Inhibition of β-Amyloid Aggregation by Perezone, a Sesquiterpene Quinone

Asteraceae, the largest family of angiosperms, includes the Mutisioideae subfamily, particularly diverse in southern South America and distinguished by its unique chemistry. Mutisioideae is divided into three tribes whose members synthesize 5-methylcoumarins and sesquiterpene quinones, especially bisabolene derivatives like perezone, compounds endowed with a range of biological activities. This study focuses on Jungia floribunda (Nassauvieae tribe), a widely distributed but understudied species in southern Brazil, with the aim of analyzing its chemical composition and potential effects on β-amyloid aggregation. Roots of J. floribunda were extracted using n-hexane and supercritical CO₂. The main compounds, perezone and a mixture of two monoisovaleryl hydroxyperezones, were isolated and identified by spectroscopic methods. Perezone was quantified in roots using a validated HPLC method, and its content was higher in the supercritical extract. The effect of perezone on Aβ fiber aggregation and disaggregation of preformed structures was evaluated, revealing a consistent inhibitory effect across all concentrations tested.