10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 4 2016 (October - December) The purpose of the current work was to study the role of lessThan i greaterThan Dunaliella salina lessThan /i greaterThan extract in ameliorating Alzheimer's disease (AD) in rat brain. Aluminium chloride (AlCl lessThan sub greaterThan 3 lessThan /sub greaterThan ) was orally administered to male albino rats (100mg/kg/day for six weeks), while, lessThan i greaterThan D. salina lessThan /i greaterThan ethanolic extract (150mg/kg/day for six weeks) was orally administered post AlCl lessThan sub greaterThan 3 lessThan /sub greaterThan treatment. At the end of experiment, AlCl lessThan sub greaterThan 3 lessThan /sub greaterThan treatment markedly increased lipid hydropyroxide (LOOH) and protein carbonyl (PC) levels while, decreased the total protein content (TPC) and total antioxidant capacity (TAC) when compared with normal control rats. As a result of AlCl lessThan sub greaterThan 3 lessThan /sub greaterThan treatment, cerebral cortex showed pyknosis and necrosis of neurons as well as focal cerebral haemorrhage while, hippocampus showed pyknosis and necrosis of pyramidal cells. Treatment of AD rats with lessThan i greaterThan D. salina lessThan /i greaterThan extract decreased the levels of lipid hydropyroxide and protein carbonyl, while it increased TPC and antioxidant status when compared with Al-induced rats. On the other hand, lessThan i greaterThan D. salina lessThan /i greaterThan administered to neurodegenerative rats declared no histopathological changes in cerebral cortex meanwhile, hippocampus showed necrosis of sporadic pyramidal cells. In addition, the cerebral cortex of rivastigmine treated rats showed necrosis of sporadic neurons while, no histopathological changes were observed in hippocampus. The current research clearly indicates the potential of lessThan i greaterThan D. salina lessThan /i greaterThan extract in counteracting the damage inflicted by AlCl lessThan sub greaterThan 3 lessThan /sub greaterThan on rat brain regions. FAROUK K. EL-BAZ AND HANAN F. ALY Dunaliella salina, Antioxidant, Oxidative stress, Alzheimer'ss disease, Rivastigmine 324-331