Exploring the Potential of Extracts from Sloanea medusula and S. calva: Formulating Two Skincare Gels with Antioxidant, Sun Protective Factor, and Anti-Candida albicans Activities

Abstract

<i>Sloanea</i> is a plant genus, native to tropical regions, used in medicinal practices for its anti-inflammatory properties. This study aimed to determine the antioxidant activity, sun protective factor (SPF), and antifungal of extracts obtained from two species of <i>Sloanea</i> and to develop extract-based gels with antioxidants, photoprotective, and anti-<i>Candida albicans</i> effects. Ethanolic extracts from <i>S. medusula</i> and <i>S. calva</i> collected in Chocó, Colombia, were used for antioxidant activity and SPF determination using the DPPH assay and the Mansur equation, respectively. Extracts were characterized using HPLC-MS and used to prepare the gels. The viscosity of the extract-based gels was evaluated using an MCR92 rheometer. In addition, the anti-<i>Candida</i> activity of extracts against five yeasts and anti-<i>C. albicans</i> of gels were evaluated following the Clinical and Laboratory Standards Institute M27, 4th Edition. High DPPH radical scavenging activity (42.4% and 44.7%) and a high SPF value (32.5 and 35.4) were obtained for the extracts of <i>S. medusula</i> and <i>S. calva</i>, respectively. Similarly, extract-based gels showed significant DPPH radical scavenging activity of 54.5% and 53.0% and maximum SPF values of 60 and 57. Extract from <i>S. medusula</i> showed an important antifungal activity against <i>C. albicans</i> (minimal inhibitory concentration (MIC) of 2 µg/mL). In contrast, <i>S. calva</i> extract was active against <i>C. krusei</i>, <i>C. albicans</i> (MIC of 2 µg/mL) and <i>C. tropicalis</i> (MIC of 4 µg/mL). <i>Sloanea medusula</i> gel (0.15%) exhibited an important <i>C. albicans</i> growth inhibition (98%), while with <i>S. calva</i> gel (0.3%) growth inhibition was slightly lower (76%). Polyphenolic and triterpenoid compounds were tentatively identified for <i>S. medusula</i> and <i>S. calva</i>, respectively. Both extracts can be considered promising sources for developing photoprotective gels to treat skin infections caused by <i>C. albicans</i>.