Talip Çeter

Preparation and characterisation of biodegradable pollen–chitosan microcapsules and its application in heavy metal removal

Biosorbents have been widely used in heavy metal removal. New resources should be exploited to develop more efficient biosorbents. This study reports the preparation of three novel chitosan microcapsules from pollens of three common, wind-pollinated plants (Acer negundo, Cupressus sempervirens and Populus nigra). The microcapsules were characterized (Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and elemental analysis) and used in removal of heavy metal ions: Cd(II), Cr(III), Cu(II), Ni(II) and Zn(II). Their sorption capacities were compared to those of cross-linked chitosan beads without pollen grains. C. sempervirens-chitosan microcapsules exhibited better performance (Cd(II): 65.98; Cu(II): 67.10 and Zn(II): 49.55 mg g(-1)) than the other microcapsules and the cross-linked beads. A. negundo-chitosan microcapsules were more efficient in Cr(III) (70.40 mg g(-1)) removal. P. nigra-chitosan microcapsules were found to be less efficient. Chitosan-pollen microcapsules (except P. nigra-chitosan microcapsules) can be used in heavy metal removal.

High hydrostatic pressure extraction of phenolic compounds from Maclura pomifera fruits

High hydrostatic pressure processing (HHPP) is a food processing method, in which food is subjected to the elevated pressure which is mostly between 100 to 800 MPa. HHPP is seen not only in food engineering, but also have other application areas, such as extraction of active ingredients from natural biomaterials. In this study, several extraction conditions such as two different solvents [methanol and solvent cocktail (dH 2 O:ethanol:methanol:acetone:CH2Cl2 - 1:2.5:2.5:2:2)], two different pressures for high hydrostatic pressure extraction (HHPE) (250 and 500 MPa), three different extraction methods (shaking at room temperature, soxhlet extractor and HHPE) and different extraction times for each extraction method (10 min for HHPE, 2 h for shaking and 14 h for soxhlet extraction) were used in order to extract phenolic compounds from Maclura pomifera fruits. The highest amount of phenolic compounds (913.173 μg gallic acid equivalent (GAE/mL) was observed in HHPE at 500 MPa using solvent cocktail, where the lowest amount (316.877 μg GAE/mL) was in soxhlet extraction using methanol. In terms of extraction efficiency, the highest amount of extraction is seen in the shortest time period. It was observed that HHPE in solvent cocktail was the most effective method when compared to the other methods tested. Key words : Maclura pomifera , Osage orange, hedge apple, phenolic compound, high hydrostatic pressure extraction.

Design and application of sporopollenin microcapsule supported palladium catalyst: Remarkably high turnover frequency and reusability in catalysis of biaryls

Bio-based catalyst support materials with high thermal and structural stability are desired for catalysts systems requiring harsh conditions. In this study, a thermally stable palladium catalyst (up to 440°C) was designed from sporopollenin, which occurs naturally in the outer exine layer of pollens and is widely acknowledged as chemically very stable and inert biological material. Catalyst design procedure included (1) extraction of sporopollenin microcapsules from Betula pendula pollens (∼25μm), (2) amino-functionalisation of the microcapsules, (3) Schiff base modification and (4) preparation of Pd(II) catalyst. The catalytic activity of the sporopollenin microcapsule supported palladium catalyst was tested in catalysis of biaryls by following a fast, simple and green microwave-assisted method. We recorded outstanding turnover number (TON: 40,000) and frequency (TOF: 400,000) for the catalyst in Suzuki coupling reactions. The catalyst proved to be reusable at least in eight cycles. The catalyst can be suggested for different catalyst systems due to its thermal and structural durability, reusability, inertness to air and its eco-friendly nature.

High hydrostatic pressure processing: a method having high success potential in pollen protein extraction

Even a single peptide that is present in the pollen wall and cytoplasm could cause pollen allergy. To produce skin-prick test kits, the first step is the extraction of these molecules. In this study, Cedrus atlantica pollens were subjected to 220 and 330 MPa for 10 and 30 min in order to extract these molecules. After high hydrostatic pressure processing (HHPP), the total amounts of proteins (TAPs) are measured and compared with the results of the conventional extraction method (CEM). As a result, the TAPs extracted by HHPP is 18.0210 μ g/mL at 220 MPa for 10 min, 22.5770 μ g/mL at 220 MPa for 30 min, 23.3810 μ g/mL at 330 MPa for 10 min and 25.9270 μ g/mL at 330 MPa for 30 min, while this is 1.9460 μ g/mL in 24 h by the CEM. In addition to these results, visual pollen deformation and eruption, pollen wall and surface damage have also been observed.

Fruit structure of 12 Turkish endemic Tripleurospermum Sch. Bip. (Asteraceae) taxa and its taxonomic implications

This study concerns the evaluation of micromorphological and anatomical characters of fruit (achene-cypsela) in 12 Turkish endemic Tripleurospermum taxa using multivariate analyses (cluster analysis, principal component analysis, one-way analysis of variance). Pericarp in all taxa examined is mainly composed of several layers of parenchymatous and sclerenchymatous cells with one vascular bundle in each rib. In the achene, the thickness and width of lateral and adaxial ribs with presence or absence of a slime envelope have high taxonomic value for Tripleurospermum at interspecific levels. The slime envelope formation is also correlated with ploidy levels and habitats of some taxa in Tripleurospermum.

Comparative seed morphology of Trigonella L. species (Leguminosae) in Turkey

Seeds morphology of 37 taxa of Trigonella L. from various regions in Turkey were examined with a scanning electron microscope and light microscope. Based on seed features such as shape, colour and surface ornamentation pattern, 7 morphological types were recognized. Type I have scabrated seed surface and this is only observed in section Samaroideae, Type II have verrucated seed surface, Type III have rugulated seed surface and a further classification has been made on the basis of vart, as those rugulate-verrucate (Trigonella lunata in section Lunatae, Trigonella isthmocarpa and Trigonella rhytidocarpa in section Isthmocarpae and Trigonella gladiata in section Foenum-graecum) and granule as those rugulate-granulate (only Trigonella carica in section Bucerates). Type IV is show ruminated seed surface. Type V have aculeated seed surface. This ornamentation are observed in section Cylindricae, section Reflexae and section Biebersteinionae and Section Cylindricae. Type VI are the ones with ridged-tuberculated-verrucated seed surface and this type has been observed in the section Bucerates, Reflexae, Uncinatae and some species of Foenum-graecum. Type VII have tuberculated seed surface and this is only observed in section Capitata. The different seed types are described, illustrated compared and their taxonomic importance is discussed. The seed surface ornamentations of taxa shows considerable variations. This character have importance in systematic discrimination of taxa. Key words: Trigonella, Fabaceae, seed morphology, scanning electron microscopy (SEM), light microscopy (LM), Turkey.

Pollen morphology of Astragalus L. section Hololeuce Bunge (Fabaceae) in Turkey

Abstract Pollen morphology of 15 taxa belonging to the section Hololeuce Bunge of genus Astragalus L. species was investigated by light microscopy and scanning electron microscopy. Pollen slides were prepared using a Wodehouse technique. Measurements were based on 20 or more pollen grains per specimen. For scanning electron microscopy studies, dried pollen grains were transferred on aluminium stubs and coated with gold for 4 min in a sputter-coater. The pollen grains of Hololeuce taxa are radially symmetric and isopolar. The pollen grains of the taxa are prolate–spheroidal, subprolate or prolate with the polar axes 21.42–32.93 μm and the equatorial axes 17.13–28.26 μm. The pollen grains are operculate and trizonocolporate. Syncolporate. Colpi were usually long and narrow (Clt: 4.13–6.68 μm, Clg: 16.56–26.52 μm), subterminal, membrane granulate or verrucate. Pores were found to be longate or circular (Plg: 5.01–7.82 μm, Plt: 5.31–8.69 μm). Operculum membrane ornamentation verrucate, granulate, rugulate and reticulate. Pollen grains show reticulate, perforate polar section and perforate, reticulate, microreticulate, perforate–granulate, microreticulate–perforate, microrugulate–perforate, microrugulate–microreticulate, granulate–perforate, microreticulate–granulate at meridional sections. Exine is subtectate and has a thickness of 1.08–1.30 μm. Ectexine is thicker than endexine. Intine has a thickness of 0.5–0.68 μm. As result of this study some pollen characteristic as pollen shape, aperture type and ornamentations are shown to vary within the section Hololeuce. Especially pollen surface ornamentation on polar section and meridional section has systematic value to distinguish taxa from each other.

A new pollen-derived microcarrier for pantoprazole delivery

Plant-derived carriers have emerged as promising materials for drug encapsulation. Especially, sporopollenin microcapsules extracted from diverse pollen species have been proved to be effective drug carriers due to their biocompatibility, homogeneity in size, resistance to harsh chemical conditions and high thermal stability. Here in this study, sporopollenin microcapsules were isolated successfully from the pollens of a common tree (Corylus avellana, the European hazelnut) and used as a carrier for pantoprazole (PaNa) (a proton pump inhibitor). The drug entrapment efficiency was recorded as 29.81%. SEM micrographs clearly showed the drug was loaded into the microcapsules through the apertures of microcapsule and also some drugs were adsorbed on the surface of microcapsules. FT-IR spectra analysis confirmed the drug loading. Thermogravimetric analysis revealed that thermal stability of PaNa was enhanced by encapsulation. In vitro release studies showed that PaNa-loaded sporopollenin microcapsules exhibited better release performance than the control. C. avellana sporopollenin microcapsules can make an efficient carrier for delivery of PaNa.

Controlled release and anti-proliferative effect of imatinib mesylate loaded sporopollenin microcapsules extracted from pollens of Betula pendula

Sporopollenin is a promising material for drug encapsulation due to its excellent properties; uniformity in size, non-toxicity, chemically and thermally resilient nature. Herein, morphologically intact sporopollenin microcapsules were extracted from Betula pendula pollens. Cancer therapeutic agent (imatinib mesylate) was loaded into the microcapsules. The encapsulation efficiency by passive loading technique was found to be 21.46%. Release behaviour of the drug from microcapsules was found to be biphasic, with an initial fast release followed by a slower rate of release. Imatinib mesylate release from the drug itself (control) was faster than from imatinib mesylate-loaded sporopollenin microcapsules. The release profiles for both free and entrapped drug samples were significantly slower and more controlled in PBS buffer (pH 7.4) than in HCl (pH 1.2) buffer. Cumulative drug release from IM-MES-loaded sporopollenin microcapsules was found to be 65% within 24h for PBS, whereas release from the control was completed within 1h. Also, a complete dissolution of control in HCl buffer was observed within first 30min. MTT assay revealed that drug-loaded microcapsules were effective on WiDr human colon carcinoma cell line. B. pendula sporopollenin can be suggested as an effective carrier for oral delivery of imatinib mesylate.

Effect of high hydrostatic pressure on the profile of proteins extracted from Betula pendula pollens

High hydrostatic pressure (HHP) has high success potential in pollen protein extraction, but its effect on pollen protein profiles has not been studied yet. The aim of this study is to put forward whether HHP processing causes a change in the protein profiles extracted from pollens or not. In this study, proteins extracted from Betula pendula pollens were studied at 100, 200 and 300 MPa at room temperature for 5 min. In addition, the efficiency of three different extraction solvents, namely phosphate buffer saline (PBS) buffer pH 7.5, trichloroacetic acid–acetone and Tris–HCl buffer pH 8.8, was also observed, and the results were compared with the conventional pollen protein extraction procedure. As a result, it is concluded that 200 MPa for 5 min has extracted similar amounts of protein compared with the conventional extraction method which lasted for 24 h, which lasted for 24 h. On the other hand, the application time for 200 MPa for 5 min is extremely shorter when it is compared to the conventional extraction method.