Lutein isolated from Scenedesmus obliquus microalga boosts immunity against cyclophosphamide-induced brain injury in rats.

Lutein is a naturally potent antioxidant carotenoid synthesized in green microalgae with a potent ability to prevent different human chronic conditions. To date, there are no reports of the immune-stimulating effect of pure lutein isolated from Scenedesmus obliquus. Thus, we isolated the natural lutein from S. obliquus and evaluated its effectiveness as an immunostimulant against cyclophosphamide-induced brain injury. We purified all-E-(3R, 3'R, 6'R)-Lutein from S. obliquus using prep-HPLC and characterized it by 1 H- and 13 C-NMR spectroscopy. We assigned rats randomly to four experimental groups: the Control group got a vehicle for lutein dimethyl sulfoxide for ten successive days. The Cyclophosphamide group received a single i.p injection of Cyclophosphamide (200 mg/kg). Lutein groups received 50 and 100 (mg/kg) of lutein one time per day for ten successive days after the cyclophosphamide dose. Lutein administration reduced brain contents of Macrophage inflammatory protein2 (MIP2), cytokine-induced- neutrophil chemoattractant (CINC), and Matrix metalloproteinase 1 (MMP1). Besides, it lowered the contents of interleukin 1 beta (IL-1β) and interleukin 18 (IL-18), associated with low content of NLR pyrin domain protein 3 (NLRP3) and consequently caspase-1 compared to the cyclophosphamide group. In the histomorphometric analysis, lutein groups (50 and 100 mg/Kg) showed mild histopathological alterations as they significantly reduced nuclear pyknosis numbers by 65% and 69% respectively, compared to the cyclophosphamide group. This is the first study that showed the immunomodulatory roles of lutein against cyclophosphamide-induced brain injury via decreasing neuroinflammation, chemokines recruitment, and neuron degeneration with the modulation of immune markers. Hence, lutein can be an effective immunomodulator against inflammation-related immune disorders.