Synthesis and dopaminergic neuroprotective activity of the proposed structure of bassiamide A, a caffeamide alkaloid derived from Bassia indica Wight

Herein, we describe the synthesis of the proposed structure of the caffeamide alkaloid bassiamide A. The amide moiety of bassiamide A was readily formed via an amide coupling reaction between caffeic acid and the known N-(3-aminopropyl)-3-methylbutanamide. However, the spectral data of the synthesized bassiamide A did not agree with that of a previous study. The structure of the synthesized bassiamide A was confirmed using combined two-dimensional NMR analysis. Extended analyses of the bioactivity of the synthesized bassiamide A revealed its efficacy in protecting dopaminergic neurons from MPP+-induced neurotoxicity in C. elegans. Additionally, treatment with bassiamide A notably ameliorated the impaired food-sensing ability and locomotion of C. elegans, suggesting a protective effect on the functionality of dopaminergic neurons.

In Vitro Antimicrobial Potential of CAPE and Caffeamide Derivatives against Oral Microbes

Caffeic acid phenethyl ester (CAPE) is a natural component isolated from propolis and used in traditional medicine. We aimed to investigate the antimicrobial properties and action mechanism of CAPE and caffeamide derivatives (26G and 36M) against oral disease microbes. We resolved the minimum inhibitory and bactericidal concentrations of 26G and 36M and their stability at different temperatures and pH. We also evaluated their effect on biofilm formation and antibiotic resistance gene expression in methicillin-resistant Staphylococcus aureus (MRSA). Our results revealed that 26G and 36M showed the best anticancer and antimicrobial activities, respectively, compared with the other four caffeamide derivatives. Both 26G and 36M showed heat-dependent decreases in antimicrobial activity. The 36M derivative was stable irrespective of pH, whereas 26G was not stable under high pH conditions. Biofilm formation and antibiotic resistance-related gene expression were consistent with their respective phenotypes. This study provides evidence for the potential application of CAPE and caffeamide derivatives in dental medicine to cure or prevent oral diseases.