THE HEALTH BENEFITS OF NATURAL SKIN UVA PHOTOPROTECTIVE COMPOUNDS FOUND IN BOTANICAL SOURCES Review Article JOHN ROJAS*, CESAR LONDOÑO, YHORS CIRO Department of Pharmacy, College of Pharmaceutical and Food Sciences, University of Antioquia, Medellin, Colombia Email: jrojasca@gmail.com Received: 24 Nov 2015 Revised and Accepted: 25 Jan 2016 ABSTRACT In recent years, botanicals have gained importance due to their dermal photoprotective effect against the harmful UV radiation. This radiation generates reactive oxygen species which attack proteins, lipids, and nucleic acids among others. This leads to the cellular oxidation, which is reflected as tanning, skin inflammation, erythema, immunosuppression, photoaging and skin cancer. The photoprotective activity of synthetic sunscreens is unsatisfactory due the proved incomplete spectral protection, toxicity, and allergenicity. The phytotherapy treatment with antioxidant compounds with potential UV absorbing capacity could offer a more effective photoprotection since they may impede, reverse or delay the process of formation of DNA adducts. The wide diversity of botanicals with photoprotective activity is attributed to several types of substances with phenolic chromophores. These compounds can be classified as flavonoids, phytoestrogens, carotenoids, xhantophylls, coumarins, proanthocyanidins, anthocyanins, catechins, phenolic acids, triterpenes, alkaloids, etc. The bioactivity of these compounds is not limited to the photoprotective action, but antioxidant, anti-inflammatory, antimutagenic and immunomodulatory properties. The regular intake of these botanicals not only prevents but also delays the deleterious effects of sun radiation onto the skin. Therefore, these botanicals have gained considerable attention and are now included in most vitamin and cosmetic products. This review gives an overview of photoprotective botanicals mainly focused on UVA chromophores that are able to inhibit or reverse the damaging effects of sun radiation. The search criterion was made essentially on UVA photoprotective botanicals and related works published in the last ten years. The literature search included mainly the Google scholar, Science direct, and ISI web of knowledge databases. Keywords: Ultraviolet radiation, Photoprotective botanicals, Antioxidants, Phytotherapy. © 2016 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/ ) INTRODUCTION The solar radiation reaching the Earth is mainly in the wavelength ranging from 200 to 4000 nm. This radiation is composed of 50% visible light (VIS, 400-800 nm), 40% infrared radiation (IR, 1300-1700 nm), and 10% ultraviolet radiation (UV, 10-400 nm)[1]. In addition, ultraviolet radiation can be divided into three categories such as long wave UVA (320-400 nm), medium wave UVB (280-320 nm) and short wave UVC (200-280 nm) [2] (fig. 1). Since UVC is highly energetic, it is extremely dangerous to living beings. Fortunately, the ozone layer and atmospheric oxygen absorb this radiation and only a small portion reaches the earth surface [3]. The UVC radiation is efficiently absorbed by mitochondrial DNA in cells located to the level of spinous layers, but not in the basal layer. It causes DNA damage producing pyrimidine dimers, such as cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) [4]. Fig. 1: The incident solar radiation on Earth Effects of UVA radiation The ratio of UVA to UVB reaching the earth surface is 20:1 and the incident UV radiation is strongest between 10 AM and 4 PM. Since UVA is of longer wavelength compared to UVB, it is less affected by altitude or atmospheric conditions. UVA rays are beneficial since they increase vitamin D3 production by irradiation of 7-dihydrocholesterol. UVA also intensifies darkening of the preformed melanin pigment favoring tanning [5]. The effectiveness of UV to induce erythema declines rapidly with longer wavelength. Therefore, 1000 times more UVA is needed to induce erythema as compared to UVB [6]. UVA can penetrate deeper than UVB through the skin, and is not filtered by window glass. Further, more than 90% of solar radiation that reaches the Earth is UVA. For this reason, even under the cloud shadow, ~50% of UVA is able to reach the ground [7]. Cellular defenses against UVA-induced damage include antioxidant molecules (i.e., glutathione, carotenoids, ascorbate, and α-tocopherol), and proteins (i.e., ferritin, heme oxygenase, glutathione peroxidase, superoxide dismutase, catalase, etc.) [8]. However, UVA could bypass these defenses reaching the dermis and affecting dendritic cells, fibroblasts, matrix metalloproteinases, T-lymphocytes, mast cells, and endothelial cells. Moreover, UVA is about 1000 times more effective in producing an immediate tanning effect when compared to UVB. Long-term exposure to UVA damages the underlying structures in the dermis causing premature photoaging. Further, UVA causes skin sagging and suppress some immunological functions. For this reason, chronically transplant immunosuppressed patients living in regions of intense sun exposure experience a high rate of skin cancer. Moreover, UVA could trigger oxidative changes in exposed individuals generating singlet oxygen, hydrogen peroxide and hydroxyl free radicals. These cause damage to cellular proteins, lipids and saccharides leading to necrosis of endothelial cells, damaging the dermal blood vessels. Further, UVA produces structural changes in DNA (i.e., the formation of di-pyrimidine photoproducts) forming malignant melanoma in 67% of cases [2]. The time course for UVA-induced erythema and tanning are biphasic. Erythema is often evidenced immediately at the end of the International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 8, Issue 3, 2016