Franz Bucar

Karl-Franzens-Universität Graz | KFU Graz · Institute of Pharmaceutical Sciences - Department of Pharmacognosy

The food industry is constantly struggling with one of the most prevalent biofilm-forming and food-borne pathogenic bacteria, Campylobacter jejuni. Different approaches are used to control biofilms in the food production chain, but none is fully effective. In this study, we aim to produce and determine the chemical profile of essential oils (EOs),...

Species from the genus Globularia L. have been used as healing agents for various ailments, with utilization of Globularia alypum L. being most frequently reported. The aim of this study was to evaluate the antidiabetic, antioxidant, anti-inflammatory, antibacterial and anticancer potential of G. alypum and three related species, G. punctata Lapeyr...

The use of natural antifungal agents has gained much attention to extend shelf-life, increase the safety of food products in the food industry and inhibit disease-causing microorganisms. The objective of this study was to evaluate the antifungal and anti-adhesion potential of 15 plant extract, essential oils and chemical compounds against Candida s...

Flavonoids are widely occurring secondary plant constituents, and are abundant in vegetable and fruit diets as well as herbal medicines. Therapeutic treatment options for bacterial infections are limited due to the spread of antimicrobial resistances. Hence, in a number of studies during the last few years, different classes of plant secondary meta...

Antibiotic resistance is a growing problem and may become the next major global health crisis if no timely actions are taken. Mycobacterial infections are widespread and, due to antibiotic resistance, also hard to treat and a major cause of mortality. Natural compounds have the potential to increase antibiotic effectiveness due to their resistance...

Reynoutria japonica Houtt. is a critical invasive alien plant in Europe and North America with a drastic impact on native flora. However, R. japonica has medicinal potential, especially as a source of stilbenes. In order to explore the potential of simple extractions of R. japonica, we conducted qualitative and quantitative analyses of fresh R. jap...

New approaches for the control of Campylobacter jejuni biofilms in the food industry are being studied intensively. Natural products are promising alternative antimicrobial substances to control biofilm production, with particular emphasis on plant extracts. Dried flowers of Lavandula angustifolia were used to produce LEO, LEF, and LEW. The chemica...

Biofilms provide a protective environment for pathogens such as Campylobacter jejuni, the most prevalent foodborne pathogen, and biofilm formation can enhance bacterial survival in hostile environments. Adhesion of bacteria to the different materials of industrial surfaces is the first step in biofilm formation. Modulation of bacterial adhesion and...

Natural products and their structural analogues have historically made a major contribution to pharmacotherapy, especially for cancer and infectious diseases. Nevertheless, natural products also present challenges for drug discovery, such as technical barriers to screening, isolation, characterization and optimization, which contributed to a declin...

Malaria and tuberculosis are still among the leading causes of death in low-income countries. The 1,4-naphthoquinone (NQ) scaffold can be found in a variety of anti-infective agents. Herein, we report an optimised, high yield process for the preparation of various 2-arylnaphthoquinones by a palladium-catalysed Suzuki reaction. All synthesised compo...

Carvotacetones (1-7) isolated from Sphaeranthus africanus were screened for their antimycobacterial and efflux pump (EP) inhibitory potential against the mycobacterial model strains Mycobacterium smegmatis mc 2 155, Mycobacterium aurum ATCC 23366, and Mycobacterium bovis BCG ATCC 35734. The minimum inhibitory concentrations (MICs) of the carvotacet...

To control Pseudomonas and Shewanella as important psychrotrophic spoilage bacteria in fish meat, we used ethanolic extracts of oregano (Origanum vulgare subsp. vulgare) and nettle (Urtica dioica), with phytochemical characterisation of the extracts and their bioactive compounds. Liquid chromatography coupled with photodiode array detection and ele...

The culinary herb Satureja montana, known as winter savory, is an ingredient of traditional dishes known in different parts of the world. As an ingredient of foods it has the potential to improve their safety. In this study, the herb’s activity was investigated against Campylobacter jejuni, the leading cause of the most prevalent bacterial gastroen...

Therapeutic treatment options for opportunistic non-tuberculous mycobacterial (NTM) infection and/or serious mycobacterial infections such as tuberculosis (TB) and leprosy are limited due to the spread of antimicrobial resistance mechanism. Plant-derived natural compounds as prospective efflux pump inhibitors may present a promising adjunct to conv...

The polyphenolic composition and anti-inflammatory activity of selected Thymus species (T. longicaulis C. Presl, T. praecox Opiz subsp. polytrichus (A. Kerner Ex Borbás) Jalas, T. pulegioides L., T. serpyllum L. subsp. serpyllum and T. striatus Vahl) was studied in comparison with T. vulgaris, as an officinal medicinal plant, to evaluate the biomed...

Majority of men are affected by symptomatic benign prostatic hyperplasia (BPH) from a certain age. Botanical extracts are frequently used in the early management of the symptoms. In a single-arm, mono-center pilot study, the effects of a proprietary oil-free hydroethanolic pumpkin seed extract on the symptoms of BPH were investigated. A total of 60...

Rhodiola rosea has been used in folk medicine as ethanolic macerates for a long time. This study aims to provide a quantitative and qualitative analysis and comparison of different ethanolic Rhodiola rosea rhizome macerates (35%, 70%, and 96% v/v) and accelerated solvent extraction (ASE) extracts prepared with 85% methanol, in order to shed light o...

Little is known about the pharmacological activities of Iris adriatica (Iridaceae), a plant endemic to Dalmatia (Croatia). We therefore performed a bioassay-guided fractionation including highperformance counter current chromatography (HPCCC) and antibacterial tests using Mycobacterium smegmatis mc² 155. One obtained fraction was found to be antimy...

A new tetracyclic saponin, 17(R),20(R)-3β,6α,16β-trihydroxycycloartanyl-23-carboxylic acid 16-lactone 3-O-β-D-glucopyranoside (1) together with one known flavonoid, camelliaside A (2) were isolated from the aerial parts of Astragalus glycyphyllos L. Their structures were determined by chemical, HRESIMS and NMR methods. On 6-hydroxydopamine in vitro...

Capsaicinoids are reported to have a bunch of promising pharmacological activities, among them antibacterial effects against various strains of bacteria. In this study the effect on efflux pumps of mycobacteria was investigated. The importance of efflux pumps, and the inhibition of these, is rising due to their involvement in antibiotic resistance...

Two novel compounds from A. glycyphylloides DC (1–2) and three rare flavonoids from A. spruneri Boiss. (3–5), alongside their neuroprotective activity and possible effects as human monoamine oxidase type B inhibitors were reported. The structural elucidation of the compounds was achieved by chemical, HRESIMS and NMR analyses. Their effects were inv...

Iris adriatica Trinajstić ex Mitić (Iridaceae L.) is a strictly endemic taxon from Croatia. It is a rhizomatous dwarf plant from the I. pumila complex with a distribution area limited to the Croatian part of the Mediterranean area, mainly central Dalmatia. The genus Iris is known for its richness in isoflavonoids which also play a significant role...

Scope Ginger is reported to be used for the prevention and treatment of cardiovascular diseases (CVD). Cholesterol efflux from macrophage foam cells is an important process in reverse cholesterol transport, whose increase may help to prevent or treat CVD. In this study, we investigated the effects of 6‐dihydroparadol from ginger on macrophage chole...

Campylobacteriosis is the world’s leading bacterial foodborne illness and the most frequently reported zoonosis in humans. The present review aims to present an overview of the alternative strategies to limit Campylobacter contamination and to prevent Campylobacter infections using natural products from various sources. Additionally, natural produc...

The food-borne pathogen Campylobacter jejuni can cause bacterial gastrointestinal infections. Biofilm formation amplifies the risk of human infection by improving survival and persistence of C. jejuni in food processing environments and its transmission through the food chain. We aimed to control C. jejuni using an alternative strategy of low doses...

A series of N-benzyl tetrahydropiperidinylidene pyrrolidinium salts have been synthesized and investigated for their antiplasmodial and antitrypanosomal activities as well as for their cytotoxic effects. The antibacterial, antimycobacterial and anticancer potencies of selected compounds were examined, too. Physicochemical parameters were calculated...

Mushrooms represent promising sources of novel bioactive compounds and can be applied as innovative strategies to control microbial contamination and infection via the food chain. We characterized aqueous extracts from 21 wild basidiomycete mushrooms and the cultivated oyster mushroom, Pleurotus ostreatus, as putative sources of antimicrobial and a...

Recently, we reported the antiprotozoal activity of tetrahydropyridylidene ammonium salts. We inserted this motif into a fused ring system, a pyrido-benzodiazepine. The synthesis includes an enamine formation followed by a Mannich reaction to cyclic products and an S-methylation. The last step is a regioselective reduction process. All new compound...

Plants produce a great number of metabolites with potentially useful biological activities. Species from the genus Globularia (Plantaginaceae) are known as sources of different phenolic and iridoid compounds. Globularia alypum L. is a medicinal plant used as a healing agent in many Mediterranean countries. Similarities in phytochemical composition...

We present a standardized, straightforward and efficient approach applicable in routine analysis of flavonoids combining sensitive NMR and HPLC experiments. The determination of the relative configuration of sugar moieties usually requires the acquisition of ¹³C-NMR shift values. We use a combination of HPLC and sensitive NMR experiments (1D-proton...

Echinops kebericho Mesfin is an Ethiopian medicinal plant which roots are traditionally fumigated and used for disinfection of brewing jars, as snake repellent, against headache and feverish illnesses [1,2]. Major compounds of the plant are sesquiterpene lactones, i.e. dehydrocostus lactone and costunolide, which revealed pronounced antiviral, anti...

Thermophilic campylobacters are a major cause of bacterial food-borne diarrhoeal disease. Adherence and biofilm formation are key elements of Campylobacter jejuni persistence in unfavourable environmental conditions. The phytochemical analysis of Euodia ruticarpa fruit ethanol solution extract (EREE) indicated that the major compounds were evodiami...

Pumpkin seeds have been known in folk medicine as remedy for kidney, bladder and prostate disorders since centuries. Nevertheless, pumpkin research provides insufficient data to back up traditional beliefs of ethnomedical practice. The bioactivity of a hydro-ethanolic extract of pumpkin seeds from the Styrian pumpkin, Cucurbita pepo L. subsp. Pepo...

Medicinal plants have a long tradition of use in folk and conventional medicine. In recent years numerous studies confirm various bioactivities of natural products, among them antibacterial activity. Natural antibacterial agents such are essential oils and isolated compounds now represent a notable source for pharmaceutical and food industry and ar...

A new flavonol tetraglycoside, quercetin-3-O-[α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-galactopyranosyl]-7-O-β-d-glucopyranoside (1), and two new flavonol alkaloids, N-(8-methylquercetin-3-O-[α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-galactopyranosyl])-3-hydroxypiperidin-2-one (2) and N-(8-methylkaempferol-3-O-[α-l-...

Ever increasing numbers of antibiotic resistances are putting more and more pressure on research and global health systems. Multidrug-resistant bacteria even escape from second-line antibiotics and only a few promising candidates are presently in the pipeline. Intrinsic resistance of bacteria mediated by efflux pumps play a crucial role in the deve...

In order to survive in food processing environments and cause disease, Campylobacter jejuni requires specific survival mechanisms, such as biofilms, which contribute to its transmission through the food chain to human host and present a critical form of resistance to a wide variety of antimicrobials. Phytochemical analysis of thyme ethanolic extrac...

Background: The traditional use of the oleo-gum-resin of Commiphora guidottii Chiov. ex. Guid., which is commonly called scented myrrh, for topical treatment of wound is well documented. The major objective of the present study was to investigate the essential oil and resin obtained from C. guidottii for their potential wound healing properties. Du...

The present study aimed to evaluate antioxidant and acetylcholinesterase (AChE) inhibitory activities of the ethanolic extracts of six selected Thymus species growing in Croatia (T. longicaulis, T. praecox subsp. polytrichus, T. pulegioides, T. serpyllum subsp. serpyllum, T. striatus, and T. vulgaris). Antioxidant effectiveness was assessed using s...

Alpinia katsumadai is used in traditional Chinese medicine for abdominal distention, pain, and diarrhoea. Campylobacter jejuni is the most common cause of bacterial food-borne diarrhoeal illnesses worldwide. Adhesion to gut epithelium is a prerequisite in its pathogenesis. The antimicrobial, cytotoxic, and anti-adhesive activities of a chemically c...

Flavonoids are regarded as essential ingredients for the anti-inflammatory activity of Epilobium angustifolium L. (Onagraceae). The metabolic profiles of medicinal plants vary aside from genetic determination due to the influence by external factors. This study evaluates the influence of altitudinal variation on the content of flavonoids in E. angu...

The aim of the study was to investigate the mode of action of (-)-α-pinene in terms of its modulation of antibiotic resistance in Campylobacter jejuni. Broth microdilution and ethidium bromide accumulation assays were used to evaluate the (-)-α-pinene antimicrobial activity, modulation of antimicrobial resistance, and inhibition of antimicrobial ef...

The aim of the study was to investigate the mode of action of (-)-α-pinene in terms of its modulation of antibiotic resistance in Campylobacter jejuni. Broth microdilution and ethidium bromide accumulation assays were used to evaluate the (-)-α-pinene antimicrobial activity, modulation of antimicrobial resistance, and inhibition of antimicrobial ef...

Several bicyclic compounds, 3-azabicyclo[3.2.2]nonanes, have been prepared. The new compounds were tested for their activities against one strain of the causative organism of Malaria tropica, Plasmodium falciparum K1, which is resistant against chloroquine and pyrimethamine. In addition, their cytotoxicity and their activity against the pathogen of...

ScopeVascular smooth muscle cell (VSMC) proliferation is involved in the pathogenesis of cardiovascular disease, making the identification of new counteracting agents and their mechanisms of action relevant. Ginger and its constituents have been reported to improve cardiovascular health, but no studies exist addressing a potential interference with...

AimsThe interaction of quinolone and indoloquinazoline alkaloids concerning their antimycobacterial activity was studied.Methods and ResultsThe antimycobacterial and modulating activity of evodiamine (1), rutaecarpine (2) and evocarpine (3) was tested on mycobacteria including three multidrug-resistant (MDR) clinical isolates of M. tuberculosis. An...

Responsibility for food safety must be taken through the entire food-production chain, to avoid consumer cross-contamination. The antimicrobial activities of an Alpinia katsumadai seed extract and epigallocatehin gallate (EGCG), and their combination, were evaluated against individual food-borne pathogenic strains of Listeria monocytogenes, Escheri...

A diverse array of 4-(1H)-quinolone derivatives bearing substituents at positions 1 and 2 were synthesized and evaluated for antiprotozoal activities against Plasmodium falciparum and Trypanosoma brucei rhodesiense, and cytotoxicity against L-6 cells in vitro. Furthermore, selectivity indices were also determined for both parasites. All compounds t...

Antimicrobial resistance of food-related bacterial pathogens is becoming a serious problem, especially after the emergence of multidrug-resistant strains. To overcome this problem, new and effective antimicrobials or resistance modulators are highly needed and plant kingdom represents a valuable source of these compounds. We investigated antimicrob...

In Ethiopian traditional medicine, the leaves of Otostegia integrifolia Benth. are used for the treatment of several diseases including malaria. In an ongoing search for effective, safe and cheap antimalarial agents from plants, the 80% methanol leaf extract O. integrifolia was tested for its in vivo antimalarial activity, in a 4-day suppressive as...