Effects of caffeoylquinic-acid-rich fractions of silver wormwood (Artemisia ludoviciana Nutt.) extract on rat kidney mitochondria functions

Abstract

Caffeoylquinic acids are specialized bioactive metabolites possess antioxidant activity [1]. Currently, increasing interest is shown towards mitochondria-targeted antioxidants. The aim of this study was to fractionate caffeoylquinic acids from cultivated silver wormwood herb acetone extract and evaluate their antioxidant activity, effects on kidney mitochondrial functions, and cytochrome-c-reducing properties. Caffeoylquinic acids were fractionated by column chromatography, aqueous monocaffeoylquinic acids (WS1) and methanolic dicaffeoylquinic acids (WS2) fractions were obtained [2]. Quantitative and qualitative analysis was performed by HPLC-PDA method. Preparation of isolated kidney mitochondria of rats described in [2], [3]. The mitochondrial functions were measured using an Oxygraph-2k high-resolution respirometry system. The reduction of cytochrome c, and antioxidant activity in vitro were recorded spectrophotometrically [2], [3]. The fractions were riched in caffeoylquinic acids. We identified chlorogenic acid (143.3 ± 2.8 mg/g DW), neochlorogenic acid (6.7 ± 0.1 mg/g DW), 4-O-caffeoylquinic acid (7.8 ± 0.2 mg/g DW) in WS1 fraction and 4,5-dicaffeoylquinic acid (101.1 ± 0.6 mg/g DW), 3,4-dicaffeoylquinic acid (175.9 ± 0.5 mg/g DW), 3,5-dicaffeoylquinic acid (378.8 ± 0.5 mg/g DW) in WS2 fraction by HPLC-PDA method. The highest radical scavenging and antiradical activities were observed in the WS2 fraction from silver wormwood herb acetone extract. The WS1 fraction showed lower antioxidant activity in vitro. WS1 at both concentrations (0.008 µg/mL and 0.8 µg/mL) had no effect on routine (V0) respiration rate. 0.8 µg/mL concentration of WS1 15% reduced state 3 respiration rates (VADP) as compared to the control group. WS2 also had no effect on V0. WS2 fraction at both concentrations diminished VADP in a dose-dependent manner. The higher concentration (0.8 µg/mL) of the WS2 23% reduced VADP as compared to the control group. The highest cytochrome c reducing capacity was observed in the WS2. WS1 less reduced cytochrome c. The results of our experiments revealed up-and-coming mitochondrial-function-modulating, antioxidant and cytochrome-c-reducing properties of caffeoylquinic-acid-rich fractions from cultivated silver wormwood herb extract based on a new mechanism of action.