Development of a photoprotective solar and antibacterial cream made from extracts of lichens from Arequipa

The objective of this research is to prepare and characterize a solar photoprotective and antibacterial cream based on extracts of lichens from Arequipa. As a first step, different extracts of 4 lichens will be prepared in various solvents such as acetone, methanol, chloroform, ethanol and hydroalcoholic, then the antibacterial tests of the obtained extracts will be carried out. After evaluating the results of the antibacterial tests, the lichen extract with the best antibacterial activity, the analysis of antioxidants and total phenols by UV-visible and quantification of usnic acid in lichens by UV-visible will be carried out. The analysis of fatty acids in lichens will be carried out by gas chromatography. In the last part of this work, the solar photoprotective cream will be prepared based on the lichen extract, then the antibacterial activity will be carried out and the cream will be characterized by determining its physicochemical and photoprotective properties.

Moderate exposure to sunlight has beneficial effects on health, generating an antidepressant effect, an improvement in the treatment of psoriasis, among other benefits. However, an abuse of this exposure can cause serious health problems (Bosquet, 2003). In this sense, ultraviolet radiation has been classified into three types UVA, UVB and UVC. UVA and UVB radiation penetrate the skin and eyes and can cause disorders such as skin cancer, skin problems, cataracts, among others. (EPA, 2001; Castro, 2010).
On the other hand, microbial resistance is a public health problem with global impact. Among the main causes that accelerate this process is the inappropriate use of drugs.
In this sense, lichens produce a wide variety of molecules such as usnic acid, nostistic acid, sekiakic acid, among others that justify their study as photoprotective agents (Santiago et al., 2017), antifungal, antibacterial (Alam, Khatoon, Huda , & Ahmad, 2020; Moreira, Braz-Filho, Mussi-Dias, & Vieira, 2015), antimycobacterial (Alam, Khatoon, Huda, & Ahmad, 2020; Nalan Y & Meral Y, 2017), anticancer (Alam, et al ., 2020) among others. Likewise, lichens live in extreme climatic conditions, this is related to the presence of fatty acids in their composition, such as linoleic acid, linolenic acid (Alpizar, 2000; Moreira et al., 2015) arachidonic acid (Alam et al., 2020) , among others, that are important in the diet of human beings.

In the present work, it is proposed to prepare and characterize a photoprotective, antibacterial cream of 4 different species of lichens sampled in the Arequipa region, as well as the study of the composition of fatty acids (FA), present in the 4 species.