Biological Activity of Japanese Quince Extract and Its Interactions with Lipids, Erythrocyte Membrane, and Human Albumin

Abstract

The aim of the study was to determine in vitro biological activity of fruit ethanol extract from Chaenomeles speciosa (Sweet) Nakai (Japanese quince, JQ) and its important constituents (-)-epicatechin (EC) and chlorogenic acid (CA). The study also investigated the structural changes in phosphatidylcholine (PC) liposomes, dipalmitoylphosphatidylcholine liposomes, and erythrocyte membranes (RBC) induced by the extract. It was found that the extract effectively inhibits oxidation of RBC, induced by 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), and PC liposomes, induced by UVB radiation and AAPH. Furthermore, JQ extract to a significant degree inhibited the activity of the enzymes COX-1 and COX-2, involved in inflammatory reactions. The extract has more than 2 times greater activity in relation to COX-2 than COX-1 (selectivity ratio 0.48). JQ extract stimulated growth of the beneficial intestinal bacteria Lactobacillus casei and Lactobacillus plantarum. In the fluorimetric method by means of the probes Laurdan, DPH and TMA-DPH, and (1)H-NMR, we examined the structural changes induced by JQ and its EC and CA components. The results show that JQ and its components induce a considerable increase of the packing order of the polar heads of lipids with a slight decrease in mobility of the acyl chains. Lipid membrane rigidification could hinder the diffusion of free radicals, resulting in inhibition of oxidative damage induced by physicochemical agents. JQ extract has the ability to quench the intrinsic fluorescence of human serum albumin through static quenching. This report thus could be of huge significance in the food industry, pharmacology, and clinical medicine.

Keywords: 1H-NMR and fluorometric study; Erythrocyte and phosphatidylcholine membranes; Human serum albumin; Japanese quince; Lipid peroxidation.

Fig. 1

Relative fluorescence intensity of DPH-PA probe as a function of time of oxidation a liposomes PC and b RBC ghosts for AAPH radicals in the presence of Japanese quince extract at selected concentrations. The relative change in fluorescence intensity F/F ₀ is a measure of the degree of lipid peroxidation

Fig. 2

a Generalized polarization (GP) of Laurdan probe as a function of Japanese quince (JQ), (−)-epicatechin (EC) and chlorogenic acid (CA) concentration (positive values for RBC, negative values for PC); b, c TMA-DPH and DPH probes fluorescence anisotropy as a function of concentration of Japanese quince. PC—phosphatidylcholine liposomes, RBC—erythrocyte membrane (ghosts). Values are mean ± SEM, n = 6. Means labeled with asterisk (*) are significantly (p < 0.05) different from control

Fig. 3

¹H-NMR spectra of liposomes formed from pure DPPC and DPPC with a Japanese quince, b (−)-epicatechin (EC); c chlorogenic acid (CA), at 1 mol%. PrCl₃ (4 mM) was added to the samples before measurement

Fig. 4

Emission spectra of HSA in the presence of various concentrations of Japanese quince (JQ) (a), (−)-epicatechin—EC (b), chlorogenic acid—CA (c), and Stern–Volmer plots of F _o/F against concentration for JQ, EC and CA. (HSA = 1.5 × 10⁻⁵ M, λ _ex = 280 nm, T = 295 K)

Fig. 5

Effect of Japanese quince extract (50–250 µg mL⁻¹) on the growth of probiotic bacteria (Lactobacillus casei and Lactobacillus plantarum). Data are percentages compared with control (ethanol–water solution in culture medium)

Fig. 6

Extent of leakage of carboxyfluorescein from PC liposomes expressed as a percentage after 15-min incubation, as a function of concentration, for Japanese quince (JQ), (−)-epicatechin (EC) and chlorogenic acid (CA)