The Structure of a New Cardenolide Diglycoside and the Biological Activities of Eleven Cardenolide Diglycosides from Nerium oleander

Abstract

A new cardenolide diglycoside (1) was isolated from Nerium oleander together with ten known cardenolide diglycosides 2—11. The structure of compound 1 was established on the basis of their spectroscopic data. The in vitro anti-inflammatory activity of compounds 1—11 was examined on the basis of inhibitory activity against the induction of the intercellular adhesion molecule-1 (ICAM-1). Compounds 2—5 were active at an IC₅₀ value of less than 0.8 μM. The cytotoxicity of compounds 1—11 was evaluated against three human cell lines normal human fibroblast cells (WI-38), malignant tumor cells induced from WI-38 (VA-13), and human liver tumor cells (HepG2). Compound 3 was active toward VA-13 cells, and compounds 2—5 were active toward HepG2 cells at IC₅₀ values of less than 1.3 μM. The multidrug resistance (MDR)-reversal activity of compounds 1—11 was evaluated on the basis of the amount of calcein in MDR human ovarian cancer 2780AD cells in the presence of each compound. Compounds 1 and 8 showed moderate effects on calcein accumulation.