Cichorium intybus L. "hairy" roots as a rich source of antioxidants and anti-inflammatory compounds

Abstract

The present study aimed to determine the bioactive profile of various extracts of Cichorium intybus L. "hairy" roots. In particular, the total content of flavonoids as well as the reducing power, antioxidant and anti-inflammatory activity of the aqueous and ethanolic (70%) extracts were evaluated. The total content of flavonoids the ethanolic extract of the dry "hairy" root reached up to 121.3 mg (RE)/g, which was twofold greater than in the aqueous one. A total of 33 diverse polyphenols were identified by the LC-HRMS method. The experimental results showed a high amount of gallic (6.103 ± 0.008 mg/g) and caffeic (7.001 ± 0.068 mg/g) acids. In the "hairy" roots, the presence of rutin, apigenin, kaempferol, quercetin, and its derivatives was found in concentrations of 0.201±0.003 - 6.710±0.052 mg/g. The broad spectrum of pharmacological activities (antioxidant, anti-inflammatory, antimutagenic, anticarcinogenic, etc.) of the key flavonoids identified in the chicory "hairy" root extract was predicted by the General Unrestricted Structure-Activity Relationships algorithm based on in the substances detected in the extract. The evaluation of the antioxidant activity showed that the EC₅₀ values of the ethanol and the aqueous extracts were 0.174 and 0.346 mg, respectively. Thus, the higher ability of the ethanol extract to scavenge the DPPH radical was observed. The calculated Michaelis and inhibition constants indicated that the ethanolic extract of C. intybus "hairy" roots is an efficient inhibitor of soybean 15-Lipoxygenase activity (IC₅₀ = 84.13 ± 7.22 μM) in a mixed mechanism. Therefore, the obtained extracts could be the basis of herbal pharmaceuticals for the therapy of human diseases accompanied by oxidative stress and inflammation, including the pandemic coronavirus disease COVID-19.

Keywords: Cichorium intybus L., “hairy” roots; DPPH test; Inhibition of enzyme; Liquid chromatography with high-resolution mass spectrometry; Polyphenols; Soybean 15-lipoxygenase.

Graphical abstract

Fig. 1

Cichorium intybus L. “hairy” root culture.

Fig. 2

Weight gain of Chicory “hairy” roots (Δm) after cultivation in the various nutrient medium.

Fig. 3

Effect of the extraction condition on the total flavonoid content, the antioxidant activity and the reducing power of the extracts of Cichorium intybus “hairy” roots.

Fig. 4

A representative TIC chromatogram of the ethanolic extracts of “hairy” roots of Cichorium intybus obtained in the negative ion mode. Peak numbers correspond to the labeling adopted in Table 1.

Fig. 5

Kinetic curves of inhibition of 15-sLOX by the ethanolic extract of “hairy” roots of Chicorium intybus at various dilutions (a) and corresponding Lineweaver–Burk plots (b).