Anti-amyloidogenic effects of Perilla frutescens var. acuta on beta-amyloid aggregation and disaggregation

Beta-amyloid (A beta) aggregates are a major cause of Alzheimer's disease (AD), and the inhibition of A beta aggregation is a good therapeutic target against AD. Thus, the effects of Perilla extract (4-100 mu g/mL) on the aggregation of A beta (20 mu M) monomers and disaggregation of pre-aggregated A beta aggregates were determined. The Perilla methanol extract and its hexane fraction significantly reduced A beta aggregation determined by a Theoflavin T fluorescence assay (IC50=24.5 and 19.8 mu g/mL, respectively) and confirmed by Western blot analysis with native gels. The inhibition of A beta aggregation by hexane fraction of Perilla extract (20 and 100 mu g/mL) rescued the PC12 cells from A aggregate-induced toxicity to the levels of DMSO-treated control groups. Furthermore, hexane fraction efficiently disaggregated the preformed A beta aggregates (IC50=10.2 mu g/mL). Perilla frutescens var. acuta leaves exhibited anti-amyloidogenic effects against A beta aggregation and disaggregation.