Biological & pharmaceutical bulletin
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It is known that RhoA is translocated from cytoplasm to cell membrane in bronchial smooth muscle when activated by acetylcholine (ACh) stimulation. In the present study, the effects of selective muscarinic receptor antagonist methoctramine, AF-DX116 (for M(2)) and 4-diphenylacetoxy N-methylpiperidine (4-DAMP; for M(3)) on the ACh-induced rat bronchial smooth muscle contraction and increase in membrane-associated RhoA were investigated to elucidate the muscarinic receptor subtype participating in these responses. To evaluate ACh-induced contraction of bronchial smooth muscle, bronchial ring of rat was prepared, suspended in an organ bath and the tension was measured isometrically. ⋯ The muscarinic M(2) and M(3) receptors were detected by using RT-PCR in rat bronchial smooth muscle. Both the ACh-induced smooth muscle contraction and increase in membrane-associated RhoA were markedly inhibited by 4-DAMP, but not by methoctramine or AF-DX116. In conclusion, these results indicated contraction for the first time that the activation of RhoA occurs via M(3) receptor in rat bronchial smooth muscle.
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Comparative Study
Quantification of sinomenine in caulis sinomenii collected from different growing regions and wholesale herbal markets by a modified HPLC method.
Caulis Sinomenii is the dried plant stems of Sinomenium acutum and Sinomenium acutum var. cinereum and has been used in Chinese medicine for treating rheumatic diseases for over a thousand years. Previous studies have demonstrated that sinomenine is a major active constituent in both plants and can be utilized as an indicator of quality of the medicinal herb Caulis Sinomenii. Currently, S. acutum and S. acutum var. cinereum are growing over a wide geographical range in China, with equally wide variations in growing conditions. ⋯ This implies that the growing region has greater impact on the quality of Caulis Sinomenii in terms of the content of sinomenine than the species and varieties. The results also showed that the content of sinomenine in commercial Caulis Sinomenii was markedly lower than that in the plants collected directly from growing regions. This suggests that to obtain the herb with higher content of sinomenine and thus ensure greater efficacy, both in clinical applications and in pharmacological investigations, the plant of Caulis Sinomenii with controlled stem size collected directly from growing regions is preferable.
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Interleukin-12 (IL-12) is a heterodimeric cytokine comprising p40 and p35 subunits produced mainly by monocytes and macrophages, and plays an essential role in the regulation of the differentiation of Th1 cells. Green tea polyphenols exhibit potent anti-oxidative activities and anti-inflammatory effects by modulating cytokine production. We investigated the effect of catechins on IL-12p40 production in murine macrophages induced by bacterial lipopolysaccharide (LPS). ⋯ EGCG inhibited LPS-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK), but not Jun N-terminal kinase (JNK), while EGCG augmented LPS-induced phosphorylation of p44/p42 extracellular signal-related kinase (ERK). In addition, both EGCG and GCG inhibited LPS-induced degradation of IkappaBalpha with concomitant inhibition of nuclear protein binding to NF-kappaB site and synthesis of IRF-1. These results suggest that gallate-containing catechins, particularly EGCG, inhibits LPS-induced IL-12p40 production in murine macrophages by inhibiting p38 MAPK while enhancing p44/p42 ERK, leading to the inhibition of IkappaBalpha degradation and NF-kappaB activation.
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Comparative Study
Inhibitory effects of the essential oil from SuHeXiang Wan on the central nervous system after inhalation.
The present study was performed to evaluate the central nervous system inhibitory effects of the essential oil from SuHeXiang Wan (Storax pill), a prescription usually used for treating epilepsy in traditional Chinese medicine, on fragrance inhalation (aroma therapy). Preinhalation of the fragrance oil markedly delayed the appearance of pentylenetetrazole-induced convulsion, but showed weak activities on picrotoxin- and strychnine-induced convulsions, which implies this drug may inhibit the convulsion by GABAergic neuromodulation. This essential oil inhibited the binding of [(3)H]Ro15-1788, a selective antagonist for the benzodiazepine receptor and also the binding of [(3)H]flunitrazepam, a selective agonist for the receptor, in the presence of gamma-aminobutyric acid (GABA) and NaCl, showing a positive GABA shift, which suggested the strong possibility of the agonistic activity of the essential oil to the GABA/benzodiazepine receptor complex in rat cerebral cortices. ⋯ The GABA level was significantly increased and glutamate content was significantly decreased in mouse brain by preinhalation of the essential oil. The above results suggest that the anticonvulsive effect of this essential oil can also originate from the enhancement of GABA level in the mouse brain, because convulsion depends partially on GABA concentration which can be properly preserved by inhibiting GABA transaminase. Fragrance inhalation progressively prolonged the pentobarbital-induced sleeping time as inhalation time was lengthened and inhibited brain lipid peroxidation, to which the anticonvulsive action is attributed; this also supported the above results, confirming the inhibitory effects of the essential oil of SuHeXiang Wan on the CNS via the GABAergic system.
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The 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS (radical +)) decolorization assay was applied to evaluate the stoichiometric radical scavenging activity of ascorbic acid (AA) and two AA derivatives, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and 2-O-alpha-D-glucopyranosyl-6-O-octanoyl-L-ascorbic acid (6-Octa-AA-2G). AA rapidly reacted with ABTS (radical +), and the reaction was completed within 10 min. ⋯ The amounts of ABTS (radical +) scavenged by one molecule of AA, AA-2G and 6-Octa-AA-2G after 2 h of reaction at pH 6.0 were approximately 2.0, 3.4 or 3.9 molecules, respectively. This study demonstrates that the quantity of ABTS (radical +) quenched by AA-2G and 6-Octa-AA-2G is superior to that of AA in a long-term reaction.