Abstract:The sun-and-skin interactions have controversial sides. Besides important beneficial effects, we need to take into consideration also some serious harmful results. In particular, these are connected to the portion of the solar spectrum traditionally identified as ultraviolet type A and B. The topical application of sunscreens (and the avoidance of extreme exposure to sun rays) is worldwide recognized as the best strategy to avoid sunburn and oedema. Moreover, such strategy can efficiently prevent the onset of skin cancer. Therefore, the first aim of sunscreen products is to efficiently minimize all damage of sun exposure, while, at the same time, keeping good skin tolerability, avoiding safety problems and developing pleasant sensorial properties. Sunscreens, i.e., substances able to reflect and/or absorb, at a partial or complete extent, UV radiation are the key actors in skin protection. They are used to implement the level of primary photoprotection against UV rays. This means that when they absorb the radiation energy, their molecules pass to an excited state and successively re-emit energy in other forms (vibrational, rotational, infrared radiation) to come back to the ground state.

No abstract

The labeling of cosmetic products provides a set of obligations, as reported in the Regulation 1223/2009, which came into force in Europe in July 2013. The indications reported on the label are intended to enable the clear identification of the functionality and proper use of cosmetics, ensure the protection of the consumer from the commercial aspects and, above all, from the safety point of view. Moreover, it should allow quick tracing of the product details and all info of toxicological relevance. However, the misuse of this tool often leads, on one side, to confusion among cosmetics, pharmaceuticals, medical devices, and biocides. On the other side, it gives rise to fanciful interpretations by a huge number of web users, who pretend to be able to judge the quality of a cosmetic product just by reading the ingredients list. This article points out the concrete purpose of cosmetic labels, in order to shed light on the use of certain categories of 'controversial' ingredients and on the real quality concepts of cosmetic products. Indeed, when properly interpreted, cosmetic labels represent a good tool for the professional investigation of adverse reactions to cosmetics.

Caesalpinia spinosa gum is a vegetal polysaccharide obtained by grinding the endosperm of Caesalpinia spinosa seeds. It is commonly used as a rheology modifier in food industry. Its rheological behavior, compatibility with common cosmetic ingredients, and application as a thickener in different types of cosmetic formulations were investigated in this article. At low concentrations (0.1–0.2%) the behavior is Newtonian; at higher percentages (0.5–2.0%) it is pseudoplastic without thixotropy. The gum was tested in combination with salts, chelating agents, humectants, thickeners, pigments, nano UV filters, surfactants, conditioners, and ethanol, as well as in acidic/alkaline conditions. The wide compatibility and the interesting sensory profile, even in association with other thickeners, make the Caesalpinia spinosa gum a very promising ingredient for the thickening of various cosmetic products.

The increasing concern about the environmental impact of ingredients largely used as sunscreens today is pushing research towards new frontiers for the synthesis and degradation potential of innovative sun protection structures. This study deals with the design, synthesis, efficacy evaluation, and environmental impact of new photo-stable molecules at extended electronic conjugation and which have the ‘charge-transfer’ type of optical transition (push and pull). They efficiently perform absorption of electro-magnetic radiation in the UVB and UVA regions. A preliminary screening, dealing with a whole series of aromatic donors, led to the selection of a key substrate derived from waste material, provided with low environmental impact and largely available on the market. As far as the acceptor was concerned, an ester with cyan-acrylic structure and functionalized with aliphatic chains emerged as the most suitable. This allowed a shift of the λ of absorption in the range of the ultraviolet wavelengths. The synthesis procedures include an acid-catalyst-fitted esterification, condensation, and cold crystallization. It was continuously monitored with suitable characterization instruments (GC-MS, 1H NMR, 13C NMR), in order to avoid by-products and parasitic reactions. The resulting structures (patent pending) are composed by a furan core condensed with cyano-acrylic esters, derivatized with branched chains of hydrocarbons of medium length. The obtained structures are capable of good absorption in the range of wavelengths between 300 and 400 nm. Because of their structures, the new molecules are largely soluble in many common oils and cosmetic ingredients. The new molecules have been successively evaluated in terms of photo-stability, biodegradability, compatibility, and UVB-UVA protection capability, both in-vivo and in-vitro, in comparison with existing sunscreens.