Abstract

The brown seaweed (Dictyota ciliolata Sonder ex Kutzing) has been identified as valuable sources of anionic polysaccharides with remarkable biological properties that may render them suitable for application in aquaculture. In this study, the chemical composition of D. ciliolata polysaccharides (DCP) was analysed using spectrophotometry and High-Performance Anion-Exchange Chromatography/ Pulsed Amperometric Detection (HPAEC-PAD). The result showed that DCP had total carbohydrate content of 56.56 ± 1.17 %, sulphate content of 4.58 ± 0.26 %, uronic acid content of 6.54 ± 0.26 % and protein content of 7.31 ± 0.24 %. HPAEC-PAD revealed that DCP composed of fucose (27.16 ± 4.27 mg/l), galactose (11.47 ± 1.38 mg/l), arabinose (11.88 ± 1.24 mg/l) and glucose (1.64 ± 0.07 mg/l). DCP was non-toxic to carp leukocytes at dosages ≤ 50 µg/ml but was found to induce cell proliferative activity. Cellular antioxidant assays showed that DCP did not disrupt glutathione and superoxide dismutase activities in CLC cells when compared to the control. However, a decrease in malondialdehyde level in CLC cells indicated that DCP did not induce oxidative stress. Therefore, DCP is a promising antioxidant source that could be effectively utilised in enhancing the health status of cultured fish species.

Key words: Dictyota ciliolata Polysaccharides; Chemical composition; Common carp leukocytes; Cell proliferation; Oxidative stress