Phenolics of Aerial Parts of Gentiana lutea L. and Their Biological Activity

Erna Karalija,Adisa Parić,Sabina Dahija,Sanja Ćavar Zeljković,Renata Bešta-Gajević

doi:10.3390/agronomy11071442

Abstract

Gentiana lutea L. is a medicinal plant the roots of which are primarily used in treatments of various human digestive disorders, but also the production of alcoholic liquors. The roots (radix) of G. lutea are described in the European Pharmacopeia, but knowledge about the chemical composition and biological activities of its aerial parts is still limited. Thus, until today aerial parts of this species have not been used in medical treatments or consumed. Therefore, flowers, leaves, and stems extracts of G. lutea obtained by using four different extraction solvents (petrol ether, chloroform, ethanol, and water) were examined for their chemical composition and biological activities. High concentrations of salicylic acid, apigenin, and naringenin were recorded for ethanol stem extracts, while significant amounts of kaempferol were detected in leaves and flowers in chloroform and water extracts, respectively. The highest antioxidant potential was recorded for flower and stem petrol ether extracts with the lowest IC50 values, ranging from 94.46 ± 9.45 to 105.38 ± 10.54 μg/mL. Ethanol extracts of flowers and stems showed moderate antioxidant activity (IC50 143.15 ± 14.32 and 146.90 ± 14.69 μg/mL) as well as strong antimicrobial activity against Candida albicans (21.00 ± 1.00 and 27.50 ± 1.78 mm inhibition zones, respectively). In addition, ethanol extracts had higher antimycotic activity compared to naturally occurring phenolic compounds that are used as positive controls. Moreover, statistical analysis of the activities of plant extracts and single compounds showed that levels of chlorogenic and caffeic acids strongly correlate with the biological activities of the extracts, i.e., they are the main carriers of these biological activities. The presented results indicate the possible use of aerial parts of G. lutea as a natural preservative, as well as a antimicrobial agent, which significantly amplifies the benefits of this medicinal crop and greatly affects the sustainability of cultivated Gentiana plantation.

Highlights

Members of the family Gentianaceae, which comprises more than 400 species, can be found from central and southern Europe, America, Australia, and New Zealand up to 2500 m of altitude
The highest antioxidant potential was recorded for flower and stem petrol ether extracts with the lowest IC50 values, ranging from 94.46 ± 9.45 to 105.38 ± 10.54 μg/mL
Considerable amounts of naringenin were recorded for stems and leaves ethanolic extracts (102.61 ± 0.72 and 91.00 ± 6.99 μmol/g, respectively), while high levels of apigenin were recorded for flowers (166.5 ± 1.19 μmol/g) and stems (158.13 ± 20.79 μmol/g) ethanol extract and in stems in chloroform extract (114.90 ± 3.61 μmol/g)

Summary

Introduction

Members of the family Gentianaceae, which comprises more than 400 species, can be found from central and southern Europe, America, Australia, and New Zealand up to 2500 m of altitude They are widely cultivated in China, continental and northern Europe, as well as in the Balkans [1]. The choleretic activity was recorded for ethanol root extracts, with significant hepatoprotective activity [8]. Active components of gentian root extracts are mainly secoiridoid bitter compounds. Extensive research of bioactive properties of Gentiana lutea extracts shows several additional effects such as anti-tubercular activity [12], radio-protective activity [13], CNS stimulation [14], anti-atherosclerotic effects [15], gastroprotective effects [16], and as ingredient in traditional remedies for atherosclerosis [15]

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