Phenylpropanoid amides and phenylethanols from Nanophyton erinaceum

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.

Bassiamide A, a new alkaloid from xero-halophyte Bassia indica Wight

N-[(3-(3-methyl-1-oxo-butyl)amino)propyl]-3-(3,4-dihydroxyphenyl)prop-2-enamide (7), named 'Bassiamide A', a new alkaloid, together with six known compounds including one lignan (1) and five lignanamides (2-6), were isolated from the aerial parts of Bassia indica Wight. The study also reported an optimal separation of a rare occurring R-isomer lignanamide derivative (6) from a natural origin, in addition to its known corresponding S-isomer (5). Structures of isolated compounds were elucidated based on NMR spectroscopic data, HR-MS, and comparison with known related ones, and they were identified as syringaresinol (1), N-trans-feruloyl-3-methoxytyramine (2), N-trans-feruloyltyramine (3), S-(-)-N-trans-feruloyl normetanephrine (4), S-(-)-N-trans-feruloyl octopamine (5), R-(+)-N-trans-feruloyl octopamine (6). The isolated compounds were evaluated for their anti-acetylcholinesterase activity, and they showed weak inhibitory activity.

Design, Antileishmanial Activity, and QSAR Studies of a Series of Piplartine Analogues

Piplartine is an alkamide found in different Piper species and possesses several biological activities, including antiparasitic properties. Thus, the aim of the present study was to evaluate a series of 32 synthetic piplartine analogues against the Leishmania amazonensis promastigote forms and establish the structure-activity relationship and 3D-QSAR of these compounds. The antileishmanial effect of the compounds was determined using the MTT method. Most compounds were found to be active against L. amazonensis. Among 32 assayed derivatives, compound (E)-(−)-bornyl 3-(3,4,5-trimethoxyphenyl)-acrylate exhibited the most potent antileishmanial activity (IC50 = 0.007 ± 0.008 μM, SI > 10), followed by benzyl 3,4,5-trimethoxybenzoate (IC50 = 0.025 ± 0.009 μM, SI > 3.205) and (E)-furfuryl 3-(3,4,5-trimethoxyphenyl)-acrylate (IC50 = 0.029 ± 0.007 μM, SI > 2.688). It was found that the rigid substituents contribute to increasing antiparasitic activity against L. amazonensis promastigotes. The presence of the unsaturated heterocyclic substituent in the phenylpropanoid chemical structure (furfuryl group) resulted in a bioactive derivative. Molecular simplification of benzyl 3,4,5-trimethoxybenzoate by omitting the spacer group contributed to the bioactivity of this compound. Furthermore, bornyl radical appears to be important for antileishmanial activity, since (E)-(−)-bornyl 3-(3,4,5-trimethoxyphenyl)-acrylate exhibited the most potent antileishmanial activity. These results show that some derivatives studied would be useful as prototype molecules for the planning of new derivatives with profile of antileishmanial drugs.