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 1H-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.

Interactions of Bioactive Quince (Cydonia oblonga Mill.) Extract with Biomolecules

“…These results well correlate with our previously published data, that the Stern-Volmer constant for the chlorogenic acid -human serum albumin association is 3.0 × 10 4 M -1 . In addition, the calculated values of the bimolecular quenching rate constant (K Q ) is 6.04 × 10 12 M -1 s indicates at the static mechanism of quenching [18]. …”

“…Such a high activity may result from favorable molecular structure of the Q components, which include phenolic acid but also flavonols and flavan-3-ols [28]. Our previous results [18] showed that the main component of the extract of quincechlorogenic acid has about 3.3 and 7.7 (for PC membrane and RBC, respectively) times greater activity than quince extract (Table 2). It can be assumed that the antioxidant activity of the extract is related to the high content of chlorogenic acid, which has a high antioxidant capacity.…”

“…Antioxidant activities of Q and AA were determined using the fluorimetric method [18,19]. The studies were carried out on RBC membranes and PC liposomes in phosphate buffer (pH 7.4) at 0.1 mg/mL that contained the fluorescent probe DPH-PA (1 µM).…”

“…The effects of extracts on the packing order of the hydrophilic phase of PC and RBC membrane were examined using the Laurdan probe, while on the basis of changes in fluorescence anisotropy of the probe DPH the effect of extract on fluidity of the hydrophobic part of the membrane was examined [18]. The effects of Q extracts on the packing order of the hydrophilic phase of PC and RBC membrane were examined using the Laurdan probe, while on the basis of changes in fluorescence anisotropy of the probe DPH the effect of extract on fluidity of the hydrophobic part of the membrane was examined.…”

“…Analysis of the potential interaction of Q and AA with human serum albumin (HSA) was performed according to the work by Trnková et al [21] and Strugała et al [18] with minor modifications. All quenching experiments were performed at 295, 300, 305 and 310 K temperature for HSA in a phosphate buffer solution of pH 7.4 and final concentration 1.5 × 10 −5 M. The excitation wavelength was set at 280 nm (excitation of the Trp and Tyr), and the emission spectra were read at 285-460 nm.…”