Protective effects of silk lutein extract from Bombyx mori cocoons on ß-Amyloid peptide-induced　apoptosis in PC12 cells.

Beta-amyloid (Aß) peptide, the hallmark of Alzheimer's disease (AD), invokes a cascade of oxidative damage to neurons and eventually leads to neuronal death. This study evaluated the protective effects of lutein extract from yellow cocoons of Bombyx mori, and its underlying mechanisms against was investigated to assess its protective effects and the underlying mechanisms against Aß25-35-induced neuronal cell death in cultured rat pheochromocytoma (PC12) cells. Aß25-35-induced neuronal toxicity is characterized by decrease in cell viability, increase in intracellular reactive oxygen species (ROS) production, activation of mitochondrial death pathway, and activation the phospholyration of mitogen-activated protein kinase (MAPKs) pathway. Pretreatment with silk lutein extract significantly attenuated Aß25-35-induced loss of cell viability, apoptosis, MAPKs pathway activation and ROS production. Taken together, our present study suggests that silk lutein extract protects PC12 cells from Aß25-35-induced neurotoxicity via the reduction of the ROS production, and subsequent attenuation of the mitochondrial death pathway and reduces the activation of the MAPK kinase pathways. This compound might beneficial as potential therapeutic agent to prevent or retard the development and progression of AD.

Immune enhancement activities of silk lutein extract from Bombyx mori cocoons

BACKGROUND: Declining immune function poses an important clinical challenge worldwide and supplementation with natural products that possessing immune enhancing properties is a promising approach for preventing or delaying immune function decline. Cocoons from yellow silkworms are a significant source of lutein, and this unexplored silk extract could be a viable alternative source for dietary lutein. This study assessed immunomodulatory activities of the silk lutein extract. Female BALB/c mice orally received lutein, either as silk or marigold extracts (10 or 20 mg/kg daily), or vehicle only (1% tween 80 in PBS pH 7.4) for 4 weeks. Natural killer (NK) cell activity, specific antibody production, lymphocyte subpopulations, mitogen-induced lymphocyte proliferation, and cytokine production were examined. RESULTS: Silk lutein extract increased NK cell activity, and the effect was dose-related whereas marigold lutein extract was ineffective. Silk lutein extract dose-dependently enhanced antibody production in pre-immunized mice but marigold lutein extract had no effect. Feeding with silk lutein extract increased the populations of CD3+ and CD4 + CD3 + cells. Silk lutein extract also stimulated concanavalin A- and lipopolysaccharide-induced proliferations of T and B lymphocytes, respectively. Moreover, silk lutein extract increased IL-2 and IFN-γ production while the effect of marigold lutein extract was undetectable. CONCLUSIONS: Together, silk lutein extract enhanced both innate and adaptive immune functions. This preparation may prove to be an effective supplement for strengthened immunity.

Protective effect of silk lutein on ultraviolet B-irradiated human keratinocytes

Carotenoids are efficient antioxidants that are of great importance for human health. Lutein and zeaxanthin are carotinoids present in high concentrations in the human retina which are involved in the photoprotection of the human eye. Lutein may also protect the skin from ultraviolet (UV)-induced damage. The present study investigated the protective effect of lutein extracted from yellow silk cocoons of Bombyx mori on human keratinocytes against UVB irradiation. A human keratinocyte cell line and primary human keratinocytes were used to investigate the UVB protection effects of silk lutein and plant lutein. Silk lutein showed no cytotoxicity to keratinocytes. Treatment with silk lutein prior to UVB irradiation enhanced cell viability and cell proliferation, and reduced cell apoptosis. The protective effects of silk lutein may be superior to those of plant lutein. Silk lutein may have a benefit for protection of keratinocytes against UVB-irradiation.