Antioxidant, Anti-inflammatory and Antiproliferative Effects of Aqueous Extracts of Three Mediterranean Brown Seaweeds of the Genus Cystoseira

Seaweeds have caused an emerging interest in the biomedical area, mainly due to their contents of bioactive substances which show great potential as anti-inflammatory, anti-microbial, anti-viral and anti-tumoral drugs. Despite the diversity in quality and quantity of the Mediterranean Tunisian coast flora, with its large contains of marine organisms and seaweeds, most of them have not yet been investigated for pharmacological and biological activities. Antioxidant, anti-inflammatory and antiproliferative effects of the aqueous extracts (AQ) of three brown seaweed respectively, Cystoseira crinita (AQ-C cri), Cystoseira sedoides (AQ-C sed) and Cystoseira compressa (AQ-C com) were investigated. Antioxidant activity was evaluated using the DPPH assay. Total phenolic contents were measured using Folin-Ciocalteu method. The anti-inflammatory activity of these extracts was determined in-vivo, using carrageenan induced rat paw oedema assay. The antiproliferative activity was studied on normal cells (MDCK and rat fibroblast) and cancer (A549, MCF7 and HCT15) cell lines by the ability of the cells to metabolically reduce MTT formazan dyes, in comparison to a reference drug the Cisplatin. Results demonstrated that AQ-C cri, AQ-C sed and AQ-C com extracts exhibited significant radical scavenging activity. AQ-C com extract had the highest total phenolic content. AQ-C cri, AQ-C sed and AQ-C com extracts exhibited significant anti-inflammatory activity in a dose dependent manner by comparison to reference drugs. Moreover, AQ-C cri, AQ-C sed and AQ-C com extracts showed an important antiproliferative activity against both Human tumor cell lines HCT15 and MCF7. These pharmacological efficacies of these AQ- extracts of Cystoseira were positively correlated with their total phenol content and their good antioxidant activity. The purification and the determination of chemical structures of compounds of these active aqueous extracts are under investigation. It could have a promising role in the future medicine and nutrition when used as drug or food additive.