*Article* **Antioxidant Potential of Sulfated Polysaccharides from** *Padina boryana***; Protective E** ff**ect against Oxidative Stress in In Vitro and In Vivo Zebrafish Model**

**Thilina U. Jayawardena 1,**†**, Lei Wang 1,2,**†**, K. K. Asanka Sanjeewa 1, Sang In Kang 3, Jung-Suck Lee 4,\* and You-Jin Jeon 1,2,\***


Received: 25 March 2020; Accepted: 13 April 2020; Published: 14 April 2020

**Abstract:** Elevated levels of reactive oxygen species (ROS) damage the internal cell components. *Padina boryana*, a brown alga from the Maldives, was subjected to polysaccharide extraction. The Celluclast enzyme assisted extract (PBE) and ethanol precipitation (PBP) of *P. boryana* were assessed against hydrogen peroxide (H2O2) induced cell damage and zebra fish models. PBP which contains the majority of sulfated polysaccharides based on fucoidan, showed outstanding extracellular ROS scavenging potential against H2O2. PBP significantly declined the intracellular ROS levels, and exhibited protection against apoptosis. The study revealed PBPs' ability to activate the Nrf2/Keap1 signaling pathway, consequently initiating downstream elements such that catalase (CAT) and superoxide dismutase (SOD). Further, ROS levels, lipid peroxidation values in zebrafish studies were declined with the pre-treatment of PBP. Collectively, the results obtained in the study sugges<sup>t</sup> the polysaccharides from *P. boryana* might be a potent source of water soluble natural antioxidants that could be sustainably utilized in the industrial applications.

**Keywords:** antioxidant; Maldives; *Padina boryana*; sulfated polysaccharide; zebrafish
