Photoprotective Activity of Plants Used for Skin Disorders by the Native Population from the Brazilian Amazon Basin: A Preliminary Study

Background: Sunscreens are essential in tropical countries with a high annual incidence of solar radiation. The incorporation of natural products in their formulations has great public acceptance and prevents several issues related to organic and inorganic filters, such as adverse reactions. The present study evaluates the antioxidant and photoprotective activities and the ability to inhibit tyrosinase of three plant species traditionally used by Amazonian inhabitants in the treatment of skin disorders. Materials and Methods: The antioxidant activity, the capacity to inhibit the enzyme tyrosinase, ratio UVA/UVB, critical wavelength, sun protection factor, and cellular viability was assessed in ethanolic extracts at 10% of Chrysobalanus icaco, Kalanchoe pinnata, and Ayapana triplinervis collected in the State of Para-Brazil. Results: Chrysobalanus icaco and Kalanchoe pinnata showed promising antioxidant activity. Ayapana triplinervis demonstrated considerable inhibition of the tyrosinase enzyme. Plants extracts had low protection against UVB radiation, but adequate UVA protection. Ayapana triplinervis presented the lowest cellular viability of keratinocytes and murine fibroblasts. Conclusion: The addition of these extracts to other natural products with high sun protection factors can provide the consumer with a natural sunscreen.