Prolidase-proline oxidase axis is engaged in apoptosis induction by birch buds flavonol santin in endometrial adenocarcinoma cell line.

Cancer of the corpus uteri and cervix uteri, collectively ranks second among new cancer cases in women after breast cancer. Therefore, investigation of new anticancer agents and identifying new molecular targets presents a challenge to improve effectiveness of chemotherapy. In this study, antiproliferative activity of flavonoids derived from the buds of silver birch and downy birch was evaluated in endometrial cancer Ishikawa cells and cervical cancer HeLa cells. It was found that flavanol santin reduced viability of both cell lines better than other flavonoids, including apigenin and luteolin. Moreover, this activity was slightly higher than that induced by the chemotherapy drug, cisplatin. Santin promoted intrinsic and extrinsic apoptosis pathways in cancer cells, but it had low toxicity in normal fibroblasts. The mechanisms of impairing cancer cell viability included induction of oxidative proline catabolism, however in different ways in the cell lines used. In HeLa cells, increase of proline oxidation was due to activation of p53 leading to proline oxidase upregulation. In contrast, in Ishikawa cells, having basal proline oxidase level significantly higher than HeLa cells, santin treatment decreased its expression. Nevertheless, proline oxidation was induced in these cells since santin increased expression and activity of prolidase, an enzyme providing proline from protein degradation. In both cell lines, proline oxidation was associated with generation of reactive oxygen species leading to reduction in cell viability. Our findings reveal the involvement of proline oxidase in induction of apoptosis by santin and identify a role of prolidase in proline oxidase-dependent apoptosis.

Secondary metabolites of downy birch buds (Betula pubescens Erch.).

The subject of this study is the composition of low-molecular-weight metabolites in downy birch (Betula pubescens) buds and their participation in protection from various kinds of stress. Using the GC-MS, 640 compounds were detected, of which 314 were identified in downy birch buds for the first time. The volatile components detected using the SPME technique mainly consisted (about 70% of the total ionic current of the chromatogram, TIC) of mixtures of sesquiterpenoids. The exudate covering the buds, along with sesquiterpenoids (approximately 60% of TIC), included flavonoids (25% of TIC). The main part of the material extracted by supercritical carbon dioxide from buds comprised sesquiterpenoids and triterpenoids (47 and 28% of TIC, respectively). Via column chromatography, 25 known compounds (mainly flavonoids and triterpenoids) were isolated, most of which were first discovered in the buds of downy birch. Many compounds of these classes have strong biological activity and probably either directly or indirectly perform a protective function in birch buds. An assumption is made about the biological role of a number of secondary metabolites (such as volatile isomeric megastigmatriens and triterpene seco-acids) as well as about these compounds' possible means of biosynthesis, which were first discovered in the buds of downy birch.

Santin and cirsimaritin from Betula pubescens and Betula pendula buds induce apoptosis in human digestive system cancer cells.

Flavonoids are bioactive secondary metabolites of plants, which exert anti-cancer effects. However, metabolism in enterocytes and the liver can influence the biological activity of flavonoids contained in the diet. Therefore, results from in vitro studies on cancer cells from the digestive tract and liver may reflect the real effects in the human body. Previously, we have found that the extract from birch buds exerts antiproliferative activity in a panel of cancer cells. In the present study, the anti-cancer activity of ten flavonoids isolated from the buds of Betula pubescens and Betula pendula was characterized. Among them, santin and cirsimaritin significantly reduced viability, proliferation and clonogenicity of gastric (AGS), colon (DLD-1) and liver (HepG2) cancer cells. Both flavonoids induced apoptosis, accompanied by activation of caspase-3, caspase-7, caspase-8 and caspase-9. Moreover, upregulation of p53 was detected only in wild-type p53 harbouring cells. Together, our results suggest that santin and cirsimaritin exhibit promising anti-cancer activity in cultures of digestive system cancer cells.

Cytotoxicity of Triterpene Seco-Acids from Betula pubescens Buds.

The present study investigated the magnitude and mechanism of the cytotoxic effect on selected cancer cell lines of 3,4-seco-urs-4(23),20(30)-dien-3-oic acid (1), 3,4-seco-olean-4(24)-en-19-oxo-3-oic acid (2), and 3,4-seco-urs-4(23),20(30)-dien-19-ol-3-oic acid (3) isolated from downy birch (Betula pubescens) buds by carbon dioxide supercritical fluid extraction and gradient column chromatography. Cell viability in six human cancer lines exposed to these compounds was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was quantified by annexin V/propidium iodide staining of gastric cancer AGS and colorectal cancer DLD-1 cells. To evaluate the mechanism of apoptosis, the expression of apoptosis-related proteins was analyzed by Western blot. Compound 1 exhibited non-specific toxicity, while compounds 2 and 3 were specifically toxic to colon and stomach cancer cells. The toxicity of compounds 2 and 3 against these two cell lines was greater than for compound 1. Cleavage of caspase-8, -9, and -3 was found in AGS and DLD-1 cells treated with all three seco-acids, indicating the induction of apoptosis via extrinsic and intrinsic pathways. Therefore, triterpene seco-acids (1-3) decreased cell viability by apoptosis induction. AGS and DLD-1 cells were more susceptible to seco-acids with an oxidized C19 than normal fibroblasts. Hence, it made them a new group of triterpenes with potential anticancer activity.

The concentration-dependent effect of anethole on collagen, MMP-2 and GAG in human skin fibroblast cultures.

PURPOSE: In aging skin and some skin disorders, components of skin extracellular matrix (ECM) are disturbed and therefore research to find skin drugs is important. Evaluation of anethole impact on collagen, GAGs and MMP-2 in human skin fibroblasts was the aim of this study. MATERIALS AND METHODS: For collagen assay the Sircol dye, 5-[3H]proline and real time-PCR were used. MMP-2 activity was detected by zymography. GAG concentration was determined using 1,9-dimethylmethylene blue (DMMB). Cell viability was assayed with MTT. RESULTS: In cells treated with 1 and 10 µM anethole, a significant increase in collagen synthesis was demonstrated. In contrast, collagen synthesis was significantly decreased in cells exposed to 100 µM anethole. Similar alterations were found in collagen type I expression. The concentration of collagen secreted into the medium was higher only in cells exposed to 1 µM anethole, while it was lower under the influence of higher compound concentrations. It may be due to the lack of pro-MMP-2 activation at 1 µM and a significant increase in the level of MMP-2 at 10 and 100 µM anethole. GAG concentration was reduced under the influence of 100 µM anethole, whereas anethole at lower concentrations revealed the ability to prevent H2O2-induced GAG increase. No significant cytotoxicity of anethole to fibroblasts was noted. CONCLUSIONS: Our findings demonstrate the concentration-dependent action of anethole on the crucial components of ECM in cultured skin fibroblasts, which may be somewhat beneficial and may possibly be developed towards a therapeutic use in some skin disorders.

Matricaria genus as a source of antimicrobial agents: From farm to pharmacy and food applications.

Matricaria is a widespread genus of flowering plants of the family Asteraceae that grow in temperate regions of Europe, Asia, America and Africa. Some of the species are also naturalized in Australia. Some species of this genus such as Chamomiles are recognized medicinal plants and cultivated in several countries for commercial purposes: to obtain its blue essence, as herbal tea, and for pharmaceutical or cosmeceutical uses. The phytochemical composition of Matricaria spp. includes volatile terpenoids (e.g., α-bisabolol, bisabolol oxide A and B, ß-trans-farnesene and chamazulene), sesquiterpene lactones such as matricin, and phenolic compounds (flavonoids, coumarins and phenolic acids). Their essential oil is obtained from the fresh or dried inflorescences by steam distillation, and additionally cohobation of the remaining water. The volatile composition of the essential oil, especially the content of the valuable components α-bisabolol and chamazulene, depends on the plant part, origin and quality of the source, genetic, and environmental factors. Moreover, other parameters, such as season of harvest and methods of extraction, can affect the extraction yield of the essential oils/extracts, their composition and, therefore, their bioactivity. Due to the importance of this genus and particularly M. recutita (M. chamomilla), this review focus on its cultivation, factor affecting essential oils' composition and their role in traditional medicine, as antibacterial agents and finally as food preservatives.

Cytotoxicity of white birch bud extracts: Perspectives for therapy of tumours.

Birch buds (Gemmae Betulae) are widely used in Russian and Chinese traditional medicine mainly as a diuretic and diaphoretic agent but also as an antiseptic, anti-inflammatory and analgesic. Despite the long history of therapeutic use of birch buds in folk medicine, the existing information on their chemical composition and pharmacological effects is insufficient. This circumstance warrants further study of the chemistry and pharmacology of birch buds. The present study was designed to investigate (a) the chemical composition of buds from two species of white birch and (b) the in vitro cytotoxic effect of extracts from these sources on selected tumour cells. Extracts from Betula pubescens Ehrh. and Betula pendula Roth. buds were obtained using three different methods: carbon dioxide supercritical fluid extraction (SFE), washing of exudate covering whole buds, and extraction of milled buds with diethyl ether. The chemical composition of extracts was investigated by GC-MS. Cytotoxicity was determined by MTT assay, and cell proliferation was determined by [3H]thymidine uptake in cancer cells and normal skin fibroblasts. The GC-MS investigation identified a total of 150 substances of different classes. The chemical composition of B. pubescens and B. pendula buds differed, with bud extracts from the former containing a relatively high quantity of sesquiterpenoids and flavonoids, while the main components of extracts from the latter were triterpenoids. The results of the biological assay indicated that birch bud extracts demonstrated time- and concentration-dependent and differential cytotoxicity. The highest cytotoxic activity demonstrated bud exudates and SFE extracts obtained from both Betula species. The rich chemical composition of birch buds suggests the possibility of a wider spectrum of biological activity than previously thought. Birch bud extracts could be a promising source of compounds with cytotoxic activity against various cancers.

Pharmacological Effects of Scutellarin, An Active Component of Genus Scutellaria and Erigeron: A Systematic Review.

Flavonoid compound scutellarin (Scu) is quite frequently met in the plant kingdom, particularly in the genus Scutellaria (Lamiaceae) and Erigeron (Asteraceae). The extract of the herb of Erigeron breviscapus, containing this component in high amount, has been used for many years in traditional Chinese medicine. In recent years, studies have made great progress on the usefulness of Scu for treating various diseases by testing its mechanism of action. They support the traditional use of Scu rich plant in heart and cerebral ischemia. Scu can potentially be applied in Alzheimer's disease, Helicobacter pylori infection, vascular complications of diabetes and as an inhibitor of certain carcinomas. Various methods were designed to improve its isolation from plant material, solubility, absorption and bioavailability. On the basis of recent studies, it is suggested that Scu could be a promising candidate for new natural drug and deserves particular attention in further research and development.

Inhibitory influence of natural flavonoids on human protein kinase CK2 isoforms: effect of the regulatory subunit.

CK2 is a pleiotropic, constitutively active protein kinase responsible for the phosphorylation of more than 300 physiological substrates. Typically, this enzyme is found in tetrameric form consisting of two regulatory subunits CK2ß and two catalytic subunits CK2α or CK2α'. Several natural occurring flavonoids were tested for their ability to inhibit both CK2 holoenzymes, CK2α2ß2 and CK2α'2ß2. We identified few substances selectively inhibiting only the α' subunit. Other compounds showed similar effect towards all four isoforms. In some cases, like chrysoeriol, pedalitin, apigenin, and luteolin, the α2ß2 holoenzyme was at least six times better inhibited than the free α subunit. Otherwise, we have found a luteolin derivative decreased the kinase activity of CK2α' with an IC50 value of 0.8 µM, but the holoenzyme only with 9.5 µM.

Gas chromatographic-mass spectrometric determination of glycosides without prior hydrolysis.

The article presents for the first time the linear temperature programmed retention indices on a column with stationary phases of 5% phenylpolydimethyl silicone and the mass spectra of trimethylsilyl (TMS) derivatives of 71 glycosides (both commercial preparations and compounds extracted from plant tissues) which were not characterized earlier by these parameters. Converted to their TMS derivatives, the glycosides were thermally stable: they exhibited single peaks on their chromatograms without products of thermal decomposition. Therefore this work demonstrates the suitability of high resolution-high temperature gas chromatography (HR-HT/GC) to analyse different groups of glycosides including compounds with disaccharide moieties without the necessity of their hydrolyses. Since a limited number of commercial and plant-isolated glycosides were available, an attempt was made to assess their retention indices using the known "structure-retention relationships" approach. It was demonstrated that the retention indices of silanised glycosides and their aglycones were characterized by a linear dependence.

Postcolumn determination of polyphenolic antioxidants in Cirsium vulgare (Savi) Ten. extracts.

Novel methods for the determination of polyphenolic antioxidants present in extracts from inflorescences of Cirsium vulgare (Savi) Ten. based on ultra-high performance liquid chromatography with photodiode array and chemiluminescence detection have been developed. Under the optimized conditions of chromatographic separation the analytical characteristic of the method was performed. The proposed method was successfully applied to the determination of ten polyphenols present in inflorescences of Cirsium vulgare. A comparison of the contents of analytes in extracts prepared by using various extraction media (methanol, ethanol, 70% methanol, 70% ethanol, and water) was carried out for the first time. For the postcolumn detection of scavenging activity of polyphenolic antioxidants against reactive oxygen species (H2 O2 , • OH, O2• - ) three systems based on chemiluminescence of luminol were used. A review of the current scientific literature shows that this is the first report on the application of luminol-based postcolumn detection for the on-line investigation of • OH scavenging activity. The main compound determined in extracts from inflorescences of Cirsium vulgare was apigenin 7-O-glucuronide, whereas the highest antioxidant activity was observed for chlorogenic acid, luteolin 7-O-glucoside, and apigenin.

Selected flavonoid compounds as promising inhibitors of protein kinase CK2α and CK2α', the catalytic subunits of CK2.

CK2 is a ubiquitous protein kinase involved in many cell functions. During the last years it became an interesting target in cancer research. A series of flavonoid compounds was tested as inhibitors of protein kinase CK2. Several substances were found to be highly active against both catalytic subunits with IC50 values below 1 µM in case of CK2α'. The most promising inhibitor we identified is chrysoeriol with IC50 values of 250 and 34 nM for CK2α and CK2α', respectively.

Chemical Composition and Antioxidant Activity of Cirsium vulgare Inflorescences.

The chemical composition of Cirsium vulgare flower heads was examined. Petrol and chloroform extracts of this plant material were analyzed by GC-MS for the presence of fatty acids, phytosterols, and triterpenes. Diethyl ether, ethyl acetate, and butanol fractions of the methanolic extract were subjected to multistep - chromatographic separations, and as a result, fourteen flavonoids were obtained (1-14). All compounds were isolated from this morphological part for the first time and eleven from the plant. Among the identified components were four aglycones, eight glycosides, and two glycoside esters, derivatives of apigenin, luteolin, kaemferol, and quercetin. One of them was a rarely occurring compound apigenin 7-0-p-(6"-butyl)-glucuronide) (14). Total flavonoid content and antioxidant activity were determined in the various fractions of methanolic extract.

Anticancer Effect of a Novel Octahydropyrazino[2,1-a:5,4-a']diisoquinoline Derivative and Its Synergistic Action with Nigella sativa in Human Gastric Cancer Cells.

Many studies have shown that naturally occurring compounds may support prevention and treatment of various diseases, including cancer. Pharmacological investigations revealed a wide spectrum of Nigella sativa biological activities. Combining natural compounds together with synthetic drugs may increase the anticancer activity and limit severe side effects of such a treatment and may be an alternative to monotherapy. The aim of the study was to evaluate the cytotoxic and proapoptotic effects of a novel octahydropyrazino[2,1-a:5,4-a']diisoquinoline derivative and its effect in combination with Nigella sativa seed oil or extract in human gastric cancer cells (AGS). Etoposide was used as a reference. Our studies proved that combination strategy based on novel octahydropyrazino[2,1-a:5,4-a']diisoquinoline derivative (OM-90) with Nigella sativa seed oil or extract represents the strongest efficacy in AGS cancer cells as compared to monotherapy and combined treatment with Nigella sativa seed oil or extract together with etoposide. Such a combination also leads to the activation of mitochondrial pathway, which plays a significant role in molecular mechanism of induction of apoptosis by these compounds.

Ultra-high Performance Liquid Chromatography with Photodiode Array and Chemiluminescence Detection for the Determination of Polyphenolic Antioxidants in Erigeron acris L. Extracts.

INTRODUCTION: The quality of herbs is directly related to the presence of polyphenolic antioxidants. This is the first report on the quantification of individual polyphenolic constituents of Erigeron acris L. OBJECTIVE: To develop a new method using ultra-high performance liquid chromatography with photodiode array and chemiluminescence (UHPLC-PDA-CL) detection for the separation and determination of polyphenols in Erigeron acris extracts. METHODOLOGY: The methanolic extracts from leaves and inflorescences of Erigeron acris were prepared by ultrasound assisted extraction. The chromatographic separation was performed on C18 column packed with 1.7-µm particles. The post-column CL detection was based on the enhancing effect of polyphenols on the CL generated in manganese(IV)-hexametaphosphate-formaldehyde system. RESULTS: The UHPLC method allowed to separate polyphenols in a short running time (13 min), which was three times shorter compared with traditional HPLC. The CL detection was characterised by 6-48 times higher sensitivity and up to three times lower detection limits compared to PDA detection. Qualitative and quantitative differences were observed in polyphenolic composition of Erigeron acris extracts. The main components of leaves were scutellarin and chlorogenic acid, whereas in inflorescences quercetin 3-O-glucoside was predominant. CONCLUSION: Coupling of UHPLC with CL detection has been developed for the first time. This advanced chromatographic technique coupled with sensitive CL detection is a powerful approach for the investigation of polyphenolic profiles in natural products. The shorter analysis time and diminished waste generation makes the UHPLC method more environmentally friendly and more cost-effective in comparison with conventional HPLC. Copyright © 2016 John Wiley & Sons, Ltd.

Phytochemical profile and therapeutic potential of Viscum album L.

Viscum album L., the European mistletoe, is a common species from the Viscaceae family. This evergreen hemiparasitic shrub grows on various trees and contains diverse, biologically active substances. Its chemical composition may vary depending on the time of harvest, species of the host tree and the manufacturing process. Among well-described and most active phytochemicals identified in V. album are lectins and viscotoxins, which play substantial role in cancer treatment because of their apoptotic and cytotoxic effects. Another group of compounds found in mistletoe are phenolic acids, phenylpropanoids and flavonoids with antioxidant and anti-inflammatory activities, which decrease blood pressure. Other mistletoe components include, among others, triterpenes with cytotoxic and apoptotic properties, and phytosterols, oligo- and polysaccharides. Extracts from the plant, especially aqueous, are applied in traditional and official medicine, among others in treating hypertension or arthritis. Potentially, it can also be used as a hepatoprotective or a sedative drug.

Prolidase-dependent mechanism of (Z)-8,9-epoxyheptadeca-1,11,14-triene-induced inhibition of collagen biosynthesis in cultured human skin fibroblasts.

The effects of polyolefinic compound from roots of Cirsium palustre, (Z)-8,9-epoxyheptadeca-1,11,14-triene (EHT) on collagen biosynthesis, prolidase activity, expression of insulin-like growth factor receptor (IGF-IR), ß1 integrin, MAP kinases (pERK1/2), the transcription factors such as nuclear factor kappa B (NF-κB) and hypoxia-inducible factor-1α (HIF-1α) were evaluated in human dermal fibroblasts treated with micromolar concentrations (40-200 µM) for 24 h. It was found that EHT-dependent inhibition of collagen biosynthesis was accompanied by parallel inhibition in prolidase activity. Since IGF-I is the most potent regulator of both processes and prolidase is regulated by ß1 integrin signalling, the effect of EHT on IGF-IR and ß1 integrin receptor expressions were evaluated. Exposure of the cells to EHT contributed to distinct increase in IGF-IR and slight increase in ß1 integrin receptor expressions. It was accompanied by decrease in expression of pERK1/2, HIF-1α and NF-κB. EHT-dependent inhibition of collagen biosynthesis results from inhibition of prolidase activity, the enzyme involved in collagen biosynthesis.

Chemical composition and antioxidant, antibacterial activity of Cirsium rivulare (Jacq) All. roots.

The mixture of three phytosterols (campesterol, stigmasterol and ß-sitosterol), ß-sitosterol 3-O-glucoside and syringin were isolated from hexane and methanol extract of Cirsium rivulare roots after chromatographic separation. The main component of the source was syringin which was obtained with the yield 0.08% of the dry source. In hexane extract, the qualitative and quantitative composition of fatty acids was determined. The predominant component was linoleic acid (23.31 mg/g of extract). The extracts showed antioxidant activity. The ability to scavenge DPPH• free radical was in correlation with appointed total phenol content. The not-defatted methanolic extract was the most active. Hexane and defatted methanol extracts showed moderate antibacterial activity against G(+) and G(-) strains with MIC and MBC ranged from 25 to 200 µg/mL.

Determination of polyphenolic compounds in Cirsium palustre (L.) extracts by high performance liquid chromatography with chemiluminescence detection.

The first method for the simultaneous determination of polyphenolic antioxidants in extracts from leaves of Cirsium palustre based on high performance liquid chromatography combined with flow injection chemiluminescence detection (HPLC-FI-CL) has been developed. The extracts were prepared by using methanol as extraction medium and two types of extraction methods (reflux and ultrasound assisted extraction). The post-column CL determination of polyphenols was based on their enhancing effect on the chemiluminescence intensity generated in manganese(IV)-hexametaphosphate-formaldehyde system in a phosphoric acid medium. Main antioxidants determined in C. palustre leaves were eriodictyol-7-O-glucoside, luteolin-7-O-glucoside and 6-hydroxyluteolin-7-O-glucoside belonging to flavonoids, and chlorogenic acid belonging to phenolic acids. Chromatographic separation was carried out on a C18 column with gradient elution by using a mobile phase containing 0.25% (v/v) phosphoric acid in water (solvent A) and 100% methanol (solvent B). Under the optimized conditions of chromatographic separation and CL detection the validation of the method was performed. The calibration curves showed good linearity in the concentration range from 0.5 to 40 µg mL(-1). The HPLC-FI-CL method was successfully applied to the determination of four polyphenolic compounds in methanolic extracts from leaves of C. palustre. The accuracy of the developed method was confirmed by the comparison of the results with those obtained by an HPLC-PDA method. The relative error of determination does not exceed 6.1%. However, the HPLC-FI-CL method is characterized by 40-65 times higher sensitivity compared to the HPLC-PDA method.

Anethole prevents hydrogen peroxide-induced apoptosis and collagen metabolism alterations in human skin fibroblasts.

The collagen metabolism alterations triggered by reactive oxygen species are involved in the development of various connective tissue diseases and skin aging. This study was designed to examine whether (E)-anethole possesses a protective effect on H2O2-induced alterations in collagen metabolism as well as whether it can prevent apoptosis in human skin fibroblasts. In cells treated with 300 µM H2O2, a decrease in collagen biosynthesis of 54% was observed. Pretreatment of cells with 0.5 µM anethole for 1 h completely prevented this alteration. Changes at the protein level positively correlated with alterations of type I collagen mRNA expression. We have shown that H2O2 caused increase in the activity of MMP-2 and MMP-9 as well as that an increase in MMP-2 activity can contribute to the 8% decrease in the amount of collagen secreted into the medium. The most efficient suppression of these changes was observed in the presence of 0.5 µM of anethole. At 10 µM, in addition to suppression, an inhibitory effect of anethole on MMP-9 activity was documented. Additionally, the 60% H2O2-induced decrease in cell viability was suppressed by 1 µM of anethole and a 4-fold increase in cell apoptosis was suppressed by 0.5 µM of anethole. Our results suggest that anethole, which is a small lipophilic and non-toxic molecule with the ability to prevent H2O2-induced collagen metabolism alterations and apoptosis in human skin fibroblasts, would prove useful in the development of effective agents in pharmacotherapy of oxidative stress-related skin diseases.