Effects of broadband mid-infrared radiation and 1,8-cineole on β-amyloid aggregation: a biophysical characterization of moxibustion-based Alzheimer's therapeutic factors.

Moxibustion is a traditional Chinese medicine (TCM) external therapy that shows notable preventive effects on Alzheimer's disease (AD). It has been postulated that the therapeutic effect of moxibustion may be mediated through the combined action of multiple factors, including heat, infrared radiation, and volatile combustion products of Artemisia argyi. However, direct evidence supporting the influence of moxibustion-related factors on AD-related pathological processes is limited, creating a knowledge gap between the clinical outcomes of moxibustion-based AD therapy and the modern biomedical understanding of its underlying mechanisms. We use biophysical approaches to investigate influences of two moxibustion-related factors, namely the broadband mid-infrared (mid-IR) radiation and 1,8-cineole (CIN), on the aggregation kinetics of β-amyloid (Aβ) peptides and the molecular structures of the resulting Aβ aggregates. Our results showed that Aβ fibrillation was decelerated with these influential factors. The macroscopic morphologies and packing, as well as the molecular-level structures of resultant Aβ aggregates are also significantly modulated. Overall, our results provide molecular-level insights into how these therapeutic factors may act on Aβ amyloidosis.