ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Study of micelles and surface properties of triterpene saponins with improved isolation method from Hedera helix

Martin Bajcura, Miloš Lukáč, Martin Pisárčik, and Branislav Horváth

Department of Chemical Theory of Drugs, Faculty of Pharmacy, Comenius University, Bratislava, Slovakia

E-mail: bajcura1@uniba.sk

Received: 21 July 2023  Accepted: 12 November 2023

Abstract:

Triterpene saponin fractions were extracted from Hedera helix, and in-depth analysis of their physicochemical properties was conducted. Hederasaponin B and hederacoside C were extracted from Hedera helix leaves, and their purification was carried out using reverse phase column chromatography with a modified method, providing an affordable alternative to HPLC. Structurally, hederacoside C differs from hederasaponin B only by the presence of a hydroxyl group at the carbon 23 of the aglycon. The critical micelle concentration (cmc) measurement confirmed hydrophilic nature of hederacoside C that led to a higher cmc value compared to hederasaponin B and alpha-hederin. Therefore, the cmc value of hederasaponin B is nearly an order of magnitude lower compared to hederacoside C. Additionally, the study of the surface tension revealed that the more lipophilic alpha-hederin displayed a greater surface tension value (γ_cmc = 39.8 mN·m⁻¹) compared to hederasaponin B and hederacoside C. Measurements of the surface tension dependence on the concentration in water were enabled to determine the area corresponding to a single saponin molecule at the water/air phase interface (A_cmc). Notably, structural changes had negligible effects, as Acmc values remained practically identical. Particle size determination further indicated that hederacoside C forms only micelles compared to the remaining substances that showed signs of vesicles formation. Alpha-hederin, as the only measured molecule capable of ionization, showed a negative zeta potential.

Keywords: Triterpene saponins; Hedera helix; Surface activity; Critical micelle concentration; Micelle size; Zeta potential

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03212-5

Chemical Papers 78 (3) 1875–1885 (2024)