Molecular complex of quercetin with hederasaponin C

Abstract

Quercetin (Quer) is one of the most famous flavonols 1 . Quer was founded in different plants. Quer has P-vitamin activity and exhibits antioxidant, anti-inflammatory, antispasmodic, antisclerotic, diuretic, and antitumor effects. 1,2 Previously, we have studied the molecular complex of Quer with triterpene glycoside glycyram (monoammonium salt of glycyrrhizic acid) 3 . Triterpene glycosides from licorice and ivy are one of the most affordable saponins. However, molecular complexes of Quer with ivy triterpene glycosides are not described. Triterpene glycoside hederasaponin C (hederacoside C, hederagenin 3-O-α-Lrhamnopyranosyl-(1→2)-O-α-L-arabinopyranosyl-28-О-α-L-rhamnopyranosyl-(1→4)-О-β-Dglucopyranosyl-(1→6)-О-β-D-glucopyranoside, HedC) was discovered in the most species of the ivy genus Hedera L. (Araliaceae), in which it is the dominant saponin.The Quer-HedC complex composition was determined by the method of isomolar series at 256 and 370 nm. This method gave a molar ratio ≈2.0, which corresponded to a 1 : 2 complex of Quer with HedC, respectively (in 2 : 8 mixture of 96 % EtOH and aqueous phosphate buffer with pH 7.2 (v/v)).The molecular complexation of Quer with HedC was studied by ATR FT-IR spectroscopy. It was shown that hydrogen bonds are formed between OH groups of complex components, and by C=O group of Quer and carbohydrate OH groups of HedC: (Н)О•••Н-О and С=ОQuer•••Н-ОHedC.