Microalgae as Potential Antioxidants: Assessment of Antioxidant Capacities in Microalgae from Selected Regions of Peninsular Malaysia

Antioxidants play critical roles in cellular defence mechanisms in both enzymatic and non-enzymatic forms within the intracellular and extracellular environments. While microalgae are recognised as a rich source of antioxidants, limited information is available on species native to Peninsular Malaysia that contain high antioxidant capacity for future applications. This study aimed to assess the antioxidant capacity of both enzymatic and non-enzymatic antioxidants in microalgae, particularly those cultivated locally in Malaysia, which are still scarce. Nineteen microalgae species collected from Kedah, Pahang, Terengganu and Johor were used in this study. Algal samples were cultured and harvested during the early stationary phase and then subjected to antioxidant assays. Enzymatic antioxidants were assessed using catalase, ascorbate peroxidase and superoxide dismutase (SOD) assays. Non-enzymatic antioxidants were evaluated through the quantification of ascorbate, α-tocopherol, and carotenoids. The findings reveal significant interspecies variation of microalgae in the types and quantities of antioxidants. Notably, Neochloris conjuncta and Mychonastes ovahimbae exhibited the highest levels of enzymatic antioxidants (p<0.05) and SOD. Hematoccous sp. had the highest concentration of ascorbic acid, while Chlorella vulgaris from Terengganu contained the most α-tocopherol, both with statistical significance (p<0.05). The data suggest that Chlorella vulgaris from Terengganu possesses considerable potential as a renewable source of antioxidants for diverse industrial applications, including food ingredients.