• Natural Product Sciences
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• v.23 no.3
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• pp.169-174
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• 2017

The aim of this study was to investigate the effect and action mechanism of quercetin on penile corpus cavernosum smooth muscle (PCCSM). PCCSM precontracted with phenylephrine (Phe) was treated with four different concentrations of quercetin ($10^{-7}$, $10^{-6}$, $10^{-5}$ and $10^{-4}M$). PCCSM were preincubated with N-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) to block nitric oxide synthase and guanylate cyclase, respectively. The changes in PCCSM tension were recorded, and cyclic nucleotides in the perfusate were measured by radioimmunoassay. The interactions of quercetin with phosphodiesterase type 5 inhibitors (PDE5-Is) such as sildenafil, udenafil and mirodenafil, were also evaluated. PCCSM relaxation induced by quercetin occurred in a concentrationdependent manner. The application of quercetin to PCCSM pre-treated with L-NAME and ODQ significantly inhibited the relaxation. Quercetin significantly increased cGMP in the perfusate. Furthermore, quercetin enhanced PDE5-Is-induced relaxation of PCCSM. Quercetin relaxed the PCCSM by activating the NO-cGMP signaling pathway, and it may be a therapeutic candidate or an alternative treatment for patients with erectile dysfunction who do not completely respond to PDE5-Is.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.12
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• pp.674-680
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• 2018

Background and Objectives The representative mucin genes in the human airway are MUC5AC and MUC5B, which are regulated by several inflammatory and anti-inflammatory substances. Triptolide (TPL), udenafil, betulinic acid, changkil saponin, and glucosteroid are some of the many anti-inflammatory substances that exist. TPL is a diterpenoid compound from the thunder god vine, which is used in traditional Chinese medicine for treatment of immune inflammatory diseases, such as rheumatoid arthritis, systemic lupus erythematosus, nephritis and asthma. However, the effects of TPL on mucin expression of human airway epithelial cells have yet to be reported. Hence, this study investigated the effect of TPL on lipopolysaccharide (LPS)-induced MUC5AC and MUC5B expression in human airway epithelial cells. Subjects and Method The NCI-H292 cells and the primary cultures of human nasal epithelial cells were used to investigate the effects of TPL on LPS-induced MUC5AC and MUC5B expression using real-time polymerase chain reaction, enzyme immunoassay, and Western blot. Results TPL significantly decreased the LPS-induced MUC5AC and MUC5B mRNA expression and protein production. TPL also significantly decreased the nuclear factor-kappa B (NF-kB) phosphorylation. Conclusion These results suggest that TPL down regulates MUC5AC and MUC5B expression via inhibition of NF-kB activation in human airway epithelial cells. This study may provide important information about the biological role of triptolide on mucus-secretion in airway inflammatory diseases and the development of novel therapeutic agents for controlling such diseases.