• BMB Reports
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• v.29 no.3
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• pp.248-252
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• 1996

The epidermal organ of the leech contains a complex glycoprotein molecule of mucus. The mucus excreted from annelids plays Significant role in protection against desiccation and parasites. Mucus from the Korean native leech, H. nipponia, was investigated for biochemical characteristics for possible development of biomaterials of cosmetic and pharmaceutical agents. The leech skin mucus was heavily glycosylated mucin-like protein with a high molecular weight comprised 80% carbohydrate and 20% protein. Threonine, serine, and glycine were the major components of the isolated protein and these accounted for 50% of total amino acids. The carbohydrate portion contained glucosamine, galactosamine. galactose, glucose. mannose and sialic acid in oligosaccharide form linked with threonine and serine residues of the glycoprotein.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.770-780
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• 2002

The airway surface liquid (ASL), often referred to as mucus, is a thin layer of fluid covering the luminal surface of the airway. The major function of mucus is to protect the lung through mucociliary clearance against foreign particles and chemicals entering the lung. The mucus is comprised of water, ions, and various kinds of macromolecules some of which possess the protective functions such as anti-microbial, anti-protease, and anti-oxidant activity. Mucus glycoproteins or mucins are mainly responsible for the viscoelastic property of mucus, which is crucial for the effective mucociliary clearance. There are at least eight mucin genes identified in the human airways, which will potentially generate various kinds of mucin molecules. At present, neither the exact structures of mucin proteins nor their regulation are understood although it seems likely that different types of mucins are involved in different functions and might also be associated with certain airway diseases. The fact that mucins are tightly associated with various macromolecules present in ASL seems to suggest that the defensive role of ASL is determined not only by these individual components but rather by a combination of these components. Collectively, mucins in ASL may be compared to aircraft carriers carrying various types of weapons in defense of airborne enemies.

• The Journal of Korean Medicine
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• v.20 no.2
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• pp.165-176
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• 1999

The in vivo effects of Fructus Benincasae (FB-Baekdongkwa(B) and FB- on the expectoration (decrease in sputum viscoelasticity) by their sorts and using rats (Sp. D. male, $150{\sim}160g$). FB was divided by seed, flesh, and bark, extracted by 95% ethanol for 3 hr. The extracts were given to rats administration and the following results were obtained: 1. When FB Recens-C extract was administered at the concentration of 300 mg/kg b.w., mucus secretion effect in the trachea was desirably stimulated. 2. The secretion of phenol red was increased in the FB-treated tracheas in the order of Semen Benincasae(SB)-B $(153{\pm}8\;%)$, FB-B $(149{\pm}10\;%)$, and FBR-C $(117{\pm}26\;%)$. In general, the effect of FB-B extract on phenol red secretion was stronger than that of FB-C. 3. When tracheobronchial lavage fluid was analyzed, the mucus secretion was relatively high $(111{\pm}14\;%)$ in FB-B compared with other extracts. 4. Microscopic analysis after direct treatment of the FB extracts to the rat tracheal tissue showed that all the FB extracts possessed no effects for the activity of the ciliary movement. 5. Glycoprotein content secreted by the seed extract of FB-B was increased compared with the control group, which represents the highest secretion effect of mucus. From the above results. we could conclude that the seed of SB-B possesses better activity for mucus secretion from trachea than the extracts of any other parts. Therefore, it is expected that the seed of SB-B may be available for the purpose of expectorant activity in the prescription of traditional medicine.

• Korean Journal of Pharmacognosy
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• v.19 no.2
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• pp.133-140
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• 1988

The effect of ethanol extracts of Gilkyung(Platicodi Radix, Platicodongrandiflorum A, DC), Onji(Polygalae Radix, Polygala tennuifolia Willdenow) and Deoduk(Codonopsis lanceolate Radix, Codonopsis lanceolata) on expectorant activity of rat trachea was investigated. Following treatment of 50% ethanol extract of these medicinal plants (25 mg/rat), the content of neurotransmitters such as acetylcholine and histamine in tissue was significantly increased. The secretions of acid glycoproteins and the artificially injected phenol red were also increased. However, there was no significant difference except Onji From the histological study through periodic acid Schiff and alcian blue stain, the thickness of inner membrane of acinar glands and the stained glycoproteins on surface of epithelium and on the glands were observed in all the rats trachea treated with extract of medicinal plants. In vitro, the viscosity of mucin solution was slightly decreased with an addition of the extracts. Onji showed the most effective expectorant activity among them at the identical conditions. The mechanism of expectorant activity of these medicinal plants seems to be due to stimulation of secretion and changes of rheological properties of mucus.

• Advances in Traditional Medicine
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• v.7 no.1
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• pp.51-64
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• 2007

Mucus is an aqueous gel complex with a constitution of about 95% water, high molecular weight glycoprotein (mucin), lipid, salts etc. Mucus appears to represent a significant barrier to the absorption of some compounds. Natural mucoadhesive agent was isolated and purified from the aqueous extract of the seeds of prosopis pallida (PP). Formulated tablet with the isolated material by wet granulation method. Some natural edible substances are in consideration for candidates as mucoadhesive agents to claim more effective controlled drug delivery as an alternative to the currently used synthetic mucoadhesive polymers. Subjected the materials obtained from natural source i.e. PP and standard synthetic substance, sodium carboxymethyl cellulose for evaluation of mucoadhesive property by various in vitro and in vivo methods. Through standard dissolution test and a model developed with rabbit, evaluated in vitro controlled release and bioadhesive property of theophylline formulation. Mucoadhesive agent obtained from PP showed good mucoadhesive potential in the demonstrated in vitro and in viνo models. The results suggest that the mucoadhesive agent showed controlled release properties by their application, substantially. In order to assess the gastrointestinal transit time in vivo, a radio opaque X-ray study performed in healthy rabbit testing the same controlled release formulation with and without bioadhesive polymer. Plasma levels of theophylline determined by the HPLC method and those allowed correlations to the in vitro mucoadhesive study results. Better correlation found between the results in different models. PP may acts as a better natural mucoadhesive agent in the extended drug delivery system.

• Molecules and Cells
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• v.46 no.11
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• pp.700-709
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• 2023

Mucus hyperproduction and hypersecretion are observed often in respiratory diseases. MUC8 is a glycoprotein synthesized by epithelial cells and generally expressed in the respiratory track. However, the physiological mechanism by which extracellular nucleotides induce MUC8 gene expression in human airway epithelial cells is unclear. Here, we show that UTP could induce MUC8 gene expression through P2Y2-PLCβ3-Ca²⁺ activation. Because the full-length cDNA sequence of MUC8 has not been identified, a specific siRNA-MUC8 was designed based on the partial cDNA sequence of MUC8. siRNA-MUC8 significantly increased TNF-α production and decreased IL-1Ra production, suggesting that MUC8 may downregulate UTP/P2Y2-induced airway inflammation. Interestingly, the PDZ peptide of ZO-1 protein strongly abolished UTP-induced TNF-α production and increased IL-1Ra production and MUC8 gene expression. In addition, the PDZ peptide dramatically increased the levels of UTP-induced ZO proteins and TEER (trans-epithelial electrical resistance). These results show that the anti-inflammatory mucin MUC8 may contribute to homeostasis, and the PDZ peptide can be a novel therapeutic candidate for UTP-induced airway inflammation.