Jan Muselík

Antiradical and Cytoprotective Activities of Several C-Geranyl-substituted Flavanones from Paulownia tomentosa Fruit

Antiradical and cytoprotective activities of several flavanones isolated from Paulownia tomentosa (Thunb.) Steud. (Scrophulariaceae) have been evaluated using different in vitro and in vivo methods. The capacity of flavanones to scavenge radicals was measured in vitro by means of DPPH and ABTS assays, the inhibition of hydroxyl radicals produced in Fenton reactions, FRAP, scavenging superoxide radicals using enzymatic and nonenzymatic assays and the inhibition of peroxynitrite-induced nitration of tyrosine. The in vivo testing involved measuring the cytoprotective effect of chosen flavanones against alloxan-induced diabetes in mice. The activity of tested compounds was expressed either as a Trolox® equivalent or was compared with rutin or morine as known antioxidant compounds. The highest activity in most tests was observed for diplacone and 3´-O-methyl-5´-hydroxydiplacone, and the structure vs. the antioxidant activity relationship of geranyl or prenyl-substituted flavonoids with different substitutions at the B and C ring was discussed.

Antiradical activity of Paulownia tomentosa (Scrophulariaceae) extracts.

Paulownia tomentosa is a large indecidous tree planted mostly for its fast growing wood and decorative purposes. The tree is also used in traditional Chinese medicine. As a part of our study of natural polyphenols, the fruits of Paulownia tomentosa were extracted by EtOH and than subjected to liquid/liquid extraction. Fractions were analysed by TLC and HPLC to determine presence of phenolic substances. We identified and quantified acteoside (1) and isoacteoside (2) in the EtOAc and n-BuOH extracts; mimulone (3) and diplacone (4) in the MeOH extract. To determine the antiradical activity of extracts we used the anti DPPH and peroxynitrite assays. The activity was expressed as Trolox C equivalents, IC50 for DPPH scavenging and a time dependency course was established. The polyphenols content was determined; results were expressed as gallic acid equivalents. Using these methods we found the fractions of the n-BuOH, EtOAc and MeOH extracts that display antiradical activity, which could be exploited as potential pharmaceuticals.

Antiproliferative, cytotoxic, antioxidant activity and polyphenols contents in leaves of four Staphylea L. species.

Staphylea has been used for long time in Traditional Chinese Medicine (TCM) and by Native Americans in a number of therapeutical indications. The present study describes in vitro antiproliferative, cytotoxic properties (MTT and LDH test) and antioxidant activities (reduction of DPPH radical and peroxynitrite radical) of Staphylea colchica Stev. (SC), S. elegans Zab. (SC), S. holocarpa Hemsl. (SH) and S. pinnata L. (SP) leave water extracts. Time- (24 and 72 h) and dose- (1-150 μg/mL) dependent effects of the above extracts were tested at the mitochondrial (MTT test) and plasma membrane level (LDH leakage) in A431 human skin carcinoma cells. Screening of these properties has shown time and dose dependent increase of harmful effects, the highest activity was observed for the SE, while the less active was the SH extract. The ED50 values for the mitochondrial and membrane damage were nearly identical for the SE and very similar for SH extract. These findings indicate simultaneous injury of both cell compartments by SE and SH extracts. The highest antioxidant potential of SE species is accompanied by the highest content of flavones/flavonols and polyphenols. Only flavonoid contents are associated with antiproliferative effects and cell membrane injury, while antioxidant properties are the result of polyphenol content. The data clearly demonstrate that individual Staphylea L. species differ, not only in the amount of biologically active compounds, but also by the extent of harmful and beneficial effects.

Soluble filler as a dissolution profile modulator for slightly soluble drugs in matrix tablets.

The purpose of this experimental work was the development of hydrophilic–lipophilic matrix tablets for controlled release of slightly soluble drug represented here by diclofenac sodium (DS). Drug dissolution profile optimization provided by soluble filler was studied. Matrix tablets were based on cetyl alcohol as the lipophilic carrier, povidone as the gel-forming agent, and common soluble filler, that is lactose or sucrose of different particle size. Physical properties of tablets prepared by melt granulation and drug release in a phosphate buffer of pH 6.8 were evaluated. In vitro studies showed that used filler type, filler to povidone ratio and sucrose particle size influenced the drug release rate. DS dissolution profile could be changed within a wide range from about 50% per 24 hours to almost 100% in 10 hours. The release constant values confirmed that DS was released from matrices by the diffusion and anomalous transport. The influence of sucrose particle size on the drug release rate was observed. As the particle size decreased, the drug release increased significantly and its dissolution profile became more uniform. Soluble fillers participated in the pore-forming process according to their solubility and particle size. Formulations containing 100 mg of the drug, 80 mg of cetyl alcohol, 40 mg of povidone, and 80 mg of either lactose or sucrose (particle size 250–125 μm) were considered optimal for 24-hour lasting dissolution of DS.

Evaluation of the Antiradical Activity of Schisandra Chinensis Lignans Using Different Experimental Models

The in vitro antiradical activity of Schisandra chinensis lignans was investigated using DPPH, ABTS+, Fenton reaction inhibition and tyrosine-nitration inhibition assays, as were the in vivo antidiabetic activities of selected lignans in an animal model of alloxan-induced diabetes. Different degrees of antiradical activity were found, depending upon the structural parameters of the tested compounds. Unfortunately, the compounds showed no antidiabetic activity in concentration range tested.

Coated hard capsules as the pH-dependent drug transport systems to ileo-colonic compartment

Purpose: The aim of this study was to investigate the suitability of hard capsules of different composition (gelatin—G, gelatin coated with hydroxypropyl cellulose—G/HPC, and hypromellose—H) for a coating with aqueous dispersion of pH-dependent synthetic polymer Eudragit® FS (EFS) and to evaluate in vitro the coated capsules as transport systems for ileo-colonic drug delivery. Methods: Three sets of hard capsules with increasing coating levels (5–30%) were obtained by Wurster technique. The release of model drug (caffeine) from prepared samples was tested using paddle dissolution method with continual pH change (pH 1.2–2 h, 6.8–4 h and 7.5–2 h). Results: During the coating process, no problems occurred and similar suitability of capsules materials for EFS application was observed in contrast to some published reports. The application of HPC subcoating onto gelatin capsules surface was shown as the redundant step. The samples G/EFS10–15% and H/EFS15–20% with 6 h lag time and fast drug release after the pH adjustment to 7.5 corresponded with the requirements for ileic drug delivery. Samples releasing the drug after the pH change to 7.5 in 2-h interval such as G/EFS 20%, G/HPC/EFS 25% and H/EFS 25% are considered as promising transport systems to ileo-colonic area. Samples G/EFS 25–30%, G/HPC/EFS 30% and H/EFS 30% with 7 h lag time could be used for colon delivery. Conclusion: The desired intestinal part could be targeted without significant formulation changes only by the selection of capsules shell forming material and suitable EFS coating thickness.

Influence of Process Parameters on Content Uniformity of a Low Dose Active Pharmaceutical Ingredient in a Tablet Formulation According to GMP

Abstract The article describes the development and production of tablets using direct compression of powder mixtures. The aim was to describe the impact of filler particle size and the time of lubricant addition during mixing on content uniformity according to the Good Manufacturing Practice (GMP) process validation requirements. Processes are regulated by complex directives, forcing the producers to validate, using sophisticated methods, the content uniformity of intermediates as well as final products. Cutting down of production time and material, shortening of analyses, and fast and reliable statistic evaluation of results can reduce the final price without affecting product quality. The manufacturing process of directly compressed tablets containing the low dose active pharmaceutical ingredient (API) warfarin, with content uniformity passing validation criteria, is used as a model example. Statistic methods have proved that the manufacturing process is reproducible. Methods suitable for elucidation of various properties of the final blend, e.g., measurement of electrostatic charge by Faraday pail and evaluation of mutual influences of researched variables by partial least square (PLS) regression, were used. Using these methods, it was proved that the filler with higher particle size increased the content uniformity of both blends and the ensuing tablets. Addition of the lubricant, magnesium stearate, during the blending process improved the content uniformity of blends containing the filler with larger particles. This seems to be caused by reduced sampling error due to the suppression of electrostatic charge.

Antioxidant Activity and Total Phenols in Different Extracts of Four Staphylea L. Species

Staphylea L. is a deciduous ornamental shrub that possesses significant cytotoxic and antibacterial activity, although the chemical composition of its extracts and the identity of the structures responsible for these biological activities are not yet known. In this study we have determined the total phenolic content in chloroform and ethyl acetate extracts of four Staphylea species: Staphylea colchica Stev., S. elegans Zab., S. holocarpa Hemsl. and S. pinnata L.. The antioxidant potential (DPPH radical and peroxynitrite scavenging activity) of these extracts was also determined and a correlation between the phenolic content and antioxidant activities of the ethyl acetate extracts has been found. Ethyl acetate extracts were more active and one of them, obtained from S. colchica Stev., possessed the highest activity.

The Chemical Composition of Achillea wilhelmsii C. Koch and Its Desirable Effects on Hyperglycemia, Inflammatory Mediators and Hypercholesterolemia as Risk Factors for Cardiometabolic Disease

This study was done to identify the content compounds of Achillea wilhelmsii (A. wilhelmsii) and to evaluate its hypoglycemic and anti-hypercholesterolemic activity and effect on inflammatory mediators. The extracts and fractions of A. wilhelmsii were thoroughly analyzed using high performance liquid chromatography (HPLC), and the total content of phenols and flavonoids was determined. The hypoglycemic activity was evaluated in vivo using alloxan-induced diabetic mice. The effect upon inflammatory mediators was evaluated in vitro using the human monocytic leukemia cell line (THP-1). The anti-hypercholesterolemic activity was evaluated in vitro using the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase assay kit. The water extract (WE)-treated group showed the highest reduction in the fasting blood glucose levels (FBGL). The chloroform fraction (CF) and ethyl acetate fraction (EAF) both showed a significant ability to reduce the secretion of tumor necrosis factor alpha (TNF-α). The EAF, however, also attenuated the levels of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). The CF showed the most significant 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) inhibition activity. The five main compounds in the CF were isolated and identified. Out of the five compounds in the CF, 1β,10β-epoxydesacetoxymatricarin (CP1) and leucodin (CP2) showed the highest anti-hypercholesterolemic potential. A molecular docking study provided corresponding results.

Preparation of pellets with controlled release of glucose as prevention of hypoglycaemia in paediatric patients.

Hypoglycaemic episodes represent serious and frequent complications of type 1 and 2 diabetes. Theoretically, the risk of hypoglycaemic states can be affected by a dosage form based on a food supplement containing a delayed release formulation of glucose. The release of glucose should compensate for balance the peak effect of an antidiabetic treatment. In clinical practice, a diet with fibre and grains is recommended and patients are broadly educated in the topic of low and high glycaemic indexes to achieve the same effect. However, a precisely-timed release of carbohydrates can favourably target expected hypoglycaemia and concurrently decrease carbohydrate content. To study the possibility of preparing the dosage form with controlled-release carbohydrates, a dosage form of pellets containing four osmotically active substances coated by a membrane created of ethylcellulose was prepared. These pellets can be administered in a mixture with liquid or semisolid food. The resulting dissolution profiles for selected compositions showed that delayed release can be achieved for 120, 240 and 360min in vitro, representing an ideal delay for clinical purposes.