Dana Flešková

Herbal polysaccharides and cough reflex.

In the last decades plant substances have become a leading form of treatment of many respiratory symptoms, including cough. It has been shown that compounds purified form polysaccharides from Adhatoda vasica, Withania somnifera, and Glycyrrhiza glabra have various biological activities, such as antioxidant, anti-inflammatory, immunomodulating, antispasmodic action, or antiallergic properties, and they often act as cough suppressants. This work demonstrates new natural substitutes for synthetic antitussives whose application is associated with numerous adverse effects. We investigated pharmacodynamic characteristics of arabinogalacatan samples extracted from A. vasica, W. somnifera, and G. glabra. These extracts showed the ability to reduce citric acid-induced cough in awake guinea pigs after oral administration in a dose of 50mg/kg. The strongest antitussive effect (81%) was found after application of the extract from G. glabra. There was a 67% cough suppression with A. vasica and 61% with W. somnifera, which was comparable with the antitussive activity of codeine (62%).

Structural features and in vivo antitussive activity of the water extracted polymer from Glycyrrhiza glabra

Antitussive drugs are amongst the most widely used medications worldwide; however no new class of drugs has been introduced into the market for many years. Herein, we have analyzed the water-extracted polymeric fraction (WE) of Glycyrrhiza glabra. This arabinogalactan protein enriched fraction, ≥ 85% of which gets precipitated with Yariv reagent, consisted mainly of 3- and 3,6-linked galactopyranosyl, and 5- and 3,5-linked arabinofuranosyl residues. Peroral administration of this polymer in a dose of 50mg/kg body weight decreases the number of citric acid induced cough efforts in guinea pigs more effectively than codeine. It does not induce significant change in the values of specific airway resistance or provoked any observable adverse effects.

In vivo anti-tussive activity and structural features of a polysaccharide fraction from water extracted Withania somnifera

AIM OF THE STUDY Anti-tussive drugs are amongst the most widely used medications worldwide; however no new class of drugs has been introduced into the market for many years. The present study aims at evaluating the structural features and in vivo anti-tussive activity of a polysaccharide fraction from water extracted Withania somnifera. MATERIALS AND METHODS Herein, we have analyzed water extracted material of Withania somnifera using chemical, chromatographic, spectroscopic and biological methods. RESULTS A polysaccharide fraction (F3) containing arabinosyl, galactosyl and galacturonosyl residues were obtained by anion exchange chromatography of the water extracted material. This polymer is branched and contained (1,5)-/(1,3,5)-linked arabinofuranosyl, (1,3)-/(1,6)-/(1,3,6)-linked galactopyranosyl residues together with small amount of terminal rhamnopyranosyl and terminal arabinofuranosyl residues. Peroral administration of this pectic arabinogalactan in a dose of 50 mg kg(-1) body weight (b.w.) decreased the number of cough efforts induced by citric acid in guinea pigs like that of codeine. CONCLUSIONS This study provides a scientific basis for the past and present ethnomedical uses of this plant.

Antitussive Activity of Withania somnifera and Opioid Receptors

Arabinogalactan is a polysaccharide isolated from the roots of the medicinal plant Withania somnifera L. It contains 65% arabinose and 18% galactose. The aim of the present study was to evaluate the antitussive activity of arabinogalactan in conscious, healthy adult guinea pigs and the role of the opioid pathway in the antitussive action. A polysaccharide extract was given orally in a dose of 50 mg/kg. Cough was induced by an aerosol of citric acid in a concentration 0.3 mol/L, generated by a jet nebulizer into a plethysmographic chamber. The intensity of cough response was defined as the number of cough efforts counted during a 3-min exposure to the aerosol. The major finding was that arabinogalactan clearly suppressed the cough reflex; the suppression was comparable with that of codeine that was taken as a reference drug. The involvement of the opioid system was tested with the use of a blood-brain barrier penetrable, naloxone hydrochloride, and non-penetrable, naloxone methiodide, to distinguish between the central and peripheral mu-opioid receptor pathways. Both opioid antagonists acted to reverse the arabinogalactan-induced cough suppression; the reversion was total over time with the latter antagonist. We failed to confirm the presence of a bronchodilating effect of the polysaccharide, which could be involved in its antitussive action. We conclude that the polysaccharide arabinogalactan from Withania somnifera has a distinct antitussive activity consisting of cough suppression and that this action involves the mu-opioid receptor pathways.

Influence of viscous Rhodella grisea (Rhodophyceae) proteoglycan on chemically induced cough reflex

An algal extracellular biopolymer (over 8.5 × 10(5)Da) composed of carbohydrates (52%) and protein (∼13%) has been isolated from a red alga Rhodella grisea growing in natural conditions by concentration of water medium, alcohol precipitation, dialysis and freeze-drying. This mucilagineous biopolymer contained xylose and its 3-O- and 4-O-methyl derivatives (∼63%), galactose (∼12%), glucuronic acid (11-12%), glucose (∼5%), rhamnose (∼4%), fucose (∼3-4%) and low content of others accompaning sugars. When tested on the citric acid-induced cough and reactivity of airways smooth muscle in vivo in the test system guinea pigs, this biopolymer assigned a significant cough suppressing effect. The reactivity of airways smooth muscle was not affected indicating that expectoration effect was not suppressed by biopolymer application, which is important from the pharmacological point of view.

Pharmacologic modulation of experimentally induced allergic asthma.

Pharmacologic modulation of experimentally induced allergic asthma Allergic asthma is the most frequent disease of the respiratory tract. The aim of the current experimental and clinical studies was to find new sources of drugs able to control asthmatic inflammation and airway hyperresponsiveness. Our experimental studies were focused on efficiency evaluation of substances able to influence activities of ion channels, phosphodiesterase (PDE) isoforms, substances from the group of polyphenols and NO metabolism modulators during experimentally induced allergic asthma.

Potential Effect of Pharmacotherapy on Sympathetic Arousal in Autism

Abstract Background: Autism spectrum disorder (ASD) is a serious neurodevelopmental disorder associated with autonomic nervous system (ANS) abnormalities. Moreover, at least 50% of children with ASD suffer from other comorbid diseases such as anxiety, depression, and attention deficit hyperactivity disorder (ADHD) associated with receiving psychotropic medication. From this context we aimed to evaluate changes in sympathetic arousal using analysis of electrodermal activity (EDA) as an index of sympathetic cholinergic activity in treated and non-treated autistic children under resting conditions. Methods: We examined 23 children with ASD and 14 healthy age- and gender-matched children at the age of 7–15 years. The ASD patients were divided into ASD non-treated group (n=12) and ASD treated group (n=11). The EDA was continuously monitored during resting phase in a supine position. The EDA amplitude (μS) was computed as an average of 5 min baseline period. Results: We found significantly lower EDA in ASD non-treated subgroup compared to controls indicating subtle abnormalities in the regulation of the sympathetic nervous system. Although no significant differences were found between the ASD treated and non-treated subgroups the ASD treated group showed comparable sympathetic activity relative to controls indicating a potential ameliorated treatment effect on sympathetic arousal in ASD. Conclusions: These findings could help to determine differences in sympathetic arousal in treated and non-treated children with ASD, which is important for assessment of autism-linked cardiovascular risk depending on pharmacotherapy.