Studies on sustained release and neuromodulatory effects of β-cyclodextrin-tyramine complex: Insights from spectroscopic characterization and Caenorhabditis elegans behavioural studies

초록

In the present work, the formation of tyramine (TA) and β-cyclodextrin (β-CD) inclusion complex was studied using absorption, FT-IR and 1H NMR spectroscopic studies. The results obtained from the absorption spectral analysis revealed the formation of a 1:1 inclusion complex of TA and β-CD with a binding constant of Kbin = 20 M−1. FT-IR and 1H NMR analysis revealed that TA has complexed within the hydrophobic cavity of β-CD to form an inclusion complex. A blind docking approach using AutoDock Vina was employed to investigate the formation of inclusion complex between TA and β-CD. The inclusion complex of TA and β-CD was then evaluated in Caenorhabditis elegans for its effects on TA release-induced immobilization, migration patterns, egg-laying behaviour, and short-term associative memory. The controlled release of TA facilitated by β-CD allowed for effective administration at lower doses compared to direct exposure, ensuring a continuous and stable release profile. The locomotory and behavioural pattern of the worms on treatment with TA and β-CD-TA revealed that treatment with β-CD-TA at a 1:1 concentration did not demonstrate a significant reduction in the migration pattern of the worm and chemotaxis index (CI) of the worm, suggesting the possibility of the slow release of TA. The number of eggs laid was significantly recovered when TA was administered as β-CD-TA inclusion complex, unlike direct TA exposure in egg laying assay. The present study provides a promising strategy for achieving controlled and sustained release of TA, with significant implications for studying behavioural patterns and neuromodulation in biological systems. © 2025 Elsevier B.V.

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