Effects of Gentiana lutea Root on Vascular Diseases.

BACKGROUND: Gentiana lutea (GL), commonly known as yellow gentian, bitter root, and bitterwort, belongs to family Gentianaceae. GL belongs to genus Gentiana, which is a rich natural source of iridoids, secoiridoids, xantones, flavonoids, triterpenoids, and carbohydrates. Medicinal plants from Gentiana species have anti-oxidant, anti-inflammatory, anti-mitogenic, anti-proliferative, and lipidlowering effects, as well as a cardioprotective, hypotensive, vasodilator and anti-platelet activities. OBJECTIVE: We reviewed the recent literature related to the effects of Gentiana species, and their active components on vascular diseases. METHODS: Data used for this review were obtained by searching the electronic database [PUBMED/ MEDLINE 1973 - February 2020]. The primary data search terms of interest were: Gentiana lutea, Gentienacea family, phytochemistry, vascular diseases, treatment of vascular diseases, antioxidant, anti-inflammatory, anti-atherogenic. CONCLUSION: Gentiana species and their constituents affect many different factors related to vascular disease development and progression. Therefore, Gentiana-based therapeutics represent potentially useful drugs for the management of vascular diseases.

Yellow gentian root extract provokes concentration- and time-dependent response in peripheral blood mononuclear cells.

Yellow gentian (Gentiana lutea L.), a medicinal plant widely used in traditional medicine, displays multiple biological effects, ranging from beneficial to toxic. Since many promising applications have been reported so far, our aim was to evaluate its potential concentration- and time- dependent cytotoxic and genotoxic effects in vitro. To that end we exposed human peripheral blood mononuclear cells to 0.5, 1, and 2 mg/mL of yellow gentian root extract (YGRE) to determine its effects on oxidative stress parameters [pro/antioxidant balance (PAB) and lipid peroxidation], DNA damage (alkaline comet assay and chromosome aberrations), and cell viability (trypan blue exclusion test). Cell viability decreased with increasing concentrations and treatment duration. Only the lowest YGRE concentration (0.5 mg/mL) increased oxidative stress but produced minor DNA damage and cytotoxicity. At higher concentrations, redox parameters returned to near control values. The percentage of chromosome aberrations and percentage of DNA in the comet tail increased with increased YGRE concentration after 48 h and declined after 72 h of treatment. This points to the activation of DNA repair mechanism (homologous recombination), evidenced by the formation of chromosomal radial figures after 72 h of treatment with the highest YGRE concentration of 2 mg/mL. Our results suggest that YGRE, despite induction of cytotoxic and genotoxic effects, activates cell repair mechanisms that counter oxidative and DNA lesions and induce cell death in highly damaged cells. Therefore, observed protective effects of yellow gentian after longer exposure could be a result of activated repair and removal of cells with irreparable damage.

Potential of Gentiana lutea for the Treatment of Obesity-associated Diseases.

BACKGROUND: Obesity, diabetes, and associated diseases are increasing all over the world, and pose a great burden on public health. According to the latest reports, 440 million people are suffering from diabetes. Diabetes is caused by impaired ability to produce or respond to the hormone insulin consequently resulting in hyperglycemia. METHODS: Data used for this review was obtained by using PUBMED/MEDLINE (1987-2018). The main data search terms were: Gentiana lutea, Gentiana lutea extract, Gentiana lutea constituents, obesity, diabetes mellitus, diabetic complications. RESULTS: In the present review, we describe the potential of root powder of yellow gentian (Gentiana lutea) for the prevention of obesity and diabetes including complications related to this disease. CONCLUSION: Reasonably effective, low-cost alternatives could fulfill an important role for a large part of the human population and could be of great value for the food market. Even a modest reduction of morbidity and mortality with respect to this disease translates into millions of lives saved.

Inhibition by blueberries (bilberries) and extract from milk thistle of rat forestomach hyperplasia induced by oral smokeless tobacco (Swedish snus).

The aim of this study was to identify palatable additives which have a significant protective action against soft tissue changes in the oral cavity caused by Swedish smokeless tobacco ("snus"), and that satisfy existing legal requirements. Although the cancer risk from snus is extremely low, long term use may result in highly undesirable keratotic lesions and associated epithelial abnormalities in the oral cavity. The rat forestomach, which is vulnerable to the irritative action of non-genotoxic compounds like butylated hydroxyanisole, propionic acid as well as snus, was chosen as an experimental model. Studied toxicological endpoints included histopathology and cellular proliferation based on DNA incorporation of bromodeoxyuridine. After 6 weeks' exposure, blueberries (bilberries) and an extract from the common milk thistle were found to exert a highly significant inhibition of cell proliferation induced by snus in the rat forestomach epithelium, indicating a potential protection with respect soft tissue changes in the human oral cavity.

Inhibition of vascular smooth muscle cell proliferation by Gentiana lutea root extracts.

Gentiana lutea belonging to the Gentianaceae family of flowering plants are routinely used in traditional Serbian medicine for their beneficial gastro-intestinal and anti-inflammatory properties. The aim of the study was to determine whether aqueous root extracts of Gentiana lutea consisting of gentiopicroside, gentisin, bellidifolin-8-O-glucoside, demethylbellidifolin-8-O-glucoside, isovitexin, swertiamarin and amarogentin prevents proliferation of aortic smooth muscle cells in response to PDGF-BB. Cell proliferation and cell cycle analysis were performed based on alamar blue assay and propidium iodide labeling respectively. In primary cultures of rat aortic smooth muscle cells (RASMCs), PDGF-BB (20 ng/ml) induced a two-fold increase in cell proliferation which was significantly blocked by the root extract (1 mg/ml). The root extract also prevented the S-phase entry of synchronized cells in response to PDGF. Furthermore, PDGF-BB induced ERK1/2 activation and consequent increase in cellular nitric oxide (NO) levels were also blocked by the extract. These effects of extract were due to blockade of PDGF-BB induced expression of iNOS, cyclin D1 and proliferating cell nuclear antigen (PCNA). Docking analysis of the extract components on MEK1, the upstream ERK1/2 activating kinase using AutoDock4, indicated a likely binding of isovitexin to the inhibitor binding site of MEK1. Experiments performed with purified isovitexin demonstrated that it successfully blocks PDGF-induced ERK1/2 activation and proliferation of RASMCs in cell culture. Thus, Gentiana lutea can provide novel candidates for prevention and treatment of atherosclerosis.

Inhibition of aldose reductase by Gentiana lutea extracts.

Accumulation of intracellular sorbitol due to increased aldose reductase (ALR2) activity has been implicated in the development of various secondary complications of diabetes. Thus, ALR2 inhibition could be an effective strategy in the prevention or delay of certain diabetic complications. Gentiana lutea grows naturally in the central and southern areas of Europe. Its roots are commonly consumed as a beverage in some European countries and are also known to have medicinal properties. The water, ethanol, methanol, and ether extracts of the roots of G. lutea were subjected to in vitro bioassay to evaluate their inhibitory activity on the ALR2. While the ether and methanol extracts showed greater inhibitory activities against both rat lens and human ALR2, the water and ethanol extracts showed moderate inhibitory activities. Moreover, the ether and methanol extracts of G. lutea roots significantly and dose-dependently inhibited sorbitol accumulation in human erythrocytes under high glucose conditions. Molecular docking studies with the constituents commonly present in the roots of G. lutea indicate that a secoiridoid glycoside, amarogentin, may be a potential inhibitor of ALR2. This is the first paper that shows G. lutea extracts exhibit inhibitory activity towards ALR2 and these results suggest that Gentiana or its constituents might be useful to prevent or treat diabetic complications.

Inhibition of myeloperoxidase and antioxidative activity of Gentiana lutea extracts.

The aim of this study was to investigate the inhibitory activity of Gentiana lutea extracts on the enzyme myeloperoxidase (MPO), as well as the antioxidant activity of these extracts and their correlation with the total polyphenol content. Extracts were prepared using methanol (100%), water and ethanol aqueous solutions (96, 75, 50 and 25%v/v) as solvents for extraction. Also, isovitexin, amarogentin and gentiopicroside, pharmacologically active constituents of G. lutea were tested as potential inhibitors of MPO. Antioxidant activity of extracts was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging test and also using cyclic voltammetry (CV). Among all extracts, the antioxidant capacity of 50% ethanol aqueous extract was the highest, both when measured using the DPPH test, with IC(50)=20.6 µg/ml, and when using CV. Also, 50% ethanol extract, showed the best inhibition of MPO activity in comparison with other extracts. In the group of the selected G. lutea constituents, gentiopicroside has proved to be the strongest inhibitor of MPO, with IC(50)=0.8 µg/ml. Also, the concentration of G. lutea constituents were determined in all extracts, using Ultra Performance Liquid Chromatography (UPLC).

Biological effects of Echinacea purpurea on human blood cells.

The aim of this study was to investigate radioprotective properties of Echinacea purpurea tablets in vivo. We analysed lymphocyte chromosome aberrations (CA), micronuclei (MN), apoptosis of leukocytes and haematological parameters in a group of radiation workers who were identified as carrying dicentric chromosomes in their lymphocytes. All radiation workers were taking two 275 mg Echinacea tablets b.i.d., according to a pharmacist's recommendation. All parameters were analysed before and after the two-week treatment. At the end of the treatment lymphocyte CA frequency dropped significantly, and the number of apoptotic cells increased. The inverse lymphocyte-to-granulocyte ratio at the beginning of the study changed to normal at its end. In conclusion, biological effects observed after administration of Echinacea purpurea preparation suggest that it may be beneficial for the prevention of adverse health effects in workers exposed to ionising radiation.

Radioprotective effects of Gentianella austriaca fractions and polyphenolic constituents in human lymphocytes.

The aim of this study was to identify active principles of Gentianella austriaca responsible for the reduction of the incidence of micronuclei in irradiated lymphocytes in vitro. The radioprotective effects of ether (EF) and methanolic (MeF) fractions, water-soluble xanthones demethylbellidifolin (1), demethylbellidifolin 8-O-glucoside (2), bellidifolin 8-O-glucoside (3), and flavonoid swertisin (4) against chromosomal damage induced by gamma-rays were determined using the micronucleus test. EF and MeF showed better protection in treatment of human lymphocytes after gamma-irradiation than did isolated compounds. Among the isolated compounds, the effectiveness in reduction of the frequency of micronuclei followed the order 4>3>2>1. The anti-lipoperoxidant activity was in the order 2>4>1, while 3 slightly increased the level of malondialdehyde. In addition, the effectiveness in induction of apoptosis followed the order, 3>2>4, while 1 had no proapoptotic effect. These results suggest that the antioxidative properties of the polyphenols tested may contribute to the radioprotective effects of G. austriaca.

Radioprotective properties of the phytochemically characterized extracts of Crataegus monogyna, Cornus mas and Gentianella austriaca on human lymphocytes in vitro.

The objective of the present study is to evaluate the radioprotective properties of extracts of Crataegus monogyna Jacq. (Rosaceae) fruit, Cornus mas L. (Cornaceae) leaves and Gentianella austriaca (A. Kern. & Jos. Kern.) Holub (Gentianaceae) aerial parts on cultured human peripheral blood lymphocytes in vitro after irradiation with 2 Gy of 60Co gamma-rays. Plants were collected at Mt. Maljen in Serbia, air-dried and powdered, and the total phenolic content was analyzed. In C. mas leaves, ellagic and gallic acid were found to be the dominant compounds, whereas C. monogyna fruit was rich in procyanidins and flavonoids. The main constituents of G. austriaca aerial parts were gamma-pyrones and secoiridoids. Cell cultures were treated with four different doses of plant extracts (0.1 mg/mL to 0.4 mg/mL). Treatment with the lowest dose gave the best protective effect. Significant radiorecovery potentials of C. mas and C. monogyna were observed, seen as a reduced incidence of radiation-induced micronuclei (19.23% and 13.24%, respectively), reduced levels of lipid peroxidation products (50.04% and 13.18%, respectively) and two-fold enhanced apoptosis. Both extracts slowed down cell proliferation gradually, enabling more time for repair. G. austriaca possesses strong antioxidant properties, significantly reducing lipid peroxidation and the incidence of micronuclei (for 30.88% and 35.56%, respectively) while enhancing apoptosis with no perturbation of the cell cycle. This study may contribute to the search for novel radioprotective agents.

Vitamin B12 reduces ribavirin-induced genotoxicity in phytohemaglutinin-stimulated human lymphocytes.

Ribavirin, an N-glycosyl nucleoside (1-beta-D-ribofuranosyl-1, 2, 4-triazole-3 carboxamide), is a synthetic purine nucleoside analogue with a broad spectrum of antiviral activity, however, its high toxicity poses a major disadvantage of its use as a therapeutic. Various studies have shown that vitamin B12 plays a significant role in maintaining the stability of the human genome. We therefore investigated the potential beneficial effect of vitamin B12 in reducing ribavirin-induced genotoxicity. To test this, we used the cytokinesis-block micronucleus (CBMN) assay. Human blood cells were treated in vitro with increasing doses of ribavirin (0.05, 0.17, 0.32, 0.47 and 0.65 micromol/ml) for three different periods of time (2, 4 and 17 hrs). Duplicate cultures were supplemented with 50 mul of vitamin B12 during the drug treatment (final concentration of 13.5 microg/ml). Micronuclei formation and cell proliferation potential were then scored in both sets of samples and the corresponding controls. The results showed that supplementation with vitamin B12 lowered the frequency of micronuclei (Z = 2.02, p < 0.04) and recovered the proliferation potential of the treated cells for each treatment period, except for the conditions with the highest concentration of ribavirin and the shortest time. These observations underscore the unique beneficial effects of vitamin B12 in reducing genotoxicity, particularly by recovering the proliferation potential of treated cells, as demonstrated by the decrease in mononucleated cells and enhancement of binucleated and polynucleated cells. The mechanism by which vitamin B12 reduces ribavirin-induced genotoxicity is related to de novo synthesis of nucleotides, and is worthy of further investigation.

Antibacterial medicinal plants Equiseti herba and Ononidis radix modulate micronucleus formation in human lymphocytes in vitro.

We assessed the in vitro cytogenetic effects of extracts of the commonly used medicinal plants Equiseti herba, Ononidis radix, and Uvae ursi on irradiated human blood lymphocytes. We examined the acquired micronucleus formation in unirradiated and irradiated samples of cultured blood lymphocytes using the cytochalasin block micronucleus test (CBMN). Centromere-positive micronuclei were identified by fluorescence in situ hybridization using a DNA probe labeled with alpha-satellite digogsigenin. Equiseti herba had weak clastogenic properties, increasing the yield of micronuclei in unirradiated samples and reducing the level of radiation-induced micronuclei in a concentration-dependent manner. In the control, unirradiated samples, 36.8% of micronuclei were centromere-positive (MNC+), while in the irradiated ones the percentage of MNC+ ranged from 10.8-15.3%, indicating a clastogenic mechanism for the micronuclei formation. Ononidis radix was a strong clastogen and radiosensitizer, rapidly increasing the yield of micronuclei in unirradiated samples up to 5-fold and potentiating the yield of radiation-induced micronuclei up to 1.7-fold. In cultures treated with Ononidis radix, the percentage of MNC+ micronuclei ranged from 18.8 to 23.8%, indicating that micronuclei originated by a clastogenic mechanism. Uvae ursi did not affect the yield of micronuclei either in unirradiated or in irradiated samples. The micronucleus formation assay is a reliable screen for plant extracts and purified compounds, for the identification of compounds that might either inhibit clastogenesis or potentiate radiotherapy for malignancy.