Dual Role of Phenyl Amides from Hempseed on BACE 1, PPARγ, and PGC-1α in N2a-APP Cells

Inhibitory activity of lignanamides isolated from hemp seed hulls(Cannabis sativa L.) against soluble epoxide hydrolase

Soluble epoxide hydrolase (sEH) is a therapeutic target for inflammation. In the present study, we isolated one new (1) and four known (2-5) compounds from the ethyl acetate fraction of hemp seed hulls. Their structures were elucidated as lignanamides via nuclear magnetic resonance and mass spectral analyses. All five compounds inhibited sEH activity, with half-maximal inhibitory concentrations of 2.7 ± 0.3 to 18.3 ± 1.0 μM. These lignanamides showed a competitive mechanism of inhibition via binding to sEH, with ki values below 10 μmol. Molecular simulations revealed that compounds 1-5 fit stably into the active site of sEH, and the key amino acid residues participating in their bonds were identified. It was confirmed that the potential inhibitors 4 and 5 continuously maintained a distance of 3.5 Å from one (Tyr383) and four amino (Asp335, Tyr383, Asn472, tyr516) residues, respectively. These findings provide a framework for the development of naturally derived sEH inhibitors.

Synthesis and properties of the kojic acid dimer and its potential for the treatment of Alzheimer's disease

The kojic acid dimer (KAD) is a metabolite derived from developing cottonseed when contaminated with aflatoxin. The KAD has been shown to exhibit bright greenish-yellow fluorescence, but little else is known about its biological activity. In this study, using kojic acid as a raw material, we developed a four-step synthetic route that achieved the gram-scale preparation of the KAD in approximately 25% total yield. The structure of the KAD was verified by single-crystal X-ray diffraction. The KAD showed good safety in a variety of cells and had a good protective effect in SH-SY5Y cells. At concentrations lower than 50 μM, the KAD was superior to vitamin C in ABTS⁺ free radical scavenging assay; the KAD resisted the production of reactive oxygen species induced by H₂O₂ as confirmed by fluorescence microscopy observation and flow cytometry analysis. Notably, the KAD could enhance the superoxide dismutase activity, which might be the mechanism of its antioxidant activity. The KAD also moderately inhibited the deposition of amyloid-β (Aβ) and selectively chelated Cu²⁺, Zn²⁺, Fe²⁺, Fe³⁺, and Al³⁺, which are related to the progress of Alzheimer's disease. Based on its good effects in terms of oxidative stress, neuroprotection, inhibition of Aβ deposition, and metal accumulation, the KAD shows potential for the multi-target treatment of Alzheimer's disease.

Possible neuroprotective effects of amide alkaloids from Bassia indica and Agathophora alopecuroides: in vitro and in silico investigations

In Alzheimer's disease (AD), the accumulation of amyloid-β plaques, overactivity of MAO-B, and phosphorylated tau protein in the central nervous system result in neuroinflammation and cognitive impairments. Therefore, the multi-targeting of these therapeutic targets has emerged as a promising strategy for the development of AD treatments. The current study reports the isolation and identification of seven amide alkaloids, namely, N-trans-feruloyl-3-methoxytyramine (1), N-trans-feruloyltyramine (2), S-(-)-N-trans-feruloylnormetanephrine (3), S-(-)-N-trans-feruloyloctopamine (4), R-(+)-N-trans-feruloyloctopamine (5), N-trans-caffeoyltyramine (6), and S-(-)-3-(4-hydroxy-3-methoxyphenyl)-N-[2-(4-hydroxyphenyl)-methoxyethyl]acrylamide (7), from B. indica and A. alopecuroides, which are halophytic plants that have been reported to contain diverse phytochemicals. Additionally, the study explores the potential inhibition effects of the isolates on β-secretase, monoamine oxidase enzymes, and phosphorylated tau protein, and their anti-aggregation effects on amyloid-β fibrils. Compounds 1, 2, and 7 showed potent inhibitory activity against BACE1, MAO-B, and phosphorylated tau protein, as well as anti-aggregation activity against Aβ-peptides. Additionally, compound 6 displayed promising inhibition activity against MAO-B enzyme. Further in-depth in silico and modeling analyses (i.e., docking, absolute binding free energy calculations, and molecular dynamics simulations) were carried out to reveal the binding mode of each active compound inside the corresponding enzyme (i.e., MAO-B and BACE1). The results indicate that B. indica, A. alopecuroides, and the isolated amide alkaloids might be useful in the development of lead compounds for the prevention of neurodegenerative diseases, especially AD.