A series of seventeen cinnamic acid hybrids (4a_ic_i) were obtained through an amidation of aminoadamantanes (amantadine, rimantadine, and memantine) with mixed anhydride generated from different substituted cinnamic acid and ethyl chloroformate. ¹H NMR, ¹³C NMR, IR, and HRMS were used for the confirmation of the structures of the synthesized hybrids. Moreover, the antioxidant profiles of amides were estimated as per five different in vitro methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid cation radical (ABTS), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC) assay, and inhibition of Fe(III)/asc induced lipid peroxidation (LP) in brain homogenate. For comparison, caffeic acid (CaffA), known as a potent naturally occurring antioxidant, was used as a reference compound in our study. The results revealed that the most prominent antioxidant activity was demonstrated by compound 4b₂, with excellent CUPRAC, FRAP, scavenging ABTS⁺˙ potential, and inhibition of Fe/ascinduced LP, followed by 4c₆>4a₆>CaffA>4c₅ and 4a₅>4a₇. Overall, the results suggest that the hybrids (4b₂, 4c₆, and 4a₆) consisting of a caffeoyl moiety and lipophilic adamantane core endow the molecules with the higher antioxidant activity than their parent compound (caffeic acid), especially against LP. Thus, these promising antioxidants could have beneficial effects in various pathological conditions, where oxidative stress is implicated.

Currently, there is an increasing interest towardsα-glucosidase inhibition of various diseases including diabetes mellitus type 2, cancer, HIV, and B- and C-type viral hepatitis. Cinnamic acid derivatives have been shown to be potentially valuable as a new group ofα-glucosidase inhibitors. Therefore, herein, theα-glucosidase inhibitory activity oftrans-N-cinnamoyl and hydroxycinnamoyl amides was studied in vitro. Results revealed that the tested hydroxycinnamoyl amides (1–16) inhibiteda-glucosidase with IC₅₀s ranging between 0.76 and 355.1 μg/ml. Compounds1,2,5,6,9,14, and15showed significant inhibition of yeastα-glucosidase, being even more potent ones than the used positive inhibitor acarbose (IC50=2.50±0.21 μg/ml).

Alzheimer’s disease (AD) is the most common neurodegenerative disease which has a rather complex pathophysiology. During its course, several neurotransmitter neuronal systems get affected such as acetylcholinergic, glutamatergic, gamma-aminobutyric acid (GABA)ergic systems, etc. Such complex physiology requires a sophisticated approach to pharmaceutical management. Therefore, multi-target drugs seem to be an appealing solution. In the present study, we designed and synthesized a hybrid molecule—N-sinapoylamide of memantine, whose parent molecules memantine (MEM) and sinapic acid have been shown in vivo to impact glutamatergic, acetylcholinergic, and GABA-ergic systems, respectively. In silico comparative testing of these molecules was performed, their patterns of interaction with the target enzymes or molecular complexes were analyzed, and some of the mechanisms of action were proposed. Consequently, in vivo testing was performed on a scopolamine mice model of AD and the results overly confirm part of the in silico findings. Therefore, the hybrid molecule (N-Sinapoyl-memantine) seems to be a potent candidate for further evaluation in the management of AD.