Chemical Profile by UPLC-HRMS and Antifungal and Antioxidant Activity of Marine Macroalgae Dictyota menstrualis

The brown macroalgae Dictyota menstrualis constitutes an organism with a rich and diverse metabolism in terms of the chemistry of natural products. It is known to mainly produce diterpenes, in addition to sterols, vitamins and polysaccharides with antiviral, anti-inflammatory, anticoagulant and antioxidant properties. Despite its vast metabolic arsenal, most studies are directed to the identification of already known diterpenes, opening the field of investigation for new approaches and discoveries. Knowing this, this work aims to chemically characterize the macroalgae D. menstrualis through the technique of Ultra Efficiency Liquid Chromatography associated with High-Resolution Mass Spectrometry (UPLC-HRMS) and perform a biological screening of potential antioxidants and antifungals through bioautography. For this, specimens of D. menstrualis were collected in the São Pedro São Paulo Archipelago (PE, Brazil) and attended to ingestion with dichloromethane and fractionation by column chromatography with silica gel. The extract and fractions were then analyzed by UPLC-HRMS with ElectroSpray Ionization (ESI) in positive mode. In addition, bioautography assays were performed to evaluate the antioxidant potential with DPPH and the antifungal potential against the Cladosporium sphaerospermum . The UPLC-HRMS analyzes allowed identifying diterpenes, sterols, faty acids, glycerolipids, derivatives of photosynthetic pigments and carotenoids. Bioautography assays suggested antifungal and antioxidant potential of the organic extract and fractions. Thus, the results suggest that D. menstrualis has pharmacological potential to be explored and that studies on its chemical composition using modern techniques such as UPLC-HRMS can lead to the discovery of new structures and reinforcement of the knowledge of the chemistry of this algae.