Is 1,8-Cineole-Rich Extract of Small Cardamom Seeds More Effective in Preventing Alzheimer's Disease than 1,8-Cineole Alone?

The present study demonstrates the efficacies of synthetic 1,8-cineole and an 1,8-cineole-rich supercritical carbon dioxide (SC-CO) extract of small cardamom seeds in preventing oligomerization of amyloid beta peptide (Aβ42) and inhibiting iron-dependent oxyradical production in vitro. The oligomerization of Aβ42 was monitored by thioflavin T assay and MALDI-TOF analysis of the oligomers. The iron-dependent production of oxygen free radicals was detected by fluorometric benzoate hydroxylation assay. We observed that both pure 1,8-cineole and 1,8-cineole-rich extract of small cardamom seeds at concentrations of 50 µM and 100 µM prevented the production of reactive hydroxyl radicals from a mixture of Fe and ascorbate. However, the 1,8-cineole-rich extract of small cardamom seeds prevented in vitro Aβ42 oligomerization more effectively vis-à-vis the synthetic (99% pure) 1,8-cineole. Additional study on SHSY5Y cells indicated that both pure 1,8-cineole and 1,8-cineole-rich SC-CO extract of small cardamom seeds prevented iron-dependent cell death. Since oxidative damage, Aβ42 aggregation and loss of cell viability (iron-induced) are characteristics of onset of Alzheimer's disease pathology, our results suggest a putative therapeutic role of 1,8-cineole-rich extract of small cardamom seeds over pure 1,8-cineole in preventing this neurodegenerative disease.