characteristic. Thirdly, the result that 28% of the applied beta-glucan entered the skin and 4% reached the dermis was not shown in details such as how the molecular weights of beta-glucan affected their penetration effect. The relationship of molecular weights to penetration effect and anti-wrinkle activity can be expected by using highly purified beta-glucan with various molecular weights, thus more effective skin care products can be designed.
The Characteristic and Application of Putus Oat beta-glucan Standards
Putus Macromolecular Sci. & Tech. Ltd. is an international corporation which has been putting effort in research, development and application of many varieties of carbohydrate polymer standards. Putus manufactures and provides high quality carbohydrate polymer standards with various structure and high chemical uniformity in terms of molecular weight and degree of branching.
Oat beta-glucan provided by Putus was extracted from the seeds of oat and demonstrated to be a linear glucan consisted of mixed glycosidic linkages (1,3, and 1,4) is a highly purified without any starch and protein detected. Putus is the only manufacturer in the world that offers oat beta-glucan standards with ultra high purity (97%), extremely narrow Mw polydispersity (1.01-1.05) and a fairly wide range of Mw available from 10,000 to 2,500,000 to meet the demands of high quality oat beta-glucan standards in the biological studies as anti-radiation, anti-wrinkle and anti-aging agents.
Reference
[1] S.B. Lee, H.W. Jeon, Y.W. Lee, Y.M.L. Lee, K.W. Song, M.H. Park, Y.S. Nam, H.C. Ahn, Bio-artificial skin composed of gelatin and (1,3), (1,6)-glucan. Biomaterials, 2003, 24: 2503-2511.
[2] S.J. Delatte, J. Evans, A. Hebra, W. Adamson, H.B. Othersen, E.P. Tagge. Effectiveness of beta-glucan collagen for treatment of partial-thickness burns in children. Journal of Pediatric Surgery. 2001, 36: 113-118
[3] Ravi Pillai, Mark Redmond, Joachim Röding. Anti-Wrinkle Therapy: Significant new findings in the non-invasive cosmetic treatment of skin wrinkle with beta-glucan. International Federation of Societies of Cosmetic Chemists, 2005, 8: 1-6
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