Artificial and natural photoprotective compounds

Abstract

A continuous increase in environmental pollutants in the biosphere has lead to substantial loss of stratospheric ozone layer, allowing unavoidable entry of ultraviolet (UV) radiations on the Earths surface. This increase in UV radiations has emerged as one of the major environmental risk factor for non-melanoma skin cancer and its overexposure can cause erythema, edema, photoaging and hyperpigmentation. The most well known way to reduce the incoming UV radiation penetration through skin is topical application of sunscreens, having potential to either absorb or reflect UV by their active molecules for long hours. Based on their photoprotective strategies active molecules in sunscreens are broadly classified as natural or artificial sunscreen. The artificial sunscreen compounds either reflect and scatter UV radiations (inorganic compounds) or have potential to absorb incoming UV radiation and reemit it as heat or light energy (organic compounds). However, photoprotection via artificial sunscreen compounds bear the risk to cause damage to living organism by alterations at genomic and proteomic constitution. Furthermore, their regular use may cause a negative impact on human health. Their continous release in environment is a matter of concern as they are not ecofriendly. The use of natural sunscreen compounds has gained significant attention as they are safe with multiple biological actions on the skin as antioxidants and being cost effective are becoming markets first choice changing the trend towards natural-green cosmetics. Their active constituents act as effective ROS (reactive oxygen species) scavenger and promise protection against oxidative stress, with the broad spectrum of UV absorption, anti-inflammatory, and immunomodulatory properties. With the increasing interest in natural sunscreen formulations, the aim of this chapter is to make a review of the different forms of photoprotective compounds available, emphasizing types and role of natural sunscreens derived from plants, and algae as substitutes for different types of synthetic sunscreen filters. Therefore, further study pertaining to sunscreen knowledge and understanding its response with sun remains important aim. © 2010 by Nova Science Publishers, Inc. All rights reserved.