Investigation of seasonal changes on the antioxidant activity of brown algae Nizamuddinia zanardinii pre- and post-Monsoon in North coasts of the Oman Sea

In the present study, the effect of seasonal variability was investigated on the antioxidant content of brown algae Nizamuddinia zanardinii in the pre (April to June 2019) and post (October to December 2019) monsoon periods. Sampling was performed from Tang Bay, Chabahar Port and Goater Bay. T-test results indicated that all indices except IC₅₀ were significantly higher in post monsoone condition compared pre monsoon (p<0.05). While, IC₅₀ significantly higher in pre monsoon (p<0.05).  Comparison of results between stations indicated the levels of anthocyanin (4.13±0.97 DW/mg) and FRAB (0.56±0.02%) at Goater bay in pre monsoon were significantly lower than compared other stations (p<0.05); While, there was no significant difference between stations in post monsoon (p>0.05). The level of flavonoids showed a significant difference between all three stations in post monsoon (p<0.05); whereas no significant difference was observed between stations in pre monsoon (p>0.05). The highest amount of flavonoids in post monsoon were measured at Chabahar Bay Station (5.41±1.51 mg QE/100g DW). The highest level of IC₅₀ was measured in both pre and post monsoon at Goater Bay (respectively 69.68±2 2.20 and 126.08±13.09 μg/ml), which was significantly higher than compared to other stations (p<0.05); But there was no significant difference between other stations in pre and post Monsoon (p>0.05).In conclusion, the results of this study showed that the level of antioxidant activity of N. zanardinii algae except IC50 after monsoon is significantly higher than pre- monsoon conditions. These results can be considered in the study of antioxidant potential of this species for commercial activities.