Bioprospecting of brown seaweed (Ochrophyta) from the Yucatan Peninsula: cytotoxic, antiproliferative, and antiprotozoal activities

Abstract

In the Yucatan Peninsula coast, a large diversity of seaweed species are found, and recent studies have reported the presence of metabolites with pharmaceutical importance. In this study, a biological screening of brown seaweed extracts from Dictyota ciliolata, Padina sanctae-crucis, Sargassum fluitans, and Turbinaria tricostata was carried out. Their cytotoxicity and antiproliferative activities were evaluated by the sulforhodamine B assay on human embryonic kidney (HEK 293), human breast cancer (MCF-7), human prostate cancer (LNCaP), and human hepatic cancer (Hep-G2) cell lines. Seaweed extracts were also tested for their anti-trichomonal (Trichomonas vaginalis) and anti-giardicidal (Giardia lamblia) properties. Fucan fractions were extracted using successive maceration with ethanol/water and freeze-dried. Organics extracts were obtained from ethanol residue from liquid–liquid fractionation. A total of four ethanol extracts, four fucan-rich fractions, four ethanolic extracts, and 12 organic fractions were obtained. Only the ethanolic extracts from Turbinaria tricostata and D. ciliolata were active against LNCaP (CC50 of 24.4 and 29.3 μg mL−1, respectively). Interestingly, the activity found in the extracts from D. ciliolata and Turbinaria tricostata was maintained when both extracts were subjected to a liquid–liquid fractionation with hexane on the LNCaP cell line (CC50 of 24.4 and 25.2 μg mL−1, respectively). The antiproliferative assays showed that both dichloromethane and ethanolic fractions from P. sanctae-crucis were active against MCF-7, with IC50 of 26.1 and 29.8 μg mL−1, respectively. These species have been selected for further bio-guided fractionation and isolation of active compounds.