Photoprotective potential of medicinal plants from Cerrado biome (Brazil) in relation to phenolic content and antioxidant activity

Publication date: Available online 13 October 2018

Source: Journal of Photochemistry and Photobiology B: Biology

Author(s): Alesandra Ricardo Nunes, Ana Livya Moreira Rodrigues, Dinalva Brito de Queiróz, Icaro Gusmão Pinto Vieira, João Francisco Câmara Neto, João Tavares Calixto Junior, Saulo Relison Tintino, Selene Maia de Morais, Henrique Douglas Melo Coutinho

Abstract

Photooxidative damage affects cellular lipids, proteins and DNA in addition to being involved in the pathobiochemistry of erythema formation, premature skin aging, photodermatoses development and skin cancer. Phenolic compounds, flavonoids and hydroxycinnamic acid esters protect plant tissues against harmful UV-radiation. This study aimed to evaluate the sun protection factor of several Brazilian plant extracts in relation to UVB radiation absorption, which causes skin cancer, and to correlate the findings with their antioxidant activity, as well as with total phenol and flavonoid content. The antioxidant activity of the extracts were evaluated using the DPPH radical scavenging test. The photoprotective effect was evaluated using the methodology developed by Mansur. The antioxidant activity from the extracts showed IC₅₀ values ranging from 4.91 to 132.24 μg/mL when compared to the standard quercetin with an IC₅₀ of 5.01 μg/mL; the phenolic content varied from 3.77 to 57.14 mg GAE/g extract while flavonoid content varied from 1.80 to 5.89 mg EQ/g extract. Almost all extracts showed a potential for UVB radiation absorption in accordance with the ANVISA (Agência Nacional de Vigilância Sanitária) technical regulation for cosmetic sunscreens. The extracts with greater sun protection factors were those originating from Lippia microphylla (SPF = 26.82) and Dimorphandra gardneriana (SPF = 20.12). A sun protection factor of 15 or higher contributes to protect the skin, where the presence of sakuranetin flavonoids and quercetin glycosides contribute to this action.