**Guidelines for the Development of Herbal-Based Sunscreen** Guidelines for the Development of Herbal-Based

DOI: 10.5772/intechopen.72712

Piergiacomo Buso, Matteo Radice, Anna Baldisserotto, Stefano Manfredini and Silvia Vertuani Piergiacomo Buso, Matteo Radice, Anna Baldisserotto, Stefano Manfredini and

Additional information is available at the end of the chapter Silvia Vertuani Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72712

#### Abstract

Sunscreen

Sun protection is a complex topic, which involves various classes of compounds. The photoprotective effectiveness of a sunscreen involves many biological activities, such as ultraviolet (UV) radiation filter properties and antioxidant, anti-inflammatory, and antimutagenic effects. Formulation strategy is also a key factor. Several studies have examined the role of natural molecules as photoprotective compounds, and a considerable number of commercially available sunscreens contain herbal extracts but not as sunfilters. Indeed, the process of evaluation of UV-filtering and photoprotective activity of herbal compounds presents certain specific difficulties and needs in vitro and in vivo studies. Nowadays, no natural compound or vegetal extract has been approved by any country as official UV filter for sunscreen. With these premises, the aim of this chapter is to define a set of tests, which can help to evaluate the efficacy of an herbal extract in the field of sun protection; in other words, we propose a rational approach to the discovery of natural UV-filtering extract and molecules. The following electronic databases have been used as a source of information: SciFinder, PubMed, Google Scholar, ISI-Web of Science, and Scopus.

Keywords: natural sunscreen, rational development, sustainable resources, SPF (sun protection factor), skin, cosmetic

#### 1. Introduction

The use of herbal extract and natural molecules in the field of solar protection represents a new trend in the cosmetic industry; in fact, over the last few years, a significant increase of the usage of herbal extracts has been registered given the growing interest of the costumer for

© 2017 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

"green" and "natural" ingredients in the finished product. A large number of studies appearing in scientific literature demonstrate the photoprotective activity of natural products due to UV-filtering activity, antioxidant activity, and DNA-protecting effects [1–3]. Despite these findings, studies regarding photoprotection activity have been developed with a wide range of different methods and different strategies of investigation, thus making difficult to understand both the actual and the claimed potential of the activity. The main cause of this situation is the lack of repeatability of the in vitro SPF tests available nowadays.

important constituents of human skin (DNA, RNA, proteins, lipids) represents the basis of the UV-mediated negative biological activities [2]. More in particular UVB radiation is responsible for the most known acute negative effect that comes after some hours of UV exposition: the UVB-induced erythema. This radiation also has a potential carcinogenic effect because it can cause direct damage to the DNA and RNA. An over exposition to deeply penetrating radiation, namely, UVA, is responsible for premature skin aging, excessive degradation, and inhibi-

Guidelines for the Development of Herbal-Based Sunscreen

http://dx.doi.org/10.5772/intechopen.72712

45

Protection from solar radiation thus represents a complex issue involving various biological activities and factors that influence the efficacy of a sunscreen product, as demonstrated by studies during the last decade. The most important biological activities in the field of sun

In our opinion, the research effort should be focused on the discovery of multifunctional compounds or mixtures that present the abovementioned biological activities. Therefore, the reports of in vitro SPF values of herbal extracts and compounds are more valuable if they are accompanied by other types of useful biological activities that are of equal importance in the

Antioxidant effect represents one of the key mechanisms of photoprotective activity of herbal extracts. The UV skin damage depends also on the generation of reactive oxygen species (ROS). ROS are considered as oxidant agents and are responsible for the development of skin disorders like skin aging, lipid peroxidation, and cancer [6]. These species include hydroxyl radicals, peroxyl radicals, superoxide anion, and, mainly, their active precursors: ozone, hydrogen peroxide, and singlet oxygen. ROS react negatively with DNA, proteins, and unsaturated fatty acids that in turn induce carcinogenic processes and inflammatory response from cells. Phenolic/polyphenolic compounds and flavonoids usually represent the main source of natural antioxidant compounds, and several types of research highlight the usefulness of

Antioxidant compounds from herbs offer new possibilities and strategies for an effective prevention and treatment of UV-mediated damages and diseases, which are mainly due to the

tion of the synthesis of collagen fibers [5].

• Antimutagenic activity • Anticancer properties

• Booster effect

protection can be summarized in six main categories:

• Antioxidant and reactive oxygen species scavenging activity

• Filtering activity against UVB/UVA radiation

• Safety stability of the active compounds

prevention of skin problems relating to UV exposure [2].

2. Biological activities connected with solar protection

2.1. Antioxidant and reactive oxygen species scavenging activity

including natural antioxidant extracts in topical products [6–8].

In the USA, sunscreen is classified as an OTC (over-the-counter) product. In the European Union (EU) countries, it is listed as cosmetics, and its production must follow the EC Regulation 1223/ 2009 of the European Parliament on Cosmetic Products. Regarding the SPF determination, the ISO 2444:2010 is nowadays regarded as the reference method; this method involves an in vivo procedure carried out on human volunteers. Due to ethical problems, the in vivo UVAPF determination by the ISO 24442:2011 has been recently substituted by the in vitro ISO 24443:2012 method.

The "gold standard" for the SPF determination nowadays is provided by the ISO 2444:2010 in vivo test. It is not applicable in the initial screening phase of the new filtering compounds due to ethical problems connected to the exposure of healthy subjects to the potentially harmful effects of UV radiation. As far as the UVA Protection Factor (UVAPF) determination is concerned, in 2012, a new in vitro method was established and integrated into the ISO 24443:2012. Also, for in vivo tests, no authority or legislator has released an official statement to support all this. In the sunscreen research field, more effective guidelines for the evaluation of naturally derived actives are required. Despite the numerous scientific reports, there is no officially approved natural commercial sunfilter. Moreover, a consistent number of commercially available solar products (sunscreen) contain herbal derivatives, but an official and a widely approved validation of this method is not available, and so it is indispensable to correct labeling of the final product's UV protection. Hence, the objective of this study is to collect any current data and exhaustive critical overview regarding the use of herbal extract and natural molecules in sunscreens. Finally, the intent of the present chapter is to provide solid types of research methodology approach in order to develop herbal or natural-based sunscreen, useful as a set of guidelines.

#### 1.1. Ultraviolet radiation

Sunlight is composed of about 40% visible light (VIS), 50% infrared light (IR), and 10% ultraviolet light (UV). As far as the biological effects of solar radiation exposure are concerned, ultraviolet radiation is the most important part of the electronic spectrum. Ultraviolet (UV) radiation can be divided into UVC (200–280 nm), UVB (280–315 nm), and UVA (315–400 nm) [2].

UV radiation (sun) is essential to human health; it is necessary for the production of vitamin D3 in the skin. Vitamin D3 is necessary for the intestinal absorption of calcium and phosphorus, and deficiency may cause osteoporosis in adults and growth retardation and skeletal deformities in children. Solar radiation has other therapeutic effects on some skin diseases such as psoriasis and eczema, thus making the outdoors a healthy lifestyle choice [2, 4].

On the other hand, the negative effects of an excessive exposure to UV radiation are well known, and these are harmful to human health; the interaction of the radiation with the most important constituents of human skin (DNA, RNA, proteins, lipids) represents the basis of the UV-mediated negative biological activities [2]. More in particular UVB radiation is responsible for the most known acute negative effect that comes after some hours of UV exposition: the UVB-induced erythema. This radiation also has a potential carcinogenic effect because it can cause direct damage to the DNA and RNA. An over exposition to deeply penetrating radiation, namely, UVA, is responsible for premature skin aging, excessive degradation, and inhibition of the synthesis of collagen fibers [5].

Protection from solar radiation thus represents a complex issue involving various biological activities and factors that influence the efficacy of a sunscreen product, as demonstrated by studies during the last decade. The most important biological activities in the field of sun protection can be summarized in six main categories:


"green" and "natural" ingredients in the finished product. A large number of studies appearing in scientific literature demonstrate the photoprotective activity of natural products due to UV-filtering activity, antioxidant activity, and DNA-protecting effects [1–3]. Despite these findings, studies regarding photoprotection activity have been developed with a wide range of different methods and different strategies of investigation, thus making difficult to understand both the actual and the claimed potential of the activity. The main cause of this

In the USA, sunscreen is classified as an OTC (over-the-counter) product. In the European Union (EU) countries, it is listed as cosmetics, and its production must follow the EC Regulation 1223/ 2009 of the European Parliament on Cosmetic Products. Regarding the SPF determination, the ISO 2444:2010 is nowadays regarded as the reference method; this method involves an in vivo procedure carried out on human volunteers. Due to ethical problems, the in vivo UVAPF determination by the ISO 24442:2011 has been recently substituted by the in vitro ISO 24443:2012 method.

The "gold standard" for the SPF determination nowadays is provided by the ISO 2444:2010 in vivo test. It is not applicable in the initial screening phase of the new filtering compounds due to ethical problems connected to the exposure of healthy subjects to the potentially harmful effects of UV radiation. As far as the UVA Protection Factor (UVAPF) determination is concerned, in 2012, a new in vitro method was established and integrated into the ISO 24443:2012. Also, for in vivo tests, no authority or legislator has released an official statement to support all this. In the sunscreen research field, more effective guidelines for the evaluation of naturally derived actives are required. Despite the numerous scientific reports, there is no officially approved natural commercial sunfilter. Moreover, a consistent number of commercially available solar products (sunscreen) contain herbal derivatives, but an official and a widely approved validation of this method is not available, and so it is indispensable to correct labeling of the final product's UV protection. Hence, the objective of this study is to collect any current data and exhaustive critical overview regarding the use of herbal extract and natural molecules in sunscreens. Finally, the intent of the present chapter is to provide solid types of research methodology approach in order

Sunlight is composed of about 40% visible light (VIS), 50% infrared light (IR), and 10% ultraviolet light (UV). As far as the biological effects of solar radiation exposure are concerned, ultraviolet radiation is the most important part of the electronic spectrum. Ultraviolet (UV) radiation

UV radiation (sun) is essential to human health; it is necessary for the production of vitamin D3 in the skin. Vitamin D3 is necessary for the intestinal absorption of calcium and phosphorus, and deficiency may cause osteoporosis in adults and growth retardation and skeletal deformities in children. Solar radiation has other therapeutic effects on some skin diseases such as

On the other hand, the negative effects of an excessive exposure to UV radiation are well known, and these are harmful to human health; the interaction of the radiation with the most

can be divided into UVC (200–280 nm), UVB (280–315 nm), and UVA (315–400 nm) [2].

psoriasis and eczema, thus making the outdoors a healthy lifestyle choice [2, 4].

situation is the lack of repeatability of the in vitro SPF tests available nowadays.

to develop herbal or natural-based sunscreen, useful as a set of guidelines.

1.1. Ultraviolet radiation

44 Herbal Medicine

• Safety stability of the active compounds

In our opinion, the research effort should be focused on the discovery of multifunctional compounds or mixtures that present the abovementioned biological activities. Therefore, the reports of in vitro SPF values of herbal extracts and compounds are more valuable if they are accompanied by other types of useful biological activities that are of equal importance in the prevention of skin problems relating to UV exposure [2].
