Orsolya Orbán-Gyapai’s research while affiliated with University of Szeged and other places

Objective Diterpene alkaloids are secondary plant metabolites and chemotaxonomical markers with a strong biological activity. These compounds are characteristic for the Ranunculaceae family, while their occurrence in other taxa is rare. Several species of the Spiraea genus (Rosaceae) are examples of this rarity. Screening Spiraea species for alkaloid content is a chemotaxonomical approach to clarify the classification and phylogeny of the genus. Novel pharmacological findings make further investigations of Spiraea diterpene alkaloids promising. ResultsSeven Spiraea species were screened for diterpene alkaloids. Phytochemical and pharmacological investigations were performed on Spiraea chamaedryfolia, the species found to contain diterpene alkaloids. Its alkaloid-rich fractions were found to exert a remarkable xanthine-oxidase inhibitory activity and a moderate antibacterial activity. The alkaloid distribution within the root was clarified by microscopic techniques.

Ten compounds have been identified in the methanol extract of cottonwood mushroom (Tricholoma populinum J.E. Lange), 9 of them for the first time in this species. Besides adenosine (8) and nicotinamide (7) the isolated compounds were ergostane type steroids (1-6) and rare sulfinyladenosine constituents (9 and 10). The chemical structures of these compounds were elucidated by means of extensive spectroscopic methods (NMR and MS). Compounds 3-6 were evaluated for their potential antiproliferative activity against human cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The xanthine oxidase (XO) inhibitory activity of 7-10 has been examined by spectrophotometric method. Cerevisterol (3), its methylated derivative (5) and 3-glycoside of ergosterol peroxide (6) showed significant antiproliferative activity on human breast cancer cell lines.

In the course of our pharmacological screening of Polygonaceae species occurring in the Carpathian Basin the extracts prepared from the roots of Rumex thyrsiflorus showed promising antiproliferative, xanthine oxidase inhibitory and antibacterial activities. The present work deals with the isolation of compounds from the root of the plant. After multistep separation process, four compounds were obtained from the n-hexane, chloroform and ethyl acetate soluble fractions of the methanol extract of the root. The structures of the isolated compounds were determined as 1-palmitoylglycerol, β-sitosterol, (-)-epicatechin, and procyanidin B5.

Ten representative Central European phellinoid Hymenochaetaceae species (Phellinus sensu lato) were selected to examine their potential pharmacological activity. In this study 40 organic (n-hexane, chloroform, 50% methanol) and aqueous extracts with different polarities were analyzed for their antimicrobial, antioxidant, and xanthine oxidase (XO)−inhibitory properties. Fomitiporia robusta, Fuscoporia torulosa, Phellopilus nigrolimitatus, and Porodaedalea chrysoloma showed moderate antibacterial activity; Bacillus subtilis ATCC 6633, methicillin-resistant Staphylococcus aureus ATCC 43300, and Moraxella catarrhalis ATCC 43617 were the strains most susceptible to the examined fungal species. The in vitro antioxidant and XO assays demonstrated that most of the selected species possess remarkable antioxidant and XO-inhibitory activities. The water extracts in general proved to be more active antioxidants than organic extracts. In the case of F. torulosa, Ph. Nigrolimitatus, and P. chrysoloma, the results of DPPH tests correlate well with those obtained by oxygen radical absorbance capacity tests; these mushrooms presented high antioxidant activities in both assays. Future studies involving phellinoid Hymenochaetaceae species are planned, which may furnish novel results in terms of the species' pharmacological activity and the specific compounds responsible for the observed activity.

Plants belonging to the genus Rumex (family Polygonaceae) are used worldwide in traditional medicine for the treatment of various diseases caused by different microorganisms (e.g. bacteria-related dermatologic conditions, dysentery and enteritis). The present study focused on the antibacterial screening of Rumex species native to the Carpathian Basin, and isolation of compounds from one of the most efficient species, Rumex aquaticus. The antibacterial effects of n-hexane, chloroform and aqueous fractions of methanol extracts prepared from different parts of 14 Rumex species (R. acetosella, R. acetosa, R. alpinus, R. aquaticus, R. conglomeratus, R. crispus, R. hydrolapathum, R. obtusifolius subsp. obtusifolius, R. obtusifolius subsp. subalpinus, R. patientia, R. pulcher, R. scutatus, R. stenophyllus and R. thyrsiflorus) were investigated against Staphylococcus epidermidis, S. aureus, MRSA, Bacillus subtilis, Moraxella catarrhalis, Streptococcus pyogenes, S. pneumoniae, S. agalactiae, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae using the disc diffusion method. Mainly the n-hexane and chloroform extracts prepared from the roots of the plants displayed high antibacterial activity (inhibition zones > 15 mm) against one or more bacterial strains. The highly active extracts of the aerial part and root of R. aquaticus were subjected to a multistep separation procedure. 19 Compounds, among them naphthalenes (musizin, and its glucoside, torachrysone-glucoside, 2-methoxystypandrone), anthraquinones (emodin, chrysophanol, physcion, citreorosein, chrysophanol-8-O-glucoside), flavonoids (quercetin, quercetin-3,3′-dimethylether, isokaempferide, quercetin 3-O-arabinoside, quercetin 3-O-galactoside, catechin), stilbenes (resveratrol, piceid), and 1-stearoylglycerol were isolated from the plant. The antibacterial activities of isolated compounds were determined, and it was observed that especially naphthalenes exerted remarkable antibacterial effects against several bacterial strains.

Background: Centaurea virgata Lam. is a species widely used in the traditional medicine in Turkey for the treatment of diabetes, allergy and gastric ulcers. The rationale of its use in the therapy has not been studied previously, therefore the present work aimed at the chemical-pharmacological evaluation of the plant. Objective: The xanthine oxidase (XO) inhibitory activity of the MeOH extract and its subextracts (n-hexane, CHCl3 and remaining MeOH-H2O) prepared from C. virgata was investigated in vitro. Moderate activity was exerted in case of the CHCl3 extract (98.9 ± 15.8 µg/mL), therefore constituents of this extract were analysed. Method: Different purification steps, such as VLC, CPC, PLC and crystallization were used for the isolation, and ESIMS, NMR, LC-MS and authentic standards were applied for identification of the compounds. XO inhibitory and DPPH assays were used for evaluation of the bioactivities. Results: Sesquiterpenes [8α-hydroxysonchucarpolide, 8α-(3,4-dihydroxy-2-methylene-butanoyloxy)-dehydromelitensine, and cnicin], flavones (apigenin, hispidulin, salvigenin, eupatorin, 3'-methyleupatorin), and the flavonol isokaempferide were isolated from the active extract. The XO-inhibitory activity of these compounds was analyzed using allopurinol as a positive control (IC50 7.49 ± 0.29 μM). It was found that sesquiterpenes and flavonoids, containing 7-OMe group, are inactive. Conclusion: 7-Hydroxyflavones (apigenin and hispidulin) exerted significant XO inhibitory effect with IC50 values of 0.99 ± 0.33 μM and 4.88 ± 1.21 μM, respectively. Therefore these compounds are responsible for the XO-inhibitory effect of the extract. The free radical scavenging activity of the isolated flavonoids were determined by DPPH assay, and it was stated that none of the compounds have substantial antioxidant activity, therefore the reduced generation of reactive oxygen species may be the consequence only of XO inhibition.

Three new iridoid glycosides, named involucratosides A-C (1-3) were isolated from the H2O subextract of crude MeOH extract prepared from the aerial parts of Asperula involucrata along with a known iridoid glycoside (adoxoside), three flavone glycosides (apigenin 7-O-β-glucopyranoside, luteolin 7-O-β-glucopyranoside, apigenin 7-O-rutinoside) as well as two phenolic acid derivatives (chlorogenic acid and ferulic acid 4-O-β-glucopyranoside). Their chemical structures were established by UV, IR, 1D- (1H, 13C and JMOD) and 2D- (COSY, HSQC, HMBC and NOESY) NMR experiments and HRESIMS. In addition, the crude extract, subextracts and isolates were evaluated for their xanthine oxidase inhibitory and antioxidant activities in in vitro tests. This is the first report on the chemical composition and bioactivities of A. involucrata. This article is protected by copyright. All rights reserved.

Nosocomial infection became a major problem not only in hospitals, but worldwide as it can cause endemic diseases. The uncontrolled usage of antibiotics led to the increased number of resistant bacteria strains. The aim of our study was to find new compounds from plants with potential antibacterial properties on several resistant strains. The members of the genus Rumex (family Polygonaceae), which are distributed worldwide, comprise approximately 200 species. Previously, anthraquinones, naphthalenes, flavonoids, stilbenoids, triterpenes, carotenoids and phenolic acids have been isolated from Rumex species. The extracts of these plants, and compounds isolated from them, have been demonstrated to possess various pharmacological activities, including anti-inflammatory, antioxidant, antitumour and antimicrobial properties. We have investigated the antimicrobial potency of the aerial parts and roots of two Rumex species, R. aquaticus and R. thyrsiflorus against different bacterial strains (methicillin-resistant Staphylococcus aureus, S. aureus, Staphylococcus epidermidis, Moraxella catarrhalis, Streptococcus pneumoniae, S. pyogenes and Bacillus subtilis) with disc-diffusion method. The ethyl-acetate fraction of the aerial parts of R. aquaticus and the roots of R. thyrsiflorus and the n-hexane, chloroform and ethyl-acetate fractions of the roots of R. aquaticus possessed remarkable antimicrobial effects. With the combination of different chromatographic methods 14 compounds, among them flavonoids (quercetin- and kaempferol-glycosides, epicatechin, procyanidin B5), anthranoids (chrysophanol, emodin, torachryson-glucoside, citreorosein), naphtalenes (musizine- and nepodine-glucoside) and a monoacyl-glycerol were isolated, some of them responsible for the pharmacological activity. Acknowledgement: This work was supported by the Hungarian Scientific Research Fund (OTKA PD101432) and a Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences.