Khongsombat O.Kamsaen F.Buapheng N.Choemsuwan P.Klinprathap K.Tunsophon S.Mahidol University2025-07-222025-07-222025-07-01Trends in Sciences Vol.22 No.7 (2025)https://repository.li.mahidol.ac.th/handle/123456789/111332Excessive exercise can lead to oxidative stress which can negatively affect the nervous system. Phycocyanin, a pigment in blue-green algae like spirulina, has potent antioxidant properties that help neutralize free radicals and reduce oxidative stress. This study examined the effects of phycocyanin on oxidative stress in the rat brain induced by prolonged strenuous exercise. The male Sprague-Dawley rats were divided into 5 groups: Control group, exercise group, exercise with low (100 mg/kg BW) or high (200 mg/kg BW) doses of phycocyanin or vitamin C (200 mg/kg BW). After the 8^th week of experiment, brain tissue was collected to analyze malondialdehyde levels (MDA) and antioxidant activity in the prefrontal cortex, hippocampus, and amygdala. The results show that excessive exercise tends to increase MDA levels and decrease superoxide dismutase (SOD) levels, although these changes are not statistically significant. However, excessive exercise significantly reduces the antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPx), which may contribute to oxidative stress. Phycocyanin, on the other hand, enhances the antioxidant activity of SOD and CAT, both of which play a critical role in mitigating oxidative damage. Interestingly, phycocyanin does not appear to significantly affect GPx levels. This suggests that phycocyanin may selectively target specific antioxidant pathways while leaving others unaffected.MultidisciplinaryArticleSCOPUS10.48048/tis.2025.99672-s2.0-10501062242527740226