Alzheimer’s disease (AD) is a progressive, neurodegenerative brain disorder associated with loss of memory and cognitive function. Beta-amyloid (Aβ) aggregates, in particular, are known to be highly neurotoxic and lead to neurodegeneration. Therefore, blockade or reduction of Aβ aggregation is a promising therapeutic approach in AD. We have previously reported an inhibitory effect of the methanol extract of Perilla frutescens (L.) Britton (Lamiaceae) and its hexane fraction on Aβ aggregation. Here, the hexane fraction of P. frutescens was subjected to diverse column chromatography based on activity-guided isolation methodology. This approach identified five asarone derivatives including 2,3-dimethoxy-5-(1E)-1-propen-1-yl-phenol (1), β-asarone (2), 3-(2,4,5-trimethoxyphenyl)-(2E)-2-propen-1-ol (3), asaronealdehyde (4), and α-asarone (5). All five asarone derivatives efficiently reduced the aggregation of Aβ and disaggregated preformed Aβ aggregates in a dose-dependent manner as determined by a Thioflavin T (ThT) fluorescence assay. Furthermore, asarone derivatives protected PC12 cells from Aβ aggregate-induced toxicity by reducing the aggregation of Aβ, and significantly reduced NO production from LPS-stimulated BV2 microglial cells. Taken together, these results suggest that asarone derivatives derived from P. frutescens are neuroprotective and have the prophylactic and therapeutic potential in AD.

Purpose: To investigate the potential anti-inflammatory effects of the seeds of Opuntina humifusa and its active constituents.Methods: The extract of O. humifusa seeds was tested for the inhibition of nitric oxide (NO) production in liposaccharide (LPS)-stimulated RAW 264.7 cells using Griess reagent. The active constituents were isolated using bioassay-guided isolation methods. The effects of the active constituent on NO, proinflammatory cytokines, nuclear factor-kappa B (NF-κB) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IκB) were evaluated by enzyme-linked immunosorbent assay (ELISA) and western blot analysis.Results: The seed extract of O. humifusa significantly attenuated LPS-induced NO production in RAW 264.7 cells (p < 0.05). Bioassay-guided fractionation resulted in the isolation of isoamericanin A as an active constituent. Isoamericanin A reduced LPS-induced production of NO, iNOS, and proinflammatory cytokines (TNF-α and IL-6) in a concentration-dependent manner (p < 0.05). Furthermore, the effect was accompanied by decreased translocation of NF-κB from the cytosol to the nucleus and the decreased phosphorylation of IκB in the cytosol induced by LPS (p < 0.05).Conclusion: The seed extract of O. humifusa and its active constituent, isoamericanin A, have antiinflammatory effects in LPS-stimulated RAW 264.7 cells, suggesting that they have potentials as antiinflammatory agents. Keywords: Opuntia humifusa seeds, Isoamericanin A, Nitric oxide, RAW 264.7 cells, NF-kappa B