Immunomodulatory, hemolytic and cytotoxic activity potentials of triterpenoid saponins from eight Cephalaria species

Abstract

Background: Saponins isolated from a number of plants possess a broad spectrum of biological and pharmacological activities by using in vitro and in vivo bioassays. The recent investigations and findings in biological activity studies of saponins have mostly focused on immunomodulatory, hemolytic and cytotoxic properties.

Hypothesis/purpose: Considering the great potential of saponins as bioactive agents, we investigated the cytotoxic, hemolytic and immunomodulatory activities of nineteen triterpenoid saponins from the aerial parts of eight Cephalaria species from Turkey.

Study design: The isolated oleanane type saponins from Cephalaria species were tested for their hemolytic, cytotoxic and immunomodulatory activities through anin vitro cell based assay systems.

Methods: HeLa, A549, and a normal cell line HEK293 were used for testing cytotoxicity using MTT method. Immunomodulatory activity was performed in stimulated whole blood cells by PMA plus ionomycin. Hemolytic activity was assessed on human erythrocytes.

Results: Aristatoside C (3) and davisianoside B (16) displayed significant inhibitory effects on cancerous A549 and HeLa cells, and non-cancerous HEK293 cells with IC₅₀ values of 3.52 ± 0.11, 35.69 ± 0.50, 8.96 ± 0.62 µM and 4.08 ± 0.06, 11.74 ± 0.82, 20.43 ± 3.21 µM, respectively. Thirteen saponins out of the nineteen tested increased IL-1β concentrations considerably, while six compounds changed IL-2 or IFN-γ levels slightly. Almost all of the saponins showed noticeable hemolysis in human erythrocyte cells based on the sugar units.

Conclusion: In this study, almost all saponins with oleanolic acid as aglycones exhibited significant hemolysis, monodesmosidic saponins with hederagenin as aglycone were the most active compounds against lung cancer cells with greater activity than standard commercial chemotherapy drug doxorubicin and some of the hederagenin type saponins induced remarkable IL-1β secretion.

Keywords: Caprifoliaceae; Cephalaria; Cytotoxic activity; Hemolytic activity; Immunomodulatory activity; Triterpene saponin.