Carnosic acid attenuates apoptosis induced by amyloid-β 1–42 or 1–43 in SH-SY5Y human neuroblastoma cells

• Aβ42 and Aβ43 induced apoptosis in cultured human neuroblastoma cells.
• Carnosic acid (CA, 10 μM) attenuated the Aβ42/43-induced apoptosis.
• CA suppressed the Aβ42/43-induced signals in caspase activation.
• CA inhibited the intracellular oligomerization of exogenous Aβ42/43.
• CA may have a potential against Aβ-mediated diseases such as Alzheimer's disease.

Amyloid-beta (Aβ) peptides, Aβ 1–42 (Aβ42) and Aβ43 in particular, cause neurotoxicity and cell death in the brain of Alzheimer's disease (AD) at higher concentrations. Carnosic acid (CA), a phenolic diterpene compound in the labiate herbs rosemary and sage, serves as an activator for neuroprotective and neurotrophic functions in brain cells. We investigated the effect of CA on apoptosis induced by Aβ42 or Aβ43 in cultured SH-SY5Y human neuroblastoma cells. Treatment of the cells with Aβ42 or Aβ43 (monomer, 10 μM each) induced apoptosis, which was confirmed by the cleavage of poly-(ADP-ribose) polymerase (PARP) and apoptosis-inducing factor (AIF). Concurrently, the Aβ treatment induced the activation of caspase (Casp) cascades including an effector Casp (Casp3) and initiator Casps (Casp4, Casp8 and Casp9). Pretreatment of the cells with CA (10 μM) partially attenuated the apoptosis induced by Aβ42 or Aβ43. CA pretreatment also reduced the cellular oligomers of Aβ42 and Aβ43. These results suggest that CA suppressed the activation of Casp cascades by reducing the intracellular oligomerization of exogenous Aβ42/43 monomer. The ingestion of an adequate amount of CA may have a potential in the prevention of Aβ-mediated diseases, particularly AD.